246 — 7 June 2013 Editor: Bo Reipurth ([email protected]) List of Contents

246 — 7 June 2013 Editor: Bo Reipurth (Reipurth@Ifa.Hawaii.Edu) List of Contents

THE STAR FORMATION NEWSLETTER An electronic publication dedicated to early stellar/planetary evolution and molecular clouds No. 246 — 7 June 2013 Editor: Bo Reipurth ([email protected]) List of Contents

The Star Formation Newsletter Interview ...... 3 My Favorite Object ...... 6 Editor: Bo Reipurth [email protected] Perspective ...... 10

Technical Editor: Eli Bressert Abstracts of Newly Accepted Papers ...... 14 [email protected] Abstracts of Newly Accepted Major Reviews . 51 Technical Assistant: Hsi-Wei Yen Dissertation Abstracts ...... 53 [email protected] Meetings ...... 56

Editorial Board Short Announcements ...... 58

Joao Alves Alan Boss Jerome Bouvier Lee Hartmann Cover Picture Thomas Henning Paul Ho NGC 7822 is an HII region, also known as Sharp- Jes Jorgensen less 171, and located in Cepheus at the relatively Charles J. Lada close distance of 800 - 1000 pc. The central cluster Thijs Kouwenhoven is known as Berkeley 59. Parts of the complex are Michael R. Meyer as young as 1-2 million years. The dominant ultra- Ralph Pudritz ◦ violet source is the O5V star BD+66 1673, which Luis Felipe Rodr´ıguez is an eclipsing binary. Ewine van Dishoeck Hans Zinnecker Image courtesy Martin Pugh.

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2 Q: Didn’t you also develop and coin the term ”competitive accretion” as a theoretical model for the IMF? Hans Zinnecker A: I guess this is correct. In my 1981 thesis I did two mod- in conversation with Bo Reipurth els of the IMF, the log-normal model (originally based on the concept of hierarchical fragmentation) and a power- law model (based on nonlinear Bondi-type gravitational accretion onto seed stars which were accreting from a limited protocluster gas reservoir, hence the competition for gas accretion). This latter model was published in 1982 in the Proc. of the Henry Draper Symposium on the Orion Nebula and was popularized by Richard Larson who kindly quoted my work. Had it not been for Richard, no-one might have taken notice of that model. Now it is one of my most cited papers. Thank you, Richard. Q: You were a theorist at heart, how come you turned into a quasi-observational astronomer? A: Yes, I started as a theorist, influenced by Prof. Kip- penhahn, and also by talking to Profs Bodenheimer and Q: Hans, we have known each other for a long time, 30 Tscharnuter. Mind you, before my PhD in astrophysics I years, since the Les Houches school ”Birth and Infancy got a diploma in physics in conformal quantum field the- of Stars”. How influential was that two week school in ory - if anybody in astronomy knows what that is. After August 1983 in the French Alps? looking around, I ended up for my thesis work in a group of A: Very influential for many of us, myself included. It far-infrared astronomers (balloon observations) at MPE in was there that long-term friendships among many young Garching, headed by Dr. Drapatz (my PhD thesis advisor astronomers were initiated. I vividly remember meet- who taught me back-of-the envelope calculations). That ing John Bally, you Bo, Bruce Elmegreen, Gareth Wynn- environment helped me to get a sense for observations and Williams, Harold Yorke, to name but a few. Many of them that the best astronomy is often done in interaction be- for the first time. This was the time when molecular out- tween theory and observations. flows were first discovered, as well as the proper motions Q: You did your postdoc years at the Royal Observatory of Herbig-Haro objects, and I particularly recall discus- Edinburgh. How did that happen? sions with George Herbig. It was also the time when the first results from the IRAS satellite began to appear, and A: Interesting story. Coincidences. After my PhD I took a during the time of the school Bart Bok died in Tucson, trip to Hawaii and managed to force my way up to UKIRT AZ, making us feel that a baton was passed to the young on Mauna Kea (ask Eric Becklin about that particular generation. facet). At Hale Pohaku (the dormitory halfway up the mountain, quite rudimentary in 1981) I happened to meet Q: You presented your thesis work, a theoretical model of Gerry Gilmore (then at ROE) and gave him a copy of my the log-normal IMF in Les Houches, didn’t you? thesis (in German). Next thing I hear, after being back A: Yes indeed. I gave a presentation on star formation as a in Garching, was that Malcolm Longair (then director at random multiplicative process. The idea was that several ROE) who was visiting ESO Garching for a colloquium, factors determine the critical protostellar mass, such as had asked my advisor to see him before his departure. temperature, density, magnetic flux, angular momentum, Indeed I met with Malcolm and he offered me to come to geometry, etc in a multiplicative fashion. By and large ROE as a postdoc, on the basis of a mixed Royal Society this model is still valid (Fred Adams introduced outflows and German Science Foundation fellowship. I stayed for in 1996) and Basu and Jones (2004) as well as Phil Myers almost 4 years. This was a crucial move to turn me from (2011) realized how to turn the high-mass lognormal tail theory to observations. into a (Salpeter) power-law slope by adding the idea that Q: Can you elaborate a little more? the accretion time is uniformly distributed. Perhaps my own contribution here was to realize that for a log-normal A:. I try. At ROE, I met Tom Geballe with whom I did IMF that turns down below a certain characteristic mass, my first observing proposal (Brackett alpha in the Orion the predicted number of brown dwarfs (or black dwarfs as Nebula), Mark McCaughrean and John Rayner, both PhD these objects were then called) is small, i.e. the numbers students of Dr. Ian McLean, as well as Colin Aspin, Mike do not diverge towards small masses, as an extrapolated Burton, Ron Garden, and others. This reads like a who is Salpeter low-mass IMF would imply. who in infrared arrays at the time (Ian McLean heading

3 the IR-CAM development). I also there met Eric Becklin a co-author and Ghez et al.). This was a great month for (on sabbatical) and Steve Beckwith (colloquium speaker), me and in fact for young binary star research. who alerted me to high angular resolution observations Q:: In 1994, you discovered the beautiful HH212 molecular (lunar occultations and infrared speckle interferometry, re- hydrogen jet. How did this discovery come about? spectively). Which I later applied to studies of pre-Main Sequence binaries (originally with Chelli and Perrier 1986 A: Another interesting story which incidentally is con- at ESO Chile and later with Leinert and Haas 1990 at nected to my deep interest in binary protostars. In 1987, Calar Alto). This exposure to infrared technology led to in the early days of IR-arrays, I was interested in near- 20 or so visits to Mauna Kea during my stay at ROE, infrared imaging of cold, low-luminosity IRAS sources, which helped anchor my connection to observational as- in the hope to discover double stars in the same cloud tronomy. core, indicative of their joint formation (which was not yet proven at the time). IRAS 05413-0104 in Orion B Q: Apropos binaries. How did you get interested in pre- indeed showed two K-band near-infrared embedded point MS binaries? sources, about 7 arcsec (300 AU) apart. Nothing hap- A: When I arrived in Edinburgh in August 1983, I had just pened until 7 years later, when persistence paid off. My come back from an IAU Colloquium on binarity and a total colleagues Mark McCaughrean and John Rayner (with solar eclipse in Indonesia. I had to write a report for the me as a co-investigator) were observing the Orion Neb- German funding agency. This developed into a review on ula Cluster with a new and better infrared array at the binary statistics and star formation. Binary star formation IRTF on Mauna Kea. Mark ran into a software problem (mass ratios) clearly was the next logical step, after deal- related to the programming of the array mosaic pattern ing with the possible origin of stellar masses. Everything and said: ”I need to fix this. You can have the telescope in those days was kind of pristine territory in the young for the next 10 min”. Well, intuition told me to have an- field of star formation. One could still read all the papers other look at that promising IRAS source with the near- ever written on the subject. As an aside, it may be worth infrared double star. So we changed target and took a mentioning that it took a discussion with a young woman short integration. Upon inspecting the image, it seemed from India (her name was Jitinder, a student at ROE) who the double star had become a quadruple system with all insisted and convinced me to confront/test my fledgling the components aligned. Another deeper image resulted theories with detailed infrared observations. Why don’t in an aligned system of 6 components. Wow. It was then you? she asked, and so I succumbed and changed my re- that we realized that this could be a series of knots in a search into a more observational direction. ROE was the molecular hydrogen jet, as the H2 vibrational emission at perfect place for me to do this. 2.12 micron fell into the K-band filter. We then switched Q: I remember a visit to ROE which hosted the Australian to the narrow-band 2.12 micron filter, and after a minute Schmidt telescope plate library in which I was interested. or so, boom, the full highly bi-symmetric knotty jet in On that visit the two of us had an important encounter. all its glory was revealed! By the way, the HH number Would you like to tell the story? (212) you gave the jet reflects the wavelength of its discovery. This serendipitous discovery was clearly my most A: Well, I was working away, but you said why don’t you exciting observational experience (and perhaps my most take a break and come for a weekend walk in the High- lasting legacy)! lands. Eventually I gave in to your persuasion. We hiked to a place called Arrochar near Glasgow and Loch Lomond Q:Which scientific question fascinates you most these days? and kept walking until we finally reached the end of the A: I would say: the formation of massive stars, in par- track. There was a wooden bench waiting for us and in- ticular the origin of the many close spectroscopic binary scribed in it was the thoughtful phrase: REST and BE systems among them. With orbital periods of a few days, THANKFUL. Something to remember. We had a long separations of the order of 1 AU, and orbital speeds of talk, and our ensuing (pre-internet) scientific interaction a few hundred km/s, these massive binaries challenge our culminated in your invitation to spend three months as imagination. Some of these close binaries may even merge, an ESO senior visitor at La Silla in 1991 to carry out to form very rapidly rotating single very massive O-stars. our plan of a CCD visual binary survey among southern Maybe the progenitors of super-energetic long-duration pre-Main Sequence stars with the NTT. We did it, and gamma-ray bursts are related to massive binary star merg- during that time I also was able to start learning Spanish ers or massive star collisions in dense clusters. In any case, (at lunch). As you know I love languages, and learning the prevalence of these tight systems implies that binary Spanish had a big influence later in my life. When our interactions are the rule rather than the exception in mas- paper was published in Nov 1993, two other independent sive stellar evolution, something that many astrophysicists but similar pre-Main Sequence binary surveys were pub- have not fully realized. lished in the very same month (Leinert et al. where I was

4 Q: Why did you decide to join the SOFIA Airborne Ob- Q: You have also worked extensively with X-ray data, right? servatory? A: Yes, I turned from infrared to X-rays in 1990 because A: I suppose I was looking for a new challenge. For 15 ROSAT, the X-ray satellite built at MPE, was launched years I was the head of the star formation group at AIP and, working at MPE, it would have been foolish to ignore Potsdam and I think we had a good group of about ten it. My interest in X-rays soon brought me to the Univ. of outstanding scientists and hence we had an unusally stim- Würzburg in Germany (where X-rays were discovered in ulating work environment. We were the coordinating node 1895 by C.W. Röntgen). I enjoyed my time at the univer- of the European Commission Research Training Network sity working with bright young people there (notably Wolf- on the Formation and Evolution of Young Stellar Clusters gang Brandner and Thomas Preibisch) and with my men- (2001-2004) and the founding partner of another EU Re- tor Harold Yorke, to whom I also owe much, as he saved me search Training Network ”Constellation” on the origin of from ”extinction” when I was unable to get a permanent stellar masses (2006-2010). Mark McCaughrean was the job at age 40. Before leaving Würzburg for a permanent driving force and the interaction with him and his vast ob- job in Potsdam (at age 45), I initiated and co-organized servational and managerial experience provided an excit- the X-ray centenary conference ”Röntgenstrahlung from ing framework and much fun for many years at AIP. Ralf the Universe” in Würzburg in 1995. (My multi-lambda Klessen added the theoretical star formation and simula- background, infrared and X-rays, earned me the job). tion component and thus our group had all the necessary Q: That was just one of the several conferences and sym- elements of strong interaction of theory and observations. posia that you initiated. Which were the others? When McCaughrean and Klessen moved on to higher positions (ESA, ITA) I felt I was too old writing grant pro- A: Well, in Potsdam I launched the IAU Symposium ”The posals to rebuild the group. Then the SOFIA opportunity Formation of Binary Stars”. I fought hard to get the came along. Germany, with a 20 percent share in this big memorable number IAUS 200 in the year 2000 for this bi- bilateral project (80 percent US, i.e. NASA), was look- nary conference. Later, in 2004, I launched another major ing for a German representative and deputy director. I conference in Tuscany/Italy ”50 years of the Initial Mass applied, not least because Eric Becklin (SOFIA chief sci- Function” in honor of Ed Salpeter who wrote his seminal entist) overwhelmingly encouraged me to do so. I got the IMF paper in 1954 (published in 1955). I am now plan- job and 3 years ago moved to California, to NASA-Ames ning a first SOFIA science symposium in the Bay Area for where the SOFIA science center is located. the summer of 2014 (just before the Brazil soccer world cup for which I want to travel to Brazil. I love soccer, I Q: How are you doing at SOFIA? played myself in my younger years in Bavaria, and I love A: Working at SOFIA has been a challenge from the be- the Brazilian people). ginning, not only because I had to learn so much about Q:You have been to more conferences than any other as- management of science and mission operations, but also tronomer that I know, and you have a large collection of because scientifically I had to switch from being mainly a photos from these meetings. Do you plan to make this near-infrared stellar astronomer to becoming a far-infrared photo archive public? interstellar astronomer. What I like about SOFIA is the broad wavelength coverage (from optical to far-infrared) A: Indeed I probably have the biggest set of private pic- with the potential of major discoveries over its projected tures of astronomers. My plan is to work on these and 20 year lifetime. SOFIA is working almost routinely now, make them available after I formally retire in 3.5 years. and flying on SOFIA is a unique and cool experience. I have flown 4 times so far. After Herschel ran out of cryo- gen, SOFIA is the only far-infrared facility for many years to come. Ending my career with SOFIA, and considering my small beginnings in the far-infrared group at MPE Garching in 1977, I feel I have come full circle, a very satisfactory emotion some 35 years later.

5 My Favorite Object IRAS 16293-2422 Luis Zapata

1 A Very Young Stellar Object One of the consequences of the formation of a star is the ”inside-out” collapse of dense parts of the molecular clouds. This evolutionary phase is characterized by a central protostar and disk within an infalling envelope of dust and gas. The infalling material passes through an Figure 1: Optical image of part of the Rho Ophiuchi accretion disk, and then to the protostar allowing it to molecular cloud and its vicinities. The yellowish star is grow (Shu, Adams, and Lizano 1987). One of the very Antares, and the M4 star cluster is to the right of Antares. first observational evidences of such infalling phenomena The location of IRAS 16293-2422 is marked with a red box. came surprisingly from the young protostar IRAS16293- This object is very embedded in its natal molecular cloud 2422 (or L1689N) in the 80’s, almost in the same year as one can be seen in this image. Image courtesy by Tom that the famous Shu et al. review paper on star forma- O’Donoghue. tion was published. Figure 1 shows with a red box the position of IRAS 16293 in the Rho Ophiuchi molecular cloud, one can see how this object is very embedded in its molecular natal cloud. The evidence for infall towards cated in the Rho Ophiuchi molecular cloud, one of the IRAS16293 was based on a detailed analysis of the J=5- closest places of recent star formation (located at a dis- 4 and 2-1 transitions of CS (Walker et al. 1986). Both tance of 120 pc; Loinard et al. 2008, Knude & Hog 1998). transitions showed strong prominent self-absorption fea- IRAS 16293 was first detected by the Infrared Astronomi- tures superposed on a broader emission from an optically cal Satellite (IRAS) space-based observatory in the 25, 60, thick molecular line. However, later Menten et al. (1987) and 100 µm bands, this source is unresolved in all bands. using higher angular resolution CS J=3-2 and other line The lack of detectable emission in the 12 µm band indi- maps argued that the kinematics of the CS gas might be cates that the source is a very cold dusty object. better interpreted as rotation or outflow motions rather Using the IRAS fluxes and a new data point at 2.7 mm ob- than infall. Recently, (sub)millimeter molecular line emis- tained with the Owens Valley Radio Observatory (OVRO), sion maps obtained with ALMA have confirmed a direct Mundy et al. (1986) estimated a bolometric luminosity detection of infall on the compact sources associated with and a dust temperature of 27 L⊙ and 40 K for IRAS 16293, IRAS16293. These studies for the first time have revealed respectively. They confirmed that indeed this object is strong inverse P-Cygni profiles towards one source asso- very cold and is associated with a young low-mass proto- ciated with IRAS16293 (Pineda et al 2012; Zapata et al. star. Such luminosity is in agreement with that value of 2013). In Figure 2 is shown the resolved infall motions 23 L⊙ obtained by Walker et al. (1986), and the value toward this component mapped at 690 GHz. obtained recently by Correia et al. (2004) of 25 L⊙ (cor- IRAS 16293 is an extremely cold far-infrared source lo- rected with a more recent value of the distance).

6 Figure 2: Upper: ALMA H13CN (blue), HC15N (magenta), and CH3OH (green) spectra from IRAS Figure 3: SMA integrated blueshifted (blue contours) and 16293−2422B. The black dashed line marks the systemic redshifted (red contours) CO J=2-1 map of the outflows −1 LSR velocity of IRAS 16293−2422B (VLSR ∼ 3 km s ). from IRAS 16293-2422. Image taken from Yeh et al. (2008). The black circles represent the FWHM of the SMA. The crosses denote the positions of the two continuum sources. Positions of the two prominent compact The observations made by Mundy et al. (1986) together components are labeled (b1 and b2). The filled ellipse with subsequent high angular resolution observations (e.g. indicates the synthesized beam size. Wootten 1989) showed that IRAS16293 is really a binary source separated by about 5′′. Moreover, the Very large Array (VLA) centimeter observations from Wootten (1989) and Loinard et al. (2002) revealed that one component of region of about 4′′ and its associated centimeter emission the binary system, IRAS 16293A, splits up into a second is most likely produced by an ionized stellar wind as dis- binary system separated by only 50 AU. This binary sys- cussed by Wootten (1989). On the other hand, the north- tem can be seen at resolutions better than about 0.2′′. western source IRAS 16293B, displays continuum emission These sources were named A1 and A2. The relative ori- which increases as ν2 throughout millimeter and centime- entation of the A1/A2 pair at the time of its discovery ter wavelengths (Estalella et al. 1991). This unique spec- was very similar to the direction of the NE-SW flow, and trum can be explained if most of the continuum emission A1 was initially believed to be an ejecta from A2. How- is arising from dust. Subsequent observations made by ever, analysis of the relative motion of A1 and A2 favors Rodr´ıguez et al. (2005) and Chandler et al. (2005) show a scenario where these two sources trace two stars in a bi- that IRAS 16293B has a spectral energy index of ν2.0−2.6 nary system (Loinard 2002; Chandler et al. 2005; Loinard and a size of only 25 AU. et al. 2007; Pech et al. 2010). The other component 2 Outflows B remains single even at the highest angular resolution available (∼ 0.05′′; Chandler et al. 2005; Rodr´ıguez et Among the first works to detect outflows associated with al. 2005). Subarcsecond submillimeter continuum ob- IRAS 16293-2422 were those of Wootten et al. (1987) and servations obtained with the Submillimeter Array (SMA) Mizuno et al. (1990). The multiple CO observations from revealed additional structure in component A called Ab these two studies revealed that the high velocity gas is re- (Chandler et al. 2005). This source has not been detected solved into four compact separate lobes, consisting of two at any other wavelengths so far, and its exact nature re- pairs of bipolar lobes, in addition to an extended monopo- mains poorly understood. lar blueshifted lobe. The quadrupolar outflow associated to this source is oriented with one bipolar flow almost Mundy et al. (1992) suggested that the southeastern source east(blueshifted)-west(redshifted) (at a position angle of IRAS 16293A contains only ∼ 0.5 M⊙ of dust and gas in a ∼ 55◦), and the second one with its axis with an orienta-

7 Figure 5: ALMA Integrated intensity of the weighted velocity (moment 1) colour map of the CO(6-5) emission from source B overlaid in contours with the 0.45 mm continuum emission (black thick line) and the velocity scale of CO(6-5) (grey thin line). Image taken from Loinard et al. (2012).

was ejected from I16293B long time ago. In addition, they mentioned that maybe I16293B is a not so young star, perhaps a T-Tauri star because of its fossil outflow. However, Figure 4: Comparison between five radio images of IRAS Laurent et al. (2013) using ALMA observations proposed 16293A at different epochs. Note how the morphology of that this east-west fossil outflow could also arise from the component A2 changes with time, while the other (A1) vicinities of I16293A. These ALMA observations revealed remains the same. Image taken from Pech et al. (2008). a very compact east-west bipolar outflow emanating from this object that maybe is the base of the large-scale outflow. tion northeast(redshifted)-southwest(blueshifted) or at a Monitoring of IRAS 16293-2422 at centimeter wavelengths ◦ position angle ∼ 110 . Both flows seem to emanate from with the VLA and now with the recently finished JVLA IRAS 16293-2422A and B. A SMA map of compact CO (Jansky Very Large Array) has allowed to detect an episodic emission obtained by Yeh et al. (2008) is presented in Fig- and compact northeast-southwest ionized flow associated ure 3. In this Figure one can clearly see the multiple east- with the source IRAS 16293 A2 (Loinard et al. 2007; Pech west outflows emanating from this complex region. Some et al. 2010), see Figure 4. This ionized flow has a a pro- of these CO lobes coincide very well with SiO emission, jected velocity of 30-80 km s−1, and with the mass of each −8 a typical outflow tracer (Hirano et al. 2001). To explain ejecta of the order of 10 M⊙. Pech et al. (2010) pro- the conspicuous quadrupolar morphology of this outflow posed that this ionized episodic outflow could energize at system, Walker et al. (1993) proposed that the two pairs large scales the northeast-southwest molecular outflow re- of lobes correspond to two independent bipolar outflows ported by Wootten et al. (1989) and Mizuno et al. (1990). driven by two independent sources. On the other hand, Recently, 690 GHz submillimeter observations with ALMA Mizuno et al. (1990) showed that the outflow is dynam- (The Atacama Large Millimeter Array) revealed that the ically interacting with the dense ambient gas clump and source IRAS 16293 B is driving a southeast compact out- suggested that a single outflow lobe could be split into two flow (Loinard et al. 2013). However, the flow has peculiar lobes by the interaction. More recent observations from properties: it is highly asymmetric, bubble-like, fairly slow Stark et al. (2004) proposed that the northeast-southwest (10 km s−1), and lacking of a jet-like feature along its sym- flow is powered by I16293A, while the east-west fossil flow

8 target of many studies trying to relate the structure of the two main components to their line emission and place them in an evolutionary scheme. As mentioned earlier the southeastern of the two components, IRAS 16293A, appears resolved in continuum observations, breaking into a number of different components at subarcsecond scales (Chandler et al. 2005; Pech et al. 2010). The northwestern component, IRAS 16293B, in contrast appears unresolved on these scales. In terms of line emission the two sources also show significant differences: both show detection of complex organic molecules (see for example: Bot- tinelli et al. 2004; Kuan et al. 2004; Remijan & Hollis 2006; Bisschop et al. 2008), but the relative line strengths and widths vary between the two sources, see Figure 6.

References: Blake, G. A., van Dishoeck, E. F., Jansen, D. J., Groesbeck, T. D., & Mundy, L. G. 1994, ApJ, 428, 680 Figure 6: ALMA Spectra in the central beams toward Bisschop, S. E., Jørgensen, J. K., Bourke, T. L., Bottinelli, S., & van the continuum peaks of IRAS 16293A (upper) and IRAS Dishoeck, E. F. 2008, A&A, 488, 959 Bottinelli, S.,Ceccarelli, C., Neri, R., et al. 2004, ApJL, 617, L69 16293B (lower). In both panels is shown the detection of Caux, E., Kahane, C., Castets, A., et al. 2011, A&A, 532, A23 the Glycolaldehyde (HCOCH2OH) molecule. Image taken Cazaux, S., Tielens, A. G. G. M., Ceccarelli, C., et al. 2003, ApJL, 593, L51 from Jørgensen et al. (2012). Ceccarelli, C., Castets, A., Loinard, L., Caux, E., & Tielens, A. G. G. M. 1998, A&A, 338, L43 Chandler, C. J., Brogan, C. L., Shirley, Y. L., & Loinard, L. 2005, ApJ, 632, 371 Correia, J. C., Griffin, M., & Saraceno, P. 2004, A&A, 418, 607 metry axis. In addition, its dynamical age is only about Estalella, R., Anglada, G., Rodriguez, L. F., & Garay, G. 1991, ApJ, 200 years. In Figure 5 is shown this bubble-like outflow 371, 626 Hirano, N., Mikami, H., Umemoto, T., Yamamoto, S., & Taniguchi, Y. as revealed by the ALMA observations. However, using 2001, ApJ, 547, 899 the same set of data, Kristensen et al. (2012), proposed Jørgensen, J. K., Bourke, T. L., Nguyen Luong, Q., & Takakuwa, S. 2011, A&A, 534, A100 that this submillimeter CO emission is not associated with Jørgensen, J. K., Favre, C., Bisschop, S. E., et al. 2012, ApJL, 757, L4 IRAS 16293 B, instead, a blue-shifted bow shock from Loinard, L., Torres, R. M., Mioduszewski, A. J., & Rodr´ıguez, L. F. 2008, ApJL, 675, L29 source A is overlapping with source B in the plane of the Loinard, L., Chandler, C. J., Rodr´ıguez, L. F., et al. 2007, ApJ, 670, sky. Outflow entrainment takes place over large scales, > 1353 Loinard, L. 2002, RMAA, 38, 61 100 AU, and wind material is decelerated through direct Loinard, L., Zapata, L. A., Rodr´ıguez, L. F., et al. 2013, MNRAS, 430, interaction with the envelope. L10 Looney, L. W., Mundy, L. G., & Welch, W. J. 2000, ApJL, 529, 477 Knude, J., & Hog, E. 1998, A&A, 338, 897 3 Molecules and Chemistry Kristensen, L. E., Klaassen, P. D., Mottram, J. C., Schmalzl, M., & Hogerheijde, M. R. 2013, A&A, 549, L6 IRAS 16293-2422 has long been considered one of the Kuan, Y.-J., Huang, H.-C., Charnley, S. B., et al. 2004, ApJL, 616, L27 ”template” sources for astrochemistry as mentioned by Menten, K. M., Serabyn, E., Guesten, R., & Wilson, T. L. 1987, A&A, 177, L57 Jørgensen et al. (2012). It has been the subject of many Mizuno, A., Fukui, Y., Iwata, T., Nozawa, S., & Takano, T. 1990, ApJ, (sub)millimeter spectroscopic studies using single dishes 356, 184 Mundy, L. G., Myers, S. T., & Wilking, B. A. 1986, ApJL, 311, L75 and interferometers (Blake et al. 1994; van Dishoeck et Mundy, L. G., Wootten, A., Wilking, B. A., Blake, G. A., & Sargent, al. 1995; Ceccarelli et al. 1998; Cazaux et al. 2003; A. I. 1992, ApJ, 385, 306 Pech, G., Loinard, L., Chandler, C. J., et al. 2010, ApJ, 712, 1403 Chandler et al. 2005; Caux et al. 2011; Jørgensen et Pineda, J. E., Maury, A. J., Fuller, G. A., et al. 2012, A&A, 544, L7 al. 2011) as well as specialized modeling efforts trying Shu, F. H., Adams, F. C., & Lizano, S. 1987, ARAA, 25, 23 Remijan, A. J., & Hollis, J. M. 2006, ApJ, 640, 842 to establish its chemical composition. Particularly, the Rodr´ıguez, L. F., Loinard, L., D’Alessio, P., Wilner, D. J., & Ho, P. T. P. variation in its molecular abundances as function of ra- 2005, ApJL, 621, L133 Walker, C. K., Lada, C. J., Young, E. T., Maloney, P. R., & Wilking, dius has been studied (e.g., Schöier et al. 2002). The B. A. 1986, ApJL, 309, L47 detections of complex molecules toward this source (e.g., Walker, C. K., Carlstrom, J. E., & Bieging, J. H. 1993, ApJ, 402, 655 Wootten, A. 1989, ApJ, 337, 858 Cazaux et al. 2003; Bottinelli et al. 2004; Kuan et al. Wootten, A., & Loren, R. B. 1987, ApJ, 317, 220 2004; Bisschop et al. 2008; Jørgensen et al. 2012) have van Dishoeck, E. F., Blake, G. A., Jansen, D. J., & Groesbeck, T. D. 1995, ApJ, 447, 760 opened new interest in the physical processes that can lead Yeh, S. C. C., Hirano, N., Bourke, T. L., et al. 2008, ApJ, 675, 454 to the evaporation of icy grain mantles. Figure 6 shows Schöier, F. L., Jørgensen, J. K., van Dishoeck, E. F., & Blake, G. A. 2002, A&A, 390, 1001 the ALMA spectrum where the complex molecule Glyco- Stark, R., Sandell, G., Beck, S. C., et al. 2004, ApJ, 608, 34 laldehyde (HCOCH2OH) is detected. It has also been the Zapata, L. A., Loinard, L., Rodr´ıguez, L. F., et al. 2013, ApJL, 764, L14

9 by expelling gas from clouds before it is able to collapse or be accreted (e.g. Whitworth, 1979). Perspective Observations (e.g. Evans et al 2009) confirm that typical star formation efficiencies on the size–scales of molecular Feedback Processes clouds are never more than ten percent in the Milky Way. by James E. Dale While these efficiencies are not low enough to account for the very slow Galactic star formation rate, they nevertheless invite explanation. Low star formation rates on GMC scales have a corollary that may provide insight into another long–standing issue, namely the dissolution of the vast majority of stellar clusters while still very young (Lada & Lada 2003). If gas expulsion occurs early enough and fast enough, the potential well of the forming embedded cluster can in principle become too shallow to retain its stars (Hills 1980). GMCs are turbulent and highly substructured, so that, even in the absence of feedback, their evolution is so complex that it must be modelled numerically. Increasing computer power and new algorithms have recently made the inclusion of stellar feedback in such simulations possible (e.g Offner et al. 2009, Krumholz et al. 2010, Walch et al 2012). Recently Dale et al (2012a,b, 2013a,b) performed a set The ability of infra–red and submillimetre space missions of smoothed–particle hydrodynamics (SPH) simulations of such as Spitzer, WISE and Herschel to see deep inside the influence of expanding HII regions on a mass–radius star–forming regions has brought extraordinary advances parameter space of turbulent clouds. We chose the pa- in our understanding of starbirth. One of the fields that rameter space to cover the observed properties of GMCs has benefitted most from this avalanche of new data is reported by Heyer et al (2009), although neglecting lower 3 the study of the effects of stellar feedback processes on mass (∼ 10 M⊙) clouds, since they are unlikely to form molecular clouds. any massive stars. This resulted in a set of clouds with On scales of ∼1 up to ∼ 100 pc, the structure of the cold interstellar medium (ISM) is dominated by hot bubbles and swept–up shells of dense, cooler material (e.g. Churchwell et al. 2006, 2007, Deharveng et al. 2010). Figure 1 shows a striking example from the WISE mission (Koenig et al., 2012). Where expanding bubbles are able to break out of their host clouds, champagne flows result. On smaller scales on the edges of bubbles or inside them, we see pillars, cometary knots and proplyds (e.g. Smith et al. 2004, Billot et al. 2010). It is clear that the structure and appearance of most star–forming regions is governed by the action of feedback from their own stars. What is much less clear from these observations is the effect of feedback on the dynamical state of the clouds and their embedded clusters, and on the star formation process itself on cloud scales. A simple model of star formation in molecular clouds based Figure 1: Infrared image of W3/4/5 from the WISE space- purely on gravitational contraction and collapse results in craft (Koenig et al. 2012). The width of the region shown star formation rates much higher than are observed on is approximately 200pc and the bubble diameters are ap- galactic scales (Zuckerman & Evans, 1974). Among the proximately 50pc. Credit: NASA, JPL-Caltech, WISE solutions proposed to this problem is the suggestion that Team. feedback processes decrease the star formation efficiency

10 4 6 Mcloud ∈ [10 , 10 ] M⊙, Rcloud ∈ [2.5, 180] pc. Clouds were ionizing photon fluxes appropriate to their masses and the seeded with turbulent velocity fields so that the initial ra- clouds were evolved for a further 3 Myr, the approximate tios of kinetic to gravitational potential energy were either interval between the formation of the first O–stars and 0.7 or 2.3, giving a set of bound and unbound clouds. their explosions as supernovae. The effects of the resulting The clouds were allowed to evolve and form stars. They all HII regions on the clouds depends strongly on the struc- exhibit complex structure generated by the imposed tur- ture and properties of the clouds themselves. The massive bulent velocity fields. The gas forms a network of dense stars and clusters are born inside the densest gas and this filaments along which gas tends to flow towards the clouds’ material initially restricts the rate at which they can ionize centres of mass. This leads to the formation of stellar clus- the gas by collimating their radiation fields. The O–stars ters at filament junctions, as has been observed by, e.g., are thus typically able to ionize only a few to ten percent Schneider et al. (2012). In some cases, the filaments are of their host clouds’ total masses. dense enough to fragment along their lengths, resulting in The temperature inside HII regions is fixed by an equilib- linear groupings of stars. However, these stars tend to fol- rium between heating and cooling process (Osterbrock & low the gas flow along the filaments into the nearest cluster Ferland 2006), so that the sound speed in the ionized gas 5 −1 on relatively short timescales. An example of a 10 M⊙ has a constant value of ≈ 10 km s . This is dynamically globally unbound cloud is shown in Figure 2.Colours rep- important because it sets an upper limit on the velocity resent gas column densities projected along the z–axis. to which expanding HII regions can accelerate surrounding White dots are SPH sink particles which, in this case, material. The ability of the HII regions to disrupt clouds represent small clusters rather than individual stars. The depends on the clouds’ escape velocities. Since filamentary structure of the gas and the association of star formation with the filaments are clearly visible. 1 2 vESC ∼ (Mcloud/Rcloud) ,

75 and the model clouds follow the observed trend of having constant column density, so that

50 2 Mcloud ∼ Rcloud,

25 it follows that

1 4 0 vESC ∼ (Mcloud) . y (pc) −25 The escape velocity is then a slowly–growing function of cloud mass. The masses of clouds in the chosen parameter space range over two orders of magnitude, so that the − 50 escape velocity varies by a factor of a few from a few km s−1 to in excess of 10 km s−1. This relatively small range −75 in one particular property is the main determinant in the reaction of the clouds to their HII regions. − − − 75 50 25 0 25 50 75 In lower–mass, low–vESC clouds, the HII regions destroy x (pc) the filamentary gas and expand into much of the cloud vol- ume, creating ∼10pc–scale bubbles and sweeping up shells −4 −3 −2 −1 0 of dense material, as shown in Figure 3. In these cases, 10 10 10 10 10 the resulting systems bear a striking resemblance to ob- −2 log Σ (g cm ) jects like W3/4/5, shown in Figure 1. In more massive clouds, however, photoionization is unable to disrupt the 5 Figure 2: Column density map of the 10 M⊙ globally filaments and ionized gas leaks into pre–existing voids gen- unbound Run UV cloud from Dale et al (2012b) before erated by the imposed turbulent velocity fields. In both the onset of feedback. White dots represent star clusters. cases, the permeability of the gas distribution allows large quantities of ionized gas to escape the clouds entirely. This Accretion flows inevitably result in a few stars growing to lowers the pressure in the HII regions and further limits be O–stars (in the simulations where individual stars could the damage done to the clouds by feedback. These results 6 be resolved), or a few clusters growing massive enough to suggest that other means of disrupting ∼ 10 M⊙ clouds host O–stars (otherwise). These objects were then given need to be found.

11 reduced the overall star formation efficiencies. The de- 75 structive effects of the massive stars/clusters on the dense filaments where most star formation was taking place out- 50 weighed any triggering taking place in outlying regions of the clouds. 25 It was also observed that the triggered objects tended to be spatially mixed with spontaneously–formed objects. This was a consequence of expanding bubbles sweeping up and 0 compressing both gas that was going to form stars any- y (pc) way, and quiescent material that would otherwise be sta- − 25 ble, and transporting it to the same locations. Thus, the geometrical association of a given star with the edge of a −50 bubble, an ionization front, or even a pillar structure, is not a foolproof indicator that the star has been induced −75 to form. This is illustrated in Figure 4 where a greyscale column–density map from the Run I simulation from Dale − − − et al. (2013b) is shown. Stars are overlaid as circles for 75 50 25 0 25 50 75 spontaneously–formed objects and triangles for triggered x (pc) objects, all colour–coded by mass. Note that the three objects near the tip of the prominent pillar in the bottom − − − − 10 4 10 3 10 2 10 1 100 left of the frame are not triggered. −2 log Σ (g cm ) 15 1.75 5 Figure 3: Column density map of the same 10 M⊙ glob- 10 1.50 ally unbound Run UV cloud from Dale et al (2012b) after 3 Myr of photoionization. White dots represent star clus- 1.25 )

5 ⊙ ters. 1.00

0.75 Although feedback is usually suggested as a means of lim- 0 y(pc) iting the star–forming capacity of clouds, there has also 0.50 been a great deal of interest in the idea that it may also −5 0.25 trigger star formation (Elmegreen & Lada 1977). This mass)Log(stellar (M immediately raises the question of what is the net effect 0.00 −10 of feedback on the star–formation efficiency. This is very −0.25 difficult to answer objectively from an observational per- −15 spective, since it requires the evaluation of a counterfac- −15 −10 −5 0 5 10 15 tual argument – that of how a given system would have x(pc) evolved in the absence of feedback. 4 The same problem is relatively easy to approach numeri- Figure 4: Column density map (greyscale) of the 10 M⊙ cally, however, simply by repeating simulations with feed- Run I cloud from Dale et al (2013b) after 3 Myr of pho- back effects switched off. If this is done using a Lagrangian toionization. Circles represent spontaneously–formed ob- hydrodynamics scheme such as SPH, it allows one to de- jects and triangles denote triggered objects, all colour– termine not only how the star formation efficiency is al- coded by mass. tered by feedback, but which stars have been induced to form, prevented from forming or simply caused to form In reality, photoionization and winds from massive stars somewhere else. act simultaneously. Capriotti & Kozminski (2001) compared the separate influence of expanding HII regions and In Dale et al. (2013b), we showed that all of these pro- winds on uniform clouds and concluded that HII regions cesses – triggered star formation, aborted star formation, were likely to be more important except in very dense gas and redistribution of spontaneously–formed stars – oper- (n> 106 cm−3). McKee et al (1984), McCray & Kafatos ate locally. Ionizing feedback can thus cause the geometry (1987), Matzner (2002) and Fryer et al (2003, 2006) all of star formation in a given cloud to be radically differ- argue that wind bubbles are likely to be trapped inside ent. However, it was found that such feedback always HII regions, except for the case of very massive stars or

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13 Abstracts of recently accepted papers

A Near-Infrared Spectroscopic Study of Young Field Ultracool Dwarfs K. N. Allers1 and Michael C. Liu2 1 Department of Physics and Astronomy, Bucknell University, Lewisburg, PA 17837, USA 2 Institute for Astronomy, University of Hawai’i, 2680 Woodlawn Drive, Honolulu, HI 96822, USA E-mail contact: k.allers at bucknell.edu We present a near-infrared (0.9–2.4 µm) spectroscopic study of 73 field ultracool dwarfs having spectroscopic and/or kinematic evidence of youth (≈10–300 Myr). Our sample is composed of 48 low-resolution (R≈100) spectra and 41 moderate-resolution spectra (R≈750-2000). First, we establish a method for spectral typing M5–L7 dwarfs at near- IR wavelengths that is independent of gravity. We find that both visual and index-based classification in the near-IR provide consistent spectral types with optical spectral types, though with a small systematic offset in the case of visual classification at J and K band. Second, we examine features in the spectra of ∼10 Myr ultracool dwarfs to define a set of gravity-sensitive indices based on FeH, VO, K, Na, and H-band continuum shape. We then create an index-based method for classifying the gravities of M6–L5 dwarfs that provides consistent results with gravity classifications from optical spectroscopy. Our index-based classification can distinguish between young and dusty objects. Guided by the resulting classifications, we propose a set of low-gravity spectral standards for the near-IR. Finally, we estimate the ages corresponding to our gravity classifications. Accepted by ApJ http://arxiv.org/pdf/1305.4418

The Mass Dependence Between Protoplanetary Disks and their Stellar Hosts Sean M. Andrews1, Katherine A. Rosenfeld1, Adam L. Kraus1 and David J. Wilner1 1 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA E-mail contact: sandrews at gmail.com We present a substantial extension of the millimeter-wave continuum photometry catalog for circumstellar dust disks in the Taurus star-forming region, based on a new ”snapshot” λ = 1.3 mm survey with the Submillimeter Array. Combining these new data with measurements in the literature, we construct a mm-wave luminosity distribution, f(Lmm), for Class II disks that is statistically complete for stellar hosts with spectral types earlier than M8.5 and has a 3-σ depth of roughly 3 mJy. The resulting census eliminates a longstanding selection bias against disks with late-type hosts, and thereby demonstrates that there is a strong correlation between Lmm and the host spectral type. By translating the locations of individual stars in the Hertzsprung-Russell diagram into masses and ages, and adopting a simple conversion between Lmm and the disk mass, Md, we confirm that this correlation corresponds to a statistically robust relationship between the masses of dust disks and the stars that host them. A Bayesian regression technique is used to characterize these relationships in the presence of measurement errors, data censoring, and significant intrinsic scatter: the best-fit results indicate a typical 1.3 mm flux density of ∼25mJy for 1 M⊙ hosts and a power-law scaling 1.5−2.0 Lmm ∝ M∗ . We suggest that a reasonable treatment of dust temperature in the conversion from Lmm to Md favors an inherently linear Md ∝ M∗ scaling, with a typical disk-to-star mass ratio of ∼0.2–0.6%. The measured RMS dispersion around this regression curve is ±0.7 dex, suggesting that the combined effects of diverse evolutionary states, dust opacities, and temperatures in these disks imprint a FWHM range of a factor of ∼40 on the inferred Md (or Lmm) at any given host mass. We argue that this relationship between Md and M∗ likely represents the origin of the inferred correlation between giant planet frequency and host star mass in the exoplanet population, and provides some basic support for the core accretion model for planet formation. Moreover, we caution that the effects of incompleteness and selection bias must be considered in comparative studies of disk evolution, and illustrate that fact with statistical comparisons of f(Lmm) between the Taurus catalog presented here and incomplete subsamples in the Ophiuchus, IC

14 348, and Upper Sco young clusters. Accepted by Astrophysical Journal http://arxiv.org/pdf/1305.5262

Asymmetric transition disks: Vorticity or eccentricity? S. Ataiee1,2, P. Pinilla1, A. Zsom3, C.P. Dullemond1, C. Dominik4,5 and J. Ghanbari2 1 Heidelberg University, Center for Astronomy, Institute for Theoretical Astrophysics, Albert Ueberle Str. 2, 69120 Heidelberg, Germany 2 Department of Physics, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad, Iran 3 Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA 4 Anton Pannekoek Institute for Astronomy, University of Amsterdam, Postbus 94249, 1090 GE Amsterdam, the Netherlands 5 Afdeling Sterrenkunde, Radboud Universiteit Nijmegen, Postbus 9010, 6500 GL, Nijmegen, the Netherlands E-mail contact: sareh.ataiee at gmail.com Transition disks typically appear in resolved millimeter observations as giant dust rings surrounding their young host stars. More accurate observations with ALMA have shown several of these rings to be in fact asymmetric: they have lopsided shapes. It has been speculated that these rings act as dust traps, which would make them important laboratories for studying planet formation. It has been shown that an elongated giant vortex produced in a disk with a strong viscosity jump strikingly resembles the observed asymmetric rings. We aim to study a similar behavior for a disk in which a giant planet is embedded. However, a giant planet can induce two kinds of asymmetries: (1) a giant vortex, and (2) an eccentric disk. We studied under which conditions each of these can appear, and how one can observationally distinguish between them. This is important because only a vortex can trap particles both radially and azimuthally, while the eccentric ring can only trap particles in radial direction. We used the FARGO code to conduct the hydro-simulations. We set up a disk with an embedded giant planet and took a radial grid spanning from 0.1 to 7 times the planet semi-major axis. We ran the simulations with various viscosity values and planet masses for 1000 planet orbits to allow a fully developed vortex or disk eccentricity. Afterwards, we compared the dust distribution in a vortex-holding disk with an eccentric disk using dust simulations. We ﬁnd that vorticity and eccentricity are distinguishable by looking at the azimuthal contrast of the dust density. While vortices, as particle traps, produce very pronounced azimuthal asymmetries, eccentric features are not able to accumulate millimeter dust particles in azimuthal direction, and therefore the asymmetries are expected to be modest. Accepted by Astronomy & Astrophysics http://arxiv.org/pdf/1304.1736

Enhanced Hα activity at periastron in the young and massive spectroscopic binary HD200775 M. Benisty1,2, K. Perraut1, D. Mourard3, P. Stee3, G. Lima1, J.B. LeBouquin1, M. Borges Fernandes4, O. Chesneau3, N. Nardetto3, I. Tallon-Bosc5, H. McAlister6,7, T. Ten Brummelaar7, S. Ridgway8, J. Sturmann7, L. Sturmann7, N. Turner7, C. Farrington7 and P.J. Goldﬁnger7 1 IPAG, Grenoble, France 2 MPIA, Heidelberg, Germany 3 OCA, Nice, France 4 Observatorio Nacional, Rio de Janeiro, Brazil 5 Universite de Lyon, France 6 Georgia State University, USA 7 CHARA Array, USA 8 NOAO, Tucson, USA E-mail contact: Myriam.Benisty at obs.ujf-grenoble.fr [A&A abstract abridged] Young close binaries clear central cavities in their surrounding circumbinary disk from which

15 the stars can still accrete material. This process takes place within the very first astronomical units, and is still not well constrained as the observational evidence has been gathered, until now, only by means of spectroscopy. During a full orbital period (∼3.6 yrs) we observed the young massive spectroscopic binary HD200775 (separation ∼5 AU) with the VEGA instrument on the CHARA array and spatially and spectrally resolved its Hα emission, at low and medium spectral resolutions (R∼1600 and 5000). Combining the radial velocity measurements and astrometric data available in the literature, we determined new orbital parameters. We observe that the Hα equivalent width varies with the orbital phase, and increases close to periastron, as expected from theoretical models that predict an increase of the mass transfer from the circumbinary disk to the primary disk. In addition, we have found marginal variations of the typical extent of the Hα emission (at 1 to 2σ level) and location (at 1 to 5σ level). The spatial extent of the Hα emission, as probed by a Gaussian FWHM, is minimum at the ascending node (0.22±0.06 AU), and more than doubles at periastron. In addition, the Gaussian photocenter is slightly displaced in the direction opposite to the secondary, ruling out the scenario in which all or most of the emission is due to accretion onto the secondary. These findings, together with the wide Hα line profile, favor a scenario in which the enhanced Hα activity at periastron may be due to a non-spherical wind around the primary and enhanced at periastron. Accepted by Astronomy & Astrophysics http://arxiv.org/pdf/1306.0390

Detection of 15NNH+ in L1544: non-LTE modelling of dyazenilium hyperfine line emission and accurate 14N/15N values Luca Bizzocchi1, Paola Caselli2, Elvira Leonardo1 and Luca Dore3 1 CAAUL, Observatório Astronómico de Lisboa, Tapada da Ajuda, 1349-018 Lisboa, Portugal 2 School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK 3 Dipartimento di Chimica ”G. Ciamician”, Universita di Bologna, via F. Selmi 2, 40126 Bologna, Italy E-mail contact: bizzocchi at oal.ul.pt Samples of pristine Solar System material found in meteorites and interplanetary dust particles are highly enriched in 15N. Conspicuous nitrogen isotopic anomalies have also been measured in comets, and the 14N/15N abundance ratio of the Earth is itself larger than the recognised pre-solar value by almost a factor of two. Ion–molecules, low-temperature chemical reactions in the proto-solar nebula have been repeatedly indicated as responsible for these 15N-enhancements. 15 + We have searched for N variants of the N2H ion in L1544, a prototypical starless cloud core which is one of the best candidate sources for detection owing to its low central core temperature and high CO depletion. The goal is the evaluation of accurate and reliable 14N/15N ratio values for this species in the interstellar gas. A deep integration of the 15NNH+ (1-0) line at 90.4 GHz has been obtained with the IRAM 30 m telescope. Non-LTE radiative transfer modelling has been performed on the J =1 − 0 emissions of the parent and 15N-containing dyazenilium ions, using a + Bonnor–Ebert sphere as a model for the source. A high-quality fit of the N2H (1–0) hyperfine spectrum has allowed + 15 + us to derive a revised value of the N2H column density in L1544, and the analysis of the observed N NH and 15NNH+ spectra yielded an abundance ratio N(N15NH+)/N(15NNH+)=1.1 ± 0.3. The obtained 14N/15N isotopic ratio is ∼ 1000 ± 200, suggestive of a sizeable 15N depletion in this molecular ion. Such a result is not consistent with 15 + the prediction of present nitrogen chemical models: as they predict large N fractionation of N2H , we suggest that 15N14N, or 15N in some other molecular form, is preferentially depleted onto dust grains. Accepted by Astronomy and Astrophysics http://arxiv.org/pdf/1306.0465

Deuterium Burning in Massive Giant Planets and Low-Mass Brown Dwarfs formed by Core-Nucleated Accretion Peter Bodenheimer1, Gennaro D’Angelo2,4,5, Jack J. Lissauer2, Jonathan J. Fortney1, and Didier Saumon3 1 UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA 2 Space Science and Astrobiology Division, NASA Ames Research Center, Moett Field, CA 94035, USA

16 3 Los Alamos National Laboratory, P. O. Box 1663, Los Alamos, NM 87545, USA 4 SETI Institute, 189 Bernardo Avenue, Mountain View, CA 94043, USA 5 Visiting Research Scientist, Los Alamos National Laboratory, Los Alamos, NM 87545, USA E-mail contact: peter at ucolick.org Formation of bodies near the deuterium-burning limit is considered by detailed numerical simulations according to the core-nucleated giant planet accretion scenario. The objects, with heavy-element cores in the range 5–30 M⊕, are assumed to accrete gas up to ﬁnal masses of 10–15 Jupiter masses (Mjup). After the formation process, which lasts 1–5 Myr and which ends with a ’cold-start’, low-entropy conﬁguration, the bodies evolve at constant mass up to an age of several Gyr. Deuterium burning via proton capture is included in the calculation, and we determined the mass, M50, above which more than 50% of the initial deuterium is burned. This often-quoted borderline between giant planets and brown dwarfs is found to depend only slightly on parameters, such as core mass, stellar mass, formation location, solid surface density in the protoplanetary disk, disk viscosity, and dust opacity. The values for M50 fall in the range 11.6–13.6 Mjup, in agreement with previous determinations that do not take the formation process into account. For a given opacity law during the formation process, objects with higher core masses form more quickly. The result is higher entropy in the envelope at the completion of accretion, yielding lower values of M50. For masses above M50, during the deuterium-burning phase, objects expand and increase in luminosity by 1 to 3 orders of magnitude. Evolutionary tracks in the luminosity-versus-time diagram are compared with the observed position of the companion to Beta Pictoris. Accepted by ApJ http://arxiv.org/pdf/1305.0980

OH (1720 MHz) Masers: A Multiwavelength Study of the Interaction between the W51C Supernova Remnant and the W51B Star Forming Region C.L. Brogan1, W.M. Goss2, T.R. Hunter1, A.M.S. Richards3, C.J. Chandler2, J.S. Lazendic4, B.-C. Koo5, I.M. Hoffman6, and M.J. Claussen2 1 National Radio Astronomy Observatory, 520 Edgemont Rd, Charlottesville, VA 22903, USA 2 National Radio Astronomy Observatory, P. O. Box 0, Socorro, NM 87801, USA 3 Jodrell Bank Centre for Astrophysics, Turing Building, University of Manchester, Manchester M13 9PL, UK 4 Monash Unversity, Clayton, VIC 3800, Australia 5 Astronomy Program, SEES, Seoul National University, Seoul 151-742, South Korea 6 Wittenberg University, Springeld, OH 45501, USA E-mail contact: cbrogan at nrao.edu We present a comprehensive view of the W51B HII region complex and the W51C supernova remnant (SNR) using new radio observations from the VLA, VLBA, MERLIN, JCMT, and CSO along with archival data from Spitzer, ROSAT, ASCA, and Chandra. Our VLA data include the first 400 cm (74 MHz) continuum image of W51 at high resolution (88′′). The 400 cm image shows non-thermal emission surrounding the G49.2-0.3 HII region, and a compact source of non-thermal emission (W51B NT) coincident with the previously-identified OH (1720 MHz) maser spots, non-thermal 21 and 90 cm emission, and a hard X-ray source. W51B NT falls within the region of high likelihood for the position of TeV γ-ray emission. Using the VLBA three OH (1720 MHz) maser spots are detected in the vicinity of W51B NT with sizes of 60 to 300 AU and Zeeman effect magnetic field strengths of 1.5 to 2.2 mG. The multiwavelength data demonstrate that the northern end of the W51B HII region complex has been partly enveloped by the advancing W51C SNR and this interaction explains the presence of W51B NT and the OH masers. This interaction also appears in the thermal molecular gas which partially encircles W51B NT and exhibits narrow pre-shock (∆v ∼ 5 km s−1) and broad post-shock (∆v ∼ 20 km s−1) velocity components. RADEX radiative transfer modeling of these two components yield physical conditions consistent with the passage of a non-dissociative C-type shock. Confirmation of the W51B/W51C interaction provides additional evidence in favor of this region being one of the best candidates for hadronic particle acceleration known thus far. Accepted by ApJ http://arxiv.org/pdf/1305.2793

17 The Turbulence Power Spectrum in Optically Thick Interstellar Clouds Blakesley Burkhart1, A. Lazarian1, V. Ossenkopf2, J. Stutzki2 1 Astronomy Department, University of Wisconsin, Madison, 475 N. Charter St., WI 53711, USA 2 Physikalisches Institut der Universität zu Köln, Zulpicher Strasse 77, 50937 Köln, Germany E-mail contact: burkhart at astro.wisc.edu The Fourier power spectrum is one of the most widely used statistical tools to analyze the nature of magnetohydrodynamic turbulence in the interstellar medium. Lazarian & Pogosyan (2004) predicted that the spectral slope should saturate to -3 for an optically thick medium and many observations exist in support of their prediction. However, there have not been any numerical studies to-date testing these results. We analyze the spatial power spectrum of MHD simulations with a wide range of sonic and Alfvénic Mach numbers, which include radiative transfer effects of the 13CO transition. We confirm numerically the predictions of Lazarian & Pogosyan (2004) that the spectral slope of line intensity maps of an optically thick medium saturates to -3. Furthermore, for very optically thin supersonic CO gas, where the density or CO abundance values are too low to excite emission in all but the densest shock compressed gas, we find that the spectral slope is shallower than expected from the column density. Finally, we find that mixed optically thin/thick CO gas, which has average optical depths on order of unity, shows mixed behavior: for super- Alfvénic turbulence, the integrated intensity power spectral slopes generally follow the same trend with sonic Mach number as the true column density power spectrum slopes. However, for sub-Alfvénic turbulence the spectral slopes are steeper with values near -3 which are similar to the very optically thick regime. Accepted by ApJ http://arxiv.org/pdf/1305.3619

The distance to the young open cluster Westerlund 2 Giovanni Carraro1, David Turner2, Daniel Majaess2, and Gustavo Baume3 1 ESO, Alonso de Cordova 3107, 19001, Santiago de Chile, Chile 2 Department of Astronomy and Physics, Saint Marys University, Halifax, NS B3H 3C3, Canada 3 Facultad de Ciencias Astron´omicas y Geof´ısicas (UNLP), Instituto de Astrof´ısica de La Plata (CONICETUNLP), Paseo del Bosque s/n, La Plata, Argentina E-mail contact: gcarraro at eso.org

A new X-ray, UBVRIc, and JHKs study of the young cluster Westerlund 2 was undertaken to resolve discrepancies tied to the cluster’s distance. Existing spectroscopic observations for bright cluster members and new multi-band photometry imply a reddening relation towards Westerlund 2 described by EU−B /EB−V =0.63+0.02 EB−V . Variable- extinction analyses for Westerlund 2 and nearby IC 2581 based upon spectroscopic distance moduli and ZAMS fitting yield values of RV = AV /EB−V = 3.88 ± 0.18 and 3.77 ± 0.19, respectively, and confirm prior assertions that anomalous interstellar extinction is widespread throughout Carina (e.g., Turner 2012). The results were confirmed by applying the color difference method to UBVRIcJHKs data for 19 spectroscopically-observed cluster members, yielding RV =3.85 ± 0.07. The derived distance to Westerlund 2 of d =2.85 ± 0.43 kpc places the cluster on the far side of the Carina spiral arm. The cluster’s age is no more than τ ∼ 2 × 106 yr as inferred from the cluster’s brightest stars and an X-ray (Chandra) cleaned analysis of its pre-main-sequence demographic. Four Wolf-Rayet stars in the cluster core and surrounding corona (WR20a, WR20b, WR20c, and WR20aa) are likely cluster members, and their inferred luminosities are consistent with those of other late-WN stars in open clusters. The color-magnitude diagram for Westerlund 2 also displays a gap at spectral type B0.5 V with associated color spread at higher and lower absolute magnitudes that might be linked to close binary mergers. Such features, in conjunction with the evidence for mass loss from the WR stars, may help to explain the high flux of γ rays, cosmic rays, and X-rays from the direction towards Westerlund 2. Accepted by A&A http://arxiv.org/pdf/1305.4309

18 Observations of gas flows inside a protoplanetary gap Simon Casassus1, Gerrit van der Plas1, Sebastian Perez M.1, William R.F. Dent2,3, Ed Fomalont4, Janis Hagelberg5, Antonio Hales2,4, Andrés Jordán6, Dimitri Mawet3, Francois Ménard7,8, Al Wootten4, David Wilner9, A. Meredith Hughes10, Matthias R. Schreiber11, Julien H. Girard3, Barbara Ercolano12, Hector Canovas11, Pablo E. Román13, Vachail Salinas1 1 Departamento de Astronom´ıa, Universidad de Chile, Casilla 36-D, Santiago, Chile 2 Joint ALMA Observatory, Alonso de Córdova 3107, Vitacura 763-0355, Santiago Chile 3 European Southern Observatory (ESO), Casilla 19001, Vitacura, Santiago, Chile 4 National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475, USA 5 Observatoire de Genève, Universitéde Genève, 51 ch. des Maillettes, 1290, Versoix, Switzerland 6 Departamento de Astronom´ıay Astrof´ısica, Ponticia Universidad Católica de Chile Santiago, Chile 7 UMI-FCA, CNRS / INSU France (UMI 3386) , and Departamento de Astronom´ıa, Universidad de Chile, Santiago, Chile 8 CNRS / UJF Grenoble 1, UMR 5274, Institut de Planétologie et dAstrophysique de Grenoble (IPAG), France 9 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 USA 10 Department of Astronomy, U. C. Berkeley, 601 Campbell Hall, Berkeley, CA 94720 11 Departamento de F´ısica y Astronom´ıa, Universidad Valparaiso, Av. Gran Bretana 111, Valparaiso, Chile 12 University Observatory, Ludwig-Maximillians University, Munich 13 Center of Mathematical Modeling, University of Chile, Av. Blanco Encalada 2120 Piso 7, Santiago, Chile E-mail contact: scasassus at u.uchile.cl Gaseous giant planet formation is thought to occur in the first few million years following stellar birth. Models predict that giant planet formation carves a deep gap in the dust component (shallower in the gas). Infrared observations of the disk around the young star HD142527, at ∼140 pc, found an inner disk ∼10 AU in radius, surrounded by a particularly large gap, with a disrupted outer disk beyond 140AU, indicative of a perturbing planetary-mass body at ∼90 AU. From radio observations, the bulk mass is molecular and lies in the outer disk, whose continuum emission has a horseshoe morphology. The vigorous stellar accretion rate would deplete the inner disk in less than a year, so in order to sustain the observed accretion, matter must flow from the outer-disk into the cavity and cross the gap. In dynamical models, the putative protoplanets channel outer-disk material into gap-crossing bridges that feed stellar accretion through the inner disk. Here we report observations with the Atacama Large Millimetre Array (ALMA) that reveal diffuse CO gas inside the gap, with denser HCO+ gas along gap-crossing filaments, and that confirm the −9 −7 horseshoe morphology of the outer disk. The estimated flow rate of the gas is in the range 7 × 10 to 2 × 10 M⊙ yr−1, which is sufficient to maintain accretion onto the star at the present rate. Accepted by Nature http://arxiv.org/pdf/1305.6062

Alignment Between Flattened Protostellar Infall Envelopes and Ambient Magnetic Fields Nicholas L. Chapman1, Jacqueline A. Davidson2, Paul F. Goldsmith3, Martin Houde4,5, Woojin Kwon6,7, Zhi-Yun Li8, Leslie W. Looney6, Brenda Matthews9,10, Tristan G. Matthews1, Giles Novak1, Ruisheng Peng11, John E. Vaillancourt12, Nikolaus H. Volgenau13 1 Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) & Dept. of Physics & Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA 2 School of Physics, University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009, Australia 3 Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, MS 264-782, Pasadena, CA 91109, USA 4 Department of Physics and Astronomy, University of Western Ontario, London, ON, Canada 5 Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA 6 Department of Astronomy, University of Illinois, 1002 West Green Street, Urbana, IL 61801, USA 7 SRON Netherlands Institute for Space Research, Landleven 12, 9747 AD, Groningen, The Netherlands 8 Astronomy Department, University of Virginia, Charlottesville, VA 22904, USA 9 Herzberg Institute of Astrophysics, National Research Council of Canada, 5071 West Saanich Road, Victoria, BC

19 V9E 2E7, Canada 10 Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 1A1, Canada 11 Caltech Submillimeter Observatory, 111 Nowelo Street, Hilo, HI 96720, USA 12 SOFIA Science Center, Universities Space Research Association, NASA Ames Research Center, MS 232-11, Moffett Field, CA 94035, USA 13 California Institute of Technology, Owens Valley Radio Observatory, Big Pine, CA 93513, USA E-mail contact: nchapman at u.northwestern.edu We present 350 µm polarization observations of four low-mass cores containing Class 0 protostars: L483, L1157, L1448-IRS2, and Serp-FIR1. This is the second paper in a larger survey aimed at testing magnetically regulated models for core-collapse. One key prediction of these models is that the mean magnetic field in a core should be aligned with the symmetry axis (minor axis) of the flattened YSO inner envelope (aka pseudodisk). Furthermore, the field should exhibit a pinched or hour-glass shaped morphology as gravity drags the field inward towards the central protostar. We combine our results for the four cores with results for three similar cores that were published in the first paper from our survey. An analysis of the 350 µm polarization data for the seven cores yields evidence of a positive correlation between mean field direction and pseudodisk symmetry axis. Our rough estimate for the probability of obtaining by pure chance a correlation as strong as the one we found is about 5%. In addition, we combine together data for multiple cores to create a source-averaged magnetic field map having improved signal-to-noise ratio, and this map shows good agreement between mean field direction and pseudodisk axis (they are within 15◦). We also see hints of a magnetic pinch in the source-averaged map. We conclude that core-scale magnetic fields appear to be strong enough to guide gas infall, as predicted by the magnetically regulated models. Finally, we find evidence of a positive correlation between core magnetic field direction and bipolar outflow axis. Accepted by ApJ http://arxiv.org/pdf/1305.2922

Structure and radial equilibrium of filamentary molecular clouds Yanett Contreras1,2, Jill Rathborne1 and Guido Garay2 1 CSIRO Astronomy and Space Science, PO Box 76, Epping NSW 1710, Australia 2 Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago, Chile E-mail contact: yanett.contreras at csiro.au Recent dust continuum surveys have shown that filamentary structures are ubiquitous along the Galactic plane. While the study of their global properties has gained momentum recently, we are still far from fully understanding their origin and stability. Theories invoking magnetic field have been formulated to help explain the stability of filaments; however, observations are needed to test their predictions. In this paper, we investigate the structure and radial equilibrium of five filamentary molecular clouds with the aim of determining the role that magnetic field may play. To do this, we use continuum and molecular line observations to obtain their physical properties (e.g. mass, temperature and pressure). We find that the filaments have lower lineal masses compared to their lineal virial masses. Their virial parameters and shape of their dust continuum emission suggests that these filaments may be confined by a toroidal dominated magnetic field. Accepted by MNRAS http://adsabs.harvard.edu/doi/10.1093/mnras/stt720

Simulated Observations of Young Gravitationally Unstable Protoplanetary Discs Tom Douglas1, Paola Caselli1, John Ilee2,1, Aaron Boley3, Tom Hartquist1, Richard Durisen4 and Jonathan Rawlings5 1 chool of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK 2 School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, KY16 9SS, UK 3 Department of Astronomy, University of Florida, 211 Bryant Space Center, PO Box 112055, USA 4 Department of Astronomy, Indiana University, 727 East 3rd Street, Swain West 319, Bloomington, IN 47405, USA 5 Department of Physics & Astronomy, University College London, London WC1E 6BT, UK

20 E-mail contact: pytd at leeds.ac.uk The formation and earliest stages of protoplanetary discs remain poorly constrained by observations. ALMA will soon revolutionise this ﬁeld. Therefore, it is important to provide predictions which will be valuable for the interpretation of future high sensitivity and high angular resolution observations. Here we present simulated ALMA observations based on radiative transfer modelling of a relatively massive (0.39 solar masses) self-gravitating disc embedded in a 10 solar mass dense core, with structure similar to the pre-stellar core L1544. We focus on simple species and conclude that C17O 3-2, HCO+ 3-2, OCS 26-25 and H2CO 404-303 lines can be used to probe the disc structure and kinematics at all scales. Accepted by MNRAS http://arxiv.org/pdf/1305.3777

The distance to the young open cluster Westerlund 2 R. Errmann1, R. Neuhäuser1, L. Marschall2, G. Torres3, M. Mugrauer1, W.P. Chen4, S.C.-L. Hu4,5, C. Briceno6, R. Chini7,8,L. Bukowiecki9, D.P. Dimitrov10, D. Kjurkchieva11, E.L.N. Jensen12, D.H. Cohen12, Z.-Y. Wu13, T. Pribulla14, M. Vanko14, V. Krushevska15, J. Budaj14, Y. Oasa16, A.K. Pandey17, M. Fernandez18, A. Kellerer19, and C. Marka1 1 Astrophysikalisches Institut und Universitäts-Sternwarte Jena, Schillergäßchen 2-3, D-07745 Jena, Germany 2 Gettysburg College Observatory, Department of Physics, 300 North Washington St., Gettysburg, PA 17325, USA 3 Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Mail Stop 20, Cambridge MA 02138, USA 4 Graduate Institute of Astronomy, National Central University, Jhongli City, Taoyuan County 32001, Taiwan (R.O.C.) 5 Taipei Astronomical Museum, 363 Jihe Rd., Shilin, Taipei 11160, Taiwan 6 Centro de Investigaciones de Astronomia, Apartado Postal 264, Merida 5101, Venezuela 7 Astronomisches Institut, Ruhr-Universität Bochum, Universitätsstr. 150, D-44801 Bochum, Germany 8 Instituto de Astronom´ıa, Universidad Católica del Norte, Antofagasta, Chile 9 ToruńCentre for Astronomy, Nicolaus Copernicus University, Gagarina 11, PL87-100 Toruń, Poland 10 Institute of Astronomy and NAO, Bulg. Acad. Sci., 72 Tsarigradsko Chaussee Blvd., 1784 Soa, Bulgaria 11 Shumen University, 115 Universitetska str., 9700 Shumen, Bulgaria 12 Dept. of Physics and Astronomy, Swarthmore College, Swarthmore, PA 19081-1390, USA 13 Key Laboratory of Optical Astronomy, NAO, Chinese Academy of Sciences, 20A Datun Road, Beijing 100012, China 14 Astronomical Institute, Slovak Academy of Sciences, 059 60, TatranskáLomnica, Slovakia 15 Main Astronomical Observatory of National Academy of Sciences of Ukraine, 27 Akademika Zabolotnoho St., 03680 Kyiv, Ukraine 16 Dept. of Astronomy and Earth Science, Saitama University, 255 Shimo-Okubo, Sakura, Saitama 338-8570, Japan 17 Aryabhatta Research Institute of Observational Science, Manora Peak, Naini Tal, 263 129, Uttarakhand, India 18 Instituto de Astrosica de Andalucia, CSIC, Apdo. 3004, 18080 Granada, Spain 19 Department of Physics, Durham University, South Road, Durham DH1 3LE, United Kingdom E-mail contact: ronny.errmann at uni-jena.de With an apparent cluster diameter of 1.5◦ and an age of ∼ 4 Myr, Trumpler 37 is an ideal target for photometric monitoring of young stars as well as for the search of planetary transits, eclipsing binaries and other sources of variability. The YETI consortium has monitored Trumpler 37 throughout 2010 and 2011 to obtain a comprehensive view of variable phenomena in this region. In this first paper we present the cluster properties and membership determination as derived from an extensive investigation of the literature. We also compared the coordinate list to some YETI images. For 1872 stars we found literature data. Among them 774 have high probability of being member and 125 a medium probability. Based on infrared data we re-calculate a cluster extinction of 0.9 – 1.2 mag. We can confirm the age and distance to be 3 – 5 Myr and ∼ 870 pc. Stellar masses are determined from theoretical models and the mass function is fitted with a power-law index of α =1.90(0.1 − 0.4M⊙) and α =1.12(1 − 10M⊙). Accepted by Astronomische Nachrichten http://arxiv.org/pdf/1305.4860

21 A Study of starless dark cloud LDN 1570: Distance, Dust properties and Magnetic field geometry C. Eswaraiah1, G. Maheswar1,2, A.K. Pandey1, J. Jose3, A.N. Ramaprakash4, H.C. Bhatt3 1 Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital 263 129, India 2 Korea Astronomy and Space Science Institute, 61-1, Hwaam-dong, Yuseong-gu, Daejeon 305-348, Republic of Korea 3 Indian Institute of Astrophysics, II Block, Koramangala, Bangalore 560 034, India 4 Inter-University Centre for Astronomy and Astrophysics, Ganeshkhind, Pune 411007, India E-mail contact: eswarbramha at gmail.com We wish to map the magnetic field geometry and to study the dust properties of the starless cloud, L1570, using multi-wavelength optical polarimetry and photometry of the stars projected on the cloud. We made R-band imaging polarimetry of the stars projected on a cloud, L1570, to trace the magnetic field orientation. We also made multiwavelength polarimetric and photometric observations to constrain the properties of dust in L1570. We estimated a distance of 394 ± 70 pc to the cloud using 2MASS JHKs colours. Using the values of the Serkowski parameters namely σ1,¯ǫ, λmax and the position of the stars on near infrared color-color diagram, we identified 13 stars that could possibly have intrinsic polarization and/or rotation in their polarization angles. One star, 2MASS J06075075+1934177, which is a B4Ve spectral type, show the presence of diffuse interstellar bands in the spectrum apart from showing Hα line in emission. There is an indication for the presence of slightly bigger dust grains towards L1570 on the basis of the dust grain size-indicators such as λmax and Rv values. The magnetic field lines are found to be parallel to the cloud structures seen in the 250 µm images (also in 8 µm and 12 µm shadow images) of L1570. Based on the magnetic field geometry, the cloud structure and the complex velocity structure, we believe that L1570 is in the process of formation due to the converging flow material mediated by the magnetic field lines. Structure function analysis showed that in the L1570 cloud region the large scale magnetic fields are stronger when compared with the turbulent component of magnetic fields. The estimated magnetic field strengths suggest that the L1570 cloud region is sub-critical and hence could be strongly supported by the magnetic field lines. Accepted by A&A http://arxiv.org/pdf/1305.5035

Mass and motion of globulettes in the Rosette Nebula G. F. Gahm1, C. M. Persson2, M. M. Mäkelä3 and L. K. Haikala3 1 Stockholm Observatory, AlbaNova University Centre, Stockholm University, SE-106 91 Stockholm, Sweden 2 Chalmers University of Technology, Department of Earth and Space Sciences, Onsala Space Observatory, SE-439 92 Onsala, Sweden 3 Department of Physics, PO Box 64, FI-00014 University of Helsinki, Finland E-mail contact: gahm at astro.su.se We have investigated tiny molecular clumps in the Rosette Nebula. In optical images these objects, so-called globulettes, appear as dark patches against the background of bright nebulosity. Radio observations were made of molecular line emission from 16 globulettes identified in a previous optical survey. In addtion, we collected images in the NIR broadband JHKs and narrow-band Paschen β and H2. Practically all globulettes were detected in our CO survey. The observed 12CO (3–2) and (2–1) line temperatures range from 0.6 K to 6 K, the 13CO being a third of this. As a rule the lines are narrow, ∼ 1.0 km s−1. Ten objects, for which we collected information from several transitions in 12CO and 13CO were modelled using a spherically symmetric model. The best fit to observed line ratios and intensities was obtained by assuming a model composed of a cool and dense centre and warm and dense surface layer. This model provides estimates of maximum and minimum mass; the average masses range from about 50 to 500 Jupiter masses, which is similar to earlier 4 −3 estimates based on extinction measures. The globulettes selected are dense, nH ∼ 10 cm , with very thin layers of fluorescent H2 emission, showing that the gas is in molecular form just below the surface. The NIR data shows that several globulettes are very opaque and contain dense cores. Internal gas motions are weak, but some larger objects show velocity-shifted components associated with tails. However, most globulettes do not show any signs of tails or pronounced bright rims. Because of the high density encountered already at the surface, the rims become thin, as evidenced by our Pβ images, which also show extended emission, that most likely comes from the backside of the

22 globulettes. We conclude that the entire complex of shells, elephant trunks, and globulettes in the northern part of the nebula is expanding with nearly the same velocity of ∼ 22 kms−1, and with a very small spread in velocity among the globulettes. Some globulettes are in the process of detaching from elephant trunks and shells, while other more isolated objects must have detached long ago and are lagging behind in the general expansion of the molecular shell. We envision that after detachment the objects erode to isolated and dense clumps. The suggestion that some globulettes might collapse to form planetary-mass objects or brown dwarfs is strengthened by our ﬁnding of dense cores in several objects. Such free-ﬂoating low-mass objects would move at high speed already from the start and escape from the region. Accepted by Astronomy and Astrophysics http://arxiv.org/pdf/1305.2485

DR 21(OH): a highly fragmented, magnetized, turbulent dense core J. M. Girart1, P. Frau1,2, Q. Zhang3, P. M. Koch4, K. Qiu5, Y.-W. Tang4, S.-P. Lai6, P.T.P. Ho4 1 Institut de Ciències de l’Espai, (CSIC-IEEC), Spain 2 Observatorio Astronómico Nacional, Spain 3 Harvard-Smithsonian Center for Astrophysics, USA 4 Academia Sinica Institute of Astronomy and Astrophysics, Taiwan 5 School of Astronomy and Space Science, Nanjing University, PR China 6 Institute of Astronomy and Department of Physics, National Tsing Hua University, PR China E-mail contact: girart at ice.cat We present high-angular-resolution observations of the massive star forming core DR21(OH) at 880 µm using the Submillimeter Array. The dense core exhibits an overall velocity gradient in a Keplerian-like pattern, which breaks at the center of the core where SMA 6 and SMA 7 are located. The dust polarization shows a complex magnetic field, compatible with a toroidal configuration. This is in contrast with the large, parsec–scale filament that surrounds the core, where there is a smooth magnetic field. The total magnetic field strengths in the filament and in the core are 0.9 and 2.1 mG, respectively. We found evidence of magnetic field diffusion at the core scales, far beyond the expected value for ambipolar diffusion. It is possible that the diffusion arises from fast magnetic reconnection in the presence of turbulence. The dynamics of the DR 21(OH) core appear to be controlled energetically in equal parts by the magnetic field, magneto–hydrodynamic (MHD) turbulence and the angular momentum. The effect of the angular momentum (this is a fast rotating core) is probably causing the observed toroidal field configuration. Yet, gravitation overwhelms all the forces, making this a clear supercritical core with a mass–to–flux ratio of ≃ 6 times the critical value. However, simulations show that this is not enough for the high level of fragmentation observed at 1000 AU scales. Thus, rotation and outflow feedback is probably the main cause of the observed fragmentation. Accepted by The Astrophysical Journal http://arxiv.org/pdf/1305.6509

The IRAM-30m line survey of the Horsehead PDR: III. High abundance of complex (iso-)nitrile molecules in UV-illuminated gas P. Gratier1, J. Pety1,2, V. Guzmán1, M. Gerin2, J.R. Goicoechea3, E. Roue4, and A. Faure5 1 Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, 38406 Saint Martin d’Hères, France 2 LERMA, UMR 8112, CNRS and Observatoire de Paris, 61 avenue de l’Observatoire, 75014 Paris, France 3 Centro de Astrobiolog´ıa. CSIC-INTA. Carretera de Ajalvir, Km 4. Torrejón de Ardoz, 28850 Madrid, Spain 4 LUTH UMR 8102, CNRS and Observatoire de Paris, Place J. Janssen, 92195 Meudon Cedex, France 5 UJF-Grenoble 1/CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, 38041 Grenoble, France E-mail contact: gratier at iram.fr

Complex (iso-)nitrile molecules, such as CH3CN and HC3N, are relatively easily detected in our Galaxy and in other galaxies. We constrain their chemistry through observations of two positions in the Horsehead edge: the photo- dissociation region (PDR) and the dense, cold, and UV-shielded core just behind it. We systematically searched for

23 lines of CH3CN, HC3N, C3N, and some of their isomers in our sensitive unbiased line survey at 3, 2, and 1mm. We derived column densities and abundances through Bayesian analysis using a large velocity gradient radiative transfer model. We report the first clear detection of CH3NC at millimeter wavelength. We detected 17 lines of CH3CN at the PDR and 6 at the dense core position, and we resolved its hyperfine structure for 3 lines. We detected 4 lines of HC3N, and C3N is clearly detected at the PDR position. We computed new electron collisional rate coefficients for CH3CN, and we found that including electron excitation reduces the derived column density by 40% at the PDR position. While CH3CN is 30 times more abundant in the PDR than in the dense core, HC3N has similar abundance at both positions. The isomeric ratio CH3NC/CH3CN is 0.15 ± 0.02. In the case of CH3CN, pure gas phase chemistry cannot reproduce the amount of CH3CN observed in the UV-illuminated gas. We propose that CH3CN gas phase abundance is enhanced when ice mantles of grains are destroyed through photo-desorption or thermal-evaporation in PDRs, and through sputtering in shocks. (abridged) Accepted by A&A http://arxiv.org/pdf/1305.2371

An Analysis of the Environments of FU Orionis Objects with Herschel Joel D. Green1, Neal J. Evans II1, ’Agnes K’osp’al2, Gregory J. Herczeg3, Sascha P. Quanz4, Thomas Henning5, Tim A. van Kempen6,7, Jeong-Eun Lee8, Michael M. Dunham9, Gwendolyn Meeus10, Jo-Hsin Chen11, Manuel Guedel12, Stephen L. Skinner13, Armin Leibhart12 and Manuel Merello1 1 Department of Astronomy, 2515 Speedway, University of Texas at Austin, Austin, TX, USA 2 European Space Agency (ESA/ESTEC), Keplerlaan 1, 2200 AG, Noordwijk The Netherlands 3 Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing, 100871, PR China 4 Institute for Astronomy, ETH, Zurich, Switzerland 5 Max Planck Institute for Astronomy, Koenigstuhl 17, 69117 Heidelberg, Germany 6 Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands 7 Joint ALMA offices, Av. Alonso de Cordova 3107, Santiago, Chile 8 Department of Astronomy & Space Science, Kyung Hee University, Gyeonggi 446-701, Korea 9 Dept. of Astronomy, Yale University, New Haven, CT, USA 10 Universidad Autonoma de Madrid, Dpt. Fisica Teorica, Campus Cantoblanco, Spain 11 Jet Propulsion Laboratory, Pasadena, CA, USA 12 Dept. of Astronomy, University of Vienna, Austria 13 Center for Astrophysics and Space Astronomy (CASA), University of Colorado, Boulder, CO 80309-0389, USA E-mail contact: joel at astro.as.utexas.edu We present Herschel-HIFI, SPIRE, and PACS 50-670 µm imaging and spectroscopy of six FU Orionis-type objects and candidates (FU Orionis, V1735 Cyg, V1515 Cyg, V1057 Cyg, V1331 Cyg, and HBC 722), ranging in outburst date from 1936-2010, from the FOOSH (FU Orionis Objects Surveyed with Herschel) program, as well as ancillary results from Spitzer-IRS and the Caltech Submillimeter Observatory. In their system properties (Lbol, Tbol, line emission), we find that FUors are in a variety of evolutionary states. Additionally, some FUors have features of both Class I and II sources: warm continuum consistent with Class II sources, but rotational line emission typical of Class I, far higher than Class II sources of similar mass/luminosity. Combining several classification techniques, we find an evolutionary sequence consistent with previous mid-IR indicators. We detect [O I] in every source at luminosities consistent with 13 Class 0/I protostars, much greater than in Class II disks. We detect transitions of CO (Jup of 5 to 8) around two sources (V1735 Cyg and HBC 722) but attribute them to nearby protostars. Of the remaining sources, three (FU Ori, V1515 Cyg, and V1331 Cyg) exhibit only low-lying CO, but one (V1057 Cyg) shows CO up to J = 23-22 and evidence for H2O and OH emission, at strengths typical of protostars rather than T Tauri stars. Rotational temperatures for cool CO components range from 20-81 K, for 1050 total CO molecules. We detect [C I] and [N II] primarily as diffuse emission. Accepted by Astrophysical Journal http://arxiv.org/pdf/1306.0666

24 Dynamical Evidence for a Magnetocentrifugal Wind from a 20 M⊙ Binary Young Stellar Object Lincoln J. Greenhill1, Ciriaco Goddi2, Claire J. Chandler3, Lynn D. Matthews4 and Elizabeth M. L. Humphreys5 1 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 USA 2 Joint Institute for VLBI in Europe, Postbus 2 7990 AA, Dwingeloo, The Netherlands 3 NRAO, P.O. Box O, Socorro, NM 87801, USA 4 MIT Haystack Observatory, Off Route 40, Westford, MA 01886, USA 5 European Southern Observatory, Karl-Schwarzschild-Strasse 2 D-85748 Garching bei Muenchen, Germany E-mail contact: goddi at jive.nl In Orion BN/KL, proper motions of λ7 mm vibrationally-excited SiO masers trace rotation of a nearly edge-on disk and a bipolar wide-angle outflow 10-100 AU from radio Source I, a binary young stellar object (YSO) of ∼20 M⊙. Here we map ground-state λ7 mm SiO emission with the Very Large Array and track proper motions over 9 years. The innermost and strongest emission lies in two extended arcs bracketing Source I. The proper motions trace a northeast-southwest bipolar outflow 100-1000AU from Source I with a median 3D motion of ∼18kms−1. An overlying distribution of λ1.3cm H2O masers betrays similar flow characteristics. Gas dynamics and emission morphology traced by the masers suggest the presence of a magnetocentrifugal disk-wind. Reinforcing evidence lies in the linearity of the flow, apparent rotation across the flow parallel to the disk rotation, and recollimation that narrows the flow opening angle ∼ 200 AU downstream. The arcs of ground-state SiO emission may mark the transition point to a shocked super-Alfvénic outflow. Accepted by ApJ Letters http://arxiv.org/pdf/1305.4150

MN Lup: X-rays from a weakly accreting T Tauri star H.M. Günther1, U. Wolter2, J. Robrade2, and S.J. Wolk1 1 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 2 Universität Hamburg, Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany E-mail contact: hguenther at cfa.harvard.edu Young T Tauri stars (TTS) are surrounded by an accretion disk, which over time disperses due to photoevaporation, accretion, and possibly planet formation. The accretion shock on the central star produces an UV/optical veiling continuum, line emission, and X-ray signatures. As the accretion rate decreases, the impact on the central star must change. In this article we study MN Lup, a young star where no indications of a disk are seen in IR observations. We present XMM-Newton and VLT/UVES observations, some of them taken simultaneously. The X-ray data show that MN Lup is an active star with LX /Lbol close to the saturation limit. However, we find high densities (ne > 3 × 10 cm−3) in the X-ray grating spectrum. This can be well fitted using an accretion shock model with an accretion rate −11 −1 of 2 × 10 M⊙ yr . Despite the simple Hα line profile which has a broad component, but no absorption signatures as typically seen on accreting TTS, we find rotational modulation in Ca ii K and in photospheric absorption lines. In the Hα line we see a prominence in absorption about 2R∗ above the stellar surface - the first of its kind on a TTS. MN Lup is also the only TTS where accretion is seen, but no dust disk is detected that could fuel it. We suggest that MN Lup presents a unique and short-lived state in the disk evolution. It may have lost its dust disk only recently and is now accreting the remaining gas at a very low rate. Accepted by ApJ http://arxiv.org/pdf/1305.3280

The Arches cluster out to its tidal radius: dynamical mass segregation and the effect of the extinction law on the stellar mass function Maryam Habibi1,2, Andrea Stolte1, Wolfgang Brandner3, Benjamin Hußmann1, Kentaro Motohara4 1 Argelander Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany

25 2Member of the International Max Planck Research School (IMPRS) for Astronomy and Astrophysics at the Univer- sities of Bonn and Cologne. 3 Max-Planck-Institut für Astronomie, Königsstuhl 17, 69117 Heidelberg, Germany 4 Institute of Astronomy, The University of Tokyo, Osawa 2-21-1, Mitaka, Tokyo 181-0015, Japan E-mail contact: [email protected] The Galactic center is the most active site of star formation in the Milky Way Galaxy, where particularly high-mass stars have formed very recently and are still forming today. However, since we are looking at the Galactic center through the Galactic disk, knowledge of extinction is crucial when studying this region. The Arches cluster is a young, massive starburst cluster near the Galactic center. We observed the Arches cluster out to its tidal radius using Ks-band imaging obtained with NAOS/CONICA at the VLT combined with Subaro/Cisco J-band data to gain a full understanding of the cluster mass distribution. We show that the determination of the mass of the most massive star in the Arches cluster, which had been used in previous studies to establish an upper mass limit for the star formation process in the Milky Way, strongly depends on the assumed slope of the extinction law. Assuming the two regimes of widely used infrared extinction laws, we show that the difference can reach up to 30% for individually derived stellar masses and ∆AKs ∼ 1 magnitude in acquired Ks-band extinction, while the present mass function slope changes by ∼ 0.17 dex. The present-day mass function slope derived assuming the Nishiyama et al. (2009) extinction law increases from a flat slope of αNishi = −1.50±0.35 in the core (r< 0.2 pc) to αNishi = −2.21±0.27 in the intermediate annulus (0.2

The Rotating Outflow, Envelope and Disk in Class-0/I protostar [BHB2007]#11 in the Pipe Nebula C. Hara1,2, Y. Shimajiri2,3, T. Tsukagoshi4, Y. Kurono2, K. Saigo2, F. Nakamura2, M. Saito2,5, D. Wilner6 and R. Kawabe2,5 1 The University of Tokyo, 7-3-1 Hongo Bunkyo, Tokyo 113-0033, Japan 2 National Astronomical Observatory of Japan, 22-21-1 Osawa Mitaka, Tokyo 181-8588, Japan 3 Nobeyama Radio Observatory, 462-2 Nobeyama Minamimaki, Minamisaku District, Nagano Prefecture 384-1305, Japan 4 Ibaraki University, 2-1-1 Bunkyo Mito, Ibaraki Prefecture 310-8512, Japan 5 Joint ALMA Observatory, Alonso de Cordova 3107 Vitacura, Santiago 763 0355, Chile 6 Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA E-mail contact: c.hara at nao.ac.jp We present the results of observations toward a low-mass Class-0/I protostar, [BHB2007]#11 (afterwards B59#11) at the nearby (d=130 pc) star forming region, Barnard 59 (B59) in the Pipe Nebula with the Atacama Submillimeter Telescope Experiment (ASTE) 10 m telescope (∼22′′ resolution) in CO(3–2), HCO+, H13CO+(4–3), and 1.1 mm dust-continuum emissions. We also show Submillimeter Array (SMA) data in 12CO, 13CO, C18O(2–1), and 1.3 mm dust-continuum emissions with ∼5′′ resolution. From ASTE CO(3–2) observations, we found that B59#11 is blowing a collimated outflow whose axis lies almost on the plane of the sky. The outflow traces well a cavity-like structure seen in the 1.1 mm dust-continuum emission. The results of SMA 13CO and C18O(2–1) observations have revealed that a compact and elongated structure of dense gas is associated with B59#11, which is oriented perpendicular to the outflow axis. There is a compact dust condensation with a size of 350×180 AU seen in the SMA 1.3 mm continuum map, and the direction of its major axis is almost the same as that of the dense gas elongation. The distributions of 13CO and C18O emission also show the velocity gradients along their major axes, which are considered to arise from the envelope/disk rotation. From the detailed analysis of the SMA data, we infer that B59#11 is surrounded by a Keplerian disk with a size of less than 350 AU. In addition, the SMA CO(2–1) image shows a velocity gradient in the outflow along the same direction as that of the dense gas rotation. We suggest that this velocity gradient shows a rotation of the outflow.

26 Accepted by ApJ http://arxiv.org/pdf/1305.2668

Gaps in Protoplanetary Disks as Signatures of Planets: II. Inclined Disks H. Jang-Condell1 and N. J. Turner2,3 1 Department of Physics & Astronomy, University of Wyoming, Laramie, WY 82071, USA 2 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA 3 Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany E-mail contact: neal.turner at jpl.nasa.gov We examine the observational appearance of partial gaps being opened by planets in protoplanetary disks, considering the effects of the inclination relative to the line of sight. We model the disks with static α-models with detailed radiative transfer, parametrizing the shape and size of the partially cleared gaps based on the results of hydrodynamic simulations. As in previous work, starlight falling across the gap leads to high surface brightness contrasts. The gap’s trough is darkened by both shadowing and cooling, relative to the uninterrupted disk. The gap’s outer wall is brightened by direct illumination and also by heating, which puffs it up so that it intercepts more starlight. In this paper, we examine the effects of inclination on resolved images of disks with and without gaps at a wide range of wavelengths. The scattering surface’s offset from the disk midplane creates a brightness asymmetry along the axis of inclination, making the disk’s near side appear brighter than the far side in scattered light. Finite disk thickness also causes the projected distances of equidistant points on the disk surface to be smaller on the near side of the disk as compared to the far side. Consequently, the gap shoulder on the near side of the disk should appear brighter and closer to the star than on the far side. However, if the angular resolution of the observation is coarser than the width of the brightened gap shoulder, then the gap shoulder on the far side may appear brighter because of its larger apparent size. We present a formula to recover the scale height and inclination angle of an imaged disk using simple geometric arguments and measuring disk asymmetries. Resolved images of circumstellar disks have revealed clearings and gaps, such as the transitional disk in LkCa 15. Models created using our synthetic imaging attempting to match the morphology of observed scattered light images of LkCa 15 indicate that the H-band flux deficit in the inner ∼0.5′′ of the disk can be explained with a planet of mass greater than 0.5 Jupiter mass. Accepted by ApJ http://arxiv.org/pdf/1305.6313

High-fidelity view of the structure and fragmentation of the high-mass, filamentary IRDC G11.11-0.12 J. Kainulainen1, S.E. Ragan1, T. Henning1, and A. Stutz1 1 Max-Planck-Institute for Astronomy, Konigstuhl 17, 69117 Heidelberg, Germany E-mail contact: jtkainul at mpia.de Star formation in molecular clouds is intimately linked to their internal mass distribution. We present an unprece- dentedly detailed analysis of the column density structure of a high-mass, filamentary molecular cloud, namely IRDC G11.11-0.12 (G11). We use two novel column density mapping techniques: high-resolution (FWHM=2′′, or ∼0.035 pc) dust extinction mapping in near- and mid-infrared, and dust emission mapping with the Herschel satellite. These two completely independent techniques yield a strikingly good agreement, highlighting their complementarity and robustness. We first analyze the dense gas mass fraction and linear mass density of G11. We show that G11 has a −1 top heavy mass distribution and has a linear mass density (Ml ∼ 600 M⊙ pc ) that greatly exceeds the critical value of a self-gravitating, non-turbulent cylinder. These properties make G11 analogous to the Orion A cloud, despite its low star-forming activity. This suggests that the amount of dense gas in molecular clouds is more closely connected to environmental parameters or global processes than to the star-forming efficiency of the cloud. We then examine hierarchical fragmentation in G11 over a wide range of size-scales and densities. We show that at scales 0.5 pc >l> 8 pc, the fragmentation of G11 is in agreement with that of a self-gravitating cylinder. At scales smaller than l< 0.5 pc, the results agree better with spherical Jeans’ fragmentation. One possible explanation for the change in fragmentation characteristics is the size-scale-dependent collapse time-scale that results from the finite size of real molecular clouds:

27 at scales l< 0.5 pc, fragmentation becomes suﬃciently rapid to be unaﬀected by global instabilities. Accepted by A&A http://arxiv.org/pdf/1305.6383

The Herschel/HIFI spectral survey of OMC-2 FIR 4 (CHESS): An overview of the 480 to 1902 GHz range M. Kama1, A. López-Sepulcre2, C. Dominik1,3, C. Ceccarelli2, A. Fuente4, E. Caux5,6, R. Higgins7, A.G.G.M. Tielens8, and T. Alonso-Albi4 1 Astronomical Institute ’Anton Pannekoek’, University of Amsterdam, Amsterdam, The Netherlands 2 UJF-Grenoble 1 / CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, Greno- ble, F-38041, France 3 Department of Astrophysics/IMAPP, Radboud University Nijmegen, Nijmegen, The Netherlands 4 Observatorio Astronómico Nacional, P.O. Box 112, 28803 Alcaláde Henares, Madrid, Spain 5 Universitéde Toulouse, UPS-OMP, IRAP, Toulouse, France 6 CNRS, IRAP, 9 Av. colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France 7 KOSMA, I. Physik. Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany 8 Leiden Observatory, P.O. Box 9513, NL-2300 RA, Leiden, The Netherlands E-mail contact: M.Kama at uva.nl Broadband spectral surveys of protostars offer a rich view of the physical, chemical and dynamical structure and evolution of star-forming regions. The Herschel Space Observatory opened up the terahertz regime to such surveys, giving access to the fundamental transitions of many hydrides and to the high-energy transitions of many other species. A comparative analysis of the chemical inventories and physical processes and properties of protostars of various masses and evolutionary states is the goal of the Herschel CHEmical Surveys of Star forming regions (CHESS) key program. This paper focusses on the intermediate-mass protostar, OMC-2 FIR 4. We obtained a spectrum of OMC-2 FIR 4 in the 480 to 1902 GHz range with the HIFI spectrometer onboard Herschel and carried out the reduction, line identification, and a broad analysis of the line profile components, excitation, and cooling. We detect 719 spectral lines from 40 species and isotopologs. The line flux is dominated by CO, H2O, and CH3OH. The line profiles are complex and vary with species and upper level energy, but clearly contain signatures from quiescent gas, a broad component likely due to an outflow, and a foreground cloud. We find abundant evidence for warm, dense gas, as well as for an outflow in the field of view. Line flux represents 2% of the 7 L⊙ luminosity detected with HIFI in the 480 to 1250 GHz range. Of the total line flux, 60% is from CO, 13% from H2O and 9% from CH3OH. A comparison with similar HIFI spectra of other sources is set to provide much new insight into star formation regions, a case in point being a difference of two orders of magnitude in the relative contribution of sulphur oxides to the line cooling of Orion KL and OMC-2 FIR 4. Accepted by A&A http://arxiv.org/pdf/1305.6421

ALMA detection of the rotating molecular disk wind from the young star HD 163296 P.D. Klaassen1, A. Juhasz1, G.S. Mathews1, J.C. Mottram1, I. De Gregorio-Monsalvo2,3, E.F. van Dishoeck1,4, S. Takahashi5, E. Akiyama6, A. Hales2, M.R. Hogerheijde1, M. Rawlings7, M. Schmalzl1 and L. Testi3,8 1 Leiden Observatory , Leiden University, P.O. Box 9513, 2300 RA, Leiden, The Netherlands 2 Joint ALMA Observatory, Alonso de Cordova 3107, Vitacura, Santiago, Chile 3 European Southern Observatory, Karl Schwarzschild Str 2, 85748, Garching, Germany 4 Max-Planck-Institut f¨ur Extraterrestrische Physik, Giessenbachstrasse 1, 85748 Garching, Germany 5 Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan 6 National Astronomical Observatory of Japan (NAOJ), 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan 7 NRAO, 520 Edgemont Road, Charlottesville, VA 22903, USA 8 INAF - Osservatorio Astroﬁsico di Arcetri, Largo E. Fermi 5, 50125, Firenze, Italy

28 E-mail contact: klaassen at strw.leidenuniv.nl Disk winds have been postulated as a mechanism for angular momentum release in protostellar systems for decades. HD 163296 is a Herbig Ae star surrounded by a disk and has been shown to host a series of HH knots (HH 409) with bow shocks associated with the farthest knots. Here we present ALMA Science Verification data of CO J=2-1 and J=3-2 emission which are spatially coincident with the blue shifted jet of HH knots, and offset from the disk by -18.6 km s−1. The emission has a double corkscrew morphology and extends more than 10′′ from the disk with embedded emission clumps coincident with jet knots. We interpret this double corkscrew as emission from material in a molecular disk wind, and that the compact emission near the jet knots is being heated by the jet which is moving at much higher velocities. We show that the J=3-2 emission is likely heavily filtered by the interferometer, but the J=2-1 emission suffers less due to the larger beam and measurable angular scales. Excitation analysis suggests temperatures −5 −4 exceeding 900 K in these compact features, with the wind mass, momentum and energy being of order 10 M⊙, 10 −1 40 M⊙ km s and 10 erg respectively. The high mass loss rate suggests that this star is dispersing the disk faster than it is funneling mass onto the star. Accepted by Astronomy and Astrophysics http://arxiv.org/pdf/1304.5436

On the simultaneous evolution of massive protostars and their host cores Rolf Kuiper1 and Harold W. Yorke1 1 Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA E-mail contact: Rolf.Kuiper at jpl.nasa.gov Studies of the evolution of massive protostars and the evolution of their host molecular cloud cores are commonly treated as separate problems. However, interdependencies between the two can be significant. Here, we study the simultaneous evolution of massive protostars and their host molecular cores using a multi-dimensional radiation hydrodynamics code that incorporates the effects of the thermal pressure and radiative acceleration feedback of the centrally forming protostar. The evolution of the massive protostar is computed simultaneously using the stellar evolution code STELLAR, modified to include the effects of variable accretion. The interdependencies are studied in three different collapse scenarios. For comparison, stellar evolutionary tracks at constant accretion rates and the evolution of the host cores using pre-computed stellar evolutionary tracks are computed. The resulting interdependencies of the protostellar evolution and the evolution of the environment are extremely diverse and depend on the order of events, in particular the time of circumstellar accretion disk formation with respect to the onset of the bloating phase of the star. Feedback mechanisms affect the instantaneous accretion rate and the protostar’s radius, temperature and luminosity on timescales equal or smaller than 5 kyr, corresponding to the accretion timescale and Kelvin-Helmholtz contraction timescale, respectively. Nevertheless, it is possible to approximate the overall protostellar evolution in many cases by pre-computed stellar evolutionary tracks assuming appropriate constant average accretion rates. Accepted by ApJ http://arxiv.org/pdf/1305.6310

The reliability of approximate radiation transport methods for irradiated disk studies Rolf Kuiper1,2 and Ralf S. Klessen3 1 Universitaet Tuebingen, Institut fuer Astronomie und Astrophysik, Computational Physics, Auf der Morgenstelle 10, D-72076 Tuebingen, Germany 2 Max-Planck-Institut fuer Astronomie Heidelberg, Koenigstuhl 17, D-69117 Heidelberg, Germany 3 Universitaet Heidelberg, Zentrum fuer Astronomie Heidelberg, Institut fuer theoretische Astrophysik, Albert-Ueberle- Strasse 2, D-69120 Heidelberg, Germany E-mail contact: rolf.kuiper at uni-tuebingen.de Context: Dynamical studies of irradiated circumstellar disks require an accurate treatment of radiation transport to, for example, properly determine cooling and fragmentation properties. At the same time the radiation transport algorithm should be as fast as the (magneto-) hydrodynamics to allow for an eﬃcient usage of computing resources.

29 Such fast radiation transport methods imply the acceptance of far-reaching approximations. Aims: We check the reliability of fast, approximate radiation transport methods for circumstellar disk studies by comparing their accuracy to previous standard radiation benchmark test results. Methods: We use different approximate radiation transport methods and compute the equilibrium temperature distribution in a setup of a central star and a slightly flared circumstellar disk, which is embedded in an optically thin envelope. We perform simulations for a wide range of optical depths of the disk’s midplane from τ550nm = 0.1 up to 6 τ810nm = 1.22 × 10 . We check the accuracy of the gray flux-limited diffusion (FLD) approximation and the gray and frequency-dependent hybrid approximation. In the hybrid method, the stellar irradiation is computed via a gray or frequency-dependent ray-tracing (RT) step and the thermal (re-)emission by dust grains is shifted to a gray FLD solver. Results: 1. For moderate optical depths, a gray approximation of the stellar irradiation yields a slightly hotter inner rim and a slightly cooler midplane of the disk at larger radii, but is otherwise in agreement with the frequency- dependent treatment. 2. The gray FLD approximation fails to compute an appropriate temperature profile in all regimes of optical depth; the maximum deviations to the comparison runs are 50% in the optically thin and up to 280% in the optically thick limit. For low optical depth, the isotropic assumption within the FLD method yields a too steep decrease of the radial temperature slope. For higher optical depths, the FLD approximation does not reproduce the shadow behind the optically thick inner rim of the circumstellar disk, yielding artificial heating at larger disk radii. 3. The frequency-dependent RT + gray FLD approximation yields remarkable accuracy for the whole range of optical depths. Conclusions: The high accuracy of the frequency-dependent hybrid radiation transport algorithm makes this method ideally suited for (magneto-) hydrodynamical studies of irradiated circumstellar disks. Accepted by Astronomy and Astrophysics http://arxiv.org/pdf/1305.2197

Spectral variability of classical T Tauri stars accreting in an unstable regime Ryuichi Kurosawa1,2 and Marina M. Romanova1 1 Department of Astronomy, Cornell University, Ithaca, NY 14853-6801, USA 2 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany E-mail contact: kurosawa at mpifr-bonn.mpg.de Classical T Tauri stars (CTTSs) are variable in different time-scales. One type of variability is possibly connected with the accretion of matter through the Rayleigh-Taylor instability that occurs at the interface between an accretion disc and a stellar magnetosphere. In this regime, matter accretes in several temporarily formed accretion streams or ‘tongues’ which appear in random locations, and produce stochastic photometric and line variability. We use the results of global three-dimensional magnetohydrodynamic simulations of matter flows in both stable and unstable accretion regimes to calculate time-dependent hydrogen line profiles and study their variability behaviours. In the stable regime, some hydrogen lines (e.g. Hβ, Hγ, Hδ, Paβ and Brγ) show a redshifted absorption component only during a fraction of a stellar rotation period, and its occurrence is periodic. However, in the unstable regime, the redshifted absorption component is present rather persistently during a whole stellar rotation cycle, and its strength varies non-periodically. In the stable regime, an ordered accretion funnel stream passes across the line of sight to an observer only once per stellar rotation period while in the unstable regime, several accreting streams/tongues, which are formed randomly, pass across the line of sight to an observer. The latter results in the quasi-stationarity appearance of the redshifted absorption despite the strongly unstable nature of the accretion. In the unstable regime, multiple hot spots form on the surface of the star, producing the stochastic light curve with several peaks per rotation period. This study suggests a CTTS that exhibits a stochastic light curve and a stochastic line variability, with a rather persistent redshifted absorption component, may be accreting in the unstable accretion regime. Accepted by MNRAS http://arxiv.org/pdf/1301.0641

30 Protostellar Disk Evolution Over Million-Year Timescales with a Prescription for Mag- netized Turbulence Russell Landry1, Sarah E. Dodson-Robinson2, Neal J. Turner3, and Greg Abram4 1 Physics Department, University of Texas at Dallas 2 Astronomy Department, University of Texas at Austin 3 Jet Propulsion Laboratory/California Institute of Technology 4 Texas Advanced Computing Center, University of Texas at Austin E-mail contact: russell.landry at gmail.com Magnetorotational instability (MRI) is the most promising mechanism behind accretion in low-mass protostellar disks. Here we present the first analysis of the global structure and evolution of non-ideal MRI-driven T-Tauri disks on million- year timescales. We accomplish this in a 1+1D simulation by calculating magnetic diffusivities and utilizing turbulence activity criteria to determine thermal structure and accretion rate without resorting to a 3-D magnetohydrodynamical (MHD) simulation. Our major findings are as follows. First, even for modest surface densities of just a few times the minimum-mass solar nebula, the dead zone encompasses the giant planet-forming region, preserving any compositional gradients. Second, the surface density of the active layer is nearly constant in time at roughly 10 g cm−2, which we use to derive a simple prescription for viscous heating in MRI-active disks for those who wish to avoid detailed MHD computations. Furthermore, unlike a standard disk with constant-α viscosity, the disk midplane does not cool off over time, though the surface cools as the star evolves along the Hayashi track. The ice line is firmly in the terrestrial planet-forming region throughout disk evolution and can move either inward or outward with time, depending on whether pileups form near the star. Finally, steady-state mass transport is a poor description of flow through an MRI-active disk. We caution that MRI activity is sensitive to many parameters, including stellar X-ray flux, grain size, gas/small grain mass ratio and magnetic field strength, and we have not performed an exhaustive parameter study here. Accepted by ApJ http://arxiv.org/pdf/1305.0770

Distribution of HNCO 505 − 404 in Massive Star-forming Regions Juan Li1,2,3, Junzhi Wang1,2, Qiusheng Gu1,2, and Xingwu Zheng1,2 1 School of Astronomy & Space Science, Nanjing University, 22 Hankou RD, Nanjing 210093, China 2 Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, Nanjing 210093, China 3 Shanghai Astronomical Observatory, CAS, 80 Nandan Road, Shanghai 200030, China E-mail contact: lijuan at shao.ac.cn The goal of this paper is to study the spatial distribution of HNCO in massive star-forming regions, and investigate its spatial association with infrared sources, as well as physical conditions in region of HNCO emission. We have mapped nine massive star-forming regions in HNCO 505 −404 with the Purple Mountain Observatory 13.7m telescope. The C18O maps of these sources were obtained simultaneously. The HNCO emission shows compact distribution, with emission peak centred on water masers. Nearly all the HNCO clumps show signs of embedded mid-infrared or far-infrared sources. The FWHM sizes of HNCO clumps are signiﬁcantly smaller than C18O clumps but rather similar to HC3N clumps. We also found good correlation between the integrated intensities, linewidths and LSR velocities of HNCO and HC3N emission, implying similar excitation mechanism of these two species. As such, collisional excitation is likely to be the dominant excitation mechanism for HNCO 505 −404 emission in galactic massive star-forming regions. Accepted by A&A http://arxiv.org/pdf/1305.1134

High angular resolution observations towards OMC-2 FIR 4: Dissecting an intermediate- mass protocluster A. L´opez-Sepulcre1, V. Taquet1, A.´ S´anchez-Monge2, C. Ceccarelli1, C. Dominik3,4, M. Kama3, E.

31 Caux5,6, F. Fontani2, A. Fuente7, P.T.P. Ho8,9, R. Neri10 and Y. Shimajiri11 1 UJF-Grenoble 1 / CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, Greno- ble, F-38041, France 2 Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50124 Firenze, Italy 3 Astronomical Institute Anton Pannekoek, University of Amsterdam, Amsterdam, The Netherlands 4 Department of Astrophysics/IMAPP, Radboud University Nijmegen, Nijmegen, The Netherlands 5 Universitéde Toulouse, UPS-OMP, IRAP, Toulouse, France 6 CNRS, IRAP, 9 Av. colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France 7 Observatorio Astronómico Nacional, P.O. Box 112, 28803 Alcaláde Henares, Madrid, Spain 8 Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan 9 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 10 IRAM, 300 rue de la piscine, F-38406 Saint-Martin d’Hères, France 11 Nobeyama Radio Observatory, 462-2 Nobeyama, Minamimaki, Minamisaku, Nagano 384-1305, Japan E-mail contact: ana.sepulcre at obs.ujf-grenoble.fr Context. Intermediate-mass stars are an important ingredient of our Galaxy and a key to understanding how high- and low-mass stars form in clusters. One of the closest known young intermediate-mass protoclusters is OMC-2 FIR 4, which is located at a distance of 420 pc in Orion. This region is one of the few where the complete 500-2000 GHz spectrum has been observed with the heterodyne spectrometer HIFI on board the Herschel satellite, and unbiased spectral surveys at 0.8, 1, 2, and 3 mm have been obtained with the JCMT and IRAM 30-m telescopes. Aims. We aim to disentangle the core multiplicity, to investigate the morphology of this region in order to study the formation of a low- and intermediate-mass protostar cluster, and to aid in interpretation of the single-dish line profiles already in our hands. Methods. We used the IRAM Plateau de Bure Interferometer to image OMC-2 FIR 4 in the 2-mm continuum emission, + 34 as well as in DCO (2–1), DCN(2–1), C S(3–2), and several CH3OH lines. In addition, we analysed observations of the NH3(1,1) and (2,2) inversion transitions that used the Very Large Array of the NRAO. The resulting maps have an angular resolution that allows us to resolve structures of 5′′, which is equivalent to 2000 AU. Results. Our observations reveal three spatially resolved sources within OMC-2 FIR 4, of one or several solar masses each, with hints of further unresolved substructure within them. Two of these sources have elongated shapes and are associated with dust continuum emission peaks, thus likely containing at least one molecular core each. One of them also displays radio continuum emission, which may be attributed to a young B3-B4 star that dominates the overall luminosity output of the region. The third identified source displays a DCO+(2–1) emission peak and weak dust continuum emission. Its higher abundance of DCO+ relative to the other two regions suggests a lower temperature, hence its possible association with either a younger low-mass protostar or a starless core. It may alternatively be part of the colder envelope of OMC-2 FIR 4. Conclusions. Our interferometric observations show the complexity of the intermediate-mass protocluster OMC- 2 FIR 4, where multiple cores, chemical dierentiation, and an ionised region all coexist within an area of only 10000 AU. Accepted by Astronomy and Astrophysics http://arxiv.org/pdf/1304.4381

Misaligned streamers around a galactic centre black hole from a single cloud’s infall W.E. Lucas1, I.A. Bonnell1, M.B. Davies2 and W.K.M. Rice3 1 SUPA, School of Physics & Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS, UK 2 Lund Observatory, Department of Astronomy and Theoretical Physics, Box 43, SE-221 00 Lund, Sweden 3 SUPA, Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ, UK E-mail contact: wel2 at st-andrews.ac.uk 6 We follow the near radial infall of a prolate cloud onto a 4 × 10 M⊙ supermassive black hole in the Galactic Centre using smoothed particle hydrodynamics (SPH). We show that a prolate cloud oriented perpendicular to its orbital plane naturally produces a spread in angular momenta in the gas which can translate into misaligned discs as is seen in the young stars orbiting Sagittarius A*. A turbulent or otherwise highly structured cloud is necessary to avoid 4 cancelling too much angular momentum through shocks at closest approach. Our standard model of a 2 × 10 M⊙

32 gas cloud brought about the formation of a disc within 0.3 pc from the black hole and a larger, misaligned streamer 4 at 0.5pc. A total of 1.5 × 10 M⊙ of gas formed these structures. Our exploration of the simulation parameter space showed that when star formation occurred, it resulted in top-heavy IMFs with stars on eccentric orbits with semi- major axes 0.02 to 0.3 pc and inclinations following the gas discs and streamers. We suggest that the single event of an infalling prolate cloud can explain the occurrence of multiple misaligned discs of young stars. Accepted by MNRAS http://arxiv.org/pdf/1305.0012

Identifying gaps in flaring Herbig Ae/Be disks using spatially resolved mid-infrared imaging. Are all group I disks transitional? K.M. Maaskant1,2, M. Honda3, L.B.F.M. Waters4,2, A.G.G.M. Tielens1, C. Dominik2,5, M. Min2, A. Verhoeff2, G. Meeus6, and M.E. van den Ancker7 1 Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden, The Netherlands 2 Anton Pannekoek Astronomical Institute, University of Amsterdam, P.O. Box 94249, 1090 GE Amsterdam, The Netherlands 3 Department of Mathematics and Physics, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kana- gawa, 259-1293, Japan 4 SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands 5 Department of Astrophysics/IMAPP, Radboud University Nijmegen, PO Box 9010 6500 GL Nijmegen, The Nether- lands 6 Universidad Autonoma de Madrid, Dpt. Fisica Teorica, Campus Cantoblanco, Spain 7 European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching b. Munchen, Germany E-mail contact: maaskant at strw.leidenuniv.nl Context. The evolution of young massive protoplanetary disks toward planetary systems is expected to include the formation of gaps and the depletion of dust and gas. Aims. A special group of flaring disks around Herbig Ae/Be stars do not show prominent silicate emission features. We focus our attention on four key Herbig Ae/Be stars to understand the structural properties responsible for the absence of silicate feature emission. Methods. We investigate Q- and N-band images taken with Subaru/COMICS, Gemini South/T-ReCS and VLT/VISIR. Our radiative transfer modeling solutions require a separation of inner- and outer- disks by a large gap. From this we characterize the radial density structure of dust and PAHs in the disk. Results. The inner edge of the outer disk has a high surface brightness and a typical temperature between ∼100–150 K and therefore dominates the emission in the Q-band. We derive radii of the inner edge of the outer disk of 34, 23, 30 and 63 AU for HD97048, HD169142, HD135344B and Oph IRS 48 respectively. For HD97048 this is the first detection of a disk gap. The continuum emission in the N-band is not due to emission in the wings of PAHs. This continuum emission can be due to VSGs or to thermal emission from the inner disk. We find that PAH emission is not always dominated by PAHs on the surface of the outer disk. Conclusions. The absence of silicate emission features is due to the presence of large gaps in the critical temperature regime. Many, if not all Herbig disks with Spectral Energy Distribution (SED) classification ’group I’ are disks with large gaps and can be characterized as (pre-) transitional. An evolutionary path from the observed group I to the observed group II sources seems no longer likely. Instead, both might derive from a common ancestor. Accepted by A&A http://arxiv.org/pdf/1305.3138

Physical characteristics of G331.5-0.1: The luminous central region of a Giant Molecular Cloud Manuel Merello1,3, Leonardo Bronfman1, Guido Garay1, Lars-Ake˚ Nyman2, Neal J. Evans II3 and C. Malcolm Walmsley4,5 1 Departamento de Astronom´ıa, Universidad de Chile, Casilla 36-D, Santiago, Chile

33 2 Joint ALMA Observatory (JAO), Alonso de Cordova 3107, Vitacura, Santiago, Chile 3 University of Texas at Austin, 1 University Station, Austin, Texas, 78712, USA 4 Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy 5 Dublin Institute of Advanced Studies, Fitzwilliam Place 31, Dublin 2, Ireland E-mail contact: manuel at astro.as.utexas.edu We report molecular line and dust continuum observations toward the high-mass star forming region G331.5-0.1, one of the most luminous regions of massive star-formation in the Milky Way, located at the tangent region of the Norma spiral arm, at a distance of 7.5 kpc. Molecular emission was mapped toward the G331.5-0.1 GMC in the CO(J =1 →0) and C18O(J = 1 →0) lines with NANTEN, while its central region was mapped in CS(J = 2 → 1 and J = 5 → 4) with SEST, and in CS(J = 7 →6) and 13CO(J = 3 →2) with ASTE. Continuum emission mapped at 1.2 mm with SIMBA and at 0.87 mm with LABOCA reveal the presence of six compact and luminous dust clumps, making this source one of the most densely populated central regions of a GMC in the Galaxy. The dust clumps are associated 3 with molecular gas and they have the following average properties: size of 1.6 pc, mass of 3.2 × 10 M⊙, molecular 4 −3 5 hydrogen density of 3.7 × 10 cm , dust temperature of 32 K, and integrated luminosity of 5.7 × 10 L⊙, consistent with values found toward other massive star forming dust clumps. The CS and 13CO spectra show the presence of two velocity components: a high-velocity component at ∼−89 km s−1, seen toward four of the clumps, and a low-velocity component at ∼−101 km s−1 seen toward the other two clumps. Radio continuum emission is present toward four of the molecular clumps, with spectral index estimated for two of them of 0.8±0.2 and 1.2±0.2. A high-velocity molecular outflow is found at the center of the brightest clump, with a line width of 26 km s−1 (FWHM) in CS(J = 7 →6) . Observations of SiO(J =7 → 6 and J =8 → 7), and SO(JK =88 → 77 and JK =87 → 76) lines provide estimates of the gas rotational temperature toward this outflow >120 K and > 75 K, respectively. Accepted by The Astrophysical Journal http://arxiv.org/pdf/1306.0042

Resolved Giant Molecular Clouds in Nearby Spiral Galaxies: Insights from the CANON CO (1-0) Survey Jennifer Donovan Meyer1,2, Jin Koda1, Rieko Momose3,4,5, Thomas Mooney1, Fumi Egusa6,7, MistyCarty8, Robert Kennicutt9, Nario Kuno10,11, David Rebolledo12, Tsuyoshi Sawada4,13, Nick Scoville7, Tony Wong12 1 Department of Physics & Astronomy, Stony Brook University, Stony Brook, NY 11794 2 National Radio Astronomy Observatory, Charlottesville, VA 22901 3 Department of Astronomy, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan 4 National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan 5 Institute for Cosmic Ray Research, University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa City, Chiba, 277-8582, Japan 6 Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Chuo-ku, Sagamihara, Kanagawa 252-5210, Japan 7 Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 8 Department of Astronomy, University of Maryland, College Park, MD 20742 9 Institute of Astronomy, University of Cambridge, Cambridge CB3 0HA, United Kingdom 10 Nobeyama Radio Observatory, Minamimaki, Minamisaku, Nagano, 384-1305, Japan 11 The Graduate University for Advanced Studies (SOKENDAI), 2-21-1 Osawa, Mitaka, Tokyo 181-0015 12 Astronomy Department, University of Illinois, Urbana, IL 61801 13 Joint ALMA Observatory, Alonso de Córdova 3107, Vitacura, Santiago 763-0355, Chile E-mail contact: jdonovanmeyer at gmail.com 5 We resolve 182 individual giant molecular clouds (GMCs) larger than 2.5 × 10 M⊙ in the inner disks of five large nearby spiral galaxies (NGC 2403, NGC 3031, NGC 4736, NGC 4826, and NGC 6946) to create the largest such sample of extragalactic GMCs within galaxies analogous to the Milky Way. Using a conservatively chosen sample of GMCs most likely to adhere to the virial assumption, we measure cloud sizes, velocity dispersions, and 12CO (J=1-0) luminosities and calculate cloud virial masses. The average conversion factor from CO flux to H2 mass (or XCO) for each galaxy is (1 − 2) × 1020 cm−2 / (K km s−1), all within a factor of two of the Milky Way disk value (∼ 2 × 1020 cm−2 / (K km s−1). We find GMCs to be generally consistent within our errors between the galaxies and with Milky

34 Way disk GMCs; the intrinsic scatter between clouds is of order a factor of two. Consistent with previous studies in the Local Group, we ﬁnd a linear relationship between cloud virial mass and CO luminosity, supporting the assumption that the clouds in this GMC sample are gravitationally bound. We do not detect a signiﬁcant population of GMCs with elevated velocity dispersions for their sizes, as has been detected in the Galactic center. Though the range of metallicities probed in this study is narrow, the average conversion factors of these galaxies will serve to anchor the high metallicity end of metallicity-XCO trends measured using conversion factors in resolved clouds; this has been previously possible primarily with Milky Way measurements. Accepted by ApJ http://arxiv.org/pdf/1305.5275

Dynamics, CO depletion, and deuterium fractionation of the dense condensations within the fragmented prestellar core Orion B9–SMM 6 Oskari Miettinen1 and Stella S. R. Offner2 1 Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland 2 Department of Astronomy, Yale University, New Haven, CT 06511, USA E-mail contact: oskari.miettinen at helsinki.fi Context. Low-mass prestellar cores are rarely found to be fragmented into smaller condensations but studying such substructure where present is essential for understanding the origin of multiple stellar systems. Aims. We attempt to better understand the kinematics and dynamics of the subfragments inside the prestellar core SMM 6 in Orion B9. Another object of the present study is to constrain the evolutionary stage of the condensations by investigating the levels of CO depletion and deuterium fractionation. 17 + + Methods. We used the APEX telescope to observe the molecular lines C O(2 − 1), N2H (3 − 2), and N2D (3 − 2) towards the condensations. We use the line data in conjunction with our previous SABOCA 350-µm dust continuum map of the source. Results. The condensations are characterised by subsonic internal non-thermal motions (σNT ≃ 0.5cs), and most of + them appear to be gravitationally bound. The dispersion of the N2H velocity centroids among the condensations is −1 very low (0.02 km s ). The CO depletion factors we derive, fD =0.8 ± 0.4 − 3.6 ± 1.5, do not suggest any significant + CO freeze-out but this may be due to the canonical CO abundance we adopt. The fractional abundances of N2H + −9 −10 and N2D with respect to H2 are found to be ∼ 0.9 − 2.3 × 10 and ∼ 4.9 − 9.9 × 10 , respectively. The deuterium + fractionation of N2H lies in the range 0.30 ± 0.07 − 0.43 ± 0.09. Conclusions. The detected substructure inside SMM 6 is likely the result of cylindrical Jeans-type gravitational fragmentation. We estimate the timescale for this fragmentation to be ∼ 1.8 × 105 yr. The condensations are unlikely to be able to interact with one another and coalesce before local gravitational collapse ensues. Moreover, significant mass growth of the condensations via competitive-like accretion from the parent core seems unfeasible. The high level of molecular deuteration in the condensations suggests that gas-phase CO should be strongly depleted. It also points towards an advanced stage of chemical evolution. The subfragments of SMM 6 might therefore be near the onset of gravitational collapse, but whether they can form protostellar or substellar objects (brown dwarfs) depends on the local star formation efficiency and remains to be clarified. Accepted by Astronomy & Astrophysics http://arxiv.org/pdf/1305.2292

Precise radial velocities of giant stars V. A brown dwarf and a planet orbiting the K giant stars tau Gem and 91 Aqr David S. Mitchell1,2, Sabine Reﬀert1, Trifon Trifonov1, Andreas Quirrenbach1 and Debra A. Fischer3 1 Landessternwarte, Zentrum fr Astronomie der Universitt Heidelberg, Knigstuhl 12, 69117 Heidelberg, Germany 2 Physics Department, California Polytechnic State University, San Luis Obispo, CA, 93407, USA 3 Department of Astronomy, Yale University, New Haven, CT, 06511, USA E-mail contact: dsmitche at calpoly.edu We aim to detect and characterize substellar companions to K giant stars to further our knowledge of planet formation

35 and stellar evolution of intermediate-mass stars. For more than a decade we have used Doppler spectroscopy to acquire high-precision radial velocity measurements of K giant stars. All data for this survey were taken at Lick Observatory. Our survey includes 373 G and K giants. Radial velocity data showing periodic variations were ﬁtted with Keplerian orbits using a χ2 minimization technique. We report the presence of two substellar companions to the K giant stars τ Gem and 91 Aqr. The brown dwarf orbiting τ Gem has an orbital period of 305.5 ± 0.1 days, a minimum mass of 20.6 MJ, and an eccentricity of 0.031 ± 0.009. The planet orbiting 91 Aqr has an orbital period of 181.4 ± 0.1 days, a minimum mass of 3.2 MJ, and an eccentricity of 0.027 ± 0.026. Both companions have exceptionally circular orbits for their orbital distance, as compared to all previously discovered planetary companions. Accepted by A&A http://arxiv.org/pdf/1305.5107

Protoplanetary Disk Masses from Stars to Brown Dwarfs Subhanjoy Mohanty1, Jane Greaves2, Daniel Mortlock1, Ilaria Pascucci3, Aleks Scholz4, Mark Thompson5, Daniel Apai3,6, Giuseppe Lodato7, Dagny Looper8 1 Imperial College London, 1010 Blackett Lab, Prince Consort Rd, London SW7 2AZ, UK 2 SUPA, Physics & Astronomy, Univ. of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS, UK 3 Dept. of Planetary Sciences and Lunar and Planetary Lab, Univ. of Arizona, Tucson AZ 85721, USA 4 School of Cosmic Physics, Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2, Ireland 5 Ctr. for Astrophysics Research, Univ. of Hertfordshire, College Lane, Hatfield AL10 9AB, UK 6 Dept. of Astronomy and Steward Observatory, Univ. of Arizona, Tucson, AZ 85721, USA 7 Dipartimento di Fisica, UniversitáDegli Studi di Milano, Via Celoria, 16 Milano, 20133, Italy 8 Institute for Astronomy, Univ. of Hawai’i, 2680 Woodlawn Dr, Honolulu, HI 96822, USA. E-mail contact: s.mohanty at imperial.ac.uk We present SCUBA-2 850µm observations for 7 very low mass stars (VLMS) and brown dwarfs (BDs): 3 in Taurus, 4 in the TWA, and all classical T Tauri (cTT) analogs. We detect 2 of the 3 Taurus disks, but none of the TWA ones. Our 3σ limits correspond to a dust mass of 1.2 M⊕ in Taurus and a mere 0.2 M⊕ in the TWA (3–10× deeper than previous work). We combine our data with other sub-mm/mm surveys of Taurus, ρ Oph and the TWA to investigate trends in disk mass and grain growth during the cTT phase. We find : (1) The minimum disk outer radius required to explain the upper envelope of sub-mm/mm fluxes is 100 AU for intermediate-mass stars, solar-types and VLMS, and 20 AU for BDs. (2) While the upper envelope of disk masses increases with M∗ from BDs to VLMS to solar-types, no increase is seen from solar-type to intermediate-mass stars. We propose this is due to enhanced photoevaporation around intermediate masses. (3) Many disks around Taurus and ρ Oph intermediate-mass and solar-type stars evince an opacity index β of 0–1, indicating large grains. Of the only four VLMS/BDs in these regions with multi-wavelength data, three are consistent with large grains, though optically thick disks are not ruled out. (4) For the TWA VLMS (TWA 30A, B), combining our fluxes with M˙ and ages suggests substantial grain growth by 10 Myr. The degree of grain growth in the TWA BDs (2M1207A, SSPM1102) remains largely unknown. (5) A Bayesian analysis shows that mean (log[Mdisk/M∗]) = −2.4, roughly constant all the way from intermediate-mass stars to VLMS/BDs, and (6) the disk mass in close solar-type Taurus binaries is significantly lower than in singles (by a factor of 10), while that in wide solar-type Taurus binaries is closer to that in singles (lower by a factor of 3). (7) We discuss the implications for planet formation, and for the dependence of M˙ on M∗. Accepted by ApJ http://arxiv.org/pdf/1305.6896

B- and A-Type Stars in the Taurus-Auriga Star Forming Region Kunal P. Mooley1, Lynne A. Hillenbrand1, Luisa M. Rebull2, Deborah L. Padgett2 and Gillian R. Knapp3 1 Department of Astronomy, California Institute of Technology, 1200 E. California Blvd., MC 249-17, Pasadena, CA 91125, USA 2 Spitzer Science Center, California Institute of Technology, Pasadena, CA, USA

36 3 Department of Astrophysics, Princeton University, Princeton, NJ, USA E-mail contact: kunal at astro.caltech.edu We describe the results of a search for early-type stars associated with the Taurus-Auriga molecular cloud complex, a diffuse nearby star-forming region noted as lacking young stars of intermediate and high mass. We investigate several sets of possible O, B and early A spectral class members. The first is a group of stars for which mid-infrared images show bright nebulae, all of which can be associated with stars of spectral type B. The second group consists of early-type stars compiled from (i) literature listings in SIMBAD; (ii) B stars with infrared excesses selected from the Spitzer Space Telescope survey of the Taurus cloud; (iii) magnitude- and color-selected point sources from the 2MASS; and (iv) spectroscopically identified early-type stars from the SDSS coverage of the Taurus region. We evaluated stars for membership in the Taurus-Auriga star formation region based on criteria involving: spectroscopic and parallactic distances, proper motions and radial velocities, and infrared excesses or line emission indicative of stellar youth. For selected objects, we also model the scattered and emitted radiation from reflection nebulosity and compare the results with the observed spectral energy distributions to further test the plausibility of physical association of the B stars with the Taurus cloud. This investigation newly identifies as probable Taurus members three B-type stars: HR 1445 (HD 28929), τ Tau (HD 29763), 72 Tau (HD 28149), and two A-type stars: HD 31305 and HD 26212, thus doubling the number of stars A5 or earlier associated with the Taurus clouds. Several additional early-type sources including HD 29659 and HD 283815 meet some, but not all, of the membership criteria and therefore are plausible, though not secure, members. Accepted by ApJ http://arxiv.org/pdf/1306.0598

X-ray properties of the young open clusters HM1 and IC2944/2948 Yael Naze1, Gregor Rauw1, Hugues Sana2 and Michael F. Corcoran3 1 Dept AGO, Univ of Liege 2 Univ. of Amsterdam 3 GSFC E-mail contact: naze at astro.ulg.ac.be Using XMM data, we study for the first time the X-ray emission of HM1 and IC2944/2948. Low-mass, pre-main- sequence objects with an age of a few Myr are detected, as well as a few background or foreground objects. Most massive stars in both clusters display the usual high-energy properties of that type of objects, though with log(Lx/Lbol) apparently lower in HM1 than in IC2944/2948. Compared with studies of other clusters, it seems that a low signal- to-noise ratio at soft energies, due to the high extinction, may be the main cause of this difference. In HM1, the two Wolf-Rayet stars show contrasting behaviors: WR89 is extremely bright, but much softer than WR87. It remains to be seen whether wind-wind collisions or magnetically confined winds can explain these emissions. In IC2944/2948, the X-ray sources concentrate around HD101205; a group of massive stars to the north of this object is isolated, suggesting that there exist two subclusters in the field-of-view. Accepted by Astron. and Astroph. http://arxiv.org/pdf/1305.5105

The Spatial Distribution of Organics toward the High-Mass YSO NGC 7538 IRS9 Karin I. Oberg¨ 1, Mavis D. Boamah2, Edith C. Fayolle3, Robin T. Garrod4, Claudia J. Cyganowski5 and Floris van der Tak6 1 Department of Chemistry, University of Virginia, USA 2 Wellesley College, USA 3 Leiden Observatory, Leiden University, The Netherlands 4 Center for Radiophysics and Space Research, Cornell University, USA 5 Harvard-Smithsonian Center for Astrophysics, USA 6 Kapteyn Astronomical Institute, University of Groningen, The Netherlands

37 E-mail contact: oberg at virginia.edu Complex molecules have been broadly classified into three generations dependent on the mode of formation and the required formation temperature (<25, 25–100 K, and >100 K). Around massive young stellar objects (MYSOs), icy grain mantles and gas are exposed to increasingly higher temperatures as material accretes from the outer envelope in toward the central hot region. The combination of this temperature profile and the generational chemistry should result in a changing complex molecular composition with radius around MYSOs. We combine IRAM 30m and Submillimeter Array observations to explore the spatial distribution of organic molecules around the high-mass young stellar object NGC 7538 IRS9, whose weak complex molecule emission previously escaped detection. We find that emission from N-bearing organics and CH3OH present substantial increases in emission around 8000 AU and R<3000 AU, while unsaturated O-bearing molecules and hydrocarbons do not. The increase in line flux for some complex molecules in the envelope, around 8000 AU or 25 K, is consistent with recent model predictions of an onset of complex ice chemistry at 20–30 K. The emission increase for many of the same molecules at R<3000 AU suggests the presence of a weak hot core, where thermal ice evaporation and hot gas-phase reactions drive the chemistry. Complex organics thus form at all radii and temperatures around this protostar, but the composition changes dramatically as the temperature increases, which is used together with an adapted gas-grain astrochemical model to constrain the chemical generation(s) to which different classes of molecules belong. Accepted by ApJ http://arxiv.org/pdf/1305.3151

Growth of a Protostar and a Young Circumstellar Disk with High Mass Accretion Rate onto the Disk Takuya Ohtani and Toru Tsuribe Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan E-mail contact: ohtani at vega.ess.sci.osaka-u.ac.jp The growing process of both a young protostar and a circumstellar disk is investigated. Viscous evolution of a disk around a single star is considered with a model where a disk increases its mass by dynamically accreting envelope and simultaneously loses its mass via viscous accretion onto the central star. We focus on the circumstellar disk with ˙ 3 high mass accretion rate onto the disk M = 8.512cs /G as a result of dynamical collapse of rotating molecular cloud core. We study the origin of the surface density distribution and the origin of the disk-to-star mass ratio by means of numerical calculations of unsteady viscous accretion disk in one-dimensional axisymmetric model. It is shown that the radial profiles of the surface density Σ, azimuthal velocity vφ, and mass accretion rate M˙ in the inner region approach to the quasi-steady state. Profile of the surface density distribution in the quasi-steady state is determined as a result of angular momentum transport rather than its original distribution of angular momentum in the cloud core. It is also shown that the disk mass becomes larger than the central star in the long time limit as long as temporary constant mass flux onto the disk is assumed. After the mass infall rate onto the disk declines owing to the depletion of the parent cloud core, the disk-to-star mass ratio Mdisk/M∗ decreases. The disk-to-star mass ratio becomes smaller than 5 6 unity after t > 10 yr and t > 10 yr from the beginning of the accretion phase in the case with α0 = 1 and 0.1, −2 respectively, where α0 is the constant part of viscous parameter. In the case with α0 ≤ 10 , Mdisk/M∗ is still larger than unity at 2 Myr from the beginning of the accretion phase. Accepted by PASJ http://arxiv.org/pdf/1305.5398

The Fate of Planetesimals in Turbulent Disks with Dead Zones. I. The Turbulent Stirring Recipe Satoshi Okuzumi1,2,3 and Chris W. Ormel4,5 1 Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8551 2 Department of Physics, Nagoya University, Nagoya, Aichi 464-8602, Japan 3 JSPS Superlative Research Fellow 4 Astronomy Department, University of California, Berkeley, CA 94720, USA

38 5 Hubble Fellow E-mail contact: okuzumi at geo.titech.ac.jp Turbulence in protoplanetary disks affects planet formation in many ways. While small dust particles are mainly affected by the aerodynamical coupling with turbulent gas velocity fields, planetesimals and larger bodies are more affected by gravitational interaction with gas density fluctuations. For the latter process, a number of numerical simulations have been performed in recent years, but a fully parameter-independent understanding has not been yet established. In this study, we present simple scaling relations for the planetesimal stirring rate in turbulence driven by magnetorotational instability (MRI), taking into account the stabilization of MRI due to Ohmic resistivity. We begin with order-of-magnitude estimates of the turbulence-induced gravitational force acting on solid bodies and associated diffusion coefficients for their orbital elements. We then test the predicted scaling relations using the results of recent Ohmic-resistive MHD simulations by Gressel et al. We find that these relations successfully explain the simulation results if we properly fix order-of-unity uncertainties within the estimates. We also update the saturation predictor for the density fluctuation amplitude in MRI-driven turbulence originally proposed by Okuzumi & Hirose. Combination of the scaling relations and saturation predictor allows to know how the turbulent stirring rate of planetesimals depends on disk parameters such as the gas column density, distance from the central star, vertical resistivity distribution, and net vertical magnetic flux. In Paper II, we apply our recipe to planetesimal accretion to discuss its viability in turbulent disks. Accepted by ApJ http://arxiv.org/pdf/1305.1889

The fate of planetesimals in turbulent disks with dead zones. II. Limits on the viability of runaway accretion C.W. Ormel1 and Satoshi Okuzumi2,3 1 Astronomy Department, University of California, Berkeley, CA 94720, USA 2 Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8551 3 Department of Physics, Nagoya University, Nagoya, Aichi 464-8602, Japan E-mail contact: ormel at astro.berkeley.edu A critical phase in the standard model for planet formation is the runaway growth phase. During runaway growth bodies in the 0.1–100 km size range (planetesimals) quickly produce a number of much larger seeds. The runaway growth phase is essential for planet formation as the emergent planetary embryos can accrete the leftover planetesimals at large gravitational focusing factors. However, torques resulting from turbulence-induced density fluctuations may violate the criterion for the onset of runaway growth, which is that the magnitude of the planetesimals’ random (eccentric) motions are less than their escape velocity. This condition represents a more stringent constraint than the condition that planetesimals survive their mutual collisions. To investigate the effects of MRI turbulence on the viability of the runaway growth scenario, we apply our semi-analytical recipes of Paper I, which we augment by a coagulation/fragmentation model for the dust component. We find that the surface area-equivalent abundance of 0.1 µm particles is reduced by factors 102–103, which tends to render the dust irrelevant to the turbulence. We express the turbulent activity in the midplane regions in terms of a size srun above which planetesimals will experience runaway growth. We find that srun is mainly determined by the strength of the vertical net field that threads the disks and the disk radius. At disk radii beyond 5 AU, srun becomes larger than ∼100 km and the collision times among these bodies longer than the duration of the nebula phase. Our findings imply that the classical, planetesimal-dominated, model for planet formation is not viable in the outer regions of a turbulent disk. Accepted by ApJ http://arxiv.org/pdf/1305.1890

Reaction of Massive Clusters to Gas Expulsion - The cluster density dependence Susanne Pfalzner1 and Thomas Kaczmarek1 1 Max-Planck Institut for Radioastronomy, Auf dem Huegel 69, 53121 Bonn, Germany E-mail contact: spfalzner at mpifr.de

39 The expulsion of the unconverted gas at the end of the star formation process potentially leads to the expansion of the just formed stellar cluster and membership loss. The degree of expansion and mass loss depends largely on the star formation efficiency and scales with the mass and size of the stellar group as long as stellar interactions can be neglected. We investigate under which circumstances stellar interactions between cluster members become so important that the fraction of bound stars after gas expulsion is significantly altered. The Nbody6 code is used to simulate the cluster dynamics after gas expulsion for different SFEs. Concentrating on the most massive clusters observed in the Milky Way, we test to what extend the results depend on the model, i.e. stellar mass distribution, stellar density profile etc., and the cluster parameters, such as cluster density and size.We find that stellar interactions are responsible for up to 20% mass loss in the most compact massive clusters in the Milky Way, making ejections the prime mass loss process in such systems. Even in the loosely bound OB associations stellar interactions are responsible for at least ∼ 5% mass loss. The main reason why the importance of encounters for massive clusters has been largely overlooked is the often used approach of a single-mass representation instead of a realistic distribution for the stellar masses. The density-dependence of the encounter-induced mass loss is shallower than expected because of the increasing importance of few-body interactions in dense clusters compared to sparse clusters where 2-body encounters dominate. Accepted by A&A http://arxiv.org/pdf/1305.6699

Spokes cluster: The search for the quiescent gas Jaime E. Pineda1,2 and Paula S. Teixeira3,4 1 European Southern Observatory (ESO), Garching, Germany 2 UK ARC Node, Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, UK 3 Universität Wien, Institut für Astrophysik, Türkenschanzstrasse 17, 1180 Vienna, Austria 4 Laboratório Associado Instituto D. Luiz-SIM, Universidade de Lisboa, Campo Grande, 1749-016, Lisboa, Portugal E-mail contact: jaime.e.pineda at gmail.com Context. Understanding the role of turbulent and thermal fragmentation is one of the most important current questions of star formation. To better understand the process of star and cluster formation, we need to study in detail the physical structure and properties of the parental molecular cloud. In particular, it is important to understand the fragmentation process itself; this may be regulated by thermal pressure, magnetic fields, and/or turbulence. The targeted region, the + Spokes cluster, or NGC 2264 D, is a rich protostellar cluster where previous N2H (1–0) observations of its dense cores presented linewidths consistent with supersonic turbulence. However, the fragmentation of the most massive of these cores appears to have a scale length consistent with that of the thermal Jeans length, suggesting that turbulence was not dominant. + Aims. These two results (derived from N2H (1–0) observations and measurements of the spatial separations of the protostars) probe different density regimes. Our aim is to determine if there is subsonic or less-turbulent gas (than previously reported) in the Spokes cluster when probing higher densities, which would reconcile both previous observational results. To study denser gas it is necessary to carry out observations using transitions with a higher critical density to directly measure its kinematics. + + Methods. We present APEX N2H (3–2) and N2D (3–2) observations of the NGC2264-D region to measure the linewidths and the deuteration fraction of the higher density gas. The critical densities of the selected transitions are + more than an order of magnitude higher than that of N2H (1–0). + + Results. We find that the N2H (3–2) and N2D (3–2) emission present significantly narrower linewidths than the + emission from N2H (1–0) for most cores. In two of the spectra, the nonthermal component is close (within 1-σ) to the sound speed. In addition, we find that the three spatially segregated cores, for which no protostar had been confirmed show the highest levels of deuteration. + + Conclusions. These results show that the higher density gas, probed with N2H and N2D (3–2), reveals more quiescent gas in the Spokes cluster than previously reported. More high-angular resolution interferometric observations using high-density tracers are needed to truly assess the kinematics and substructure within NGC2264-D. Accepted by A&A http://uk.arxiv.org/pdf/1305.3329

40 Explaining millimeter-sized particles in brown dwarf disks P. Pinilla1, T. Birnstiel2,3, M. Benisty4, L. Ricci5, A. Natta6, C. P. Dullemond1, C. Dominik7,8 and L. Testi9,10 1 Universität Heidelberg, Zentrum für Astronomie, Institut für Theoretische Astrophysik, Germany 2 Harvard-Smithsonian Center for Astrophysics, USA 3 Excellence Cluster Universe, Garching, Germany 4 Laboratoire d’Astrophysique, Observatoire de Grenoble, France 5 California Institute of Technology, USA 6 INAF - Osservatorio Astrofisico di Arcetri, Italy 7 School of Cosmic Physics, Dublin Institute for Advanced Studies, Ireland 8 Astronomical Institute ’Anton Pannekoek’, University of Amsterdam, The Netherlands 9 Department of Astrophysics/IMAPP, Radboud University Nijmegen, The Netherlands 10 European Southern Observatory, Garching, Germany E-mail contact: pinilla at uni-heidelberg.de Context. Planets have been detected around a variety of stars, including low-mass objects, such as brown dwarfs. However, such extreme cases are challenging for planet formation models. Recent sub-millimeter observations of disks around brown dwarf measured low spectral indices of the continuum emission that suggest that dust grains grow to mm-sizes even in these very low mass environments. Aims. To understand the first steps of planet formation in scaled-down versions of T-Tauri disks, we investigate the physical conditions that can theoretically explain the growth from interstellar dust to millimeter-sized grains in disks around brown dwarf. Methods. We modeled the evolution of dust particles under conditions of low-mass disks around brown dwarfs. We used coagulation, fragmentation and disk-structure models to simulate the evolution of dust, with zero and non-zero radial drift. For the non-zero radial drift, we considered strong inhomogeneities in the gas surface density profile that mimic long-lived pressure bumps in the disk. We studied different scenarios that could lead to an agreement between theoretical models and the spectral slope found by millimeter observations. Results. We find that fragmentation is less likely and rapid inward drift is more significant for particles in brown dwarf disks than in T-Tauri disks. We present different scenarios that can nevertheless explain millimeter-sized grains. As an example, a model that combines the following parameters can fit the millimeter fluxes measured for brown dwarf disks: strong pressure inhomogeneities of ∼ 40% of amplitude, a small radial extent ∼ 15 AU, a moderate turbulence −3 −1 strength αturb = 10 , and average fragmentation velocities for ices vf = 10 m s . Accepted by A&A http://arxiv.org/pdf/1304.6638

HST/WFC3 Imaging of Protostellar Jets in Carina: [Fe II] Emission Tracing Massive Jets from Intermediate Mass Protostars Megan Reiter1 and Nathan Smith1 1 University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721-0065, USA E-mail contact: mreiter at as.arizona.edu We present narrowband Wide Field Camera 3 (WFC3)-UVIS and -IR images of four externally irradiated protostellar jets in the Carina nebula: HH 666, HH 901, HH 902, and HH 1066. These massive jets are unusual because they are bathed in UV radiation from dozens of nearby O-type stars, but despite the strong incident ionizing radiation, portions of the jet remain neutral. Near-IR [Fe II] images reveal dense, neutral gas that was not seen in previous studies of Hα emission. We show that near-IR [Fe II] emitting gas must be self-shielded from Lyman continuum photons, regardless of its excitation mechanism (shocks, FUV radiation, or both). High densities are required for the survival of Fe+ amid the strong Lyman continuum luminosity from Tr14, raising estimates of the mass-loss rates by an order of magnitude. Higher jet mass-loss rates require higher accretion rates onto their driving protostars, implying that these jets are driven by intermediate-mass (∼ 2 − 8 M⊙) stars. Indeed, the IR driving sources of two of these outﬂows have luminosities that require intermediate-mass protostars (the other two are so deeply embedded that their luminosity is uncertain). All four of these HH jets are highly collimated, with opening angles of only a few degrees, similar to

41 those observed in low-mass protostars. We propose that these jets reflect essentially the same outflow phenomenon seen in wide-angle molecular outflows associated with intermediate- and high-mass protostars, but that the collimated atomic jet core is irradiated and rendered observable in the harsh radiative environment of the Carina nebula. In more quiescent environments, this atomic core remains invisible, and outflows traced by shock-excited molecules in the outflow cavity give the impression that these outflows have a wider opening angle. Thus, the externally irradiated jets in Carina constitute a new view of collimated jets from intermediate-mass protostars, and offer strong additional evidence that stars up to at least ∼ 8 M⊙ form by the same accretion mechanisms as low-mass stars. Accepted by MNRAS http://arxiv.org/pdf/1305.6904

Understanding the origin of the [OI] low-velocity component from T Tauri stars Elisabetta Rigliaco1, Ilaria Pascucci1, Uma Gorti2,3, Suzan Edwards4 and David Hollenbach2 1 Department of Planetary Science - University of Arizona - 1629 E. University Blvd, 85721 Tucson, AZ, USA 2 Seti Institute, Mountain View, CA 94043, USA 3 NASA Ames research center, Moffet Field, CA, USA 4 Astronomy Department, Smith College, Northampton, MA 01063, USA E-mail contact: rigliaco at lpl.arizona.edu The formation time, masses, and location of planets are strongly impacted by the physical mechanisms that disperse protoplanetary disks and the timescale over which protoplanetary material is cleared out. Accretion of matter onto the central star, protostellar winds/jets, magnetic disk winds, and photoevaporative winds operate concurrently. Hence, disentangling their relative contribution to disk dispersal requires identifying diagnostics that trace different star-disk environments. Here we analyze the low velocity component (LVC) of the Oxygen optical forbidden lines, which is found to be blueshifted by a few km/s with respect to the stellar velocity. We find that the [O i] LVC profiles are different from those of [Ne ii] at 12.81µm and CO at 4.7µm lines pointing to different origins for these gas lines. We report a correlation between the luminosity of the [O i] LVC and the accretion luminosity (Lacc). We do not find any correlation with the X-ray luminosity, while we find that the higher is the stellar FUV luminosity, the higher is the luminosity of the [O i] LVC. In addition, we show that the [O i]6300A/5577˚ A˚ ratio is low (ranging between 1 and 8). These findings favor an origin of the [O i] LVC in a region where OH is photodissociated by stellar FUV photons and argue against thermal emission from an X-ray-heated layer. Detailed modeling of two spectra with the highest S/N and resolution shows that there are two components within the LVC: a broad, centrally peaked component that can be attributed to gas arising in a warm disk surface in Keplerian rotation (with FWHM between ∼40 and ∼60 km/s), and a narrow component (with FWHM∼10 km/s and small blueshifts of ∼2 km/s) that may arise in a cool (∼<1,000 K) molecular wind. Accepted by ApJ http://arxiv.org/pdf/1305.6641

Measuring Protoplanetary Disk Accretion with H I Pfund beta Colette Salyk1, Gregory J. Herczeg2, Joanna M. Brown3, Geoﬀrey A. Blake4, Klaus M. Pontoppidan5 and Ewine F. van Dishoeck6,7 1 National Optical Astronomy Observatory, 950 N Cherry Ave, Tucson, AZ 85719, USA 2 The Kavli Institute for Astronomy and Astrophysics at Peking University, Yi He Yuan Lu 5, Hai Dian Qu, Beijing 100871, China 3 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 4 Division of Geological & Planetary Sciences, Mail Code 150-21, California Institute of Technology, Pasadena, CA 91125, USA 5 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA 6 Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden, The Netherlands 7 Max-Planck-Institute fur Extraterrestriche Physik, Giessenbachstrasse 1, D-85748 Garching, Germany E-mail contact: csalyk at noao.edu

42 In this work, we introduce the use of H I Pfund β (Pfβ; 4.6538 µm) as a tracer of mass accretion from protoplanetary disks onto young stars. Pfβ was serendipitously observed in NIRSPEC and CRIRES surveys of CO fundamental emission, amounting to a sample size of 120 young stars with detected Pfβ emission. Using a subsample of disks with previously measured accretion luminosities, we show that Pfβ line luminosity is well correlated with accretion luminosity over a range of at least three orders of magnitude. We use this correlation to derive accretion luminosities for all 120 targets, 65 of which are previously unreported in the literature. The conversion from accretion luminosity to accretion rate is limited by the availability of stellar mass and radius measurements; nevertheless, we also report accretion rates for 67 targets, 16 previously unmeasured. Our large sample size and our ability to probe high extinction values allow for relatively unbiased comparisons between different types of disks. We find that the transitional disks in our sample have lower than average Pfβ line luminosities, and thus accretion luminosities, at a marginally significant level. We also show that high Pfβ equivalent width is a signature of transitional disks with high inner disk gas/dust ratios. In contrast, we find that disks with signatures of slow disk winds have Pfβ luminosities comparable to those of other disks in our sample. Finally, we investigate accretion rates for stage I disks, including significantly embedded targets. We find that stage I and stage II disks have statistically indistinguishable Pfβ line luminosities, implying similar accretion rates, and that the accretion rates of stage I disks are too low to be consistent with quiescent accretion. Our results are instead consistent with both observational and theoretical evidence that stage I objects experience episodic, rather than quiescent, accretion. Accepted by The Astrophysical Journal http://arxiv.org/pdf/1303.4804

Direct detection of the tertiary component in the massive multiple HD 150 136 with VLTI J. Sanchez-Bermudez1,2, R. Schödel1, A. Alberdi1, R. H. Barbá3, C. A. Hummel2, J. Ma´ız Apellániz1 and J.-U. Pott4 1 Instituto de Astrofsica de Andaluca (CSIC), Glorieta de la Astronoma S/N, 18008 Granada, Spain 2 European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching, Germany 3 Departamento de F´ısica, Universidad de la Serena, Benavente 980, 204000 La Serena, Chile 4 Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany E-mail contact: sanchezj at eso.org Massive stars are of fundamental importance for almost all aspects of astrophysics, but there still exist large gaps in our understanding of their properties and formation because they are rare and therefore distant. It has been found that most O-stars are multiples. HD 150 136 is the nearest system to Earth with > 100M⊙, and provides a unique opportunity to study an extremely massive system. Recently, evidence for the existence of a third component in HD 150 136, in addition to the tight spectroscopic binary that forms the main component, was found in spectroscopic observations. Our aim was to image and obtain astrometric and photometric measurements of this component using long baseline optical interferometry to further constrain the nature of this component. We observed HD 150 136 with the near-infrared instrument AMBER attached to the ESO VLT Interferometer. The recovered closure phases are robust to systematic errors and provide unique information on the source asymmetry. Therefore, they are of crucial relevance for both image reconstruction and model fitting of the source structure. The third component in HD 150 136 is clearly detected in the high-quality data from AMBER. It is located at a projected angular distance of 7.3 mas, or about 13 AU at the line-of-sight distance of HD 150 136, at a position angle of 209 degrees East of North, and has a flux ratio of 0.25 with respect to the inner binary. We resolved the third component of HD 150 136 in J, H and K filters. The luminosity and color of the tertiary agrees with the predictions and shows that it is also an O main-sequence star. The small measured angular separation indicates that the tertiary may be approaching the periastron of its orbit. These results, only achievable with long baseline near infrared interferometry, constitute the first step towards the understanding of the massive star formation mechanisms. Accepted by A & A http://arxiv.org/pdf/1305.3431

43 Evolution and excitation conditions of outflows in high-mass star-forming regions A. Sanchez-Monge1, A. Lopez-Sepulcre2, R. Cesaroni1, C.M. Walmsley1,3, C. Codella1, M.T. Beltran1, M. Pestalozzi4 and S. Molinari4 1 Osservatorio Astrofisico di Arcetri, INAF, Largo Enrico Fermi 5, I-50125, Firenze, Italy 2 UJF-Grenoble 1 / CNRS-INSU, Institut de Planetologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, Greno- ble, F-38041 3 Dublin Institute for Advanced Studies (DIAS), 31 Fitzwilliam Place, Dublin 2, Ireland 4 INAF - Istituto di Astrofisica e Planetologia Spaziali, Via Fosso de Cavaliere 100, I-00133, Roma, Italy E-mail contact: asanchez at arcetri.astro.it Theoretical models suggest that massive stars form via disk-mediated accretion, in a similar fashion to low-mass stars. In this scenario, bipolar outflows ejected along the disk axis play a fundamental role, and their study can help to characterize the different evolutionary stages involved in the formation of a high-mass star. A recent study toward massive molecular outflows has revealed a decrease of the SiO line intensity as the object evolves. The present study aims at characterizing the variation of the molecular outflow properties with time, and at studying the SiO excitation conditions in outflows associated with high-mass young stellar objects (YSOs). We used the IRAM 30-m telescope on Pico Veleta (Spain) to map 14 high-mass star-forming regions in the SiO(2–1), SiO(5–4) and HCO+ (1–0) lines, which trace the molecular outflow emission. The FTS backend, covering a total frequency range of ∼15 GHz, allowed us to + 13 simultaneously map several dense gas (e. g., N2H , C2H, NH2D, H CN) and hot core (CH3CN) tracers. We used the Hi-GAL data to improve the previous spectral energy distributions, and obtain a more accurate dust envelope mass and bolometric luminosity for each source. We calculated the luminosity-to-mass ratio, which is believed to be a good indicator of the evolutionary stage of the YSO. We detect SiO and HCO+ outflow emission in all the fourteen sources, and bipolar structures in six of them. The outflow parameters are similar to those found toward other massive 3 4 + YSOs with luminosities 10 –10 L⊙. We find an increase of the HCO outflow energetics as the object evolve, and a decrease of the SiO abundance with time, from 10−8 to 10−9. The SiO (5–4) to (2–1) line ratio is found to be low at the ambient gas velocity, and increases as we move to red/blue-shifted velocities, indicating that the excitation conditions of the SiO change with the velocity of the gas. In particular, the high-velocity SiO gas component seems to arise from regions with larger densities and/or temperatures, than the SiO emission at the ambient gas velocity. The properties of the SiO and HCO+ outflow emission suggest a scenario in which SiO is largely enhanced in the first evolutionary stages, probably due to strong shocks produced by the protostellar jet. As the object evolves, the power of the jet would decrease and so does the SiO abundance. During this process, however, the material surrounding the protostar would have been been swept up by the jet, and the outflow activity, traced by entrained molecular material (HCO+), would increase with time. Accepted by Astronomy and Astrophysics http://arxiv.org/pdf/1305.3471

Properties of dense cores in clustered massive star-forming regions at high angular resolutions A. Sanchez-Monge1,2, A. Palau3, F. Fontani1, G. Busquet4, C. Juarez3,2, R. Estalella2, J.C. Tan5, I. Sepulveda2, P.T.P. Ho6,7, Q. Zhang7 and S. Kurtz8 1 Osservatorio Astrofisico di Arcetri, INAF, Largo Enrico Fermi 5, I-50125, Firenze, Italy 2 Dpt d’Astronomia i Meteorologia (IEEC-UB), ICC, Universitat de Barcelona, Marti i Franques 1, E-08028, Barcelona, Spain 3 Institut de Ciencies de l’Espai (CSIC-IEEC), Campus UAB, Facultat de Ciencies, Torre C-5p, E-08193, Bellaterra, Spain 4 INAF - Istituto di Astrofisica e Planetologia Spaziali, Via Fosso de Cavaliere 100, I-00133, Roma, Italy 5 Dpt of Astronomy and Physics, University of Florida, Gainesville, FL 32611, USA 6 Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan 7 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 8 Centro de Radioastronomia y Astrofisica, UNAM, P.O. Box 3-72, 58090, Morelia, Mexico E-mail contact: asanchez at arcetri.astro.it

44 We aim at characterising dense cores in the clustered environments associated with intermediate/high-mass star- forming regions. For this, we present an uniform analysis of Very Large Array NH3 (1,1) and (2,2) observations towards a sample of 15 intermediate/high-mass star-forming regions, where we identify a total of 73 cores, classify them as protostellar, quiescent starless, or perturbed starless, and derive some physical properties. The average sizes and ammonia column densities of the total sample are ∼ 0.06 pc and ∼ 1015 cm−2, respectively, with no significant differences between the starless and protostellar cores, while the linewidth and rotational temperature of quiescent starless cores are smaller, ∼ 1.0kms−1 and 16 K, than linewidths and temperatures of protostellar (∼ 1.8kms−1 and 21 K), and perturbed starless (∼ 1.4 km s−1 and 19 K) cores. Such linewidths and temperatures for these quiescent starless cores in the surroundings of intermediate/high-mass stars are still significantly larger than the typical linewidths and rotational temperatures measured in starless cores of low-mass star-forming regions, implying an important non- thermal component. We confirm at high angular resolutions (spatial scales ∼ 0.05 pc) the correlations previously found with single-dish telescopes (spatial scales ∼>0.1 pc) between the linewidth and the rotational temperature of the cores, as well as between the rotational temperature and the linewidth with respect to the bolometric luminosity. In addition, we find a correlation between the temperature of each core and the incident flux from the most massive star in the cluster, suggesting that the large temperatures measured in the starless cores of our sample could be due to heating from the nearby massive star. A simple virial equilibrium analysis seems to suggest a scenario of a self-similar, self-graviting, turbulent, virialised hierarchy of structures from clumps (∼ 0.1–10 pc) to cores (∼ 0.05 pc). A closer inspection of the dynamical state taking into account external pressure effects, reveal that relatively strong magnetic field support may be needed to stabilise the cores, or that they are unstable and thus on the verge of collapse. Accepted by Monthly Notices of the Royal Astronomical Society http://arxiv.org/pdf/1304.5136

Multiwavelength interferometric observations and modeling of circumstellar disks A.A. Schegerer1,2, T. Ratzka3, P.A. Schuller4, S. Wolf5, L. Mosoni6, Ch. Leinert2 1 Bundesamt für Strahlenschutz, Fachbereich für Strahlenschutz und Gesundheit, Ingolstädter Landstrae 1, 85764 Neuherberg, Germany 2 Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany 3 Ludwig-Maximilians-Universität, Universitäts-Sternwarte München, Scheinerstraße 1, 81679 München, Germany 4 Universität zu Köln, I. Physikalisches Institut, Zülpicher Straße 77, 50937 Köln, Germany 5 Universität Kiel, Institut für Theoretische Physik und Astrophysik, Leibnizstraße 15, 24098 Kiel, Germany 6 MTA Research Center for Astronomy and Earth Sciences, Konkoly Thege Miklós Astronomical Institute, 1525 Budapest, Hungary E-mail contact: aschegerer at bfs.de We investigate the structure of the innermost region of three circumstellar disks around pre-main sequence stars HD 142666, AS 205 N, and AS 205 S. We determine the inner radii of the dust disks and, in particular, search for transition objects where dust has been depleted and inner disk gaps have formed at radii of a few tenths of AU up to several AU. We performed interferometric observations with IOTA, AMBER, and MIDI in the infrared wavelength ranges 1.6 – 2.5 µmand8–13 µm with projected baseline lengths between 25 m and 102 m. The data analysis was based on radiative transfer simulations in 3D models of young stellar objects (YSOs) to reproduce the spectral energy distribution and the interferometric visibilities simultaneously. Accretion effects and disk gaps could be considered in the modeling approach. Results from previous studies restricted the parameter space. The objects of this study were spatially resolved in the infrared wavelength range using the interferometers. Based on these observations, a disk gap could be found for the source HD 142666 that classifies it as transition object. There is a disk hole up to a radius of Rin = 0.30 AU and a (dust-free) ring between 0.35 AU and 0.80 AU in the disk of HD 142666. The classification of AS 205 as a system of classical T Tauri stars could be confirmed using the canonical model approach, i.e., there are no hints of disk gaps in our observations. Accepted by A&A http://arxiv.org/pdf/1305.2681

45 Interstellar Detection of c-C3D2 Silvia Spezzano1, Sandra Brünken1, Peter Schilke1, Paola Caselli2, Karl M. Menten3, Michael C. McCarthy4, Luca Bizzocchi5, Sandra Trenivo-Morales6, Yuri Aikawa7 and Stephan Schlemmer1 1 I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany 2 School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK 3 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany 4 Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138, and School of Engineering & Applied Sciences, Harvard University, 29 Oxford St., Cambridge, MA 02138, USA 5 Centro de Astronomia e Astrofisica, Observ. Astronomico de Lisboa Tapada da Ajuda, 1349-018 Lisboa, Portugal 6 IRAM, 18012, Granada, Spain 7 Department of Earth and Planetary Sciences, Kobe University, Kobe 657-8501, Japan E-mail contact: spezzano at ph1.uni-koeln.de

We report the first interstellar detection of c-C3D2. The doubly deuterated cyclopropenylidene, a carbene, has been detected toward the starless cores TMC-1C and L1544 using the IRAM 30m telescope. The JKa,Kc = 30,3 − 21,2, 31,3 − 20,2, and 22,1 − 11,0 transitions of this species have been observed at 3 mm in both sources. The expected 1:2 intensity ratio has been found in the 30,3 -21,2 and 31,3 -20,2 lines, belonging to the para and ortho species respectively. 13 We also observed lines of the main species, c-C3H2, the singly deuterated c-C3HD, and the species with one C off 13 of the principal axis of the molecule, c-H CC2H. The lines of c-C3D2 have been observed with high signal to noise ratio, better than 7.5σ in TMC-1C and 9σ in L1544. The abundance of doubly deuterated cyclopropenylidene with respect to the normal species is found to be (0.4 - 0.8)% in TMC-1C and (1.2 - 2.1)% in L1544. The deuteration of this small hydrocarbon ring is analysed with a comprehensive gas-grain model, the first including doubly deuterated species. The observed abundances of c-C3D2 can be explained solely by gas-phase processes, supporting the idea that c-C3H2 is a good indicator of gas-phase deuteration. Accepted by ApJ Letters http://arxiv.org/pdf/1305.1954

A Semi-Analytical Description for the Formation and Gravitational Evolution of Pro- toplanetary Disks Sanemichi Z. Takahashi1,2, Shu-ichiro Inutsuka1, and Masahiro N. Machida3 1 Department of Physics, Nagoya University, Furocho, Chikusa-ku, Nagoya, Aichi, 464-8602, Japan 2 Department of Physics, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan 3 Department of Earth and Planetary Science, Kyushu University, Higashi-ku, Fukuoka 812-8581, Japan E-mail contact: takahashi.sanemichi at a.mbox.nagoya-u.ac.jp We investigate the formation process of self-gravitating protoplanetary disks in unmagnetized molecular clouds. The angular momentum is redistributed by the action of gravitational torques in the massive disk during its early formation. We develop a simplified one-dimensional accretion disk model that takes into account the infall of gas from the envelope onto the disk and the transfer of angular momentum in the disk with an effective viscosity. First we evaluate the gas accretion rate from the cloud core onto the disk by approximately estimating the effects of gas pressure and gravity acting on the cloud core. We formulate the effective viscosity as a function of the Toomre Q parameter that measures the local gravitational stability of the rotating thin disk. We use a function for viscosity that changes sensitively with Q when the disk is gravitationally unstable. We find a strong self-regulation mechanism in the disk evolution. During the formation stage of protoplanetary disks, the evolution of the surface density does not depend on the other details of the modeling of effective viscosity, such as the prefactor of the viscosity coefficient. Next, to verify our model, we compare the time evolution of the disk calculated with our formulation with that of three-dimensional hydrodynamical simulations. The structures of the resultant disks from the one-dimensional accretion disk model agree well with those of the three-dimensional simulations. Our model is a useful tool for the further modeling of chemistry, radiative transfer, and planet formation in protoplanetary disks. Accepted by ApJ http://arxiv.org/pdf/1305.3413

46 12 13 The relation of H2CO, CO, and CO in molecular clouds Xin. Di. Tang1,2, Jarken. Esimbek1,3, Jian. Jun. Zhou1,3, Gang. Wu1,3, Wei. Guang. Ji1,2, and Daniel. Okoh1,4 1 Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Urumqi 830011, PR China 2 Graduate University of the Chinese Academy of Sciences, Beijing 100080, PR China 3 Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, Urumqi 830011, PR China 4 Physics & Astronomy Department, University of Nigeria, Nsukka 410001, Nigeria E-mail contact: tangxindi at xao.ac.cn Aims. We seek to understand how the 4.8 GHz formaldehyde absorption line is distributed in the MON R2, S156, 12 13 DR17/L906, and M17/M18 regions. More speciﬁcally, we look for the relationship among the H2CO, CO, and CO spectral lines. Methods. The four regions of MON R2 (60′ × 90′), S156 (50′ × 70′), DR17/L906 (40′ × 60′), and M17 /M18 (70′ × ′ ′ ′ ′ 12 80 ) were observed for H2CO (beam 10 ), H110α recombination (beam 10 ), 6 cm continuum (beam 10 ), CO (beam ′ 13 ′ 12 13 1 ), and CO (beam 1 ). We compared the H2CO, CO, CO, and continuum distributions, and also the spectra 12 13 13 line parameters of H2CO, CO, and CO. Column densities of H2CO, CO, and H2 were also estimated. 12 13 Results. We found out that the H2CO distribution is similar to the CO and the CO distributions on a large 13 12 scale. The correlation between the CO and the H2CO distributions is better than between the CO and H2CO 13 distributions. The H2CO and the CO tracers systematically provide consistent views of the dense regions. Their maps have similar shapes, sizes, peak positions, and molecular spectra and present similar central velocities and line 13 widths. Such good agreement indicates that the H2CO and the CO arise from similar regions. Accepted by A&A (551, A28, 2013) http://arxiv.org/pdf/1305.2718

Discovery of Methyl Acetate and Gauche Ethyl Formate in Orion B. Tercero1, I. Kleiner2, J. Cernicharo1, H.V.L. Nguyen2, A. López1, and G.M. Muñoz Caro1 1 Department of Astrophysics, CAB. INTA-CSIC. Crta Torrejón-Ajalvir, km. 4. 28850 Torrejón de Ardoz. Madrid. Spain 2 Laboratoire Interuniversitaire des Systémes Atmosphériques, CNRS/IPSL UMR7583 et Universités Paris Diderot et Paris Est, 61 av Général de Gaulle, 94010, Créteil, France E-mail contact: terceromb at cab.inta-csic.es

We report on the discovery of methyl acetate, CH3COOCH3, through the detection of a large number of rotational lines from each one of the spin states of the molecule: AA species (A1 or A2), EA species (E1), AE species (E2), EE species (E3 or E4). We also report the detection, for the first time in space, of the gauche conformer of ethyl formate, CH3CH2OCOH, in the same source. The trans conformer is also detected for the first time outside the galactic center source SgrB2. From the derived velocity of the emission of methyl acetate we conclude that it arises mainly from the compact ridge region with a total column density of (4.2 ± 0.5) × 1015 cm−2. The derived rotational temperature is 150 K. The column density for each conformer of ethyl formate, trans and gauche, is (4.5 ± 1.0) × 1014 cm−2. Their abundance ratio indicates a kinetic temperature of 135 K for the emitting gas and suggests that gas phase reactions could participate efficiently in the formation of both conformers in addition to cold ice mantle reactions on the surface of dust grains. Accepted by ApJL http://arxiv.org/pdf/1305.1135

Millimeter Recombination Lines from LkHα 101 C. Thum1, R. Neri2, A. BáezRubio3, and M. Krips2 1 Instituto de Radio Astronom´ıaMilimétrica, Avenida Divina Pastora 7, Núcleo Central, 18012 Granada, Spain 2 Institut de Radio Astronomie Millimétrique, 300 rue de la Piscine, Dom. Univ. de Grenoble, 38406 Saint Martin d’Hères, France

47 3 Centro de Astrobiolog´ıa(CSIC/INTA) Ctra de Torrejón a Ajalvir, km 4, 28850 Torrejón de Ardoz, Madrid Spain E-mail contact: thum at iram.es We present new millimeter observations of the ionized wind from the massive young stellar object LkHα101, made with the IRAM interferometer and 30m telescope. Several recombination lines, including higher order transitions, were detected for the first time at radio wavelengths in this source. From three α-transitions we derive an accurate value for the stellar velocity and, for the first time, an unambiguous expansion velocity of the wind which is 55 km −1 −6 −1 s , much slower than reported previously, and the mass loss rate is 1.8 × 10 M⊙ yr . The wide band continuum spectra and the interferometer visibilities show that the density of the wind falls off more steeply than compatible with constant-velocity expansion. We argue that these properties indicate that the wind is launched from a radially narrow region of the circumstellar disk, and we propose that slow speed and a steep density gradient are characteristic properties of the evolutionary phase where young stars of intermediate and high mass clear away the gaseous component of their accretion disks. The recombination lines are emitted close to local thermal equilibrium, but the higher order transitions appear systematically broader and weaker than expected, probably due to impact broadening. Finally, we show that LkHα101 shares many properties with MWC349, the only other stellar wind source where radio recombination lines have been detected, some of them masing. We argue that LkHα101 evades masing at millimeter wavelengths because of the disk’s smaller size and unfavorable orientation. Some amplification may however be detectable at shorter wavelengths. Accepted by A&A http://arxiv.org/pdf/1305.3527

Modeling the Resolved Disk Around the Class 0 Protostar L1527 John J. Tobin1,8, Lee Hartmann2, Hsin-Fang Chiang3,4, David J. Wilner5, Leslie W. Looney3, Laurent Loinard6,7, Nuria Calvet2, Paola D’Alessio6 1 National Radio Astronomy Observatory, Charlottesville, VA 22903, USA 2 Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA 3 Department of Astronomy, University of Illinois, Urbana, IL 61801, USA 4 Institute for Astronomy and NASA Astrobiology Institute, University of Hawaii at Manoa, Hilo, HI 96720, USA 5 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA 6 Centro de Radioastronom´ıay Astrof´ısica, UNAM, Apartado Postal 3-72 (Xangari), 58089 Morelia, Michoacán, México 7 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany 8 Hubble Fellow E-mail contact: jtobin at nrao.edu We present high-resolution sub/millimeter interferometric imaging of the Class 0 protostar L1527 IRS (IRAS 04368+2557) at 870 µm and 3.4 mm from the Submillimeter Array (SMA) and Combined Array for Research in Millimeter As- tronomy (CARMA). We detect the signature of an edge-on disk surrounding the protostar with an observed diameter of 180 AU in the sub/millimeter images. The mass of the disk is estimated to be 0.007 M⊙, assuming optically thin, isothermal dust emission. The millimeter spectral index is observed to be quite shallow at all the spatial scales probed; α ∼ 2, implying a dust opacity spectral index beta ∼ 0. We model the emission from the disk and surrounding envelope using Monte Carlo radiative transfer codes, simultaneously fitting the sub/millimeter visibility amplitudes, sub/millimeter images, resolved L′ image, spectral energy distribution, and mid-infrared spectrum. The best fitting model has a disk radius of R = 125 AU, is highly flared (H ∝ R1.3), has a radial density profile ρ ∝ R−2.5, and has a mass of 0.0075 M⊙. The scale height at 100 AU is 48 AU, about a factor of two greater than vertical hydrostatic equilibrium. The resolved millimeter observations indicate that disks may grow rapidly throughout the Class 0 phase. The mass and radius of the young disk around L1527 is comparable to disks around pre-main sequence stars; however, the disk is considerably more vertically extended, possibly due to a combination of lower protostellar mass, infall onto the disk upper layers, and little settling of ∼1 µm-sized dust grains. Accepted by ApJ http://arxiv.org/pdf/1305.3604

48 Studying the kinematics of the giant star-forming region 30 Doradus. I. The data S. Torres-Flores1, R. Barbá1,2, J. Ma´ız Apellániz3, M. Rubio4, G. Bosch5, V. Hénault-Brunet6, C. J. Evans7 1 Departamento de F´ısica, Universidad de La Serena, Av. Cisternas 1200 Norte, La Serena, Chile 2 Instituto de Ciencias Astronómicas, de la Tierra y del Espacio, Casilla 467, 5400 San Juan, Argentina 3 Instituto de Astrof´ısica de Andaluc´ıa-CSIC, Glorieta de la Astronom´ıas/n, 18008 Granada, Spain 4 Departamento de Astronom´ıa, Universidad de Chile, Casilla 36-D, Santiago, Chile 5 Facultad de Ciencias Astronómicas y Geof´ısicas, Universidad Nacional de la La Plata, Paseo del Bosque s/n, 1900 La Plata, Argentina 6 Institute for Astronomy, Royal Observatory Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ, UK 7 UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ, UK E-mail contact: storres at dfuls.cl We present high-quality VLT-FLAMES optical spectroscopy of the nebular gas in the giant star-forming region 30 Doradus. In this paper, the first of a series, we introduce our observations and discuss the main kinematic features of 30 Dor, as revealed by the spectroscopy of the ionized gas in the region. The primary data set consists of regular grid of nebular observations, which we used to produce a spectroscopic datacube of 30 Dor, centered on the massive star cluster R136 and covering a field-of-view of 10′ × 10′. The main emission lines present in the datacube are from Hα and [Nii] 6548,6584. The Hα emission-line profile varies across the region from simple single-peaked emission to complex, multiple-component profiles, suggesting that different physical mechanisms are acting on the excited gas. To analyse the gas kinematics we fit Gaussian profiles to the observed Hα features. Unexpectedly, the narrowest Hα profile in our sample lies close to the supernova remnant 30 Dor B. We present maps of the velocity field and velocity dispersion across 30 Dor, finding five previously unclassified expanding structures. These maps highlight the kinematic richness of 30 Dor (e.g. supersonic motions), which will be analysed in future papers. Accepted by A&A http://arxiv.org/pdf/1305.0042

The Responses of Magnetically Sub-Critical Cores to Shocks B. Vaidya1, T.W. Hartquist1 and S.A.E.G. Falle2 1 School of Physics and Astronomy, University of Leeds, Leeds, UK 2 Department of Applied Mathematics, University of Leeds, Leeds, UK E-mail contact: B.Vaidya at leeds.ac.uk An ideal magnetohydrodynamics (MHD) code with adaptive mesh refinement (AMR) was used to investigate the interactions of fast-mode shocks with self-gravitating, isothermal cores with mass-to-flux ratios that are somewhat below the minimum value required for gravitational collapse. We find that shock focussing produces colliding flows along the field lines that generate very high densities, even for relatively weak shocks. Self-gravity plays only a minor role in determining the highest density that is reached, but it does play a role in the subsequent evolution. The densities at comparable times differ by a factor of a few for shocks initially propagating perpendicularly or obliquely to the magnetic field in the ambient medium. Accepted by MNRAS http://arxiv.org/pdf/1305.1716

Outﬂow forces of low mass embedded objects in Ophiuchus: a quantitative comparison of analysis methods N. van der Marel1, L.E. Kristensen1,2, R. Visser3, J.C. Mottram1, U.A. Yıldız1, and E.F. van Dishoeck1,4 1 Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden, the Netherlands 2 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 3 Department of Astronomy, University of Michigan, 500 Church St., Ann Arbor, MI 48109-1042, USA 4 Max-Planck-Institut f¨ur Extraterrestrische Physik, Giessenbachstrasse 1, 85748 Garching, Germany

49 E-mail contact: nmarel at strw.leidenuniv.nl The outflow force of molecular bipolar outflows is a key parameter in theories of young stellar feedback on their surroundings. The focus of many outflow studies is the correlation between the outflow force, bolometric luminosity and envelope mass. However, it is difficult to combine the results of different studies in large evolutionary plots over many orders of magnitude due to the range of data quality, analysis methods and corrections for observational effects such as opacity and inclination. We aim to determine the outflow force for a sample of low luminosity embedded sources. We will quantify the influence of the analysis method and the assumptions entering the calculation of the outflow force. We use the James Clerk Maxwell Telescope to map 12CO J = 3 − 2 over 2′ × 2′ regions around 16 Class I sources of a well-defined sample in Ophiuchus at 15′′ resolution. The outflow force is then calculated using seven different methods differing e.g. in the use of intensity-weighted emission and correction factors for inclination. The results from the analysis methods differ from each other by up to a factor of 6, whereas observational properties and choices in the analysis procedure affect the outflow force by up to a factor of 4. For the sample of Class I objects, bipolar outflows are detected around 13 sources including 5 new detections, where the three non-detections are confused by nearby outflows from other sources. When combining outflow forces from different studies, a scatter by up to a factor of 5 can be expected. Although the true outflow force remains unknown, the separation method (separate calculation of dynamical time and momentum) is least affected by the uncertain observational parameters. The correlations between outflow force, bolometric luminosity and envelope mass are further confirmed down to low luminosity sources. Accepted by A&A http://arxiv.org/pdf/1305.6453

Systematic Variations of Interstellar Linear Polarization and Growth of Dust Grains N. V. Voshchinnikov1, H. K. Das2, I. S. Yakovlev1, V. B. Il’in1,3,4 1Sobolev Astronomical Institute, St. Petersburg University, Russia 2 Inter-University Center for Astronomy and Astrophysics, Pune, India 3Pulkovo Observatory, St. Petersburg, Russia 4St. Petersburg State University of Aerospace Instrumentation, St. Petersburg, Russia E-mail contact: nvv at astro.spbu.ru A quantitative interpretation of the observed relation between the interstellar linear polarization curve parameters K and λmax characterizing the width and the wavelength of a polarization maximum, respectively, is given. The observational data available for 57 stars located in the dark clouds in Taurus, Chamaeleon, around the stars ρ Oph and R CrA are considered. The spheroidal particle model of interstellar dust grains earlier applied to simultaneously interpret the interstellar extinction and polarization curves in a wide spectral range is utilized. The observed trend K ≈ 1.7λmax is shown to be most likely related to a growth of dust grains due to coagulation rather than mantle accretion. The relation of the parameters K and λmax with an average size of silicate dust grains is discussed. Accepted by Astronomy Letters (39, 421–431, 2013) http://arXiv.org/pdf/1303.1033

Unveiling the Evolutionary Sequence from Infalling Envelopes to Keplerian Disks around Low-Mass Protostars Hsi-Wei Yen1,2, Shigehisa Takakuwa2, Nagayoshi Ohashi2,3 and Paul T.P. Ho2,4 1 Institute of Astrophysics, National Taiwan University, Taipei 10617, Taiwan 2 Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan 3 Subaru Telescope, National Astronomical Observatory of Japan, 650 North Aohoku Place, Hilo, HI 96720, USA 4 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA E-mail contact: hwyen at asiaa.sinica.edu.tw We performed SMA observations in the C18O (2–1) emission line toward six Class 0 and I protostars, to study rotational motions of their surrounding envelopes and circumstellar material on 100 to 1000 AU scales. C18O (2–1) emission with

50 intensity peaks located at the protostellar positions is detected toward all the six sources. The rotational velocities of the protostellar envelopes as a function of radius were measured from the Position–Velocity diagrams perpendicular to the outflow directions passing through the protostellar positions. Two Class 0 sources, B335 and NGC 1333 IRAS 4B, show no detectable rotational motion, while L1527 IRS (Class 0/I) and L1448-mm (Class 0) exhibit rotational motions −1.0±0.2 −1.0±0.1 with radial profiles of Vrot ∝ r and ∝ r , respectively. The other Class I sources, TMC-1A and L1489 IRS, exhibit the fastest rotational motions among the sample, and their rotational motions have flatter radial profiles −0.6±0.1 −0.5±0.1 −1 of Vrot ∝ r and ∝ r , respectively. The rotational motions with the radial dependence of ∼ r can be interpreted as rotation with a conserved angular momentum in a dynamically infalling envelope, while those with the radial dependence of ∼ r−0.5 can be interpreted as Keplerian rotation. These observational results demonstrate categorization of rotational motions from infalling envelopes to Keplerian-disk formation. Models of the inside-out collapse where the angular momentum is conserved are discussed and compared with our observational results. Accepted by ApJ http://arxiv.org/pdf/1305.6877

Abstracts of recently accepted major reviews

Observation of rotation in star forming regions: clouds, cores, disks, and jets Arnaud Belloche1 1 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany E-mail contact: belloche at mpifr-bonn.mpg.de Angular momentum plays a crucial role in the formation of stars and planets. It has long been noticed that parcels of gas in molecular clouds need to reduce their specific angular momentum by 6 to 7 orders of magnitude to participate in the building of a typical star like the Sun. Several physical processes on different scales and at different stages of evolution can contribute to this loss of angular momentum. In order to set constraints on these processes and better understand this transfer of angular momentum, a detailed observational census and characterization of rotation at all stages of evolution and over all scales of star forming regions is necessary. This review presents the main results obtained in low-mass star forming regions over the past four decades in this field of research. It addresses the search and characterization of rotation in molecular clouds, prestellar and protostellar cores, circumstellar disks, and jets. Perspectives offered by ALMA are briefly discussed. Accepted by the Proceedings of the Evry Schatzman School 2012 of PNPS and CNRS/INSU on the ”Role and mechanisms of angular momentum transport during the formation and early evolution of stars” (eds. P. Hennebelle and C. Charbonnel) http://arxiv.org/pdf/1305.0627

Formation of the First Stars Volker Bromm1 1 Department of Astronomy, University of Texas, 2511 Speedway, Austin, TX 78712, USA E-mail contact: vbromm at astro.as.utexas.edu Understanding the formation of the ﬁrst stars is one of the frontier topics in modern astrophysics and cosmology. Their emergence signaled the end of the cosmic dark ages, a few hundred million years after the Big Bang, leading to a fundamental transformation of the early Universe through the production of ionizing photons and the initial

51 enrichment with heavy chemical elements. We here review the state of our knowledge, separating the well understood elements of our emerging picture from those where more work is required. Primordial star formation is unique in that its initial conditions can be directly inferred from the Lambda Cold Dark Matter (LCDM) model of cosmological structure formation. Combined with gas cooling that is mediated via molecular hydrogen, one can robustly identify 6 the regions of primordial star formation, the so-called minihalos, having total masses of ∼ 10 M⊙ and collapsing at redshifts z ∼ 20 − 30. Within this framework, a number of studies have defined a preliminary standard model, with the main result that the first stars were predominantly massive. This model has recently been modified to include a ubiquitous mode of fragmentation in the protostellar disks, such that the typical outcome of primordial star formation may be the formation of a binary or small multiple stellar system. We will also discuss extensions to this standard picture due to the presence of dynamically significant magnetic fields, of heating from self-annihalating WIMP dark matter, or cosmic rays. We conclude by discussing possible strategies to empirically test our theoretical models. Accepted by Rep. Prog. Phys. http://arxiv.org/pdf/1305.5178

MRI-driven angular momentum transport in protoplanetary disks Sébastien Fromang1 1 Laboratoire AIM, CEA/DSM-CNRS-UniversitéParis Diderot, IRFU/Service d’Astrophysique, CEASaclay F-91191 Gif-sur-Yvette, France E-mail contact: sebastien.fromang at cea.fr Angular momentum transport in accretion disk has been the focus of intense research in theoretical astrophysics for many decades. In the past twenty years, MHD turbulence driven by the magnetorotational instability has emerged as an efficient mechanism to achieve that goal. Yet, many questions and uncertainties remain, among which the saturation level of the turbulence. The consequences of the magnetorotational instability for planet formation models are still being investigated. This lecture, given in September 2012 at the school ’Role and mechanisms of angular momentum transport in the formation and early evolution of stars’ in Aussois (France), aims at introducing the historical developments, current status and outstanding questions related to the magnetorotational instability that are currently at the forefront of academic research. Accepted by proceedings of the Evry Schatzman School 2012 on the ”Role and mechanisms of angular momentum transport during the formation and evolution of stars” (eds. P. Hennebelle and C. Charbonnel) http://arxiv.org/pdf/1305.3416

Cosmic-ray propagation in molecular clouds Marco Padovani1 and Daniele Galli2 1 Laboratoire de Radioastronomie Millimétrique, UMR 8112 du CNRS, Ecole´ Normale Supérieure et Observatoire de Paris, 24 rue Lhomond, 75231 Paris cedex 05, France 2 INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy E-mail contact: Marco.Padovani at lra.ens.fr Cosmic rays constitute the main ionising and heating agent in dense, starless, molecular cloud cores. We reexamine the physical quantities necessary to determine the cosmic-ray ionisation rate (especially the cosmic ray spectrum at E < 1 GeV and the ionisation cross sections), and calculate the ionisation rate as a function of the column density of molecular hydrogen. Available data support the existence of a low-energy component (below about 100 MeV) of cosmic-ray electrons or protons responsible for the ionisation of diffuse and dense clouds. We also compute the attenuation of the cosmic-ray flux rate in a cloud core taking into account magnetic focusing and magnetic mirroring, following the propagation of cosmic rays along flux tubes enclosing different amount of mass and mass-to-flux ratios. We find that mirroring always dominates over focusing, implying a reduction of the cosmic-ray ionisation rate by a factor of 3-4 depending on the position inside the core and the magnetisation of the core. Accepted by ”Cosmic Rays in Star-Forming Environments”, Proceedings of the 2nd Session of the Sant Cugat Forum on Astrophysics. D. F. Torres and O. Reimer (Editors), 2013, Springer http://arxiv.org/pdf/1305.5393

52 Dissertation Abstracts

Determination of physical conditions in the accretion spots of T Tauri stars based on analysis of their spectra A. V. Dodin

Thesis work conducted at: Sternberg Astronomical Institute, Moscow State University, Russia Current address: Sternberg Astronomical Institute, Moscow 119991, Universitetskii pr. 13, Russia Electronic mail: dodin [email protected] Ph.D dissertation directed by: Sergei Lamzin Ph.D degree awarded: May 2013 We have calculated the structure and emergent spectrum of a hot spot that appear on CTTS surface due to heating by radiation from an accretion shock. For the first time not only continuum but also line emission of the hot spot was taken into account. Our calculations confirmed hypotheis of Petrov et al. (2001), Gahm et al. (2008) and Petrov et al. (2011) that the strongest of these lines manifest themselves as narrow components of helium and metal emission lines, while the weaker ones decrease significantly the depth of photospheric absorption lines, although until now, this effect has been thought to be due to the emission continuum alone. It appeared that the relative contribution of lines to the veiling increased with decreasing accretion flux, i.e. veiling by lines is the most important for CTTSs with moderate veiled spectra. We found that neglecting the contribution of lines to the veiling could produce an appreciable errors in determining the effective temperature, interstellar extinction, radial velocity, and v sin i for CTTS.

Assuming the pre-shock gas density N0 and velocity V0 to be the same at all points of the accretion stream cross section, we have calculated the spectrum of the star+circular spot system at various N0, V0, and parameters characterizing the star and the spot. Using nine stars as an example, we have shown that the theoretical optical spectra reproduce well the observed veiling of photospheric absorption lines in 0.4-1.2 µm spectral band, as well as the proﬁles and intensities of the so-called narrow components of He II and Ca I emission lines with an appropriate choice of parameters. The 12 −3 accreted gas density N0 in all of the investigated stars except DK Tau has been found to be > 10 cm .

We have discovered a longitudinal magnetic field Bz in the hot accretion spot in three classical T Tauri stars: DO Tau, DR Tau and DS Tau. In all three stars the magnetic field is detected at a level above 2σ in the formation region of the narrow component of the HeI 5876 A˚ emission line. In the case of DS Tau the longitudinal field Bz in the hot spot was also measured from the narrow emission components of the Na I D lines, implying +0.8 ± 0.3 kG, which is equal to the Bz field component measured from the HeI 5876 A˚ line.

Eleven new measurements of the magnetic field were obtained in case of fourth star: RW Aur A. We found that Bz in the formation region of He I 5876 line’s narrow component varied from −1.47 ± 0.15 kG to +1.10 ± 0.15 kG. Our data are consistent with a stellar rotational period of ≃ 5.6d and with a model of two hot spots with an opposite polarity of o the magnetic field and with a difference in a longitude about 180 . The spot with Bz < 0 is located at the hemisphere above the midplane of RW Aur’s accretion disc and the spot with Bz > 0 is below the midplane. The following upper limits for Bz (at 3σ level) were found after averaging of all our observations: 180 G for photosperic lines, 220 G and 230 G for formation regions of Hα and [OI] 6300 lines respectively. Upper limit 600 G were found in the region where broad components of emisson lines form. For two cases out of 11 we observed the field in a formation region of a blue absorption wing of Na I D lines i.e. in an outflow: Bz = −180 ± 50 G and −810 ± 80 G.

53 Radiative Transfer Models of Protoplanetary Disks: Theory vs. Observations

Gijs Mulders

API, University of Amsterdam API, Postbus 94249, 1090 GE, Amsterdam, Netherlands Address as of September 2013: LPL, University of Arizona, 1629 E University Blvd, Tucson AZ 85721 Electronic mail: gdmulders at gmail.com Ph.D dissertation directed by: Carsten Dominik Ph.D degree awarded: March 2013

What can we learn about planet formation by observing protoplanetary disks, the planet forming regions around young stars? To answer such a question, we need to connect the radiative transfer models that we use to interpret these observations, to theoretical models that describe the physics in these disks. In this thesis, I have used the radiative transfer code and disk modeling tool MCMax to fit spectral energy distributions, images, spectra and interferometric visibilities of the dust in protoplanetary disks. We combine these with theoretical models of dust settling and grain growth – the first steps of planet formation – and the dynamical impact of giant planets – a possible end point of planet formation. We find that, contrary to previous results, the first steps of planet formation are independent of the host star. We also zoom in on HD 100546, a transitional disk with a large annular gap. We find the it harbors large dust aggregates in its surface layers, and that its unusual mineralogy is connected to the presence of the gap. Using hydrodynamical models, we show that the gap is likely caused by a companion brown dwarf, rather than a giant planet. http://dare.uva.nl/en/record/440375

54 Warm and Cold Gas in Low-Mass Protostars Herschel Space Observatory and Ground-Based Surveys

Umut Yıldız

Thesis work conducted at: Leiden Observatory, Leiden University, The Netherlands Current address: Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands Address as of Sep 2013: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena CA, 91109, USA Electronic mail: [email protected] Ph.D dissertation directed by: Ewine F. van Dishoeck and Lars E. Kristensen Ph.D degree awarded: May 2013

The primary focus of this thesis is the study of physics and chemistry of low-mass young stellar objects (YSOs) using data on CO and O2 obtained by the Herschel Space Observatory, complemented by ground-based observations from APEX and the JCMT. High-J CO lines (Jup≥5) toward 26 sources in the sample are observed (Eup/kB ∼250-300 K) with the “Heterodyne Instrument for the Far Infrared” (HIFI) onboard Herschel, in order to trace warm material (T ≥50 K) in the protostellar envelopes, where previous studies concentrated on low-J CO (Jup≤4) lines, thus tracing lower temperatures. We found that CO and its isotopologs have different line profiles tracing different material in the protostellar regions (outflows vs. quiescent gas). The excitation conditions for embedded Class 0 and Class I protostars are similar with Tkin ∼100–200 K, and does not change with the increasing Lbol, Menv and n(1000 AU). Radiative transfer modeling was performed to determine the CO abundance structure in the envelope for some of the sources. Analysis of the C18O lines resulted in evidence for significant freeze-out in the coldest regions and evaporation back into the gas phase in the parts of the envelope where the temperature exceeds 25 K. Interestingly, the inner abundance was found to be lower than the canonical value of 2.7×10−4, indicating processing of CO into other species. The effect of dust opacity is found very low even in the higher-J C18O transitions. Through our 13CO 6–5 maps, we presented the first direct observational evidence of the location and the quantification for the UV-heated gas around the outflow cavity walls, where its mass is found comparable to the mass of the outflow. This result shows that close to the source position on scales of a few thousand AU, UV heating is just as important as shock heating in terms of exciting CO.

Molecular oxygen, O2 at 487 GHz was observed toward a deeply embedded low-mass Class 0 protostar, NGC 1333- IRAS 4A with the HIFI. The deep spectrum fails to detect O2 at the velocity of the dense protostellar envelope, −9 implying one of the deepest abundance upper limits of O2/H2 at ≤6×10 (3σ). Pure gas-phase models and gas-grain 6 chemical models require a long pre-collapse phase (∼0.7–1×10 years) to explain the absence of O2 in the protostellar −1 envelope. Moreover, a tentative (4.5σ) detection of O2 is seen at the velocity, shifted by 1 km s relative to the protostar, implying emission originates from the surrounding more extended NGC 1333 molecular cloud. https://openaccess.leidenuniv.nl/handle/1887/20855

55 Meetings of Possible Interest

Massive Stars: From Alpha to Omega 10 - 14 June 2013 Rhodes, Greece http://a2omega.astro.noa.gr Lin-Shu Symposium: Celebrating the 50th Anniversary of the Density-Wave Theory 24 - 28 June 2013 Beijing, China http://events.asiaa.sinica.edu.tw/conference/20130624/ Physics at the Magnetospheric Boundary 25 - 28 June 2013 Geneva, Switzerland http://www.isdc.unige.ch/magbound/ Protostars and Planets VI 15 - 20 July 2013 Heidelberg, Germany http://www.ppvi.org Dust Growth in Star & Planet Formation 2013 22 - 25 July 2013 MPIA, Heidelberg, Germany http://www.mpia.de/DG13/ 2013 Sagan Summer Workshop: Imaging Planets and Disks 29 July - 2 August 2013 Pasadena, CA, USA http://nexsci.caltech.edu/workshop/2013/ IAUS 302 - Magnetic Fields Throughout Stellar Evolution 26 - 30 August 2013 Biarritz, France http://iaus302.sciencesconf.org Meteoroids 2013. An International Conference on Minor Bodies in the Solar System 26 - 30 August 2013 Dep. of Physics, A.M. University, Poznan, Poland http://www.astro.amu.edu.pl/Meteoroids2013/index.php Exoplanets and Brown Dwarfs 2 - 5 September 2013 de Havilland, University of Hertfordshire, Hatﬁeld, Nr. London, UK no web site yet Evolution of Star Clusters: From Star Formation to Cosmic Ages 24 - 27 September 2013 Splinter Meeting E at the Annual Meeting of the Astronomische Gesellschaft, T¨ubingen, Germany http://www-astro.physik.tu-berlin.de/~harfst/AG2013_SplinterE/ Dust Radiative Transfer - Codes and Benchmarks 9 - 11 October 2013 http://ipag.osug.fr/RT13/index.php 400 Years of Stellar Rotation 17 - 22 November 2013, Natal, Brazil http://www.dfte.ufrn.br/400rotation/ The Life Cycle of Dust in the Universe: Observations, Theory, and Laboratory Experiments 18 - 22 November 2013 Taipei, Taiwan http://events.asiaa.sinica.edu.tw/meeting/20131118/ An Olympian Symposium for Star Formation 26 - 30 May 2014 Paralia Katerinis, Mount Olympus, Greece http://zuserver2.star.ucl.ac.uk/$\sim$tb/

56 EPoS2014 The Early Phase of Star Formation 1 - 6 June 2014 Ringberg Castle, Tegernsee, Germany http://www.mpia-hd.mpg.de/homes/stein/EPoS/epos.php The Dance of Stars: Dense Stellar Systems from Infant to Old 2 - 6 June 2014 Bad Honnef, Germany http://www.astro.uni-bonn.de/$\sim$sambaran/DS2014/index.html The 18th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun 9 - 13 June 2014 Flagstaﬀ, Arizona, USA http://www2.lowell.edu/workshops/coolstars18/ Summer School on Protoplanetary Disks: Theory and Modeling meet Observations 16 - 20 June 2014 Groningen, The Netherlands no website yet Living Together: Planets, Stellar Binaries and Stars with Planets 8 - 12 September 2014 Litomysl Castle, Litomysl, Czech Republic http://astro.physics.muni.cz/kopal2014/ Planet Formation and Evolution 2014 10 - 12 September 2014 Kiel, Germany http://www1.astrophysik.uni-kiel.de/$\sim$2014/main/ Towards Other Earths II. The Star-Planet Connection 15 - 19 September 2014 Portugal http://www.astro.up.pt/toe2014

Other meetings: http://www1.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/meetings/

57 Short Announcements

CORNISH (Co-Ordinated Radio ’N’ Infrared Survey for High-mass star formation): Data release

Here we announce the public release of the on-line database for the CORNISH survey. This is a 5 GHz, 1.5 arcsecond resolution, VLA continuum survey of the portion of the northern Galactic plane that was also covered by the Spitzer GLIMPSE I survey. It was designed to give a complete sample of ultra-compact H II regions as well as providing complementary data to the many other surveys that cover the same region of the plane (Hoare et al. 2012). The on-line database contains the high reliability (7σ) catalogue described by Purcell et al. (2013), which has about 250 ultra-compact H II regions amongst the nearly 3000 sources. All sources have been visually inspected for quality control and object type classiﬁcation. The database contains individual pages for each source with information and cutouts of complementary data from other IR, millimetre and radio surveys. You can also download an image or the uv data for any location within the survey. If you make use of these data then please cite the original references. The database can be found at http://cornish.leeds.ac.uk.

Melvin Hoare, on behalf of the CORNISH team

ACS Astrochemistry Subdivision Opens Up Affiliate Status for AAS and DPS Members The recently established Astrochemistry Subdivision http://www.chem.hawaii.edu/Bil301/ACSAstrochemistry.html of the Division of Physical Chemistry of the American Chemical Society (ACS) http://phys-acs.org invites members of the American Astronomical Society (AAS) and of the Division of Planetary Sciences (DPS) to join the ACS Astrochem- istry Subdivision http://www.chem.hawaii.edu/Bil301/ACSAstrochemistryjoin.html as an Affiliate Member. Please complete a division application form http://portal.acs.org/portal/PublicWebSite/membership/td/join/CTP 004160 and email [email protected] or fax (614-4473671) it to ACS Member Services. Note that the PHYS annual membership dues are US$15, which should be remitted with the form. Please indicate that you would like to join the Astrochemistry Subdivision. The Subdivision of Astrochemistry provides an interdisciplinary ”home” for individuals interested in astrochemically related research via experiments, theory, observations, space missions, and modeling. Astrochemistry is the study of the abundances and chemical reactions of atoms, molecules, and ions and how they interact with radiation in the gas phase and in the condensed phase in Solar Systems and in the Interstellar Medium (ISM) leading to the formation and breaking of chemical bonds. Astrochemistry presents both an interdisciplinary and a multidisciplinary field with ties to the traditional disciplines chemistry, planetary science, chemical biology, physics, and astronomy. Here, chemistry, defined as the change of matter is vital in unraveling the chemical and astrobiological evolution of matter on the microscopic (elementary chemical reactions) and also on the macroscopic level (planets, moons, interstellar medium). Since the present composition of each macroscopic environment reflects the matter from which it was formed and the chemical processes which have changed the chemical nature since the origin, a detailed investigation of the processes altering the chemical composition of the pristine environment is critical to rationalize its contemporary makeup and to understand its origin and chemistry. Astrochemistry exploits molecular tracers to rationalize the origin and chemical evolution of the Interstellar Medium and of Solar Systems by combining laboratory studies (chemical dynamics and kinetics, spectroscopy), theoretical chemistry, astrochemical modeling, astronomical observations, and space missions. This work requires a concerted interdisciplinary relationship between chemists, physicists, astronomers, chemical biologists, and planetary scientists. We would also like to thank those of you who supported the establishment of the Astrochemistry Subdivision! We hope that this creates a thriving Astrochemistry Subdivision that is able to serve the community.

58 Best regards, Ralf Kaiser (Chair), Arthur Suits (Chair-Elect), Martin Head-Gordon (Vice-Chair)

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