THE STAR FORMATION NEWSLETTER An electronic publication dedicated to early stellar/planetary evolution and molecular clouds No. 274 — 15 October 2015 Editor: Bo Reipurth ([email protected]) List of Contents

The Star Formation Newsletter Interview ...... 3 Perspective ...... 6 Editor: Bo Reipurth [email protected] Abstracts of Newly Accepted Papers ...... 11

Technical Editor: Eli Bressert Abstracts of Newly Accepted Major Reviews . 47 [email protected] Dissertation Abstracts ...... 48 Technical Assistant: Hsi-Wei Yen New Jobs ...... 49 [email protected] Meetings ...... 52

Editorial Board Summary of Upcoming Meetings ...... 53 Short Announcements ...... 54 Joao Alves Alan Boss Jerome Bouvier Lee Hartmann Thomas Henning Paul Ho Cover Picture Jes Jorgensen Charles J. Lada The HH 24 jet complex emanates from a dense Thijs Kouwenhoven cloud core in the L1630 cloud in Orion which hosts a Michael R. Meyer small multiple protostellar system known as SSV63. Ralph Pudritz The nebulous star to the south is the visible Luis Felipe Rodr´ıguez star SSV59. Color image obtained based on the Ewine van Dishoeck following filters with composite image color assign- Hans Zinnecker ments in parenthesis: g (blue), r (cyan), I (orange), Hα (red), [S II] (blue). The images were obtained The Star Formation Newsletter is a vehicle for with GMOS on Gemini North in 0.5 arcsecond see- fast distribution of information of interest for as- ing. The field of view is 4.2x5 arcminutes, and the tronomers working on star and planet formation orientation is north up, east left. and molecular clouds. You can submit material Images by Bo Reipurth and Colin Aspin. for the following sections: Abstracts of recently Color mosaic by Travis Rector. accepted papers (only for papers sent to refereed journals), Abstracts of recently accepted major re- views (not standard conference contributions), Dis- sertation Abstracts (presenting abstracts of new Ph.D dissertations), Meetings (announcing meet- ings broadly of interest to the star and planet for- mation and early solar system community), New Submitting your abstracts Jobs (advertising jobs specifically aimed towards persons within the areas of the Newsletter), and Latex macros for submitting abstracts Short Announcements (where you can inform or re- and dissertation abstracts (by e-mail to quest information from the community). Addition- [email protected]) are appended to ally, the Newsletter brings short overview articles each Call for Abstracts. You can also on objects of special interest, physical processes or submit via the Newsletter web inter- theoretical results, the early solar system, as well face at http://www2.ifa.hawaii.edu/star- as occasional interviews. formation/index.cfm Newsletter Archive www.ifa.hawaii.edu/users/reipurth/newsletter.htm entails for a career in the absence of a long-term funding perspective, but it somehow worked, and diffusing into Manuel G¨udel other research areas has become an important constant in in conversation with Bo Reipurth my career ever since – I never regretted it! I joined Jeff Linsky’s group at JILA, University of Colorado in Boul- der, an exciting environment to put my plan into action. I worked on linking coronal particle acceleration (traced by radio emission) with coronal heating (traced by X-rays). Those , the early-to-mid nineties, were a golden age of X-ray astronomy with new space observatories launched almost every other (ROSAT, EUVE, ASCA, Bep- poSAX and others). It gave me the opportunity to move into X-ray astronomy and stellar coronal research. We dis- covered what I thought was to be expected from solar flare physics, namely a linear correlation between the radio and X-ray of active stellar coronae. Arnold Benz and I interpreted this finding quantitatively as evidence for continuous heating by particle beams accelerated like in solar flares. The correlation was good enough to pre- dict radio fluxes from X-rays from very hot (>10 million degrees) coronal plasma. Thus came our first radio dis- Q: What was your thesis about, and who was your adviser? coveries of young (first EK Draconis, the star that A: It all happened somewhat by chance. After my under- has guided my career to the present ), rather precisely graduate studies in theoretical physics at ETH Zurich, I at the predicted flux level. The correlation is by no means was torn between pursuing a PhD in theory (I was much universal – it applies only to very hot coronae of active attracted – and still am! – by fundamental physics like stars (and fails miserably for our !). This point was quantum field theory that blossomed at ETH) or rather unfortunately often ignored and led to some misunder- getting back to my deep interest since my childhood, name- standings. In any case, we left it there, and if it was of ly astronomy. Luckily (I would guess) I followed the calling any interest at all, it was referred to as the ”radio–X-ray of my heart and decided in favor of astronomy. I was fortu- correlation”. About a decade later, the newly nate that Arnold Benz offered me a PhD position at ETH discovered radio and X-ray emitting brown dwarfs were to work in plasma astrophysics and on the solar corona. found to severely violate our correlation; ironically, this That was the best of all worlds for me – concepts of mag- was the moment when colleagues started referring to the netic fields in plasmas and radiation propagation pleased ”G¨udel-Benz relation”. Obviously, the interest in different my theoretical streak. I worked on the interpretation of physics was awakened. the shortest, millisecond solar radio bursts resulting from The rich harvest from the X-ray satellites was also ideal to unstable coronal particle distributions. I had enough time study stellar activity evolution. By sheer luck, I met Ed to also spread out into other fields, like the theory of soli- Guinan in a half-empty lecture hall of a solar conference ton propagation in a multi-fluid plasma, numerical parti- a seat row in front of me; we were both silently working cle simulations (with a few thousand particles to follow - on papers about EK Dra - without knowing of each other! a good standard at the time!), and observations with the A chat in the coffee break started our joint studies of the VLA and other big radio dishes to look for solar analo- ”Sun in Time”, including X-rays; planetary atmospheric gies in the radio emission of low- stars. My generous physicists later used this work to study planet evolution mentor thus paved the way for my future career. – especially people in Austria where, in a funny turn of Q: Your observational work started at radio continuum events one and a half decades later, I found my new home. wavelengths, but you soon switched to X-ray studies of stel- Q: Why did you turn your attention to star formation? lar coronae. What motivated this change? I was lucky to obtain a tenure-track position in Switzer- A: Solar radio astronomy offered, and still offers, exciting land after my third postdoc year abroad and requested research and physical insight but it takes place in a rela- tenure after another two years. Now I could diffuse eas- tively small and somewhat isolated community. I wanted ily into new fields with less career risk; I engaged myself to apply solar concepts to the bigger world of stars and in- in large space projects for which our institute developed vested my first one-year postdoc grant to give up on solar instrumentation. I became a science Co-I of the XMM- physics and move into stellar radio astronomy. I was ob- Newton Reflection Grating Spectrometer (RGS) and took viously not aware of the risk such a full-blown turnaround

3 the position of the Swiss Co-Principal Investigator of MIRI In my own Chandra campaign on protostellar X-ray jets, on JWST (which I’m keeping at ETH Zurich in parallel among them DG Tau B, we found strongly absorbed stellar to my new job in Vienna). With Spitzer and Herschel on X-rays but no jets. I was vaguely aware of the CTTS DG the horizon, my fascination for young stars, and the many Tau nearly an arcminute north of DG Tau B but initially new X-ray findings in star formation, I got interested in didn’t pay attention. But there was this fuzzy cloud of a studying the influence of high-energy, ionizing radiation few excess X-ray counts around it. It turned out to be the on stellar environments, specifically protoplanetary disks, trace of a luminous X-ray jet. The most fascinating feature which led to fruitful new projects and collaborations. I am was DG Tau’s X-ray spectrum – composed of two entirely confident that JWST will push this field much further. independent components which we now know to be a soft Q: T Tauri stars (TTS) are often X-ray emitters. What component from the jet very close to the star (20-30 AU is the basic mechanism? and closer) and a highly absorbed component from a very hot, flaring corona. The absorption lacks the expected, A: TTS X-rays were discovered in the early days of X-ray accompanying dust ; our model for these ”Two astronomy. They are akin to X-rays from other young, Absorber X-ray” (TAX) sources posits that absorption is active stars and so are thought to be coronal. Strong due to dust-depleted gas streams close to the star, most magnetic fields abound on T Tauri stars, after all. There likely the accretion streams but maybe also disk winds. are some interesting, distinctive properties of classical T Tauris (CTTS), however. For the same bolometric lu- Q: You led the major “XMM-Newton extended survey of minosity, they are statistically about half as X-ray lu- the molecular cloud” (XEST). What were the main minous as weak-lined T Tauris (WTTS). Perhaps accre- results? tion streams completely absorb some X-rays. Also, CTTS A: XEST was a real adventure. In early 2003 I called coronae are systematically hotter than WTTS coronae, a Thierry Montmerle to check his opinion about my some- result obtained by one of my graduate students, Alessan- what eccentric idea to map 5 square degrees of Taurus dra Telleschi. We don’t understand this feature yet. with XMM-Newton. He bursted out, ”are you crazy?? An interesting turn came when Joel Kastner et al. sug- But then this is interesting!” And off we went. With a gested that the unusually soft X-rays from TW Hya are team of about two dozen, XEST was set up to survey produced in accretion shocks. The model is not easy to a nearby, low-mass star-forming region devoid of mas- prove and faces some problems with photoelectric absorp- sive stars; it complements the Chandra Orion Ultradeep tion but it was an important step. When we looked at Project (COUP) led by Eric Feigelson in many ways. We high-resolution CTTS X-ray spectra, we discovered sys- did not have the luxury of integrating over nearly two tematic excess emission in the O vii lines compared to weeks but with fluxes on average about ten times higher WTTS, a feature we dubbed the ”X-ray soft excess”. Clear- and a larger collecting area, XEST got excellent spec- ly, accretion adds a lot of moderately hot (∼ 1 MK) plasma troscopy of many targets and collected the largest high- to the otherwise much hotter coronal plasma. Nancy Brick- resolution spectroscopy sample of CTTS plus Herbigs at house et al. subsequently proposed that accretion drives the time. The major strength of XEST was therefore in material flow from the accretion hot spot into coronal the physical characterization of the X-ray sources rather loops from where X-rays can easily be observed. than in the time domain but we did some flare studies as well. We could confirm important trends (correlations Q: You have studied X-rays from Herbig-Haro jets, and between X-rays and bolometric luminosity and between discovered X-ray emission from the DG Tau jet. Various X-rays and , etc) but significantly less com- models exist to explain the data, what is your view? promised by scatter and error bars. XEST showed that A: We know two types of sources, those at the working the two relations just mentioned are not independent. We surfaces of HH objects far away from the star, and those also found some weak negative correlation with the accre- in the jets very close to the central engine. Shocks are usu- tion rate and a slight decline of X-rays with age. ally held responsible for the X-rays, either forming against A big boost came from XMM-Newton’s RGS that led to the interstellar medium or between plasma blobs in the jet. our discovery of the CTTS ”X-ray soft excess”, and also to The big difficulty are the high shock speeds required to ex- the first detailed spectral X-ray characterization of a Her- plain plasma temperatures of 4-6 MK. In a collaboration big star. AB Aur showed both an anomalously soft spec- led by Stephen Skinner, we suggested that high-speed plas- trum and a periodicity known from optical observations moids ejected by the star or the star-disk magnetic fields of the Herbig star so that ambiguities related to possible (like coronal mass ejections) are guided along the jet to late-type companions were removed for the first time in eventually collide further out and produce the X-rays. An X-rays. XEST also provided a large sample of ultraviolet interesting possibility is local heating by magnetic recon- flux measurements and flare observations. Other findings nection. We need a better insight into jet magnetic fields! related to jets, CTTS rotation, and coronal composition.

4 Q: Most recently, you and colleagues have studied the ef- of disks. We would like to better understand how disks fects of X-ray and UV radiation on the habitability of exo- evolve in time, and are also performing advanced hydro planets and have summarized your ideas in a major review simulations. We have secured and interpreted the first X- in Protostars and Planets VI. What are the key points? ray observations of a bona-fide FUor in its early outburst A: Our habitability project has its own funny history. phase. We discovered large columns of dust-depleted gas, Around the time (2009) when I accepted a chair at the probably related to accretion streams or disk winds. University of Vienna, I attended a small science meeting Q: Astronomy in Austria has seen a major rejuvenation in Graz where a group of scientists around Helmut Lam- and expansion in recent years, and star and planet forma- mer studied planetary atmospheric loss driven by stellar tion has been strengthened. What has driven this welcome activity. They in fact used results from my X-ray studies development, and what are prospects for the coming years of the Sun in Time in the nineties. As my move to Vi- for Austrian astronomy? enna was imminent, we seized the opportunity and kicked A: As a recent (2010) immigrant from Switzerland, I’m off discussions toward a large, national program on hab- still trying to understand the complexities of Austrian as- itability. The two-year-long painstaking preparation and tronomy during the past decades. It is a ground truth that evaluation of this major project succeeded beyond any ex- Austria became a member of ESO only in 2008, despite en- pectations and against all odds, and I am deeply hon- ergetic efforts undertaken by a number of forward-looking ored to now lead a team of over forty junior and senior astronomers back to the seventies. In a small country like scientists in Austria, involving many international collab- Austria, the way forward is to unite and speak with one orations. The key objectives start with star formation voice. I think this didn’t happen for too long; groups and protoplanetary disks as the latter are the factories of worked in relative isolation and were supporting small, important molecules, but also regulate protoatmospheric local telescopes. Only in 2002, the Austrian Society for accretion onto growing planets. This also gives me the Astronomy and Astrophysics was founded; one of its ma- rewarding opportunity to add new research perspectives jor goals was to establish Austrian membership in ESO. to my interest in star formation. Our team further ad- Negotiations with the ministry were far from easy but fi- dresses the high-energy evolution of the host star starting nally succeeded. Then, the institutes used the fresh mo- at the time of planet formation. In what returned my mentum to negotiate new astronomy university chairs to attention to my early postdoctoral studies of the Sun in effectively strengthen the science return from ESO. When Time – and rewards my decision to jump between var- the University of Vienna doubled from two to four as- ious research fields in my career –, we just published a trophysics chairs and a previous one got vacant, we were self-consistent activity evolution model for low-mass stars three new professors moving in at the same time (apart including rotation, spin-down, wind mass loss, magnetic from myself Jo˜ao Alves and Bodo Ziegler); all of us are activity and high-energy emission. In these models, hab- interested in galactic or extragalactic star formation and itability evolution strongly depends on initial conditions have proactively argued, each one separately in his appli- at the T Tauri stage. Other teams within the project cation and negotiations, in favor of modern research using deal with small-body collisions to study transport to ESO and ESA facilities. Capitalizing on this unlikely suc- planets in the habitable zone; such calculations require hy- cess, each of us engaged into becoming a co-investigator drodynamic simulations including solid-state features such of one of the planned E-ELT instruments (now METIS, as crack formation and stress. Another important area is MICADO, and MOSAIC); we then united all astronomy dynamics in multi-planet systems, planetesimal disks, and university institutes in Austria once again, also includ- binary stellar systems. We are presently going through the ing mathematicians, to formulate a special request to the evaluation of the continuation proposal phase (formulated ministry for a national E-ELT instrumentation program. in a 493-page document) to obtain support until 2020. And once more we succeeded and are on track. The same Q: You are head of the Star and Planet Formation Group is happening with ESA projects where I am enjoying ex- at the University of Vienna. What other topics are you tremely rewarding national collaboration in projects such and your group working on? as CHEOPS, PLATO, or Athena+. Similar things to say A: I am proudly leading a terrific 400% group: 50% exo- about our national organizing committee for the IAU Gen- planets–50% star formation; 50% postdocs–50% grad stu- eral Assembly 2018 in Vienna. Our key program on hab- dents; 50% theoreticians–50% observers; and 50% female– itability has set up a national collaboration on the science 50% male. Jets and protoplanetary disks are one of the side, now actually co-operating with the CHEOPS and key topics. We are partners in a European project on disk PLATO projects. In my view, we are extremely well set modeling using archival samples. Our goal is to interpret up for the next decade and even beyond. But the message multi-wavelength disk data including stellar irradiation is clear: In a country where every astronomer personally to self-consistently model the thermo-chemical structure knows every other, the way to success is to stand together.

5 vances, and outstanding open questions, in studying one key statistic of molecular clouds: the probability distribu- Perspective tion of their column densities. Density structure of molecular clouds and star formation 2 The missing ingredient Jouni Kainulainen The major analytic theories that have emerged to predict star formation rates all share a common, quite intuitive general framework: star formation rates are essentially es- timated from the mass of gravitationally unstable gas that collapses to form stars in its own free-fall time-scale (re- viewed in Padoan et al. 2014; Federrath & Klessen 2012). Calculation of the unstable gas mass requires knowledge of the density distribution of the interstellar medium (ISM). This information is encapsulated in the probability den- sity function of gas densities (ρ-PDF, for short), which describes the probability of a unit volume to have a cer- tain density. While the details of different theories may greatly differ, most of them employ the ρ-PDF function as a basic ingredient. The fundamental missing piece in this approach is that 1 Introduction the ρ-PDF function has not been observationally well con- strained. Two problems contribute to this. First, the den- How exactly different physical processes give rise to the sity structure of molecular clouds is not directly accessible star formation rates of molecular clouds is a decades old with observations. Instead, observations can only measure open question. Most of all, we do not understand how column densities. However today, this problem is allevi- the different processes mould the structure and dynam- ated by studies that have established transformations be- ics of the clouds, eventually causing a (small!) fraction of tween the column density PDFs (N-PDF, for short) and their gas to have conditions favourable for gravitational the ρ-PDFs. These studies have also shown that N-PDFs collapse and star formation. Observationally, we know can carry the same information as the ρ-PDFs (e.g., Brunt very well that the star formation rates and efficiencies of et al. 2010; Federrath & Klessen 2013; Kainulainen et al. molecular clouds depend strongly on the internal struc- 2014). Second, also mapping column densities is difficult; ture of the clouds (e.g., Kainulainen et al. 2009, 2014; mapping entire molecular clouds with high sensitivity, and Lada et al. 2012; Evans et al. 2014). Therefore, the first simultaneously with high spatial resolution, is an obser- step in understanding the regulation of star formation is vational challenge. Data allowing this have only become understanding the regulation of this internal cloud struc- available during the past decade or so. ture. This, in turn, calls for a comprehensive, systematic characterisation of the molecular cloud structure. In lack of observational constraints, the star formation the- ories have turned to numerical simulations for informa- Unfortunately, describing the observed structure of molec- tion about the ρ-PDF function. These simulations have ular clouds is nothing if not confusing. Terms such as heavily concentrated in modelling supersonic turbulence, cloud, clump, core, and filament are in a daily use in the including also other physics (self-gravity, magnetic fields, field, and an easy way to start an endless debate is to chemistry) as computational capabilities have begun to al- ask what these words actually mean. Observations have low it. The fundamental result of the simulations is that established that the structure of molecular clouds is frac- isothermal, supersonic, driven turbulence develops a log- tal and hierarchical (reviewed in, e.g., Elmegreen & Scalo normal ρ-PDF. The important parameter of this function 2004); characterising such structure by discretising it un- is its width that is directly coupled with gas physics: it avoidably delivers a very biased and/or reduced picture. depends on the turbulent energy of the media, the rela- However, right now is the Golden Age of the cloud struc- tive amount of compressive energy, and the magnetic field ture studies. The new observational techniques and fa- strength (e.g., V´azquez-Semadeni 1994; Federrath et al. cilities are just about to enable us to build a new view of 2010; Molina et al. 2012). Consequently, the ρ-PDF is not molecular clouds based on the statistics of their structural only a crucial input for star formation models, but also a characteristics. In this article, I discuss some recent ad- fundamental prediction of the entire turbulence-regulated

6 Figure 1: Left: Column density map of the Ophiuchus molecular cloud, derived using near-infrared dust extinction mapping (Kainulainen et al. 2009). Right: N-PDFs of a non-star-forming cloud (Lupus V) and a star-forming cloud (Taurus). AV, the dust extinction, is used as the tracer of column density. The red curve is a fit of a log-normal function to the peak of the distribution. The N-PDFs of most clouds, i.e., clouds that are forming stars, are poorly fit with single log-normal functions (Kainulainen et al. 2009. The figures have been prepared with the help of MPIA Graphics Department.).

ISM framework. The above techniques have already given us a basic pic- In lack of observational constraints, the star formation ture of what the column density distributions, N-PDFs, rate theories commonly adopt this framework and with of molecular clouds are like. Now more than six years ago, it the lognormal ρ-PDF. This means that the key ingre- we performed the first systematic survey of the N-PDFs in dient of the models, and also the fundamental prediction the Solar neighbourhood clouds (Kainulainen et al. 2009). of the turbulence-regulated ISM framework, remains not In this work, we analysed dust extinction-derived column confronted by systematic observations. density maps of practically all clouds closer than 260 pc to the Sun. This work gave rise to two important re- sults. First, we showed that the N-PDFs of most clouds 3 Universal link between the PDFs are poorly fitted with log-normal functions when consider- ing their entire column density range (see Fig. 1). Rather, and star formation? they showed a possibly log-normal shape only at low-column densities (N(H) < 4 − 6 × 1021 cm−2), while higher col- Observational works are now in progress to change this umn densities showed a significant, power-law like excess picture; they are beginning to provide systematic con- to that shape. This was an important result, as it seemed straints for the column density statistics of molecular clouds. to at least partially contradict the prediction adopted from This progress has been made possible by the novel dust ex- the turbulence-regulated ISM framework that molecular tinction mapping techniques in near-infrared and Herschel clouds might carry log-normal ρ-PDF (and N-PDF, e.g., dust emission measurements in far-infrared and sub-mm Federrath & Klessen 2013). (e.g., Lombardi 2009; Andr´eet al. 2010). These tech- The second important result from Kainulainen et al. (2009) niques use dust to trace the column density distributions was that the N-PDFs showed a variety of shapes that of the clouds and can provide high-sensitivity maps with correlated with the number of young stars in the clouds. resolution that reaches some 0.05 pc in the Solar neigh- Specifically, clouds with more young stellar objects (YSOs) bourhood clouds. Such resolution means that the resulting showed more top-heavy N-PDFs than those with less YSOs. maps contain hundreds of thousands of independent res- In the extreme of this relation, the couple of clouds in the olution elements, enabling studies of the column density sample that had no young stars within had very bottom- statistics. heavy, close-to log-normal N-PDFs (see Fig. 1). We quan-

7 tified this trend better later by showing that the mean star formation rate per unit area in entire molecular clouds correlates with the top-heaviness of their ρ-PDFs (Kainu- lainen et al. 2014). Herschel can map column densities in molecular clouds based on dust emission measurements in 18′′ resolution, which is a factor of about four finer than can be achieved with near-infrared extinction mapping in the Solar neigh- borhood (Fig. 2). Studies employing Herschel data have found the same trend between the star formation activ- ity and the shape of the N-PDFs (e.g., Schneider et al. 2013; Alves de Oliveira et al. 2014). They have also raised a question whether the N-PDFs of any clouds are log-normal, or are all N-PDFs better described by power- laws (Lombardi et al. 2015). The first Herschel studies have also reached outside the Solar neighbourhood, to- wards more massive molecular clouds in the Galaxy (e.g., Schneider et al. 2015). However so far, Herschel data have been clearly underexploited; this is surely expected to change in the near future. One great advantage of the resolution provided by the Her- schel data is that it allows us to zoom in and study the N- PDFs within molecular clouds in the Solar neighbourhood (e.g., Stutz & Kainulainen 2015; see Fig. 2). This allows linking the N-PDFs not only to the mean star formation activity of the clouds, but also to their local star formation rate and efficiency. In practice, this is possible because the protostars are identifiable in the Solar neighbourhood clouds, e.g., using Herschel data and/or near- and mid- infrared colour selections. The first works taking advan- tage of this have found that also within clouds the number of Class 0 protostars per unit area correlates with the top- heaviness of the N-PDFs (Sadavoy et al. 2014; Stutz & Kainulainen 2015). This means that within clouds, at the scales of about a , the on-going star formation rate activity is linked to the local gas mass distribution. Intriguingly, the first small-scale studies have very recently Figure 2: Top: Column density map of Orion A derived found that the evolutionary time-scale of parsec-scale re- using Herschel dust emission observations (Stutz & Kain- gions inferred from Class 0 and 1 protostars anti-correlates ulainen 2015). The white crosses show the protostars in with the top-heaviness of the N-PDFs (Stutz & Kainu- the cloud. The boxes show the eight regions in which lainen 2015, Fig. 2). In other words, regions with more the relation between protostars and N-PDFs was studied. top-heavy N-PDFs seem to have shorter protostellar time- Bottom: Class 0 protostar fraction as a function of the N- scales. This is curious, as it suggests that regions with PDF power-law slope in the eight regions within Orion A flatter N-PDFs may be younger. Such a result is not triv- (see the top panel). The y-axis on the right gives the evo- ial to interpret in the light of current theoretical models lutionary time-scale assuming a constant star formation for N-PDF evolution (elaborated in Section 4). rate. Under that assumption, high Class 0 fractions cor- respond to short evolutionary time-scales (Stutz & Kain- Is the strong relationship between star formation and den- ulainen 2015). The grey data points are for the Perseus sity distributions also prevalent at Galactic scales? The cloud (Sadavoy 2013, Sadavoy et al. 2014). answer seems to be yes. Abreu Vicente et al. (2015) per- formed the first systematic Galactic scale study of the N- PDFs, analysing 330 molecular clouds in the first Galactic to trace the column density distributions. The main re- quadrant (see Fig. 3). This work used the Galactic plane sult of this work was that indeed, objects that showed dust emission survey ATLASGAL (Schuller et al. 2009) no signs of on-going star formation had the most bottom-

8 roughly corresponding to a size of a giant molecular cloud. These observations again suggest a fundamental correla- tion between the column density structure and star for- mation activity, especially showing its prevalence at the scales of entire galaxies.

4 The outstanding open question: how do N-PDFs evolve?

How can the observed, quite possibly universal trend be- tween the column density distributions and star formation activity be understood? During the past few years, the ob- servational findings have triggered a wealth of theoretical works examining the ρ-PDFs (and usually also N-PDFs). 0 These works have heavily concentrated on analysing the ρ- PDFs in magneto-hydrodynamic simulations of self-gravi- −1 tating, driven turbulence (e.g., Kritsuk et al. 2010; Fed- errath & Klessen 2012, 2013; Ward et al. 2014). Ana-

) −2 ]

s lytic theories have also been constructed (e.g., Girichidis [ p (

10 et al. 2014). These works commonly share a framework in −3 log which an initially turbulence-generated density field in a computational domain with periodic boundary conditions −4 is let to evolve under self-gravity (and possibly continu- ing energy injection at large scales). In these simulations, −5 −3 −2 −1 0 1 2 3 4 5 the ρ-PDFs evolve from the initial, turbulence-dominated s = ln(A /A ) V V stage to a gravity-dominated stage. The shape of the ini- Figure 3: Top: The first Galactic-scale study of the molec- tial ρ-PDF is determined by the properties of turbulence ular cloud N-PDFs, performed using ATLASGAL 870 µm (cf., Section 2), and it is typically narrow, i.e., bottom- dust emission data (Abreu Vicente et al. 2015; Partial fig- heavy, compared to later stages. After a time that roughly ure credit: NASA/JPL-Caltech/R. Hurt (SSC-Caltech)). corresponds to the free-fall time at the mean density of The red, blue, and green symbols show the HII regions, the model, the ρ-PDFs reach a gravity-dominated stage. star-forming clouds, and starless clumps. Bottom: The At this stage, the ρ-PDFs have developed a power-law- total N-PDFs of each object class. The colours are as in like slope at the high-density side that is approximately in the top panel. The starless clumps (green) have the most agreement with the flattest observed slopes. bottom-heavy N-PDFs and the clouds containing HII re- At least qualitatively, the above framework reproduces the gions (red) the most top-heavy N-PDFs. observed variety of N-PDFs. It also provides a possible explanation for why non-star-forming clouds have narrow N-PDFs in comparison to star-forming clouds: (at least heavy N-PDFs. Star-forming clouds that harbour proto- most of) the clouds with narrow N-PDFs are young and stars had more top-heavy N-PDFs, and finally, the most have not yet started to form stars. In the future, they active clouds that contained HII regions had the most top- may evolve by gathering more material to high-column heavy N-PDFs (Fig. 3). This finding showed that the densities, leading to a more top-heavy N-PDF and active correlation between the N-PDFs and star formation ex- star formation. ists also at Galactic scales; therefore, it must represent a fundamentally important relation describing star forma- However successful the above framework may at first seem, tion in the ISM. the evolutionary picture it suggests should be taken with some caution. Consider this: in this framework, we have Finally, indications of a similar trend have also been de- a turbulence-generated initial density field; then the self- tected in external galaxies. Using interferometic observa- gravity is (literally) switched on and the model evolves tions of CO emission from the entire M51 galaxy, Hughes under it (possibly without further driving of turbulence). et al. (2013) showed that regions that had higher sur- Given this setup, it does not seem a very surprising re- face density of star clusters also showed more top-heavy sult to find evolution from a turbulence-dominated to a N-PDFs. The resolution of their data was about 40 pc, gravity-dominated state. Rather, it seems a quite natu-

9 ral consequence of the initial conditions of the framework, arcsecond-scale resolution in mapping young infrared dark questioning the evolutionary picture predicted by it. clouds and their surroundings, making it possible to map The way forward is to break away from the idealised setup thousands of clouds in the Galactic plane. All together, in which the turbulence-dominated and gravity-dominated the above observational approaches will soon create a tenth- phases are separated by construction. Instead, we need to of-a-parsec resolution observational picture of the molecu- look into large-scale simulations in which molecular cloud lar cloud structure in a volume that is relevant for Galactic- formation, and subsequent evolution, takes place in situ, scale star formation. as a result of large-scale processes. One setup for this is a While the previous half a decade saw the coming of sys- framework in which two warm gas flows collide, resulting tematic constraints for the (column) density distributions in formation of a colder gas phase and dense gas resem- of molecular clouds, the next half a decade will see the bling molecular clouds. In this framework, the N-PDFs growth of that picture into the Galactic context. Most derived for the entire computational domain evolve from a importantly, this enables us to bridge together the star bottom-heavy, log-normal-like shape to a top-heavy, power- formation relations observed at the scales of entire galax- law-like shape (e.g., Ballesteros-Paredes et al. 2011). This ies and the physical processes that regulate star formation suggests that it may be able to reproduce the observed va- within individual molecular clouds. riety of N-PDFs, and that evolution of N-PDFs may be References: the ultimate reason causing the variety. However, it is un- clear how the N-PDFs of individual molecular clouds in Abreu Vicente et al. 2015, A&A, in press, arXiv:1507.00538 these simulations behave, and especially, to what degree Alves de Oliveira et al. 2014, A&A, 568, A98 the N-PDFs of individual clouds show evolution. This re- Andr´eet al. 2010, A&A, 518, L102 Ballesteros-Paredes et al. 2011, MNRAS, 416, 1436 mains an open question that is likely to be answered in Brunt et al. 2010, MNRAS, 405, L56 the immediate future. All in all, studying the evolution Evans et al. 2014, ApJ, 782, 114 of PDFs in global-scale numerical simulations is a topic Federrath & Klessen 2012, 761, 156 actively worked on in the field at this very moment. Federrath & Klessen 2013, 763, 51 Federrath et al. 2010, A&A, 512, A81 Girichidis et al. 2014, ApJ, 781, 91 Hughes et al. 2013, ApJ, 779, 44 Kainulainen et al. 2009, A&A, 508, L35 5 The next five years Kainulainen et al. 2011a, A&A, 530, A64 Kainulainen et al. 2011b, A&A, 536, A48 The near future of cloud structure/star formation studies Kainulainen et al. 2013, A&A, 557, 120 will witness a fundamental advance. This advance results Kainulainen et al. 2014, Science, 344, 183 Kainulainen & Tan 2013, A&A, 549, A53 from the ability to (finally!) link together the processes Kritsuk et al. 2010, ApJL, 727, L20 taking place at the scale of galaxies and those acting within Lombardi et al. 2009, A&A, 493, 735 individual molecular clouds. On the one hand, the com- Lombardi et al. 2015, A&A, 576, L1 putational capabilities are right now starting to allow sim- Molina et al. 2012, MNRAS, 423, 2680 Padoan et al. 2014, in Protostars and Planets VI, 77 ulations of entire galaxies in high-enough resolution that Sadavoy 2013, PhD Thesis, University of Victoria the internal structure of molecular clouds is well resolved Sadavoy et al. 2014, ApJL, 787, L18 (e.g., Smith et al. 2014). This means that it will be pos- Schneider et al. 2013, ApJL, 766, L17 Schneider et al. 2015, A&A, 575, A79 sible to give predictions for the internal cloud structure Schuller et al. 2009, A&A, 504, 415 statistics as a function of the galaxy-scale environment. Smith et al. 2014, MNRAS, 441, 1628 Stutz & Kainulainen 2015, A&A, 557L, 6 On the other hand, the observations will establish a sys- V´azquez-Semadeni 1994, ApJ, 423, 681 tematic, Galactic-scale view of the internal cloud struc- Ward et al. 2014, MNRAS, 445, 1575 ture that can be used to confront those predictions. This view will be partly built by full exploitation of the Her- schel data in the Solar neighbourhood. However, reach- ing equally high spatial resolution farther away in the Galaxy requires other techniques. In principle, ALMA can map molecular clouds at arcsecond-scale resolution in high-enough sensitivity, but such observing programs will time-wise be expensive, only allowing studies of small cloud samples. A highly complementary alternative is a novel dust extinction mapping technique that combines near- and mid-infrared observations (Kainulainen & Tan 2013, Kainulainen et al. 2013). This technique can reach

10 Abstracts of recently accepted papers

First X-ray detection of the young variable V1180 Cas S. Antoniucci1, A. A. Nucita2,3, T. Giannini1, D. Lorenzetti1, B. Stelzer4, D. Gerardi2, S. Delle Rose2, A. Di Paola1, M. Giordano2,3, L. Manni2,3 and F. Strafella2 1 INAF-Osservatorio Astronomico di Roma, Via Frascati 33, I-00078, Monte Porzio Catone, Italy 2 Department of Mathematics and Physics E. De Giorgi, University of Salento, Via per Arnesano, CP 193, I-73100, Lecce, Italy 3 INFN, Sez. di Lecce, via per Arnesano, CP 193, I-73100, Lecce, Italy 4 INAF-Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, 90134, Palermo, Italy E-mail contact: simone.antoniucci at oa-roma.inaf.it V1180 Cas is a young variable that has shown strong photometric fluctuations (∆I ∼ 6 mag) in the recent past, which have been attributed to events of enhanced accretion. The source has entered a new high-brightness state in September 2013, which we have previously analysed through optical and near-infrared spectroscopy. To investigate the current active phase of V1180 Cas, we performed observations with the Chandra satellite aimed at studying the X-ray emission from the object and its connection to accretion episodes. Chandra observations were performed in early August 2014. Complementary JHK photometry and J-band spectroscopy were taken at our Campo Imperatore facility to relate the X-ray and near-infrared emission from the target. We observe a peak of X-ray emission at the nominal position of V1180 Cas and estimate that the confidence level of the detection is about 3σ. The observed signal corresponds to an X-ray luminosity LX (0.5-7 kev) in the range 0.8÷2.2 ×1030 erg s−1. Based on the relatively short duration of the dim states in the light curve and on stellar luminosity considerations, we explored the possibility that the brightness minima of V1180 Cas are driven by extinction variations. From the analysis of the spectral energy distribution of the high state we infer a stellar luminosity of 0.8-0.9 L⊙ and find that the derived LX is comparable to the average X-ray luminosity values observed in T Tauri objects. Moreover, the X-ray luminosity appears to be lower than the X-ray emission levels around 5×1030 ÷ 1 × 1031 erg s−1 detected at outbursts in similar low-mass objects. Our analysis suggests that at least part of the photometric fluctuations of V1180 Cas might be extinction effects rather than the result of accretion excess emission. However, because the source displays spectral features indicative of active accretion, we speculate that its photometric variations might be the result of a combination of accretion-induced and extinction-driven effects, as suggested for other young variables, such as V1184 Tau and V2492 Cyg. Accepted by A&A http://arxiv.org/pdf/1509.07730

Star formation triggered by cloud-cloud collisions S. K. Balfour1, A. P. Whitworth1, D. A. Hubber2,3 and S. E. Jaffa1 1 School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA, Wales, UK 2 University Observatory Munich, Ludwig-Maximilians-University Munich, Scheinerstr.1, 81679 Munich, Germany 3 Excellence Cluster Universe, Boltzmannstr. 2, 85748 Garching, Germany E-mail contact: scott.balfour at astro.cf.ac.uk

We present the results of SPH simulations in which two clouds, each having mass M0 =500M⊙ and radius R0 =2 pc, −1 collide head-on at relative velocities of ∆v0 =2.4, 2.8, 3.2, 3.6 and 4.0kms . There is a clear trend with increasing

∆v0 . At low ∆v0 , star formation starts later, and the shock-compressed layer breaks up into an array of predominantly radial filaments; stars condense out of these filaments and fall, together with residual gas, towards the centre of the layer, to form a single large-N cluster, which then evolves by competitive accretion, producing one or two very massive protostars and a diaspora of ejected (mainly low-mass) protostars; the pattern of filaments is reminiscent of the hub and

11 spokes systems identified recently by observers. At high ∆v0 , star formation occurs sooner and the shock-compressed layer breaks up into a network of filaments; the pattern of filaments here is more like a spider’s web, with several small-N clusters forming independently of one another, in cores at the intersections of filaments, and since each core only spawns a small number of protostars, there are fewer ejections of protostars. As the relative velocity is increased, the mean protostellar mass increases, but the maximum protostellar mass and the width of the mass function both decrease. We use a Minimal Spanning Tree to analyse the spatial distributions of protostars formed at different relative velocities. Accepted by MNRAS http://arxiv.org/pdf/1509.05287

Sh2-138: Physical environment around a small cluster of massive stars T. Baug1, D.K. Ojha1, L.K. Dewangan2, J.P. Ninan1, B.C. Bhatt3, S.K. Ghosh1,4 and K.K. Mallick1 1 Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India 2 Instituto Nacional de Astrof´ısica, Optica´ y Electr´onica, Luis Enrique Erro # 1, Tonantzintla, Puebla, M´exico C.P. 72840, M´exico 3 Indian Institute of Astrophysics, Koramangala, Bangalore 560 034, India 4 National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune 411 007, India E-mail contact: tapas.baug at tifr.res.in We present a multi-wavelength study of the Sh2-138, a Galactic compact H ii region. The data comprise of optical and near-infrared (NIR) photometric and spectroscopic observations from the 2-m Himalayan Chandra Telescope, radio observations from the Giant Metrewave Radio Telescope (GMRT), and archival data covering radio through NIR wavelengths. A total of 10 Class I and 54 Class II young stellar objects (YSOs) are identified in a 4′.6×4′.6 area of the Sh2-138 region. Five compact ionized clumps, with four lacking of any optical or NIR counterparts, are identified using the 1280 MHz radio map, and correspond to sources with spectral type earlier than B0.5. Free-free emission spectral energy distribution fitting of the central compact H ii region yields an electron density of ∼2250±400 cm−3. With the aid of a wide range of spectra, from 0.5–15 µm, the central brightest source - previously hypothesised to be the main ionizing source - is characterized as a Herbig Be type star. At large scale (15′×15′), the Herschel images (70–500 µm) and the nearest neighbour analysis of YSOs suggest the formation of an isolated cluster at the junction of filaments. Furthermore, using a greybody fit to the dust spectrum, the cluster is found to be associated with the highest column density (∼3×1022 cm−2) and high temperature (∼35 K) regime, as well as with the radio continuum emission. The mass of the central clump seen in the column density map is estimated to be ∼3770 M⊙. Accepted by MNRAS http://xxx.lanl.gov/pdf/1509.08716.pdf

Accretion disks in luminous young stellar objects M.T. Beltr´an1,2, and W.J. de Wit3 1 INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze, Italy 2 Senior Scientific Visitor at ESO Chile 3 European Southern Observatory, Alonso de C´ordova 3107, Vitacura, Casilla 19001, Santiago de Chile, Chile E-mail contact: mbeltran at arcetri.astro.it An observational review is provided of the properties of accretion disks around young stars. It concerns the primordial disks of intermediate- and high-mass young stellar objects in embedded and optically revealed phases. The properties were derived from spatially resolved observations and therefore predominantly obtained with interferometric means, either in the radio/(sub)millimeter or in the optical/infrared wavelength regions. We make summaries and comparisons of the physical properties, kinematics, and dynamics of these circumstellar structures and delineate trends where possible. Amongst others, we report on a quadratic trend of mass accretion rates with mass from TTauri stars to the highest mass young stellar objects and on the systematic difference in mass infall and accretion rates. http://arxiv.org/pdf/1509.08335

12 Filament Fragmentation in High-Mass Star Formation Henrik Beuther1, Sarah Ragan2, Katharine Johnston2, Thomas Henning1, Alvaro Hacar3 and Jouni Kainulainen1 1 Max Planck Institute for Astronomy, K¨onigstuhl 17, 69117 Heidelberg, Germany 2 University of Leeds, Leeds, LS2 9JT, UK 3 University of Vienna, T¨urkenschanzstr. 17, A-1180 Vienna, Austria E-mail contact: beuther at mpia.de Context: Filamentary structures in the interstellar medium are crucial ingredients in the star formation process. They fragment to form individual star-forming cores, and at the same time they may also funnel gas toward the central gas cores providing an additional gas reservoir. Aims: We want to resolve the length-scales for filament formation and fragmentation (resolution ≤0.1 pc), in particular the Jeans length and cylinder fragmentation scale. Methods: We have observed the prototypical high-mass star-forming filament IRDC18223 with the Plateau de Bure + Interferometer (PdBI) in the 3.2 mm continuum and N2H (1–0) line emission in a ten field mosaic at a spatial resolution of ∼ 4′′ (∼14000 AU). Results: The dust continuum emission resolves the filament into a chain of at least 12 relatively regularly spaced cores. The mean separation between cores is ∼0.40(±0.18)pc. While this is approximately consistent with the fragmentation −1 of an infinite, isothermal, gravitationally bound gas cylinder, a high mass-to-length ratio of M/l ≈ 1000M⊙ pc + requires additional turbulent and/or magnetic support against radial collapse of the filament. The N2H (1 − 0) data reveal a velocity gradient perpendicular to the main filament. Although rotation of the filament cannot be excluded, the data are also consistent with the main filament being comprised of several velocity-coherent sub-filaments. Furthermore, this velocity gradient perpendicular to the filament resembles recent results toward Serpens south that are interpreted as signatures of filament formation within magnetized and turbulent sheet-like structures. Lower- density gas tracers ([CI] and C18O) reveal a similar red/blueshifted velocity structure on scales around 60′′ east and west of the IRDC 18223 filament. This may tentatively be interpreted as a signature of the large-scale cloud and the smaller-scale filament being kinematically coupled. We do not identify a velocity gradient along the axis of the filament. This may either be due to no significant gas flows along the filamentary axis, but it may partly also be caused by a low inclination angle of the filament with respect to the plane of the sky that could minimize such signature. Conclusions: The IRDC 18223 3.2 mm continuum data are consistent with thermal fragmentation of a gravitationally bound and compressible gas cylinder. However, the large mass-to-length ratio requires additional support – likely + turbulence and/or magnetic fields – against collapse. The N2H spectral line data indicate a kinematic origin of the filament, but we cannot conclusively differentiate whether it has formed out of (pre-existing) velocity-coherent sub-filaments and/or whether magnetized converging gas flows, a larger-scale collapsing cloud or even rotation played a significant role during filament formation. Accepted by Astronomy & Astrophysics http://www.mpia.de/homes/beuther/papers.html

Protostellar spin-down: a planetary lift? Jerome Bouvier1 and David Cebron2 1 Universit´eGrenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France 2 Universit´eGrenoble Alpes, CNRS, ISTerre, F-38000 Grenoble, France E-mail contact: Jerome.Bouvier at obs.ujf-grenoble.fr When they first appear in the HR diagram, young stars rotate at a mere 10% of their break-up velocity. They must have lost most of the angular momentum initially contained in the parental cloud, the so-called angular momentum problem. We investigate here a new mechanism by which large amounts of angular momentum might be shed from young stellar systems, thus yielding slowly rotating young stars. Assuming that planets promptly form in circumstellar disks and rapidly migrate close to the central star, we investigate how the tidal and magnetic interactions between the protostar, its close-in planet(s), and the inner circumstellar disk can efficiently remove angular momentum from the central object. We find that neither the tidal torque nor the variety of magnetic torques acting between the star and the embedded planet are able to counteract the spin up torques due to accretion and contraction. Indeed, the

13 former are orders of magnitude weaker than the latter beyond the corotation radius and are thus unable to prevent the young star from spinning up. We conclude that star-planet interaction in the early phases of does not appear as a viable alternative to magnetic star-disk coupling to understand the origin of the low angular momentum content of young stars. Accepted by MNRAS http://arxiv.org/pdf/1509.02951

Near-Infrared Spectroscopy of 2M0441+2301 AabBab: A Quadruple System Spanning the Stellar to Planetary Mass Regimes Brendan P. Bowler1 and Lynne A. Hillenbrand1 1 California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA E-mail contact: bpbowler at caltech.edu We present Keck/NIRC2 and OSIRIS near-infrared imaging and spectroscopy of 2M0441+2301 AabBab, a young (1–3 Myr) hierarchical quadruple system comprising a low-mass star, two brown dwarfs, and a planetary-mass companion in Taurus. All four components show spectroscopic signs of low surface gravity, and both 2M0441+2301 Aa and Ab possess Paβ emission indicating they each harbor accretion subdisks. spanning 2008–2014 reveals orbital motion in both the Aab (0′′. 23 separation) and Bab (0′′. 095 separation) pairs, although the implied orbital periods of >300 years means dynamical will not be possible in the near future. The faintest component (2M0441+2301 Bb) has an angular H-band shape, strong molecular absorption (VO, CO, H2O, and FeH), and shallow alkali lines, confirming its young age, late spectral type (L1±1), and low temperature (≈1800 K). With individual masses of +100 200−50 Mjup, 35±5 Mjup, 19±3 Mjup, and 9.8±1.8 Mjup, 2M0441+2301 AabBab is the lowest-mass quadruple system known. Its hierarchical orbital architecture and mass ratios imply that it formed from the collapse and fragmentation of a molecular cloud core, demonstrating that planetary-mass companions can originate from a stellar-like pathway analogous to higher-mass quadruple star systems as first speculated by Todorov et al. More generally, cloud fragmen- tation may be an important formation pathway for the massive exoplanets that are now regularly being imaged on wide orbits. Accepted by ApJL (811:L30) http://iopscience.iop.org/article/10.1088/2041-8205/811/2/L30

Compositional evolution during rocky protoplanet accretion Philip J. Carter1, Zo¨eM. Leinhardt1, Tim Elliott2, Michael J. Walter2, and Sarah T. Stewart3 1 School of Physics, University of Bristol, H. H. Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, UK 2 School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen?s Road, Bristol BS8 1RJ, UK 3 Department of Earth and Planetary Sciences, University of California, One Shields Avenue, Davis, CA 95616, USA E-mail contact: p.carter at bristol.ac.uk The Earth appears non-chondritic in its abundances of refractory lithophile elements, posing a significant problem for our understanding of its formation and evolution. It has been suggested that this non-chondritic composition may be explained by collisional erosion of differentiated planetesimals of originally chondritic composition. In this work, we present N-body simulations of terrestrial planet formation that track the growth of planetary embryos from planetesimals. We simulate evolution through the runaway and oligarchic growth phases under the Grand Tack model and in the absence of giant planets. These simulations include a state-of-the-art collision model which allows multiple collision outcomes, such as accretion, erosion, and bouncing events, that enables tracking of the evolving core mass fraction of accreting planetesimals. We show that the embryos grown during this intermediate stage of planet formation exhibit a range of core mass fractions, and that with significant dynamical excitation, enough mantle can be stripped from growing embryos to account for the Earth’s non-chondritic Fe/Mg ratio. We also find that there is a large diversity in the composition of remnant planetesimals, with both iron-rich and silicate-rich fragments produced via collisions. Accepted by ApJ http://arxiv.org/pdf/1509.07504

14 Discovery of Young Methane Dwarfs in the ρ Ophiuchi L 1688 Dark Cloud Poshih Chiang1 and W. P. Chen1 1 Graduate Institute of Astronomy, National Central University, 300 Jhongda Road, Zhongli 32001, Taiwan E-mail contact: pschiang at gmail.com We report the discovery of two methane dwarfs in the dark cloud L 1688 of the ρ Oph star-forming region. The two objects were among the T dwarf candidates with possible methane absorption and cool atmospheres, as diagnosed by infrared colors using deep WIRCam/CFHT HK plus CH4ON images, and IRAC/Spitzer c2d data. Follow-up spectroscopic observations with the FLAMINGOS-2/Gemini South confirmed the methane absorption at 1.6 µm. Compared with spectral templates of known T dwarfs in the field, i.e., of the old populations, Oph J162738−245240 (Oph-T3) is a T0/T1 type, whereas Oph J162645−241949 (Oph-T17) is consistent with a T3/T4 type in the H band but an L8/T1 in the K band. Compared with the BT-Settl model, both Oph-T3 and Oph-T17 are consistent with being cool, ∼1000 K and ∼900 K, respectively, and of low surface gravity, log(g)=3.5. With an age no more than a couple Myr, these two methane dwarfs thereby represent the youngest T dwarfs ever confirmed. A young late L dwarf, OphJ162651−242110, was found serendipitously in our spectroscopic observations. Accepted by ApJL http://arxiv.org/pdf/1509.03949

Could or Saturn Have Ejected a Fifth Giant Planet? Ryan Cloutier1,2, Daniel Tamayo2,3, and Diana Valencia2,1 1 Dept. of Astronomy & Astrophysics University of Toronto, 50 St. George Street, Toronto, Ontario, Canada, M5S 3H4 2 Centre for Planetary Sciences, University of Toronto, Department of Physical & Environmental Sciences, 1265 Military Trail, Toronto, Ontario, Canada, M1C 1A4 3 Canadian Institute for Theoretical Astrophysics, 60 St. George Street, Toronto, Ontario, Canada, M5S 3H8 E-mail contact: cloutier at astro.utoronto.ca Models of the dynamical evolution of the early solar system following the dispersal of the gaseous protoplanetary disk have been widely successful in reconstructing the current orbital configuration of the giant planets. Statistically, some of the most successful dynamical evolution simulations have initially included a hypothetical fifth giant planet, of ice giant mass, which gets ejected by a gas giant during the early solar system’s proposed instability phase. We investigate the likelihood of an ice giant ejection event by either Jupiter or Saturn through constraints imposed by the current orbits of their wide-separation regular satellites Callisto and Iapetus respectively. We show that planetary encounters that are sufficient to eject an ice giant, often provide excessive perturbations to the orbits of Callisto and Iapetus making it difficult to reconcile a planet ejection event with the current orbit of either satellite. Quantitatively, we compute the likelihood of reconciling a regular Jovian satellite orbit with the current orbit of Callisto following an ice giant ejection by Jupiter of ∼42% and conclude that such a large likelihood supports the hypothesis of a fifth giant planet’s existence. A similar calculation for Iapetus reveals that it is much more difficult for Saturn to have ejected an ice giant and reconcile a Kronian satellite orbit with that of Iapetus (likelihood ∼1%), although uncertainties regarding the formation of Iapetus, on its unusual orbit, complicates the interpretation of this result. Accepted by ApJ http://arxiv.org/pdf/1509.05397

Orbital motions and light curves of young binaries XZ Tau and VY Tau A.V. Dodin1, N.V. Emelyanov1, A.V. Zharova1, S.A. Lamzin1, E.V. Malogolovets2 and J.M. Roe3 1 Sternberg Astronomical Institute, Moscow State University, Universitetskij pr., 13, 119992 Moscow, Russia 2 Special Astrophysical Observatory, N. Arkhyz, Karachai-Cherkesia 369167, Russia 3 AAVSO, PO Box 174, Bourbon, MO 65441, USA E-mail contact: lamzin at sai.msu.ru

15 The results of our speckle interferometric observations of young binaries VY Tau and XZ Tau are presented. For the first time, we found a relative displacement of VY Tau components as well as a preliminary orbit for XZ Tau. It appeared that the orbit is appreciably non-circular and is inclined by i < 47o from the plane of the sky. It means that the rotation axis of XZ Tau A and the axis of its jet are significantly non-perpendicular to the orbital plane. We found that the average brightness of XZ Tau had been increasing from the beginning of the last century up to the mid-thirties and then it decreased by ∆B > 2 mag. The maximal brightness has been reached significantly later on the time of periastron passage. The total brightness of XZ Tau’s components varied in a non-regular way from 1970 to 1985 when eruptions of hot gas from XZ Tau A presumably had occurred. In the early nineties the variations became regular following which a chaotic variability had renewed. We also report that a flare activity of VY Tau has resumed after 40 yr pause, parameters of the previous and new flares are similar, and the flares are related with the A component. Accepted by Astronomy Letters http://arxiv.org/pdf/1509.04966

Magnetic activity and hot of young Suns: the weak-line T Tauri stars V819 Tau and V830 Tau J.-F. Donati1,2, E. H´ebrard1,2, G.A.J. Hussain3,1, C. Moutou4, L. Malo4, K. Grankin5, A.A. Vidotto6, S.H.P. Alencar7, S.G. Gregory8, M.M. Jardine8, G. Herczeg9, J. Morin10, R. Fares11, F. M´enard12, J. Bouvier13,14, X. Delfosse13,14, R. Doyon15, M. Takami16, P. Figueira17, P. Petit1,2, I. Boisse18,19 and the MaTYSSE collaboration 1 Universit´ede Toulouse, UPS-OMP, IRAP, 14 avenue E. Belin, Toulouse, F–31400 France 2 CNRS, IRAP / UMR 5277, Toulouse, 14 avenue E. Belin, F–31400 France 3 ESO, Karl-Schwarzschild-Str. 2, D-85748 Garching, Germany 4 CFHT Corporation, 65-1238 Mamalahoa Hwy, Kamuela, Hawaii 96743, USA 5 Crimean Astrophysical Observatory, Nauchny, Crimea 298409 6 Observatoire de Gen`eve, Chemin des Maillettes 51, CH-1290 Versoix, Switzerland 7 Departamento de F`ısica – ICEx – UFMG, Av. Antˆonio Carlos, 6627, 30270-901 Belo Horizonte, MG, Brazil 8 SUPA, School of Physics and Astronomy, Univ. of St Andrews, St Andrews, Scotland KY16 9SS, UK 9 Kavli Institute for Astronomy and Astrophysics, Peking University, Yi He Yuan Lu 5, Haidian Qu, Beijing 100871, China 10 LUPM, Universit´ede Montpellier, CNRS, place E. Bataillon, F–34095 Montpellier, France 11 INAF - Osservatorio Astrofisico di Catania, via S. Sofia 78, I–95123 Catania, Italy 12 CNRS, UMI-FCA / UMI 3386, France, and Universidad de Chile, Santiago, Chile 13 Universit´eGrenoble Alpes, IPAG, BP 53, F–38041 Grenoble C´edex 09, France 14 CNRS, IPAG / UMR 5274, BP 53, F–38041 Grenoble C´edex 09, France 15 D´epartement de physique, Universit´ede Montr´eal, C.P. 6128, Succursale Centre-Ville, Montr´eal, QC, Canada H3C 3J7 16 Institute of Astronomy and Astrophysics, Academia Sinica, PO Box 23-141, 106, Taipei, Taiwan 17 Centro de Astrof`ısica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal 18 Universit´eAix-Marseille, LAM, F–13388 Marseille, France 19 CNRS, LAM / UMR 7326, F–13388 Marseille, France E-mail contact: jean-francois.donati at irap.omp.eu We report results of a spectropolarimetric and photometric monitoring of the weak-line T Tauri stars (wTTSs) V819 Tau and V830 Tau within the MaTYSSE programme, involving the ESPaDOnS spectropolarimeter at the Canada- France-Hawaii Telescope. At ∼3 Myr, both stars dissipated their discs recently and are interesting objects for probing star and planet formation. Profile distortions and Zeeman signatures are detected in the unpolarized and circularly- polarized lines, whose rotational modulation we modelled using tomographic imaging, yielding brightness and magnetic maps for both stars. We find that the large-scale magnetic fields of V819 Tau and V830 Tau are mostly poloidal and can be approximated at large radii by 350–400 G dipoles tilted at ∼30◦ to the rotation axis. They are significantly weaker than the field of GQ Lup, an accreting classical (cTTS) with similar mass and age which can be used to compare

16 the magnetic properties of wTTSs and cTTSs. The reconstructed brightness maps of both stars include cool spots and warm plages. Surface differential rotation is small, typically ∼4.4 × smaller than on the Sun, in agreement with previous results on wTTSs. Using our Doppler images to model the activity jitter and filter it out from the (RV) curves, we obtain RV residuals with dispersions of 0.033 and 0.104 km s−1 for V819 Tau and V830 Tau respectively. RV residuals suggest that a hot Jupiter may be orbiting V830 Tau, though additional data are needed to confirm this preliminary result. We find no evidence for close-in giant planet around V819 Tau. Accepted by MNRAS http://arxiv.org/pdf/1509.02110

The young cluster NGC 2282 : a multi-wavelength perspective Somnath Dutta1, S. Mondal1, J. Jose2, R. K. Das1, M. R. Samal3 and S. Ghosh1 1 S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata-700098, India 2 Kavli Institute for Astronomy and Astrophysics,Peking University, Yi He Yuan Lu 5, Haidian District, Beijing 100871, China 3 Aix Marseille Universit´e, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, 13388 Marseille, France E-mail contact: somnath12 at boson.bose.res.in We present the analysis of the stellar content of NGC 2282, a young cluster in the Monoceros , using deep optical BV I and IPHAS photometry along with infrared (IR) data from UKIDSS and Spitzer-IRAC. Based on the stellar surface density analysis using nearest neighborhood method, the radius of the cluster is estimated as ∼ 3.15 arcmin. From optical spectroscopic analysis of 8 bright sources, we have classified three early B-type members in the cluster, which includes, HD 289120, a previously known B2 V type star, a Herbig Ae/Be star (B0.5 Ve) and a B5 V star. From spectrophotometric analyses, the distance to the cluster has been estimated as ∼ 1.65 kpc. The K-band extinction map is estimated using nearest neighborhood technique, and the mean extinction within the cluster area is found to be AV ∼ 3.9 mag. Using IR colour-colour criteria and Hα-emission properties, we have identified a total of 152 candidate young stellar objects (YSOs) in the region, of which, 75 are classified as Class II, 9 are Class I YSOs. Our YSO catalog also includes 50 Hα-emission line sources, identified using slitless spectroscopy and IPHAS photometry data. Based on the optical and near-IR colour-magnitude diagram analyses, the cluster age has been estimated to be in the range of 2 − 5 Myr, which is in agreement with the estimated age from disc fraction (∼ 58%). Masses of these YSOs are found to be ∼ 0.1−2.0 M⊙. Spatial distribution of the candidate YSOs shows spherical morphology, more or less similar to the surface density map. Accepted by MNRAS http://arxiv.org/pdf/1509.08594v1.pdf

Radio monitoring of the periodically variable IR source LRLL 54361: No direct corre- lation between the radio and IR emissions Jan Forbrich1,2, Luis F. Rodr´ıguez3, Aina Palau3, Luis A. Zapata3, James Muzerolle4 and Robert A. Gutermuth5 1 University of Vienna, Department of Astrophysics, T¨urkenschanzstraße 17, 1180 Vienna, Austria 2 Harvard-Smithsonian Center for Astrophysics, 60 Garden St MS 72, Cambridge, MA 02138, USA 3 Instituto de Radioastronom´ıay Astrof´ısica, UNAM, Apdo. Postal 3-72 (Xangari), 58089 Morelia, Michoac´an, M´exico 4 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA 5 Department of Astronomy, University of Massachusetts, Amherst, MA 01003, USA E-mail contact: jan.forbrich at univie.ac.at LRLL 54361 is an infrared source located in the star forming region IC 348 SW. Remarkably, its infrared luminosity increases by a factor of 10 during roughly one week every 25.34 days. To understand the origin of these remarkable periodic variations, we obtained sensitive 3.3 cm JVLA radio continuum observations of LRLL 54361 and its surround- ings in six different epochs: three of them during the IR-on state and three during the IR-off state. The radio source

17 associated with LRLL 54361 remained steady and did not show a correlation with the IR variations. We suggest that the IR is tracing the results of fast (with a timescale of days) pulsed accretion from an unseen binary companion, while the radio traces an ionized outflow with an extent of ∼100 AU that smooths out the variability over a period of order a year. The average flux density measured in these 2014 observations, 27±5 µJy, is about a factor of two less than that measured about 1.5 years before, 53±11 µJy, suggesting that variability in the radio is present, but over larger timescales than in the IR. We discuss other sources in the field, in particular two infrared/X-ray stars that show rapidly varying gyrosynchrotron emission. Accepted by The Astrophysical Journal http://arxiv.org/pdf/1510.01233

Squeezed between shells? On the origin of the Lupus I molecular cloud. APEX/LABOCA, Herschel, and Planck observations B. Gaczkowski1, T. Preibisch1, T. Stanke2, M.G.H. Krause1,3,4, A. Burkert1,3, R. Diehl3,4, K. Fierlinger1,4, D. Kroell1,3, J. Ngoumou1 and V. Roccatagliata1 1 Universit¨ats-Sternwarte M¨unchen, Ludwig-Maximilians-Universit¨at, Scheinerstr. 1, 81679 M¨unchen, Germany 2 ESO, Karl-Schwarzschild-Strasse 2, 85748 Garching bei M¨unchen, Germany 3 Max-Planck-Institut f¨ur extraterrestrische Physik, Postfach 1312, 85741 Garching, Germany 4 Excellence Cluster Universe, Technische Universit¨at M¨unchen, Boltzmannstrasse 2, 85748 Garching, Germany E-mail contact: bengac at usm.uni-muenchen.de The Lupus I cloud is found between the Upper-Scorpius (USco) and the Upper-Centaurus-Lupus (UCL) sub-groups of the Scorpius-Centaurus OB-association, where the expanding USco H I shell appears to interact with a bubble currently driven by the winds of the remaining B-stars of UCL. We want to study how collisions of large-scale interstellar gas flows form and influence new dense clouds in the ISM. We performed LABOCA continuum sub-mm observations of Lupus I that provide for the first time a direct view of the densest, coldest cloud clumps and cores at high angular resolution. We complemented those by Herschel and Planck data from which we constructed column density and temperature maps. From the Herschel and LABOCA column density maps we calculated PDFs to characterize the density structure of the cloud. The northern part of Lupus I is found to have on average lower densities and higher temperatures as well as no active star formation. The center-south part harbors dozens of pre-stellar cores where density and temperature reach their maximum and minimum, respectively. Our analysis of the column density PDFs from the Herschel data show double peak profiles for all parts of the cloud which we attribute to an external compression. In those parts with active star formation, the PDF shows a power-law tail at high densities. The PDFs we calculated from our LABOCA data trace the denser parts of the cloud showing one peak and a power-law tail. With LABOCA we find 15 cores with masses between 0.07 and 1.71 M⊙ and a total mass of ≈ 8 M⊙. The total gas and dust mass of the cloud is ≈ 164 M⊙ and hence ∼ 5% of the mass is in cores. From the Herschel and Planck data we find a total mass of ≈ 174 M⊙ and ≈ 171 M⊙, respectively. The position, orientation and elongated shape of Lupus I, the double peak PDFs and the population of pre-stellar and protostellar cores could be explained by the large-scale compression from the advancing USco H I shell and the UCL wind bubble. Accepted by A&A http://arxiv.org/pdf/1509.07368

Dense gas in the Galactic central molecular zone is warm and heated by turbulence Adam Ginsburg1, Christian Henkel2,3, Yiping Ao4,5, Denise Riquelme2, Jens Kauffmann2, Thushara Pillai2, Elisabeth A.C. Mills6, Miguel A. Requena-Torres2, Katharina Immer1, Leonardo Testi1, Juer- gen Ott6, John Bally7, Cara Battersby8, Jeremy Darling7, Susanne Aalto9, Thomas Stanke1, Sarah Kendrew10, J.M. Diederik Kruijssen11, Steven Longmore12, James Dale13, Rolf Guesten2, Karl M. Menten2 1European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei Muenchen, Germany 2Max Planck Institute for Radio Astronomy, auf dem Hugel, Bonn 3Astron. Dept., King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia

18 4National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan 5Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China 6National Radio Astronomy Observatory, Socorro 7CASA, University of Colorado, 389-UCB, Boulder, CO 80309, USA 8Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 9Department of Earth and Space Sciences, Chalmers University of Technology, Sweden 10Department of Astrophysics, The Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK 11Max-Planck Institut f¨ur Astrophysik, Karl-Schwarzschild-Straße 1, 85748 Garching, Germany 12Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF, United Kingdom 13University Observatory Munich, Scheinerstr. 1, D-81679 M¨unchen, Germany E-mail contact: [email protected] The Galactic center is the closest region in which we can study star formation under extreme physical conditions like those in high-redshift galaxies. We measure the temperature of the dense gas in the central molecular zone (CMZ) and examine what drives it. We mapped the inner 300 pc of the CMZ in the temperature-sensitive J = 3 − 2 para- formaldehyde (p-H2CO) transitions. We used the 32,1–22,0 / 30,3–20,2 line ratio to determine the gas temperature in n ∼ 104 − 105 cm−3 gas. We have produced temperature maps and cubes with 30 arcsec and 1 km/s resolution and published all data in FITS form. Dense gas temperatures in the Galactic center range from ∼ 60 K to > 100 K in selected regions. The highest gas temperatures TG > 100 K are observed around the Sgr B2 cores, in the extended Sgr B2 cloud, the 20 km/s and 50 km/s clouds, and in “The Brick” (G0.253+0.016). We infer an upper limit on the cosmic −14 −1 ray ionization rate ζCR < 10 s . The dense molecular gas temperature of the region around our Galactic center is similar to values found in the central regions of other galaxies, in particular starburst systems. The gas temperature is uniformly higher than the dust temperature, confirming that dust is a coolant in the dense gas. Turbulent heating can readily explain the observed temperatures given the observed line widths. Cosmic rays cannot explain the observed variation in gas temperatures, so CMZ dense gas temperatures are not dominated by cosmic ray heating. The gas temperatures previously observed to be high in the inner ∼ 75 pc are confirmed to be high in the entire CMZ. Accepted by A&A http://arxiv.org/pdf/1509.01583 The data can be accessed from doi:10.7910/DVN/27601 and are available from CDS via anonymous ftp to cdsarc.u- strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/

ALMA images of discs: are all gaps carved by planets? J.-F. Gonzalez1, G. Laibe2, S.T. Maddison3, C. Pinte4,5, and F. M´enard4,5 1 Universit´ede Lyon, Lyon, F-69003, France; Universit´eLyon 1, Observatoire de Lyon, 9 avenue Charles Andr´e, Saint-Genis Laval, F-69230, France; CNRS, UMR 5574, Centre de Recherche Astrophysique de Lyon ; Ecole´ Normale Suprieure de Lyon, Lyon, F-69007, France 2 School of Physics and Astronomy, University of Saint Andrews, North Haugh, St Andrews, Fife KY16 9SS, United Kingdom 3 Centre for Astrophysics and Supercomputing, Swinburne University of Technology, PO Box 218, Hawthorn, VIC 3122, Australia 4 UMI-FCA, CNRS/INSU France (UMI 3386), and Departamento de Astronom´ıa, Universidad de Chile, Casilla 36-D Santiago, Chile 5 UJF-Grenoble 1 / CNRS-INSU, Institut de Plan´etologie et d?Astrophysique de Grenoble, UMR 5274, Grenoble, F-38041, France E-mail contact: jean-francois.gonzalez at ens-lyon.fr Protoplanetary discs are now routinely observed and exoplanets, after the numerous indirect discoveries, are starting to be directly imaged. To better understand the planet formation process, the next step is the detection of forming planets or of signposts of young planets still in their disc, such as gaps. A spectacular example is the ALMA science verification image of HL Tau showing numerous gaps and rings in its disc. To study the observability of planet gaps, we ran 3D hydrodynamical simulations of a gas and dust disc containinga5 MJ gap-opening planet and characterised

19 the spatial distribution of migrating, growing and fragmenting dust grains. We then computed the corresponding synthetic images for ALMA. For a value of the dust fragmentation threshold of 15 m s−1 for the collisional velocity, we identify for the first time a self-induced dust pile up in simulations taking fragmentation into account. This feature, in addition to the easily detected planet gap, causes a second apparent gap that could be mistaken for the signature of a second planet. It is therefore essential to be cautious in the interpretation of gap detections. Accepted by MNRAS Letters http://arxiv.org/pdf/1509.00691

Possible smoking-gun evidence for initial mass segregation in re-virialized post-gas ex- pulsion globular clusters Hosein Haghi1, Akram Hasani Zonoozi1, Pavel Kroupa2, Sambaran Banerjee2,3 and Holger Baumgardt4 1 Institute for Advanced Studies in Basic Sciences (IASBS), P.O. Box 11365-9161, Zanjan, Iran 2 Helmholtz-Institut f¨ur Strahlen-und Kernphysik (HISKP), Universit¨at Bonn, Rheinische Friedrich-Wilhelms-Universit¨at Nussallee 14-16 D-53115 Bonn Germany 3 Argelander Institute f¨ur Astronomie (AIfA), Auf dem H¨ugel 71, 53121 Bonn, Germany 4 University of Queensland, School of Mathematics and Physics, Brisbane, QLD 4072, Australia E-mail contact: haghi at iasbs.ac.ir We perform a series of direct N-body calculations to investigate the effect of residual gas expulsion from the gas- embedded progenitors of present-day globular clusters (GCs) on the stellar mass function (MF). Our models start either tidally filling or underfilling, and either with or without primordial mass segregation. We cover 100 Myr of the evolution of modeled clusters and show that the expulsion of residual gas from initially mass-segregated clusters leads to a significantly shallower slope of the stellar MF in the low- (m ≤ 0.50M⊙) and intermediate-mass (≃ 0.50 − 0.85M⊙) regime. Therefore, the imprint of residual gas expulsion and primordial mass segregation might be visible in the present-day MF. We find that the strength of the external tidal field, as an essential parameter, influences the degree of flattening, such that a primordially mass-segregated tidally-filling cluster with rh/rt ≥ 0.1 shows a strongly depleted MF in the intermediate stellar mass range. Therefore, the shape of the present-day stellar MF in this mass range probes the birth place of clusters in the Galactic environment. We furthermore find that this flattening agrees with the observed correlation between the concentration of a cluster and its MF slope, as found by de Marchi et al.. We show that if the expansion through the residual gas expulsion in primordial mass segregated clusters is the reason for this correlation then GCs most probably formed in strongly fluctuating local tidal fields in the early proto-Milky Way potential, supporting the recent conclusion by Marks & Kroupa. Accepted by MNRAS http://arxiv.org/pdf/1509.07119

The Early ALMA View of the FU Ori Outburst System A.S. Hales1,2, S.A. Corder1,2, W.R.D. Dent1,3, S.M. Andrews4, J.A. Eisner5 and L.A. Cieza6,7 1 Atacama Large Millimeter/Submillimeter Array, Joint ALMA Observatory, Alonso de C´ordova 3107, Vitacura 763- 0355, Santiago - Chile 62 National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, Virginia, 22903-2475, United States 3 European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748, Garching bei M¨unchen, Germany 4 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, United States 5 Steward Observatory, University of Arizona, 933 N Cherry Ave., Tucson, AZ 85721, United States 6 N´ucleo de Astronom´ıa, Facultad de Ingenier´ıa, Universidad Diego Portales, Chile 7 Millenium Nucleus, Protoplanetary Disks in ALMA Early Science, Chile E-mail contact: ahales at alma.cl We have obtained ALMA Band 7 observations of the FU Ori outburst system at 0′′. 6 × 0′′. 5 resolution to measure the link between the inner disk instability and the outer disk through sub-mm continuum and molecular line observations. Our observations detect continuum emission which can be well modeled by two unresolved sources located at the position of each binary component. The interferometric observations recover the entire flux reported in previous

20 single-dish studies, ruling out the presence of a large envelope. Assuming that the dust is optically thin, we derive disk −4 −5 dust masses of 2 × 10 M⊙ and 8 × 10 M⊙, for the north and south components respectively. We place limits on the disks’ radii of r < 45 AU. We report the detection of molecular emission from 12CO(3–2), HCO+(4–3) and from HCN(4–3). The 12CO appears widespread across the two binary components, and is slightly more extended than the continuum emission. The denser gas tracer HCO+ peaks close to the position of the southern binary component, while HCN appears peaked at the position of the northern component. This suggests that the southern binary component is embedded in denser molecular material, consistent with previous studies that indicate a heavily reddened object. At this angular resolution any interaction between the two unresolved disk components cannot be disentangled. Higher resolution images are vital to understanding the process of star formation via rapid accretion FU Ori-type episodes. Accepted by ApJ http://arxiv.org/pdf/1509.02543

The Evolution of Inner Disk Gas in Transition Disks K. Hoadley1,2, K. France1,2, R.D. Alexander3, M. McJunkin1,2, and P.C. Schneider4 1 Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303-7814, USA 2 Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309-0389, USA 3 Department of Physics & Astronomy, University of Leicester, University Road, Leicester, LE1 7RH, UK 4 ESTEC/ESA, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands E-mail contact: keri.hoadley at colorado.edu Investigating the molecular gas in the inner regions of protoplanetary disks provides insight into how the molecular disk environment changes during the transition from primordial to debris disk systems. We conduct a small survey of molecular hydrogen (H2) fluorescent emission, using 14 well-studied Classical T Tauri stars at two distinct dust disk evolutionary stages, to explore how the structure of the inner molecular disk changes as the optically thick warm dust dissipates. We simulate the observed HI-Lyman α-pumped H2 disk fluorescence by creating a 2D radiative transfer model that describes the radial distributions of H2 emission in the disk atmosphere and compare these to observations from the Hubble Space Telescope. We find the radial distributions that best describe the observed H2 FUV emission arising in primordial disk targets (full dust disk) are demonstrably different than those of transition disks (little-to-no warm dust observed). For each best-fit model, we estimate inner and outer disk emission boundaries (rin and rout), describing where the bulk of the observed H2 emission arises in each disk, and we examine correlations between these and several observational disk evolution indicators, such as n13−31, rin,CO, and the mass accretion rate. We find strong, positive correlations between the H2 radial distributions and the slope of the dust SED, implying the behavior of the molecular disk atmosphere changes as the inner dust clears in evolving protoplanetary disks. Overall, we find that H2 inner radii are ∼4 times larger in transition systems, while the bulk of the H2 emission originates inside the dust gap radius for all transitional sources. Accepted by ApJ http://arxiv.org/pdf/1509.02172

Periodic Accretion Instabilities in the Protostar L1634 IRS 7 Klaus W. Hodapp1 and Rolf Chini2 1 University of Hawaii, Institute for Astronomy, 640 N. Aohoku Place, Hilo, HI 96720, USA 2 Ruhr-Universitaet Bochum, Astronomisches Institut, Universitaetsstrasse 15, D-44801 Bochum, Germany E-mail contact: hodapp at ifa.hawaii.edu The small molecular cloud Lynds 1634 contains at least three outflow sources. We found one of these, IRS 7, to be variable with a period of 37.14 ± 0.04 days and an amplitude of approximately 2 mag in the Ks band. The light curve consists of a quiescent phase with little or no variation, and a rapid outburst phase. During the outburst phase, the rapid brightness variation generates light echoes that propagate into the surrounding molecular cloud, allowing a measurement of the distance to IRS 7 of 404 pc ± 35 pc. We observed only a marginally significant change in the H − K color during the outburst phase. The K-band spectrum of IRS 7 shows CO bandhead emission but its equivalent width does not change significantly with the phase of the light curve. The H2 1–0 S(1) line emission does

21 not follow the variability of the continuum flux. We also used the imaging data for a study of the outflows originating from the IRS 7 and the FIR source IRAS 05173-0555, and confirm that these are indeed distinct outflows. Accepted by The Astrophysical Journal http://arxiv.org/pdf/1510.00429

The Arches Cluster: Extended Structure and Tidal Radius Matthew W. Hosek Jr.1, Jessica R. Lu1, Jay Anderson2, Andrea M. Ghez3, Mark R. Morris3 and William I. Clarkson4 1 Institute for Astronomy, University of Hawaii, USA 2 Space Telescope Science Institute, USA 3 UCLA, USA 4 University of Michigan-Dearborn, USA E-mail contact: mwhosek at hawaii.edu At a projected distance of ∼26 pc from Sgr A*, the Arches cluster provides insight to star formation in the extreme Galactic Center (GC) environment. Despite its importance, many key properties such as the cluster’s internal structure and orbital history are not well known. We present an astrometric and photometric study of the outer region of the Arches cluster (R > 6.25”) using HST WFC3IR. Using proper motions we calculate membership probabilities for stars down to F153M = 20 mag (∼2.5 M⊙) over a 120” x 120” field of view, an area 144 times larger than previous astrometric studies of the cluster. We construct the radial profile of the Arches to a radius of 75” (∼3 pc at 8 kpc), which can be well described by a single power law. From this profile we placea3σ lower limit of 2.8 pc on the observed tidal radius, which is larger than the predicted tidal radius (1 – 2.5 pc). Evidence of mass segregation is observed throughout the cluster and no tidal tail structures are apparent along the orbital path. The absence of breaks in the profile suggests that the Arches has not likely experienced its closest approach to the GC between ∼0.2 – 1 Myr ago. If accurate, this constraint indicates that the cluster is on a prograde orbit and is located front of the sky plane that intersects Sgr A*. However, further simulations of clusters in the GC potential are required to interpret the observed profile with more confidence. Accepted by ApJ http://arxiv.org/pdf/1509.04716

A Keplerian-like disk around the forming O-type star AFGL 4176 Katharine G. Johnston1, Thomas P. Robitaille2, Henrik Beuther2, Hendrik Linz2, Paul Boley3, Rolf Kuiper4,2, Eric Keto5, Melvin G. Hoare1 and Roy van Boekel2 1 School of Physics & Astronomy, E.C. Stoner Building, The University of Leeds, Leeds, LS2 9JT, UK 2 Max Planck Institute for Astronomy, K¨onigstuhl 17, D-69117 Heidelberg, Germany 3 Ural Federal University, Astronomical Observatory, 51 pr. Lenina, Ekaterinburg, Russia 4 Institute of Astronomy and Astrophysics, Eberhard Karls University T¨ubingen, Auf der Morgenstelle 10, D-72076 T¨ubingen, Germany 5 Harvard-Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138, USA E-mail contact: k.g.johnston at leeds.ac.uk We present Atacama Large Millimeter/submillimeter Array (ALMA) line and continuum observations at 1.2 mm with ∼0.3′′ resolution that uncover a Keplerian-like disk around the forming O-type star AFGL 4176. The continuum emission from the disk at 1.21 mm (source mm1) has a deconvolved size of 870±110AU × 330±300AU and arises from a structure ∼8 M⊙ in mass, calculated assuming a dust temperature of 190K. The first-moment maps, pixel-to- pixel line modeling, assuming local thermodynamic equilibrium (LTE), and position-velocity diagrams of the CH3CN J=13–12 K-line emission all show a velocity gradient along the major axis of the source, coupled with an increase in velocity at small radii, consistent with Keplerian-like rotation. The LTE line modeling shows that where CH3CN J=13–12 is excited, the temperatures in the disk range from ∼70 to at least 300K and that the H2 column density peaks at 2.8×1024 cm−2. In addition, we present Atacama Pathfinder Experiment (APEX) 12CO observations which

22 show a large-scale outflow from AFGL 4176 perpendicular to the major axis of mm1, supporting the disk interpretation. Finally, we present a radiative transfer model of a Keplerian disk surrounding an O7 star, with a disk mass and radius of 12M⊙ and 2000 AU, that reproduces the line and continuum data, further supporting our conclusion that our observations have uncovered a Keplerian disk around an O-type star. Accepted by the Astrophysical Journal Letters http://arxiv.org/pdf/1509.08469

The past photometric history of the FU Ori-type young eruptive star 2MASS J06593158−0405277 = V960 Mon Rajka Jurdana-vepi´ca1 and Ulisse Munari2 1 Physics Department, University of Rijeka, Radmile Matejvi´c, 51000, Rijeka, Croatia 2 INAF Astronomical Observatory of Padova, via dell’Osservatorio 8, 36012 Asiago (VI), Italy E-mail contact: ulisse.munari at oapd.inaf.it The known FU Ori-type young eruptive stars are exceedingly rare (a dozen or so confirmed objects) and 2MASS J06593158−0405277, with its 2014 outburst, is likely the latest addition to the family. All members have displayed just one such eruption in their recorded history, an event lasting for decades. To test the FU Ori nature of 2MASS J06593158−0405277, we have reconstructed its photometric history by measuring its brightness on Harvard photo- graphic plates spanning the time interval 1899–1989. No previous large amplitude eruption similar to that initiated in 2014 has been found, as in bona fide FU Ori-type objects. The median value of the brightness in quiescence of 2MASS J06593158−0405277 is B=15.5, with the time interval 1935–1950 characterized by a large variability (∼1 mag amplitude) that contrasts with the remarkable photometric stability displayed at later epochs. The variability during 1935–1950 can either be ascribed to some T Tau like activity of 2MASS J06593158−0405277 itself or to the also young and fainter star 2MASS J06593168−0405224 that lies 5′′ to the north and forms an unresolved pair at the astrometric scale of Harvard photographic plates. Accepted by New Astronomy http://arxiv.org/pdf/1509.04642

Galactic cold cores VI. Dust opacity spectral index M. Juvela1, K. Demyk2,3, Y. Doi5, A. Hughes3,2,8, C. Lef`evre7, D. J. Marshall9, C. Meny2,3, J. Montillaud4, L. Pagani7, D. Paradis2,3, I. Ristorcelli2,3, J. Malinen1, L. A. Montier2,3, R. Paladini6, V.-M. Pelkonen1 and A. Rivera-Ingraham2,10 1 Department of Physics, P.O.Box 64, FI-00014, University of Helsinki, Finland 2 Universit´ede Toulouse, UPS-OMP, IRAP, F-31028 Toulouse cedex 4, France 3 CNRS, IRAP, 9 Av. colonel Roche, BP 44346, F-31028 Toulouse cedex 4, France 4 Institut UTINAM, CNRS UMR 6213, OSU THETA, Universit´ede Franche-Comt´e, 41 bis avenue de l’Observatoire, 25000 Besan¸con, France 5 The University of Tokyo, Komaba 3-8-1, Meguro, Tokyo, 153-8902, Japan 6 IPAC, Caltech, Pasadena, USA 7 LERMA, CNRS UMR8112, Observatoire de Paris, 61 avenue de l’observatoire 75014 Paris, France 8 Max-Planck-Institut f¨ur Astronomie, Knigstuhl 17, D-69117 Heidelberg, Germany 9 Laboratoire AIM, IRFU/Service d’Astrophysique - CEA/DSM - CNRS - Universit´eParis Diderot, Bt. 709, CEA- Saclay, F-91191, Gif-sur-Yvette Cedex, France 10 European Space Astronomy Centre (ESA-ESAC), PO Box 78, 28691, Villanueva de la Caada, Madrid, Spain E-mail contact: mika.juvela at helsinki.fi The Galactic Cold Cores project has carried out Herschel photometric observations of 116 fields where the Planck survey has found signs of cold dust emission. The fields contain sources in different environments and different phases of star formation. Previous studies have revealed variations in their dust submillimetre opacity. The aim is to measure the value of dust opacity spectral index and to understand its variations spatially and with respect to other parameters, such as temperature, column density, and Galactic location. The dust opacity spectral index β and the dust colour

23 temperature T are derived using Herschel and Planck data. The relation between β and T is examined for the whole sample and inside individual fields. Based on IRAS and Planck data, the fields are characterised by a median colour temperature of 16.1K and a median opacity spectral index of β = 1.84. The values are not correlated with Galactic longitude. We observe a clear T –β anti-correlation. In Herschel observations, constrained at lower resolution by Planck data, the variations follow the column density structure and βFIR can rise to ∼ 2.2 in individual clumps. The highest values are found in starless clumps. The Planck 217GHz band shows a systematic excess that is not restricted to cold clumps and is thus consistent with a general flattening of the dust emission spectrum at millimetre wavelengths. When fitted separately below and above 700 µm, the median spectral index values are βFIR ∼ 1.91 and β(mm) ∼ 1.66. The spectral index changes as a function of column density and wavelength. The comparison of different data sets and the examination of possible error sources show that our results are robust. However, β variations are partly masked by temperature gradients and the changes in the intrinsic grain properties may be even greater. Accepted by A&A http://arxiv.org/pdf/1509.08023

Fingerprints of giant planets in the atmospheres of Herbig stars Mihkel Kama1, Colin P. Folsom2,3 and Paola Pinilla1 1 Leiden Observatory, P.O. Box 9513, NL-2300 RA, Leiden, The Netherlands 2 Universit´ede Grenoble Alpes, IPAG, F-38000 Grenoble, France 3 CNRS, IPAG, F-38000 Grenoble, France E-mail contact: mkama at strw.leidenuniv.nl Around 2% of all A stars have photospheres depleted in refractory elements. This is hypothesised to arise from gas being accreted more efficiently than dust, but the specific processes and the origin of the material – circum- or interstellar – are not known. The same depletion is seen in 30% of young, disk-hosting Herbig Ae/Be stars. We investigate whether the chemical peculiarity originates in a circumstellar disk. Using a sample of systems for which both the stellar abundances and the protoplanetary disk structure are known, we find that stars hosting warm, flaring group I disks typically have Fe, Mg and Si depletions of 0.5 dex compared to the solar-like abundances of stars hosting cold, flat group II disks. The volatile, C and O, abundances in both sets are identical. Group I disks are generally transitional, having radial cavities depleted in millimetre-sized dust grains, while those of group II are usually not. Thus we propose that the depletion of heavy elements emerges as Jupiter-like planets block the accretion of part of the dust, while gas continues to flow towards the central star. We calculate gas to dust ratios for the accreted material and find values consistent with models of disk clearing by planets. Our results suggest that giant planets of ∼0.1 to 10 MJup are hiding in at least 30% of Herbig Ae/Be disks. Accepted by A&A Letters http://arxiv.org/pdf/1509.02741

Spiral-driven accretion in protoplanetary discs - I. 2D models Geoffroy Lesur1,2, Patrick Hennebelle3, and S´ebastien Fromang3 1 Univ. Grenoble Alpes, IPAG, F-38000 Grenoble, France 2 CNRS, IPAG, F-38000 Grenoble, France 3 Laboratoire AIM, CEA/DSM–CNRS–Universit´eParis 7, Irfu/Service d’Astrophysique, CEA-Saclay, 91191 Gif-sur- Yvette, France E-mail contact: geoffroy.lesur at ujf-grenoble.fr We numerically investigate the dynamics of a 2D non-magnetised protoplanetary disc surrounded by an inflow coming from an external envelope. We find that the accretion shock between the disc and the inflow is unstable, leading to the generation of large-amplitude spiral density waves. These spiral waves propagate over long distances, down to radii at least ten times smaller than the accretion shock radius. We measure spiral-driven outward angular momentum −4 −2 −8 −1 transport with 10 <α< 10 for an inflow accretion rate M˙ inf > 10 M⊙ yr . We conclude that the interaction of the disc with its envelope leads to long-lived spiral density waves and radial angular momentum transport with rates that cannot be neglected in young non-magnetised protostellar discs.

24 Accepted by A&A Letters http://arxiv.org/pdf/1509.04859

Spectroscopically resolved far-IR observations of the massive star-forming region G5.89– 0.39 S. Leurini1, F. Wyrowski1, A. Gusdorf2,3, R. Guesten1, M. Gerin2,3, F. Levrier2,3, H. W. Heubers4,5, K. Jacobs6 and O. Ricken1 1 Max-Planck-Institut f¨ur Radioastronomie, Auf dem H¨ugel 69, D-53121, Bonn, Germany 2 ERMA, Observatoire de Paris, Ecole´ Normale Sup´erieure, PSL Research University, CNRS, UMR 8112, F-75014, Paris, France 3 Sorbonne Universit´es, UPMC Univ. Paris 6, UMR 8112, LERMA, F-75005, Paris, France 4 Deutsches Zentrum fr Luft-und Raumfahrt (DLR), Institute of Optical Sensor Systems, Rutherfordstrasse 2, D- 12489, Berlin, Germany 5 Humboldt-Universit¨at zu Berlin, Department of Physics, Newtonstr. 15, 12489 Berlin, Germany 6 K¨olner Observatorium f¨ur Submm Astronomie (KOSMA), I. Physikalisches Institut, Universit¨at zu K¨oln, Z¨ulpicher Str. 77, 50937 Cologne, Germany E-mail contact: sleurini at mpifr.de

The fine-structure line of atomic oxygen at 63 µm ([OI]63µm) is an important diagnostic tool in different fields of astrophysics: it is for example predicted to be the main coolant in several environments of star-forming regions (SFRs). However, our knowledge of this line relies on observations with low spectral resolution, and the real contribution of each component (photon-dominated region, jet) in the complex environment of SFRs to its total flux is poorly understood. We investigate the contribution of jet and photon-dominated region emission, and of absorption to the [OI]63µm line towards the hot gas around the ultra-compact Hii region G5.89–0.39 and study the far-IR line luminosity of the source in different velocity regimes through spectroscopically resolved spectra of atomic oxygen, [CII], CO, OH, and H2O. We mapped G5.89–0.39 in [OI]63µm and in CO(16–15) with the GREAT receiver onboard SOFIA. We also observed 2 the central position of the source in the ground-state OH Π3/2,J = 5/2 → J = 3/2 triplet and in the excited OH 2 Π1/2,J = 3/2 → J = 1/2 triplets with SOFIA. These data were complemented with APEX CO(6–5) and CO(7–6) maps and with Herschel/HIFI maps and single-pointing observations in lines of [CII], H2O, and HF. The [OI] spectra in G5.89–0.39 are severely contaminated by absorptions from the source envelope and from different clouds along the line of sight. Emission is detected only at high velocities, and it is clearly associated with the compact north-south outflows traced by extremely high-velocity emission in low-J CO lines. The mass-loss rate and the energetics of the jet system derived from the [OI]63µm line agree well with previous estimates from CO, thus suggesting that the molecular outflows in G5.89–0.39 are driven by the jet system seen in [OI]. The far-IR line luminosity of G5.89–0.39 is dominated by [OI] at high-velocities; the second coolant in this velocity regime is CO, while [CII], OH and H2O are minor contributors to the total cooling in the outflowing gas. Finally, we derive −8 −6 abundances of different molecules in the outflow: water has low abundances relative to H2 of 10 − 10 , and OH of −8 −8 10 . Interestingly, we find an abundance of HF to H2 of 10 , comparable with measurements in diffuse gas. Our study shows the importance of spectroscopically resolved observations of the [OI]63µm line for using this transition as diagnostic of star-forming regions. While this was not possible until now, the GREAT receiver onboard SOFIA has recently opened the possibility of detailed studies of the [OI]63µm line to investigate the potential of the transition for probing different environments. Accepted by Accepted by Astronomy & Astrophysics http://arxiv.org/pdf/1510.00366

Probing the effects of external irradiation on low-mass protostars through unbiased line surveys Johan E. Lindberg1,2, Jes K. Jørgensen1, Yoshimasa Watanabe3, Suzanne E. Bisschop1, Nami Sakai3 and Satoshi Yamamoto3 1 Centre for Star and Planet Formation, Niels Bohr Institute and Natural History Museum of Denmark, University of

25 Copenhagen, Øster Voldgade 5-7, DK-1350 Copenhagen K, Denmark 2 NASA Goddard Space Flight Center, Astrochemistry Laboratory, Mail Code 691, 8800 Greenbelt Road, Greenbelt, MD 20771, USA 3 Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan E-mail contact: johan.lindberg at nasa.gov Context: The envelopes of molecular gas around embedded low-mass protostars show different chemistries, which can be used to trace their formation history and physical conditions. The excitation conditions of some molecular species can also be used to trace these physical conditions, making it possible to constrain e.g. sources of heating and excitation. Aims: To study the range of influence of an intermediate-mass Herbig Be protostar, and to find what chemical and physical impact feedback effects from the environment may have on embedded protostars. Methods: We follow up on an earlier line survey of the Class 0/I source R CrA IRS7B in the 0.8 mm window with an unbiased line survey of the same source in the 1.3 mm window using the Atacama Pathfinder Experiment (APEX) telescope. We also study the excitation of the key species H2CO, CH3OH, and c-C3H2 in a complete sample of the 18 embedded protostars in the Corona Australis star-forming region. Radiative transfer models are employed to establish abundances of the molecular species. Results: We detect line emission from in total 20 molecular species (32 including isotopologues) in the two surveys. The most complex species detected are CH3OH, CH3CCH, CH3CHO, and CH3CN (the latter two are only tentatively detected). CH3CN and several other complex organic molecules are significantly under-abundant in comparison with what is found towards “hot corino” protostars. The H2CO rotational temperatures of the sources in the region decrease with the distance to the Herbig Be star R CrA, whereas the c-C3H2 temperatures remain constant across the star- forming region. Conclusions: The high H2CO temperatures observed towards objects close to R CrA suggest that this star has a sphere of influence of several 10 000 AU in which it increases the temperature of the molecular gas to 30–50 K through irradiation. The chemistry in the IRS7B envelope differs significantly from many other embedded protostars, which could be an effect of the external irradiation from R CrA. Accepted by A&A http://arxiv.org/pdf/1509.02514v1

Infall, outflow, and turbulence in massive star-forming cores in the G333 giant molecular cloud N. Lo1, B. Wiles2, M.P. Redman2, M.R. Cunningham3, I. Bains4, P.A. Jones1,3, M.G. Burton3, and L. Bronfman1 1 Departamento de Astronom´ıa, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago, Casilla 36-D, Chile 2 Centre for Astronomy, School of Physics, National University of Ireland Galway, University Road, Galway, Ireland 3 School of Physics, University of New South Wales, Sydney 2052, Australia 4 Centre for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218, Hawthorn, VIC 3122, Australia E-mail contact: nlo at das.uchile.cl We present molecular line imaging observations of three massive molecular outflow sources, G333.6−0.2, G333.1−0.4, and G332.8−0.5, all of which also show evidence for infall, within the G333 giant molecular cloud (GMC). All three are within a beam size (36′′) of IRAS sources, 1.2-mm dust clumps, various masing species and radio continuum- detected HII regions and hence are associated with high-mass star formation. We present the molecular line data and derive the physical properties of the outflows including the mass, kinematics, and energetics and discuss the inferred characteristics of their driving sources. Outflow masses are of 10 to 40 M⊙ in each lobe, with core masses of order 3 4 10 M⊙. outflow size scales are a few tenth of a parsec, timescales are of several × 10 years, mass loss rates a few × −4 −1 10 M⊙ yr . We also find the cores are turbulent and highly supersonic. Accepted by MNRAS http://arxiv.org/pdf/1509.03308

26 Ambipolar diffusion in low-mass star formation. I. General comparison with the ideal MHD case J. Masson1, G. Chabrier1,2, P. Hennebelle3, N. Vaytet2, and B. Commer¸con2 1 School of Physics, University of Exeter, Exeter, EX4 4QL, UK 2 Ecole´ Normale Sup´erieure de Lyon, CRAL, UMR CNRS 5574, Universit´ede Lyon, 46 All´ee d?Italie, 69364 Lyon Cedex 07, France 3 Laboratoire de radioastronomie, UMR CNRS 8112, Ecole´ Normale Sup´erieure et Observatoire de Paris, 24 rue Lhomond, 75231 Paris Cedex 05, France E-mail contact: jacques.masson at ens-lyon.fr In this paper, we provide a more accurate description of the evolution of the magnetic flux redistribution during prestellar core collapse by including resistive terms in the magnetohydrodynamics (MHD) equations. We focus more particularly on the impact of ambipolar diffusion. We use the adaptive mesh refinement code RAMSES to carry out such calculations. The resistivities required to calculate the ambipolar diffusion terms were computed using a reduced chemical network of charged, neutral and grain species. The inclusion of ambipolar diffusion leads to the formation of a magnetic diffusion barrier in the vicinity of the core, preventing accumulation of magnetic flux in and around the core and amplification of the field above 0.1G. The mass and radius of the first Larson core remain similar between ideal and non-ideal MHD models. This diffusion plateau has crucial consequences on magnetic braking processes, allowing the formation of disk structures. Magnetically supported outflows launched in ideal MHD models are weakened when using non-ideal MHD. Contrary to ideal MHD misalignment between the initial rotation axis and the magnetic field direction does not significantly affect the results for a given µ, showing that the physical dissipation truly dominate over numerical diffusion. We demonstrate severe limits of the ideal MHD formalism, which yield unphysical behaviours in the long-term evolution of the system. This includes counter rotation inside the outflow, interchange instabilities, and flux redistribution triggered by numerical diffusion, none observed in non-ideal MHD. Disks with Keplerian velocity profiles form in all our non-ideal MHD simulations, with final mass and size which depend on the initial magnetisation. This ranges from a few 0.01 M⊙ and 20–30 AU for the most magnetised case (µ = 2) to 0.2 M⊙ and 40–80 AU for a lower magnetisation (µ = 5). Accepted by A&A http://arxiv.org/pdf/1509.05630

The AU Mic Debris Disk: far-infrared and submillimeter resolved imaging Brenda C. Matthews1,2, Grant Kennedy3, Bruce Sibthorpe4, Wayne Holland5,6, Mark Booth7, Paul Kalas8,9, Meredith MacGregor10, David Wilner10, Bart Vandenbussche11, G¨oran Olofsson12, Joris Blommaert13,14, Alexis Brandeker12, W.R.F. Dent15, Bernard L. de Vries12,16, James Di Francesco1,2, Malcolm Fridlund17,18, James R. Graham8, Jane Greaves19, Ana M. Heras20, Michiel Hogerheijde18, R.J. Ivison21,5, Eric Pantin22, and G¨oran L. Pilbratt20 1 National Research Council of Canada Herzberg Astronomy & Astrophysics Programs, 5071 West Saanich Road, Victoria, BC, Canada, V9E 2E7 2 University of Victoria, 3800 Finnerty Road, Victoria, BC, V8P 5C2, Canada 3 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA, UK 4 SRON Netherlands Institute for Space Research, Groningen, The Netherlands 5 Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK 6 UK Astronomy Technology Centre, Science and Technology Facilities Council, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ, UK 7 Instituto de Astrofsica, Pontificia Universidad Cat´olica de Chile, Vicua Mackenna 4860, 7820436 Macul, Santiago, Chile 8 Department of Astronomy, University of California, 601 Campbell Hall, Berkeley, CA, 94720, USA 9 SETI Institute, Mountain View, CA 94043, USA 10 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 USA 11 Institute of Astronomy KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium 12 Department of Astronomy, AlbaNova University Centre, Stockholm University, SE-106 91 Stockholm, Sweden 13 Astronomy and Astrophysics Research Group, Department of Physics and Astrophysics, Vrije Universiteit Brussel,

27 Pleinlaan 2, 1050 Brussels, Belgium 14 Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol, Belgium 15 Joint ALMA Observatory, Alonso de Cordova 3107, Vitacura 763-0355, Santiago, Chile 16 Stockholm University Astrobiology Centre, SE-106 91 Stockholm, Sweden 17 Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, 439 92, Onsala, Sweden 18 Leiden Observatory, Leiden University, Postbus 9513, 2300 RA, Leiden, The Netherlands 19 School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS, UK 20 ESA, Scientific Support Office, Directorate of Science and Robotic Exploration, European Space Research and Technology Centre (ESTEC/SRE-S), Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands 21 European Southern Observatory, Karl Schwarzschild Strasse 2, Garching, Germany 22 Laboratoire AIM, CEA/DSM - CNRS - Universit Paris Diderot, IRFU/SAp, 91191 Gif sur Yvette, France E-mail contact: brenda.matthews at nrc-cnrc.gc.ca We present far-infrared and submillimeter maps from the Herschel Space Observatory and the James Clerk Maxwell Telescope of the debris disk host star AU Microscopii. Disk emission is detected at 70, 160, 250, 350, 450, 500 and 850 µm. The disk is resolved at 70, 160 and 450 µm. In addition to the planetesimal belt, we detect thermal emission from AU Mic’s halo for the first time. In contrast to the scattered light images, no asymmetries are evident in the −4 disk. The fractional luminosity of the disk is 3.9 × 10 and its mm-grain dust mass is 0.01 M⊕ (±20%). We create a simple spatial model that reconciles the disk SED as a blackbody of 53±2 K (a composite of 39 and 50 K components) and the presence of small (non-blackbody) grains which populate the extended halo. The best fit model is consistent with the “birth ring” model explored in earlier works, i.e., an edge-on dust belt extending from 8.8–40 AU, but with an additional halo component with an r−1.5 surface density profile extending to the limits of sensitivity (140 AU). We confirm that AU Mic does not exert enough radiation force to blow out grains. For stellar mass loss rates of 10–100 × solar, compact (zero porosity) grains can only be removed if they are very small, consistently with previous work, if the porosity is 0.9, then grains approaching 0.1 µm can be removed via corpuscular forces (i.e., the stellar wind). Accepted by ApJ http://arxiv.org/pdf/1509.06415

A distance limited sample of massive star forming cores from the RMS survey L.T. Maud1,2, S.L. Lumsden1, T.J.T. Moore3, J.C. Mottram2, J.S. Urquhart4, and A. Cicchini1,5 1 School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK 2 Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands 3 Astrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool, L5 3RF, UK 4 Max-Planck-Institute f¨ur Radioastronomie, Auf dem H¨ugel 69, D-53121 Bonn, Germany 5 School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK E-mail contact: maud at strw.leidenuniv.nl We analyse C18O (J=3–2) data from a sample of 99 infrared-bright massive young stellar objects (MYSOs) and compact HII regions that were identified as potential molecular-outflow sources in the Red MSX source (RMS) survey. We extract a distance limited (D< 6 kpc) sample shown to be representative of star formation covering the transition between the source types. At the spatial resolution probed, Larson-like relationships are found for these cores, though the alternative explanation, that Larson’s relations arise where surface-density-limited samples are considered, is also consistent with our data. There are no significant differences found between source properties for the MYSOs and HII regions, suggesting that the core properties are established prior to the formation of massive stars, which subsequently have little impact at the later evolutionary stages investigated. There is a strong correlation between dust-continuum and C18O-gas masses, supporting the interpretation that both trace the same material in these IR-bright sources. A clear linear relationship is seen between the independently established core masses and luminosities. The position of MYSOs and compact HII regions in the mass-luminosity plane is consistent with the luminosity expected a cluster of protostars when using a ∼40% star-formation efficiency and indicates that they are at a similar evolutionary stage, near the end of the accretion phase. Accepted by MNRAS http://arxiv.org/pdf/1509.00176

28 CSO and CARMA Observations of L1157. I. A Deep Search for Hydroxylamine (NH2OH) Brett A. McGuire1,2, P. Brandon Carroll2, Niklaus M. Dollhopf3,1, Nathan R. Crockett4, Joanna F. Corby3,1, Ryan A. Loomis5, Andrew Burkhardt2,1, Christopher Shingledecker3, Geoffrey A. Blake2,4, Anthony J. Remijan1 1 National Radio Astronomy Observatory, Charlottesville, VA 22903 2 Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125 3 Department of Astronomy, University of Virginia, Charlottesville, VA 22903 4 Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 5 Department of Astronomy, Harvard University, Cambridge, MA 02138 E-mail contact: bmcguire at nrao.edu

A deep search for the potential glycine precursor hydroxylamine (NH2OH) using the Caltech Submillimeter Observa- tory (CSO) at λ=1.3 mm and the Combined Array for Research in Millimeter-wave Astronomy (CARMA) at λ=3 mm is presented toward the molecular outflow L1157, targeting the B1 and B2 shocked regions. We report non-detections of NH2OH in both sources. We a perform non-LTE analysis of CH3OH observed in our CSO spectra to derive kinetic temperatures and densities in the shocked regions. Using these parameters, we derive upper limit column densities 13 −2 13 −2 of NH2OH of ≤1.4 × 10 cm and ≤1.5 × 10 cm toward the B1 and B2 shocks, respectively, and upper limit −8 −8 relative abundances of NNH2OH/NH2 ≤ 1.4 × 10 and ≤1.5 × 10 , respectively. Accepted by ApJ http://arxiv.org/pdf/1509.03779

High resolution Brγ spectro-interferometry of the transitional Herbig Ae/Be star HD 100546: a Keplerian gaseous disc inside the inner rim I. Mendigut´ıa1, W.J. de Wit2, R.D. Oudmaijer1, J.R. Fairlamb1, A.D. Carciofi3, J.D. Ilee4 and R.G. Vieira3 1 School of Physics and Astronomy, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK. 2 European Southern Observatory, Casilla 19001, Santiago 19, Chile 3 Instituto de Astronomia, Geof´ısica e Ciˆencias atmosf´ericas, Universidade de S˜ao Paulo (USP), Rua do Mat˜ao 1226, Cidade Universit´aria, S˜ao Paulo, SP - 05508-900, Brazil 4 SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, KY16 9SS, UK E-mail contact: I.Mendigutia at leeds.ac.uk We present spatially and spectrally resolved Brγ emission around the planet-hosting, transitional Herbig Ae/Be star HD 100546. Aiming to gain insight into the physical origin of the line in possible relation to accretion processes, we carried out Brγ spectro-interferometry using AMBER/VLTI from three different baselines achieving spatial and spectral resolutions of 2 – 4 mas and 12000. The Brγ visibility is larger than that of the continuum for all baselines. Differential phases reveal a shift between the photocentre of the Brγ line –displaced ∼ 0.6 mas (0.06 au at 100 pc) NE from the star– and that of the K-band continuum emission –displaced ∼ 0.3 mas NE from the star. The photocentres of the redshifted and blueshifted components of the Brγ line are located NW and SE from the photocentre of the peak line emission, respectively. Moreover, the photocentre of the fastest velocity bins within the spectral line tends to be closer to that of the peak emission than the photocentre of the slowest velocity bins. Our results are consistent < with a Brγ emitting region inside the dust inner rim (∼ 0.25 au) and extending very close to the central star, with a Keplerian, disc-like structure rotating counter-clockwise, and most probably flared (∼ 25◦). Even though the main contribution to the Brγ line does not come from gas magnetically channelled on to the star, accretion on to HD −7 −1 100546 could be magnetospheric, implying a mass accretion rate of a few 10 M⊙ yr . This value indicates that the observed gas has to be replenished on time-scales of a few months to years, perhaps by planet-induced flows from the outer to the inner disc as has been reported for similar systems. Accepted by MNRAS [http://arxiv.org/pdf/1509.05411

29 Triggered fragmentation in self-gravitating discs: forming fragments at small radii Farzana Meru1 1 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA, UK E-mail contact: farzana.meru at ast.cam.ac.uk We carry out three dimensional radiation hydrodynamical simulations of gravitationally unstable discs to explore the movement of mass in a disc following its initial fragmentation. We find that the radial velocity of the gas in some parts of the disc increases by up to a factor of ≈ 10 after the disc fragments, compared to before. While the movement of mass occurs in both the inward and outward directions, the inwards movement can cause the inner spirals of a self-gravitating disc to become sufficiently dense such that they can potentially fragment. This suggests that the dynamical behaviour of fragmented discs may cause subsequent fragmentation to occur at smaller radii than initially expected, but only after an initial fragment has formed in the outer disc. Accepted by Monthly Notices of the Royal Astronomical Society http://arxiv.org/pdf/1509.03635v2 Movies of Simulation 1 available at: http://www.ast.cam.ac.uk/\%7Efmeru/Movies/massmovementsigma.mov and http://www.ast.cam.ac.uk/\%7Efmeru/Movies/massmovementvR.mov

The JCMT Plane Survey: early results from the l = 30 degree field T.J.T. Moore1, R. Plume2, M.A. Thompson3, H. Parsons4, J.S. Urquhart5, D.J. Eden1,6, J.T. Dempsey4, L.K. Morgan1, H.S. Thomas4, J. Buckle7,8, C.M. Brunt9, H. Butner10, D. Carretero8, A. Chrysostomou3, H.M. deVilliers3, M. Fich11, M.G. Hoare12, G. Manser3, J.C. Mottram13, C. Natario3, F. Olguin12, N. Peretto14, D. Polychroni15, R.O. Redman4, A.J. Rigby1, C. Salji8, L.J. Summers9, D. Berry4, M.J. Currie4, T. Jenness4,16, M. Pestalozzi17, A. Traficante18, P. Bastien19, J. diFrancesco20, C.J. Davis1, A. Evans21, P. Friberg4, G.A. Fuller18, A.G. Gibb22, S.J. Gibson23, T. Hill24, D. Johnstone4,20,25, G. Joncas26, S.N. Longmore1, S.L. Lumsden12, P.G. Martin27, Q. Nguyˆe˜n Lu’o’ng27, J. E. Pi˜neda18, C. Purcell28, J.S. Richer8, G.H. Schieven20, R. Shipman29, M. Spaans30, A.R. Taylor2, S. Viti31, B. eferling32, G.J. White33,34, M. Zhu35 1 Astrophysics Research Institute, Liverpool John Moores University, Ic2 Liverpool Science Park, 146 Brownlow Hill Liverpool, L3 5RF, UK 2 Department of Physics & Astronomy, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N1N4, Canada 3 Centre for Astrophysics Research, Science & Technology Research Institute, University of Hertfordshire, College Lane, Hatfield, Herts, AL10 9AB, UK 4 Joint Astronomy Centre, 660 N. A’ohoku Place, University Park, Hilo, Hawaii 96720, USA 5 Max-Planck-Institut f¨ur Radioastronomie, Auf dem H¨ugel 69, 53121 Bonn, Germany 6 Observatoire astronomique de Strasbourg, Universit´ede Strasbourg, CNRS, UMR 7550, France 7 Astrophysics Group, Cavendish Laboratory, J J Thomson Avenue, Cambridge, CB3 0HE, UK 8 Kavli Institute for Cosmology, Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA, UK 9 Astrophysics Group, School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL, UK 10 Department of Physics and Astronomy, James Madison University, MSC 4502-901 Carrier Drive, Harrisonburg, VA 22807, USA 11 Department of Physics, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada 12 School of Physics and Astronomy, E C Stoner Building, University of Leeds, Leeds LS2 9JT, UK 13 Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden, The Netherlands 14 School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA, UK 15 University of Athens, Department of Astrophysics, Astronomy and Mechanics, Faculty of Physics, Panepistimiopolis, 15784 Zografos, Athens, Greece 16 501 Space Sciences, Cornell University, Ithaca, NY 14853 USA 17 Istituto di Astrofisica e Planetologia Spaziali (IAPS-INAF), via Fosso del Cavaliere 100, 00133, Roma, Italy

30 18 Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL, UK 19 Centre de recherche en astrophysique du Qu´ebec and D´epartment de Physique, Universit´ede Montr´eal, Montr´eal, H3C 3J7, Canada 20 NRC Herzberg Astronomy and Astrophysics, 5071 West Saanich Road, Victoria, BC, V9E 2E7, Canada 21 Astrophysics Group, Keele University, Keele, Staffordshire ST5 5BG, UK 22 Department of Physics & Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada 23 Department of Physics and Astronomy, Western Kentucky University, Bowling Green, KY 42101, USA 24 Joint ALMA Observatory, 3107 Alonso de Cordova, Vitacura, Santiago, Chile 25 Department of Physics and Astronomy, University of Victoria, Victoria, BC, V8P 1A1, Canada 26 D´epartement de physique, de g´enie physique et d’optique, Centre de Recherche en Astrophysique du Qu´ebec, Universit´eLaval, QC G1K 7P4, Canada 27 Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto, ON M5S 3H8, Canada 28 Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006, Australia 29 SRON Netherlands Institute for Space Research, University of Groningen PO-Box 800, 9700 AV Groningen The Netherlands 30 Kapteyn Astronomical Institute, PO Box 800, NL-9700 AV Groningen, the Netherlands 31 Department of Physics and Astronomy, University College London, WC1E 6BT London, UK 32 Universit¨at Bamberg, Markusplatz 3, Bamberg, 96045 Germany 33 Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA, UK 34 RALSpace, The Rutherford Appleton Laboratory, Chilton, Didcot OX11 0NL, UK 35 National Astronomical Observatories, Chinese Academy of Science, 20A Datun Road, Chaoyang District, Beijing 100012, China E-mail contact: T.J.Moore at ljmu.ac.uk We present early results from the JCMT Plane Survey (JPS), which has surveyed the northern inner Galactic plane between longitudes l =7◦ and l = 63◦ in the 850 µm continuum with SCUBA-2, as part of the James Clerk Maxwell Telescope Legacy Survey programme. Data from the l = 30◦ survey region, which contains the massive star-forming regions W43 and G29.96, are analysed after approximately 40% of the observations had been completed. The pixel-to- pixel noise is found to be 19 mJy beam−1, after a smooth over the beam area, and the projected equivalent noise levels in the final survey are expected to be around 10 mJy beam−1. An initial extraction of compact sources was performed using the FellWalker method resulting in the detection of 1029 sources above a 5σ surface-brightness threshold. The completeness limits in these data are estimated to be around 0.2 Jy beam−1 (peak flux density) and 0.8 Jy (integrated flux density) and are therefore probably already dominated by source confusion in this relatively crowded section of the survey. The flux densities of extracted compact sources are consistent with those of matching detections in the shallower ATLASGAL survey. We analyse the virial and evolutionary state of the detected clumps in the W43 star-forming complex and find that they appear younger than the Galactic-plane average. Accepted by MNRAS http://arxiv.org/pdf/1509.00318

The CH+ Abundance in Turbulent, Diffuse Molecular Clouds Andrew T. Myers1, Christopher F. McKee2,3, and Pak Shing Li3 1 Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA 2 Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA 3 Department of Astronomy, University of California, Berkeley, Berkeley, CA 94720, USA E-mail contact: atmyers at lbl.gov The intermittent dissipation of interstellar turbulence is an important energy source in the diffuse ISM. Though on average smaller than the heating rates due to cosmic rays and the photoelectric effect on dust grains, the turbulent cascade can channel large amounts of energy into a relatively small fraction of the gas that consequently undergoes significant heating and chemical enrichment. In particular, this mechanism has been proposed as a solution to the

31 long-standing problem of the high abundance of CH+ along diffuse molecular sight lines, which steady-state, low temperature models under-produce by over an order of magnitude. While much work has been done on the structure and chemistry of these small-scale dissipation zones, comparatively little attention has been paid to relating these zones to the properties of the large-scale turbulence. In this paper, we attempt to bridge this gap by estimating the temperature and CH+ column density along diffuse molecular sight-lines by post-processing 3-dimensional MHD turbulence simulations. Assuming reasonable values for the cloud density (30 cm−3), size (20 pc), and velocity dispersion (2.3 km s−1), we find that our computed abundances compare well with CH+ column density observations, as well as with observations of emission lines from rotationally excited H2 molecules. Accepted by MNRAS http://arxiv.org/pdf/1509.03259

+ Chemical evolution of the HC3N and N2H molecules in dense cores of the Vela C giant molecular cloud complex Satoshi Ohashi1, Ken’ichi Tatematsu2,3, Kosuke Fujii1, Patricio Sanhueza2, Quang Nguyen Luong2, Minho Choi4, Tomoya Hirota2 and Norikazu Mizuno1,2 1 Department of Astronomy, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 133-0033, Japan 2 National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan 3 Department of Astronomical Science, SOKENDAI (The Graduate University for Advanced Studies), 2-21-1 Osawa, Mitaka, Tokyo 181-8588 4 Korea Astronomy and Space Science Institute, Daedeokdaero 7 76, Yuseong, Daejeon 305-348, South Korea E-mail contact: satoshi.ohashi at nao.ac.jp + We have observed the HC3N (J = 10 − 9) and N2H (J =1 − 0) lines toward the Vela C molecular clouds with the Mopra 22 m telescope to study chemical characteristics of dense cores. The intensity distributions of these molecules are similar to each other at an angular resolution of 53′′, corresponding to 0.19 pc suggesting that these molecules trace + the same dense cores. We identified 25 local peaks in the velocity-integrated intensity maps of the HC3N and/or N2H emission. Assuming LTE conditions, we calculated the column densities of these molecules and found a tendency that + N2H /HC3N abundance ratio seems to be low in starless regions while it seems to be high in star-forming regions, + similar to the tendencies in the NH3/CCS, NH3/HC3N, and N2H /CCS abundance ratios found in previous studies of dark clouds and the Orion A GMC. We suggest that carbon chain molecules, including HC3N, may trace chemically + young molecular gas and N-bearing molecules, such as N2H , may trace later stages of chemical evolution in the Vela + C molecular clouds. It may be possible that the N2H /HC3N abundance ratio of sim 1.4 divides the star-forming + and starless peaks in the Vela C, although it is not as clear as those in NH3/CCS, NH3/HC3N, and N2H /CCS for the Orion A GMC. This less clear separation may be caused by our lower spatial resolution or the misclassification of star-forming and starless peaks due to the larger distance of the Vela C. It might be also possible that the HC3N (J = 10 − 9) transition is not a good chemical evolution tracer compared with CCS (J =4 − 3 and 7 − 6) transitions. Accepted by PASJ http://arxiv.org/pdf/1509.08642.pdf

Impact of the initial disk mass function on the disk fraction Ryou Ohsawa1, Takashi Onaka2, Chikako Yasui2 1 Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan 2 Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan E-mail contact: ohsawa at astron.s.u-tokyo.ac.jp The disk fraction, the percentage of stars with disks in a young cluster, is widely used to investigate the lifetime of the protoplanetary disk, which can impose an important constraint on the planet formation mechanism. The relationship between the decay timescale of the disk fraction and the mass dissipation timescale of an individual disk, however, remains unclear. Here we investigate the effect of the disk mass function (DMF) on the evolution of the disk fraction.

32 We show that the time variation in the disk fraction depends on the spread of the DMF and the detection threshold of the disk. In general, the disk fraction decreases more slowly than the disk mass if a typical initial DMF and a detection threshold are assumed. We find that, if the disk mass decreases exponentially, the mass dissipation timescale of the disk can be as short as 1 Myr even when the disk fraction decreases with the time constant of ∼2.5 Myr. The decay timescale of the disk fraction can be an useful parameter to investigate the disk lifetime, but the difference between the mass dissipation of an individual disk and the decrease in the disk fraction should be properly appreciated to estimate the timescale of the disk mass dissipation. Accepted by PASJ http://arxiv.org/pdf/1509.02280

Cosmic-ray acceleration in young protostars Marco Padovani1,2, Patrick Hennebelle3, Alexandre Marcowith1 and Katia Ferri`ere4 1 Laboratoire Univers et Particules, Universit´ede Montpellier, France 2 INAF–Osservatorio Astrofisico di Arcetri, Firenze, Italy 3 CEA, IRFU, SAp, Centre de Saclay, Gif-Sur-Yvette, France 4 IRAP, Universit´ede Toulouse, France E-mail contact: Marco.Padovani at umontpellier.fr The main signature of the interaction between cosmic rays and molecular clouds is the high ionisation degree. This decreases towards the densest parts of a cloud, where star formation is expected, because of energy losses and magnetic effects. However recent observations hint to high levels of ionisation in protostellar systems, therefore leading to an apparent contradiction that could be explained by the presence of energetic particles accelerated within young protostars. Our modelling consists of a set of conditions that has to be satisfied in order to have an efficient particle acceleration through the diffusive shock acceleration mechanism. We find that jet shocks can be strong accelerators of protons which can be boosted up to relativistic energies. Another possibly efficient acceleration site is located at protostellar surfaces, where shocks caused by impacting material during the collapse phase are strong enough to accelerate protons. Our results demonstrate the possibility of accelerating particles during the early phase of a proto- Solar-like system and can be used as an argument to support available observations. The existence of an internal source of energetic particles can have a strong and unforeseen impact on the star and planet formation process as well as on the formation of pre-biotic molecules. Accepted by Astronomy & Astrophysics http://arxiv.org/pdf/1509.06416

Narrow Na and K Absorption Lines Toward T Tauri Stars - Tracing the Atomic Envelope of Molecular Clouds I. Pascucci1, S. Edwards2, M. Heyer3, E. Rigliaco4, L. Hillenbrand5, U. Gorti6, D. Hollenbach6 and M. N. Simon1 1 Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ 85721, USA 2 Five College Astronomy Department, Smith College, Northampton, MA 01063, USA 3 Department of Astronomy, University of Massachusetts, Amherst, MA 01003-9305, USA 4 Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich, Switzerland 5 Department of Astronomy, California Institute of Technology, Pasadena, CA 91125, USA 6 SETI Institute, Mountain View, CA 94043, USA E-mail contact: pascucci at lpl.arizona.edu We present a detailed analysis of narrow Na i and K i absorption resonance lines toward nearly 40 T Tauri stars in Taurus with the goal of clarifying their origin. The Na i 5889.95 A˚ line is detected toward all but one source, while the weaker K i 7698.96 A˚ line in about two thirds of the sample. The similarity in their peak centroids and the significant positive correlation between their equivalent widths demonstrate that these transitions trace the same atomic gas. The absorption lines are present towards both disk and diskless young stellar objects, which excludes cold gas within the circumstellar disk as the absorbing material. A comparison of Na i and CO detections and peak centroids demonstrates

33 that the atomic and molecular gas are not co-located, the atomic gas is more extended than the molecular gas. The width of the atomic lines corroborates this finding and points to atomic gas about an order of magnitude warmer than the molecular gas.The distribution of Na i radial velocities shows a clear spatial gradient along the length of the filaments. This suggests that absorption is associated with the Taurus molecular cloud. Assuming the gradient is due to cloud rotation, the rotation of the atomic gas is consistent with differential galactic rotation while the rotation of the molecular gas, although with the same rotation axis, is retrograde. Our analysis shows that narrow Na i and K i absorption resonance lines are useful tracers of the atomic envelope of molecular clouds. In line with recent findings from giant molecular clouds, our results demonstrate that the velocity fields of the atomic and molecular gas are misaligned. The angular momentum of a molecular cloud is not simply inherited from the rotating Galactic disk from which it formed but may be redistributed by cloud-cloud interactions. Accepted by The Astrophysical Journal http://arxiv.org/pdf/1510.02022

The dust grain size – stellar luminosity trend in debris discs Nicole Pawellek1 and Alexander V. Krivov1 1 Astrophysikalisches Institut und Universit¨atssternwarte, Friedrich-Schiller-Universit¨at, Schillerg¨aßchen 2-3, 07745 Jena, Germany E-mail contact: nicole.pawellek at uni-jena.de The cross section of material in debris discs is thought to be dominated by the smallest grains that can still stay in bound orbits despite the repelling action of stellar radiation pressure. Thus the minimum (and typical) grain size smin is expected to be close to the radiation pressure blowout size sblow. Yet a recent analysis of a sample of Herschel-resolved debris discs showed the ratio smin/sblow to systematically decrease with the stellar luminosity from about ten for solar-type stars to nearly unity in the discs around the most luminous A-type stars. Here we explore this trend in more detail, checking how significant it is and seeking to find possible explanations. We show that the trend is robust to variation of the composition and porosity of dust particles. For any assumed grain properties and stellar parameters, we suggest a recipe of how to estimate the “true” radius of a spatially unresolved debris disc, based solely on its spectral energy distribution. The results of our collisional simulations are qualitatively consistent with the trend, although additional effects may also be at work. In particular, the lack of grains with small smin/sblow for lower luminosity stars might be caused by the grain surface energy constraint that should limit the size of the smallest collisional fragments. Also, a better agreement between the data and the collisional simulations is achieved when assuming debris discs of more luminous stars to have higher dynamical excitation than those of less luminous primaries. This would imply that protoplanetary discs of more massive young stars are more efficient in forming big planetesimals or planets that act as stirrers in the debris discs at the subsequent evolutionary stage. Accepted by MNRAS http://arxiv.org/pdf/1509.04032

Grain Growth in the Circumstellar Disks of the Young Stars CY Tau and DoAr 25 Laura M. P´erez1,2, Claire J. Chandler1, Andrea Isella3, John M. Carpenter4, Sean M. Andrews5, Nuria Calvet6, Stuartt A. Corder7, Adam T. Deller8, Cornelis P. Dullemond9, Jane S. Greaves10, Robert J. Harris11, Thomas Henning12, Woojin Kwon13, Joseph Lazio14, Hendrik Linz12, Lee G. Mundy15, Luca Ricci5, Anneila I. Sargent4, Shaye Storm15, Marco Tazzari16, Leonardo Testi16,17, David J. Wilner5 1 National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801, USA 2 Jansky Fellow of the National Radio Astronomy Observatory 3 Rice University, 6100 Main Street, Houston, TX 77005, USA 4 California Institute of Technology, 1200 East California Blvd, Pasadena, CA 91125, USA 5 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 6 University of Michigan, 830 Dennison Building, 500 Church Street, Ann Arbor, MI 48109, USA 7 Joint ALMA Observatory, Av. Alonso de C?ordova 3107, Vitacura, Santiago, Chile 8 The Netherlands Institute for Radio Astronomy (ASTRON), 7990-AA Dwingeloo, The Netherlands

34 9 Heidelberg University, Center for Astronomy, Albert Ueberle Str 2, Heidelberg, Germany 10 University of St. Andrews, Physics and Astronomy, North Haugh, St Andrews KY16 9SS 11 University of Illinois, 1002 West Green St., Urbana, IL 61801, USA 12 Max-Planck-Institut f¨ur Astronomie, K¨onigstuhl 17, 69117 Heidelberg, Germany 13 Korea Astronomy and Space Science Institute, 776 Daedeok-daero, Yuseong-gu, Daejeon 34055, Korea 14 Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr, Pasadena, CA 91106 15 University of Maryland, College Park, MD 20742, USA 16 European Southern Observatory, Karl Schwarzschild str. 2, 85748 Garching, Germany 17 INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy E-mail contact: lperez at nrao.edu We present new results from the Disks@EVLA program for two young stars: CY Tau and DoAr 25. We trace continuum emission arising from their circusmtellar disks from spatially resolved observations, down to tens of AU scales, at λ = 0.9, 2.8, 8.0, and 9.8 mm for DoAr25 and at λ = 1.3, 2.8, and 7.1 mm for CY Tau. Additionally, we constrain the amount of emission whose origin is different from thermal dust emission from 5 cm observations. Directly from interferometric data, we find that observations at 7 mm and 1 cm trace emission from a compact disk while millimeter-wave observations trace an extended disk structure. From a physical disk model, where we characterize the disk structure of CY Tau and DoAr 25 at wavelengths shorter than 5 cm, we find that (1) dust continuum emission is optically thin at the observed wavelengths and over the spatial scales studied, (2) a constant value of the dust opacity is not warranted by our observations, and (3) a high-significance radial gradient of the dust opacity spectral index, β, is consistent with the observed dust emission in both disks, with low-β in the inner disk and high-β in the outer disk. Assuming that changes in dust properties arise solely due to changes in the maximum particle size (amax), we constrain radial variations of amax in both disks, from cm-sized particles in the inner disk (R< 40 AU) to millimeter sizes in the outer disk (R> 80 AU). These observational constraints agree with theoretical predictions of the radial-drift barrier, however, fragmentation of dust grains could explain our amax(R) constraints if these disks have lower turbulence and/or if dust can survive high-velocity collisions. Accepted by ApJ http://arxiv.org/pdf/1509.07520

Testing particle trapping in transition disks with ALMA P. Pinilla1, N. van der Marel1, L. M. P´erez2,3, E. F. van Dishoeck1,4, S. Andrews5, T. Birnstiel5, G. Herczeg6, K. M. Pontoppidan7 and T. van Kempen1 1 Leiden Observatory, Leiden University, P.O. Box 9513, 2300RA Leiden, The Netherlands 2 National Radio Astronomy Observatory, P.O. Box O, Socorro NM 87801, USA 3 Jansky Fellow 4 Max-Planck-Institut f¨ur Extraterrestrische Physik, Giessenbachstrasse 1, 85748, Garching, Germany 5 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 6 Kavli Institute for Astronomy and Astrophysics, Peking University, Yi He Yuan Lu 5, Haidian District, Beijing 100871, China 7 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA E-mail contact: pinilla at strw.leidenuniv.nl Some protoplanetary disks show evidence of inner dust cavities. Recent observations of gas and dust of these so-called transition disks have given major support to the hypothesis that the origin of such cavities is trapping in pressure bumps. We present new Atacama Large Millimeter/submillimeter Array (ALMA) continuum observations at 336 GHz of two transition disks, SR21 and HD 135344B. In combination with previous ALMA observations from Cycle 0 at 689 GHz, we compare the visibility profiles at the two frequencies and calculate the spectral index (αmm). The observations of SR 21 show a clear shift in the visibility nulls, indicating radial variations of the inner edge of the cavity at the two wavelengths. Notable radial variations of the spectral index are also detected for SR 21 with values < of αmm ∼ 3.8 − 4.2 in the inner region (r ∼ 35 AU) and αmm ∼ 2.6 − 3.0 outside. An axisymmetric ring (“ring model”) or a ring with the addition of an azimuthal Gaussian profile, for mimicking a vortex structure (“vortex model”), is assumed for fitting the disk morphology. For SR 21, the ring model better fits the emission at 336 GHz, conversely the vortex model better fits the 689 GHz emission. For HD 135344B, neither a significant shift in the null of the visibilities

35 nor radial variations of αmm are detected. Furthermore, for HD 135344B, the vortex model fits both frequencies better than the ring model. However, the azimuthal extent of the vortex increases with wavelength, contrary to model predictions for particle trapping by anticyclonic vortices. For both disks, the azimuthal variations of αmm remain uncertain to confirm azimuthal trapping. The comparison of the current data with a generic model of dust evolution that includes planet-disk interaction suggests that particles in the outer disk of SR 21 have grown to millimetre sizes and have accumulated in a radial pressure bump, whereas with the current resolution there is not clear evidence of radial trapping in HD 135344B, although it cannot be excluded either. Accepted by A&A http://arxiv.org/pdf/1509.03040.pdf

Chemical Imaging of the CO Snow Line in the HD 163296 Disk Chunhua Qi1, Karin I. Oberg¨ 1, Sean, M. Andrews1, David, J. Wilner1, Edwin A. Bergin2, A. Meredith Hughes3, Michiel Hogherheijde4 and Paola D’Alessio5 1 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA 2 University of Michigan, Ann Arbor, MI 48109, USA 3 Wesleyan University, Middletown, CT 06459, USA 4 Leiden University, 2300 RA Leiden, The Netherlands 5 UNAM, 58089 Morelia, Michoac´an, M´exico E-mail contact: cqi at cfa.harvard.edu

The condensation fronts (snow lines) of H2O, CO and other abundant volatiles in the midplane of a protoplanetary disk affect several aspects of planet formation. Locating the CO snow line, where the CO gas column density is expected to drop substantially, based solely on CO emission profiles is challenging. This has prompted an exploration of chemical + + signatures of CO freeze-out. We present ALMA Cycle 1 observations of the N2H J = 3 − 2 and DCO J = 4 − 3 emission lines toward the disk around the Herbig Ae star HD 163296 at ∼ 0.5′′ (60 AU) resolution, and evaluate their + utility as tracers of the CO snow line location. The N2H emission is distributed in a ring with an inner radius at 90 AU, corresponding to a midplane temperature of 25 K. This result is consistent with a new analysis of optically 18 + thin C O data, which implies a sharp drop in CO abundance at 90 AU. Thus N2H appears to be a robust tracer of the midplane CO snow line. The DCO+ emission also has a ring morphology, but neither the inner nor the outer radius coincides with the CO snow line location of 90 AU, indicative of a complex relationship between DCO+ emission and CO freeze-out in the disk midplane. Compared to TW Hya, CO freezes out at a higher temperature in the disk around HD 163296 (25 vs. 17 K in the TW Hya disk), perhaps due to different ice compositions. This highlights the importance of actually measuring the CO snow line location, rather than assuming a constant CO freeze-out temperature for all disks. Accepted by ApJ http://arxiv.org/pdf/1510.00968

Kepler observations of A–F pre-main sequence stars in Upper Scorpius: Discovery of six new δ Scuti and one γ Doradus stars V. Ripepi1, L. Balona2, G. Catanzaro3, M. Marconi1, F. Palla4, M. Giarrusso5 1 INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, I-80131, Napoli, Italy 2 South African Astronomical Observatory, PO Box 9, Observatory 7935, Cape Town, South Africa 3 INAF-Osservatorio Astrofisico di Catania, Via S.Sofia 78, I-95123, Catania, Italy 4 Osservatorio Astrofisico di Arcetri, Firenze, Italy 5 Universit´adegli studi di Catania, Via S.Sofia 78, I-95123 Catania, Italy E-mail contact: ripepi at oacn.inaf.it We present light curves and periodograms for 27 stars in the young Upper Scorpius association (age=11±1 Myr) obtained with the Kepler spacecraft. This association is only the second stellar grouping to host several pulsating pre- main sequence (PMS) stars which have been observed from space. From an analysis of the periodograms, we identify six δ Scuti variables and one γ Doradus star. These are most likely PMS stars or else very close to the zero-age main

36 sequence. Four of the δ Scuti variables were observed in short-cadence mode, which allows us to resolve the entire frequency spectrum. For these four stars, we are able to infer some qualitative information concerning their ages. For the remaining two δ Scuti stars, only long-cadence data are available, which means that some of the frequencies are likely to be aliases. One of the stars appears to be a rotational variable in a hierarchical triple system. This is a particularly important object, as it allows the possibility of an accurate mass determination when radial velocity observations become available. We also report on new high-resolution echelle spectra obtained for some of the stars of our sample. Accepted by MNRAS http://arxiv.org/pdf/1509.06943

A network of filaments detected by Herschel in the Serpens Core: A laboratory to test simulations of low-mass star formation V. Roccatagliata1, J. E. Dale1,2, T. Ratzka3, L. Testi4,5,2, A. Burkert1,2, C. Koepferl6,7, A. Sicilia- Aguilar8,9, C. Eiroa9 and B. Gaczkowski1 1 Universit¨ats-Sternwarte M¨unchen, Ludwig-Maximilians-Universit¨at, Scheinerstr. 1, 81679 M¨unchen, Germany 2 Excellence Cluster ‘Universe’, Boltzmannstr. 2, 85748 Garching bei M¨unchen, Germany 3 nstitute for Physics / IGAM, NAWI Graz, Karl-Franzens-Universit¨at, Universit¨atsplatz 5/II, 8010 Graz, Austria 4 ESO, Karl-Schwarzschild-Strasse 2 D-85748 Garching bei M¨unchen, Germany 5 INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze, Italy 6 Max Planck Institute for Astronomy, K¨onigstuhl 17, 69117 Heidelberg, Germany 7 Max Planck International Research School for Astronomy and Cosmology, Heidelberg, Germany 8 SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK 9 Departamento de F´ısica Te´orica, Facultad de Ciencias, Universidad Aut´onoma de Madrid, 28049 Cantoblanco, Madrid, Spain E-mail contact: vrocca at usm.uni-muenchen.de Context. Filaments represent a key structure during the early stages of the star formation process. Simulations show that filamentary structures commonly formed before and during the formation of cores. Aims. The Serpens Core is an ideal laboratory for testing the state of the art of simulations of turbulent Giant Molecular Clouds. Methods. We used Herschel observations of the Serpens Core to compute temperature and column density maps of the region. We selected the early stages of a recent simulation of star-formation, before stellar feedback was initiated, with similar total mass and physical size as the Serpens Core. We also derived temperature and column density maps from the simulations. The observed distribution of column densities of the filaments was analyzed, first including and then masking the cores. The same analysis was performed on the simulations as well. Results. A radial network of filaments was detected in the Serpens Core. The analyzed simulation shows a striking morphological resemblance to the observed structures. The column density distribution of simulated filaments without cores shows only a log-normal distribution, while the observed filaments show a power-law tail. The power-law tail becomes evident in the simulation if the focus is only the column density distribution of the cores. In contrast, the observed cores show a flat distribution. Conclusions. Even though the simulated and observed filaments are subjectively similar–looking, we find that they behave in very different ways. The simulated filaments are turbulence-dominated regions; the observed filaments are instead self-gravitating structures that will probably fragment into cores. Accepted by A&A

An ALMA Survey for Disks Orbiting Low-Mass Stars in the TW Hya Association David R. Rodriguez1, Gerrit van der Plas1,2, Joel H. Kastner3, Adam C. Schneider4, Jacqueline K. Faherty5,6, Diego Mardones1, Subhanjoy Mohanty7, and David Principe2,8 1 Departamento de Astronom´ıa, Universidad de Chile, Casilla 36-D, Santiago, Chile 2 Millennium Nucleus Protoplanetary Disks, Chile 3 Center for Imaging Science, School of Physics & Astronomy, and Laboratory for Multiwavelength Astrophysics,

37 Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623, USA 4 Department of Physics and Astronomy, University of Toledo, 2801 W. Bancroft St., Toledo, OH 43606, USA 5 Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washing- ton, DC 20015, USA 6 Hubble Fellow 7 Imperial College London, 1010 Blackett Lab., Prince Consort Road, London SW7 2AZ, UK 8 N´ucleo de Astronom´ıa, Facultad de Ingenier´ıa, Universidad Diego Portales, Av. Ejercito 441, Santiago, Chile E-mail contact: drodrigu at das.uchile.cl

We have carried out an ALMA survey of 15 confirmed or candidate low-mass (<0.2 M⊙) members of the TW Hya Association (TWA) with the goal of detecting molecular gas in the form of CO emission, as well as providing constraints on continuum emission due to cold dust. Our targets have spectral types of M4–L0 and hence represent the extreme low end of the TWA’s mass function. Our ALMA survey has yielded detections of 1.3mm continuum emission around 4 systems (TWA 30B, 32, 33, & 34), suggesting the presence of cold dust grains. All continuum sources are unresolved. TWA 34 further shows 12CO(2–1) emission whose velocity structure is indicative of Keplerian rotation. Among the sample of known ∼7–10 Myr-old star/disk systems, TWA 34, which lies just ∼50 pc from Earth, is the lowest mass star thus far identified as harboring cold molecular gas in an orbiting disk. Accepted by A&A http://arxiv.org/pdf/1509.04589

Terrestrial-type planet formation: Comparing different types of initial conditions M.P. Ronco1, G.C. de El´ıa1 and O.M. Guilera1 1 Facultad de Ciencias Astronmicas y Geof´ısicas, Universidad Nacional de La Plata and Instituto de Astrofsica de La Plata, CCT La Plata-CONICET-UNLP, Paseo del Bosque S/N (1900), La Plata, Argentina E-mail contact: mpronco at fcaglp.unlp.edu.ar To study the terrestrial-type planet formation during the post oligarchic growth, the initial distributions of planetary embryos and planetesimals used in N-body simulations play an important role. Most of these studies typically use ad hoc initial distributions based on theoretical and numerical studies. We analyze the formation of planetary systems without gas giants around solar-type stars focusing on the sensitivity of the results to the particular initial distributions of planetesimals and embryos. The formation of terrestrial planets in the habitable zone (HZ) and their final water contents are topics of interest. We developed two different sets of N-body simulations from the same protoplanetary disk. The first set assumes ad hoc initial distributions for embryos and planetesimals and the second set obtains these distributions from the results of a semi-analytical model which simulates the evolution of the gaseous phase of the disk. Both sets form planets in the HZ. Ad hoc initial conditions form planets in the HZ with masses from 0.66 M⊕ to 2.27 M⊕. More realistic initial conditions obtained from a semi-analytical model, form planets with masses between 1.18 M⊕ and 2.21 M⊕. Both sets form planets in the HZ with water contents between 4.5% and 39.48% by mass. Those planets with the highest water contents respect to those with the lowest, present differences regarding the sources of water supply. We suggest that the number of planets in the HZ is not sensitive to the particular initial distribution of embryos and planetesimals and thus, the results are globally similar between both sets. However, the main differences are associated to the accretion history of the planets in the HZ. These discrepancies have a direct impact in the accretion of water-rich material and in the physical characteristics of the resulting planets. Accepted by A&A http://arxiv.org/pdf/1509.07217

A possible link between the power spectrum of interstellar filaments and the origin of the prestellar core mass function A. Roy1, Ph. Andr´e2, D. Arzoumanian1,2, N. Peretto3, P. Palmeirim1, V. K¨onyves1, N. Schneider1,4,M. Benedettini5, J. Di Francesco6,7, D. Elia5, T. Hill1,8, B. Ladjelate1, F. Louvet9, F. Motte1, S. Pezzuto5, E. Schisano5, Y. Shimajiri1, L. Spinoglio5, D. Ward-Thompson10, G. White11,12 1Laboratoire AIM, CEA/DSM-CNRS-Universit´eParis Diderot, IRFU / Service d’Astrophysique, C.E. Saclay, Orme

38 des Merisiers, 91191 Gif-sur-Yvette 2 Institut d’Astrophysique Spatiale, CNRS/Universit´eParis-Sud 11, 91405 Orsay, France 3 School of Physics & Astronomy, Cardiff University, Cardiff, CF29, 3AA, UK 4 Universit´ede Bordeaux, LAB, CNRS/INSU, UMR 5804, BP 89, 33271, Floirac Cedex, France 5 INAF-Istituto di Astrofisica e Planetologia Spaziali, via Fosso del Cavaliere 100, I-00133 Rome, Italy 6 Department of Physics and Astronomy, University of Victoria, P.O. Box 355, STN CSC, Victoria, BC, V8W 3P6, Canada 7 National Research Council Canada, 5071 West Saanich Road, Victoria, BC, V9E 2E7, Canada 8 Joint ALMA Observatory, Alonso de C´ordova 3107, Vitacura, Santiago, Chile 9 Departamento de Astronom´ıa, Universidad de Chile, Santiago, Chile 10 Jeremiah Horrocks Institute, University of Central Lancashire, Preston, Lancashire, PR1 2HE, UK 11 Department of Physics and Astronomy, The Open University, Walton Hall Milton Keynes, MK7 6AA, United Kingdom 12 RAL Space, STFC Rutherford Appleton Laboratory, Chilton Didcot, Oxfordshire OX11 0QX, United Kingdom E-mail contact: Arabindo.roy at cea.fr, Philippe.andre at cea.fr A complete understanding of the origin of the prestellar core mass function (CMF) is crucial. Two major features of the prestellar CMF are: 1) a broad peak below 1 M⊙, presumably corresponding to a mean gravitational fragmentation scale, and 2) a characteristic power-law slope, very similar to the Salpeter slope of the stellar initial mass function (IMF) at the high-mass end. While recent Herschel observations have shown that the peak of the prestellar CMF is close to the thermal Jeans mass in marginally supercritical filaments, the origin of the power-law tail of the CMF/IMF at the high-mass end is less clear. In 2001, Inutsuka proposed a theoretical scenario in which the origin of the power-law tail can be understood as resulting from the growth of an initial spectrum of density perturbations seeded along the long axis of star-forming filaments by interstellar turbulence. Here, we report the statistical properties of the line-mass fluctuations of filaments in the Pipe, Taurus, and IC5146 molecular clouds observed with Herschel for a sample of subcritical or marginally supercritical filaments using a 1-D power spectrum analysis. The observed filament power α spectra were fitted by a power-law function (Ptrue(s) ∝ s ) after removing the effect of beam convolution at small scales. A Gaussian-like distribution of power-spectrum slopes was found, centered at −1.6. The characteristic index of the observed power spectra is close to that of the one-dimensional velocity power spectrum generated by subsonic Kolomogorov turbulence (−1.67). Given the errors, the measured power-spectrum slope is also marginally consistent with the power spectrum index of −2 expected for supersonic compressible turbulence. With such a power spectrum of initial line-mass fluctuations, Inutsuka’s model would yield a mass function of collapsed objects along filaments approaching dN/dM ∝ M −2.3±0.1 at the high-mass end (very close to the Salpeter power law) after a few free-fall 0.5 1.4±0.1 times. An empirical correlation, P (s0) ∝ hNH2 i , was also found between the amplitude of each filament power spectrum P (s0) and the mean column density along the filament hNH2 i. Finally, the dispersion of line-mass

fluctuations along each filament σMline was found to scale with the physical length L of the filament, roughly as 0.7 σMline ∝ L . Overall, our results are consistent with the suggestion that the bulk of the CMF/IMF results from the gravitational fragmentation of filaments. Accepted by A&A http://arxiv.org/pdf/1509.01819v1.pdf

Velocity and magnetic fields within 1000 AU from a massive YSO A. Sanna1, G. Surcis2, L. Moscadelli3, R. Cesaroni3, C. Goddi4, W.H.T. Vlemmings5 and A. Caratti o Garatti6 1 Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, 53121 Bonn, Germany 2 JIVE, Joint Institute for VLBI in Europe, Postbus 2, 7990 AA Dwingeloo, The Netherlands 3 INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy 4 Department of Astrophysics/IMAPP, Radboud University Nijmegen, PO Box 9010, NL-6500 GL Nijmegen, The Netherlands 5 Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-439 92 Onsala, Sweden 6 Dublin Institute for Advanced Studies, School of Cosmic Physics, Astronomy & Astrophysics Section, 31 Fitzwilliam

39 Place, Dublin 2, Ireland E-mail contact: asanna at mpifr-bonn.mpg.de We want to study the velocity and magnetic field morphology in the vicinity (<1000 AU) of a massive young stellar object (YSO), at very high spatial resolution (10-100 AU). We performed milli-arcsecond polarimetric observations of the strong CH3OH maser emission observed in the vicinity of an O-type YSO, in G023.01-00.41. We have combined this information with the velocity field of the CH3OH masing gas previously measured at the same angular resolution. We analyse the velocity and magnetic fields in the reference system defined by the direction of the molecular outflow and the equatorial plane of the hot molecular core at its base, as recently observed on sub-arcsecond scales. We provide a first detailed picture of the gas dynamics and magnetic field configuration within a radius of 2000 AU from a massive YSO. We have been able to reproduce the magnetic field lines for the outer regions (>600 AU) of the molecular envelope, where the magnetic field orientation shows a smooth change with the maser cloudlets position (0.2 degree/AU). Overall, the velocity field vectors well accommodate with the local, magnetic field direction, but still show an average misalignment of 30 degrees. We interpret this finding as the contribution of a turbulent velocity field of about 3.5 km/s, responsible for braking up the alignment between the velocity and magnetic field vectors. We do resolve different gas flows which develop both along the outflow axis and across the disk plane, with an average speed of 7 km/s. In the direction of the outflow axis, we establish a collimation of the gas flow, at a distance of about 1000 AU from the disk plane. In the disk region, gas appears to stream outward along the disk plane for radii greater than 500-600 AU, and inward for shorter radii. Accepted by Astronomy & Astrophysics http://arxiv.org/pdf/1509.05428

Young Stellar Objects in the Massive Star Forming Region: W49 G. Saral1,2, J.L. Hora1, S.E. Willis1, X.P. Koenig3, R.A. Gutermuth4, A.T. Saygac5 1 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge 02138, MA 2 Istanbul University, Graduate School of Science and Engineering, Bozdogan Kemeri Cad. 8, Vezneciler-Istanbul- Turkey 3 Yale University, Department of Astronomy, 208101, New Haven, 06520-8101, CT 4 University of Massachusetts, Department of Astronomy, Amherst, 01003, MA 5 Istanbul University, Faculty of Science, Astronomy and Space Sciences Department, Istanbul-Turkey E-mail contact: saralgozde at gmail.com We present the initial results of our investigation of the star-forming complex W49, one of the youngest and most luminous massive star forming regions in our Galaxy. We used Spitzer/Infrared Array Camera (IRAC) data to investigate massive star formation with the primary objective to locate a representative set of protostars and the clusters of young stars that are forming around them. We present our source catalog with the mosaics from the IRAC data. In this study we used a combination of IRAC, MIPS, Two Micron All Sky Survey (2MASS) and UKIRT Deep Infrared Sky Survey (UKIDSS) data to identify and classify the Young Stellar Objects (YSOs). We identified 232 Class 0/I YSOs, 907 Class II YSOs, and 74 transition disk candidate objects using color-color and color-magnitude diagrams. In addition, to understand the evolution of star formation in W49 we analysed the distribution of YSOs in the region to identify clusters using a minimal spanning tree method. The fraction of YSOs that belong to clusters with >7 members is found to be 52% for a cut-off distance of 96′′ and the ratio of Class II/I objects is 2.1. We compared the W49 region to the G305 and G333 star forming regions and concluded that the W49 has the richest population with 7 subclusters of YSOs. Accepted by ApJ http://arxiv.org/pdf/1509.05749

X-ray to NIR emission from AA Tauri during the dim state – Occultation of the inner disk and gas-to-dust ratio of the absorber P.C. Schneider1,2, K. France3,7, H.M. G¨unther4, G.J. Herczeg5, J. Robrade2, J. Bouvier6, M. McJunkin3, and J.H.M.M. Schmitt2

40 1 European Space Research and Technology Centre (ESA/ESTEC), Keplerlaan 1, 2201 AZ Noordwijk, The Nether- lands 2 Hamburger Sternwarte, Gojenbergsweg 112, Hamburg, 21029 Germany 3 Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309, USA 4 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02139, USA 5 The Kavli Institute for Astronomy and Astrophysics, Peking University, Yi He Yuan Lu 5, Hai Dian Qu, Beijing 100871, China 6 Univ. Grenoble Alpes, IPAG, F-38000 Grenoble, France CNRS, IPAG, F-38000 Grenoble, France 7 Laboratory for Atmospheric and Space Physics, University of Colorado, 392 UCB, Boulder, CO 80309 E-mail contact: christian.schneider at esa.int AA Tau is a well-studied, nearby classical T Tauri star, which is viewed almost edge-on. A warp in its inner disk periodically eclipses the central star, causing a clear modulation of its optical light curve. The system underwent a major dimming event beginning in 2011 caused by an extra absorber, which is most likely associated with additional disk material in the line of sight toward the central source. We present new XMM-Newton X-ray, Hubble Space Telescope FUV, and ground based optical and near-infrared data of the system obtained in 2013 during the long- lasting dim phase. The line width decrease of the fluorescent H2 disk emission shows that the extra absorber is located at r> 1 AU. Comparison of X-ray absorption (NH ) with dust extinction (AV ), as derived from measurements obtained one inner disk orbit (eight days) after the X-ray measurement, indicates that the gas-to-dust ratio as probed by the NH to AV ratio of the extra absorber is compatible with the ISM ratio. Combining both results suggests that the extra absorber, i.e., material at r > 1 AU, has no significant gas excess in contrast to the elevated gas-to-dust ratio previously derived for material in the inner region (∼<0.1 AU). Accepted by A&A http://arxiv.org/pdf/1509.05007

CSI 2264: Accretion process in classical T Tauri stars in the young cluster NGC 2264 A. P. Sousa1, S. H. P. Alencar1, J. Bouvier2,3, J. Stauffer4, L. Venuti2,3, L. Hillenbrand5, A.M. Cody6, P. S. Teixeira7, M. M. Guimares8, P. T. McGinnis1, L. Rebull4, E. Flaccomio9, G. Frsz10 and J. F. Gameiro11 1 Departmento de F´ısica-Icex-UFMG, Antˆonio Carlos, 6627, 31270-90. Belo Horizonte, MG, Brazil 2 Univ. Grenoble Alpes, IPAG, F-38000 Grenoble, France 3 CNRS, IPAG, F-38000 Grenoble, France 4 Spitzer Science Center, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA 5 Astronomy Department, California Institute of Technology, Pasadena, CA 91125, USA 6 NASA Ames Research Center, Kepler Science Office, Mountain View, CA 94035, USA 7 Universitt Wien, Institut fr Astrophysik, Trkenschanzstrasse 17, 1180 Vienna, Austria 8 Departmento de F´ısica, Universidade Federal de Sergipe, Aracaju, SE, Brazil 9 INAFOsservatorio Astronomico di Palermo, Piazza del Parlamento 1, I-90134 Palermo, Italy 10 MIT Kavli Institute for Astrophysics and Space Research, 77 Mass Ave 37-582f, Cambridge, MA 02139, USA 11 Instituto de Astrofsica e Cincias Espaciais and Faculdade de Cincias Universidade do Porto, CAUP, Rua da Estrelas, PT4150-762 Porto, Portugal E-mail contact: alana at fisica.ufmg.br NGC 2264 is a young stellar cluster (∼ 3 Myr) with hundreds of low-mass accreting stars that allow a detailed analysis of the accretion process taking place in the pre-main sequence. Our goal is to relate the photometric and spectroscopic variability of classical T Tauri stars to the physical processes acting in the stellar and circumstellar environment, within a few stellar radii from the star. NGC 2264 was the target of a multiwavelength observational campaign with CoRoT, MOST, Spitzer, and Chandra satellites and photometric and spectroscopic observations from the ground. We classified the CoRoT light curves of accreting systems according to their morphology and compared our classification to several accretion diagnostics and disk parameters. The morphology of the CoRoT light curve reflects the evolution of the accretion process and of the inner disk region. Accretion burst stars present high mass-accretion rates and optically thick inner disks. AA Tau-like systems, whose light curves are dominated by circumstellar dust obscuration, show

41 intermediate mass-accretion rates and are located in the transition of thick to anemic disks. Classical T Tauri stars with spot-like light curves correspond mostly to systems with a low mass-accretion rate and low mid-IR excess. About 30% of the classical T Tauri stars observed in the 2008 and 2011 CoRoT runs changed their light-curve morphology. Transitions from AA Tau-like and spot-like to aperiodic light curves and vice versa were common. The analysis of the Hα emission line variability of 58 accreting stars showed that 8 presented a periodicity that in a few cases was coincident with the photometric period. The blue and red wings of the Hα line profiles often do not correlate with each other, indicating that they are strongly influenced by different physical processes. Classical T Tauri stars have a dynamic stellar and circumstellar environment that can be explained by magnetospheric accretion and outflow models, including variations from stable to unstable accretion regimes on timescales of a few years. Accepted by A&A http://arxiv.org/pdf/1509.05354

The Gaia-ESO Survey: chemical signatures of rocky accretion in a young solar-type star L. Spina1, F. Palla2, S. Randich2, G. Sacco2, R. Jeffires3, L. Magrini2, E. Franciosini2, M.R. Meyer4, G. Tautvaisiene5, G. Gilmore6, E. J. Alfaro7, C. Allende Prieto8,9, T. Bensby10, A. Bragaglia11, E. Flaccomio12, S. E. Koposov6,13, A. C. Lanzafame14, M. T. Costado7, A. Hourihane6, C. Lardo15, J. Lewis6, L. Monaco16, L. Morbidelli2, S. G. Sousa17, C. C. Worley6 and S. Zaggia18 1 Departamento de Astronomia do IAG/USP, Universidade de So Paulo, Rua do Mtao 1226, So Paulo, 05509-900 SP, Brasil 2 INAF - Osservatorio Astrofisico di Arcetri, Largo E. Fermi, 5, 50125, Firenze, Italy 3 Astrophysics Group, Research Institute for the Environment, Physical Sciences and Applied Mathematics, Keele University, Keele, Staffordshire, ST5 5BG, United Kingdom 4 Institute for Astronomy, ETH Zurich, Wolfgang-Pauli Strasse 27, 8093 Zurich, Switzerland 5 Institute of Theoretical Physics and Astronomy, Vilnius University, A. Gostauto 12, 01108, Vilnius, Lithuania 6 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, United Kingdom 7 Instituto de Astrofsica de Andalucia-CSIC, Apdo. 3004, 18080, Granada, Spain 8 Instituto de Astrofsica de Canarias, E-38205 La Laguna, Tenerife, Spain 9 Universidad de La Laguna, Dept. Astrofisica, E-38206 La Laguna, Tenerife, Spain 10 Lund Observatory, Department of Astronomy and Theoretical Physics, Box 43, SE-221 00 Lund, Sweden 11 INAF - Osservatorio Astronomico di Bologna, via Ranzani 1, 40127, Bologna, Italy 12 INAF - Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, 90134, Palermo, Italy 13 Moscow MV Lomonosov State University, Sternberg Astronomical Institute, Moscow 119992, Russia 14 Dipartimento di Fisica e Astronomia, Sezione Astrofisica, Universita di Catania, via S. Sofia 78, 95123, Catania, Italy 15 Astrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool L3 5RF, United Kingdom 16 Departamento de Ciencias Fisicas, Universidad Andres Bello, Re- publica 220, Santiago, Chile 17 Instituto de Astrofsica e Ciencias do Espaco, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762 Porto, Portugal 18 INAF - Padova Observatory, Vicolo dell Osservatorio 5, 35122 Padova, Italy E-mail contact: lspina at usp.br It is well known that newly formed planetary systems undergo processes of orbital reconfiguration and planetary migration. As a result, planets or protoplanetary objects may accrete onto the central star, being fused and mixed into its external layers. If the accreted mass is sufficiently high and the star has a sufficiently thin convective envelope, such events may result in a modification of the chemical composition of the stellar photosphere in an observable way, enhancing it with elements that were abundant in the accreted mass. The recent Gaia-ESO Survey observations of the 10-20 Myr old Gamma Velorum cluster have enabled identifying a star that is significantly enriched in iron with respect to other cluster members. In this Letter we further investigate the abundance pattern of this star, showing that its abundance anomaly is not limited to iron, but is also present in the refractory elements, whose overabundances are correlated with the condensation temperature. This finding strongly supports the hypothesis of a recent accretion of rocky material.

42 Accepted by Astronomy and Astrophysics http://arxiv.org/pdf/1509.00933v2.pdf

Searching for Trans Ethyl Methyl Ether in Orion KL B. Tercero1, J. Cernicharo1, A. L´opez1,2, N. Brouillet3, L. Kolesnikov´a4, R.A. Motiyenko5, L. Margul`es5, J.L. Alonso4, and J.-C. Guillemin6 1 Grupo de Astrof´ısica Molecular. Instituto de CC. de Materiales de Madrid (ICMM-CSIC). Sor Juana In´es de la Cruz, 3, Cantoblanco, 28049 Madrid, Spain 2 Dpto. de Astrof´ısica, CAB. INTA-CSIC. Crta Torrej´on-Ajalvir, km. 4. 28850 Torrej´on de Ardoz. Madrid. Spain 3 Univ. Bordeaux, LAB, UMR 5804, F-33270 Floirac, France; CNRS, LAB, UMR 5804, F-33270 Floirac, France 4 Grupo de Espectroscop´ıaMolecular (GEM), Edificio Quifima, Area´ de Qu´ımica-F´ısica, Laboratorios de Espectro- scop´ıay Bioespectroscop´ıa, Parque Cientfico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain 5 Laboratoire de Physique des Lasers, Atomes, et Mol´ecules, UMR CNRS 8523, Universit de Lille I, F-59655 Villeneuve d’Ascq C´edex, France 6 Institut des Sciences Chimiques de Rennes, Ecole Nationale Sup´erieure de Chimie de Rennes, CNRS, UMR 6226, 11 All´ee de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France E-mail contact: b.tercero at icmm.csic.es

We report on the tentative detection of trans Ethyl Methyl Ether (tEME), t-CH3CH2OCH3, through the identification of a large number of rotational lines from each one of the spin states of the molecule towards Orion KL. We also search for gauche-trans-n-propanol, Gt-n-CH3CH2CH2OH, an isomer of tEME in the same source. We have identified lines of both species in the IRAM 30m line survey and in the ALMA Science Verification data. We have obtained ALMA maps to establish the spatial distribution of these species. Whereas tEME mainly arises from the compact ridge component of Orion, Gt-n-propanol appears at the emission peak of ethanol (south hot core). The derived column densities of these species at the location of their emission peaks are ≤(4.0±0.8)×1015 cm−2 and ≤(1.0±0.2)×1015 cm−2 for tEME and Gt-n-propanol, respectively. The rotational temperature is ∼100K for both molecules. We also provide maps of CH3OCOH, CH3CH2OCOH, CH3OCH3, CH3OH, and CH3CH2OH to compare the distribution of these organic saturated O-bearing species containing methyl and ethyl groups in this region. Abundance ratios of related species and upper limits to the abundances of non-detected ethers are provided. We derive an abundance ratio N(CH3OCH3)/N(tEME)≥150 in the compact ridge of Orion. Accepted by A&A Letters http://arxiv.org/pdf/1509.00179

A circumbinary disc model for the variability of the eclipsing binary CoRoT 223992193 Caroline Terquem1,2, Paul Magnus Sørensen–Clark3,4 and J´erˆome Bouvier3,5 1 Physics Department, University of Oxford, Keble Road, Oxford OX1 3RH, UK 2 Institut d’Astrophysique de Paris, UPMC Univ Paris 06, CNRS, UMR7095, 98 bis bd Arago, F–75014, Paris, France 3 Universit´eGrenoble Alpes, IPAG, F–38000 Grenoble, France 4 Institute of Theoretical Astrophysics, University of Oslo, Oslo 0315, Norway 5 CNRS, IPAG, F–38000 Grenoble, France E-mail contact: caroline.terquem at physics.ox.ac.uk We calculate the flux received from a binary system obscured by a circumbinary disc. The disc is modelled using two dimensional hydrodynamical simulations, and the vertical structure is derived by assuming it is isothermal. The gravitational torque from the binary creates a cavity in the disc’s inner parts. If the line of sight along which the system is observed has a high inclination I, it intersects the disc and some absorption is produced. As the system is not axisymmetric, the resulting light curve displays variability. We calculate the absorption and produce light curves for different values of the dust disc aspect ratio H/r and mass of dust in the cavity Mdust. This model is applied to the high inclination (I = 85◦) eclipsing binary CoRoT 223992193, which shows 5–10% residual photometric variability after the eclipses and a spot model are subtracted. We find that such variations for I ∼ 85◦ can be obtained

43 −3 −12 for H/r = 10 and Mdust ≥ 10 M⊙. For higher H/r, Mdust would have to be close to this lower value and I somewhat less than 85◦. Our results show that such variability in a system where the stars are at least 90% visible at all phases can be obtained only if absorption is produced by dust located inside the cavity. If absorption is dominated by the parts of the disc located close to or beyond the edge of the cavity, the stars are significantly obscured. Accepted by MNRAS http://arxiv.org/pdf/1509.08509

Hunting for planets in the HL Tau disk L. Testi1,2,3, A. Skemer4,5, Th. Henning6, V. Bailey4, D. Defr`ere4, Ph. Hinz4, J. Leisenring4, A. Vaz4, S. Esposito2, A. Fontana7, A. Marconi8, M. Skrutskie9 and C. Veillet10 1 ESO, Karl Schwarzschild str. 2, D-85748 Garching bei Muenchen, Germany 2 INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze, Italy 3 Excellence Cluster ‘Universe’, Boltzmann str. 2, D-85748 Garching bei Muenchen, Germany 4 Steward Observatory, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721, USA 5 University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA 6 Max Planck Institute for Astronomie, K¨onigstuhl 17, D-69117 Heidelberg, Germany 7 INAF-Osservatorio Astronomico di Roma, Monte Porzio, Italy 8 Universit´adegli Studi di Firenze, Dipartimento di Fisica e Astronomia, Firenze, Italy 9 University of Virginia, 530 McCormick Road, Charlottesville, VA 22904, USA 10 LBT Observatory, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721, USA E-mail contact: ltesti at eso.org Recent ALMA images of HL Tau show gaps in the dusty disk that may be caused by planetary bodies. Given the young age of this system, if confirmed, this finding would imply very short timescales for planet formation, probably in a gravitationally unstable disk. To test this scenario, we searched for young planets by means of direct imaging in the L′-band using the Large Binocular Telescope Interferometer mid-infrared camera. At the location of two prominent dips in the dust distribution at ∼70 AU (∼0.′′5) from the central star we reach a contrast level of ∼ 7.5 mag. We did not detect any point source at the location of the rings. Using evolutionary models we derive upper limits of ∼10-15 MJup at ≤ 0.5-1 Ma for the possible planets. With these sensitivity limits we should have been able to detect companions sufficiently massive to open full gaps in the disk. The structures detected at mm-wavelengths could be gaps in the distributions of large grains on the disk midplane, caused by planets not massive enough to fully open gaps. Future ALMA observations of the molecular gas density profile and kinematics as well as higher contrast infrared observations may be able to provide a definitive answer. Accepted by The Astrophysical Journal Letters http://arxiv.org/pdf/1509.06068

Turbulent mixing layers in supersonic protostellar outflows, with application to DG Tauri Marc C White1, Geoffrey V Bicknell1, Ralph Sutherland1, Raquel Salmeron1 and Peter J McGregor1 1 Research School of Astronomy & Astrophysics, The Australian National University, Mount Stromlo Observatory, Cotter Rd, Weston Creek, ACT, 2611, Australia E-mail contact: marc.white at anu.edu.au Turbulent entrainment processes may play an important role in the outflows from young stellar objects at all stages of their evolution. In particular, lateral entrainment of ambient material by high-velocity, well-collimated protostellar jets may be the cause of the multiple emission-line velocity components observed in the microjet-scale outflows driven by classical T Tauri stars. Intermediate-velocity outflow components may be emitted by a turbulent, shock-excited mixing layer along the boundaries of the jet. We present a formalism for describing such a mixing layer based on Reynolds decomposition of quantities measuring fundamental properties of the gas. In this model, the molecular wind from large disc radii provides a continual supply of material for entrainment. We calculate the total stress profile in the mixing layer, which allows us to estimate the dissipation of turbulent energy, and hence the luminosity of the

44 layer. We utilize mappings IV shock models to determine the fraction of total emission that occurs in [Fe ii] 1.644 µm line emission in order to facilitate comparison to previous observations of the young stellar object DG Tauri. Our model accurately estimates the luminosity and changes in mass outflow rate of the intermediate-velocity component of the DG Tau approaching outflow. Therefore, we propose that this component represents a turbulent mixing layer surrounding the well-collimated jet in this object. Finally, we compare and contrast our model to previous work in the field. Accepted by MNRAS http://arxiv.org/pdf/1510.01394

No Keplerian Disk >10 AU around the Protostar B335: Magnetic Braking or Young Age? Hsi-Wei Yen1, Shigehisa Takakuwa1, Patrick M. Koch1, Yusuke Aso2, Shin Koyamatsu2,3, Ruben Krasnopolsky1 and Nagayoshi Ohashi1,3 1 Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan 2 Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan 3 Subaru Telescope, National Astronomical Observatory of Japan, 650 North A’ohoku Place, Hilo, HI 96720, USA E-mail contact: hwyen at asiaa.sinica.edu.tw 18 We have conducted ALMA cycle 2 observations in the 1.3 mm continuum and in the C O (2–1) and SO (56–45) lines at a resolution of ∼0′′. 3 toward the Class 0 protostar B335. The 1.3 mm continuum, C18O, and SO emission all show central compact components with sizes of ∼40–180 AU within more extended components. The C18O component shows signs of infalling and rotational motion. By fitting simple kinematic models to the C18O data, the protostellar −5 −1 mass is estimated to be 0.05 M⊙. The specific angular momentum, on a 100 AU scale, is (4.3±0.5) × 10 km s pc. A similar specific angular momentum, (3–5) × 10−5 km s−1 pc, is measured on a 10 AU scale from the velocity gradient observed in the central SO component, and there is no clear sign of an infalling motion in the SO emission. By comparing the infalling and rotational motion, our ALMA results suggest that the observed rotational motion has not yet reached Keplerian velocity neither on a 100 AU nor even on a 10 AU scale. Consequently, the radius of the Keplerian disk in B335 (if present) is expected to be 1–3 AU. The expected disk radius in B335 is one to two orders of magnitude smaller than those of observed Keplerian disks around other Class 0 protostars. Based on the observed infalling and rotational motion from 0.1 pc to inner 100 AU scales, there are two possible scenarios to explain the presence of such a small Keplerian disk in B335: magnetic braking and young age. If our finding is the consequence of magnetic braking, ∼50% of the angular momentum of the infalling material within a 1000 AU scale might have been removed, and the magnetic field strength on a 1000 AU scale is estimated to be ∼200 µG. If it is young age, the infalling radius in B335 is estimated to be ∼2700 AU, corresponding to a collapsing time scale of ∼5 × 104 yr. Accepted by ApJ http://arxiv.org/pdf/1509.04675

Origin and kinematics of the eruptive flow from XZ Tau revealed by ALMA Luis A. Zapata1, Roberto Galv´an-Madrid1, Carlos Carrasco-Gonz´alez1, Salvador Curiel2, Aina Palau1, Luis F. Rodr´ıguez1, Stan E. Kurtz1, Daniel Tafoya1, and Laurent Loinard1 1 Instituto de Radioastronom´ıay Astrof´ısica, UNAM, Apdo. Postal 3-72 (Xangari), 58089 Morelia, Michoac´an, M´exico 2 Instituto de Astronom´ıa, Universidad Nacional Aut´onoma de M´exico, Ap. 70-264, 04510 DF, M´exico E-mail contact: [email protected] We present high angular resolution (∼0.94′′) 12CO(1-0) Atacama Large Millimeter/Submillimeter Array (ALMA) observations obtained during the 2014 long baseline campaign from the eruptive bipolar flow from the multiple XZ Tau stellar system discovered by the Hubble Space Telescope (HST). These observations reveal, for the first time, the kinematics of the molecular flow. The kinematics of the different ejections close to XZ Tau reveal a rotating and expanding structure with a southeast-northwest velocity gradient. The youngest eruptive bubbles unveiled in the optical HST images are inside of this molecular expanding structure. Additionally, we report a very compact and

45 collimated bipolar outflow emanating from XZ Tau A, which indicates that the eruptive outflow is indeed originating −7 37 from this object. The mass (3 × 10 M⊙) and energetics (Ekin = 3 × 10 ergs) for the collimated outflow are comparable with those found in molecular outflows associated with young brown dwarfs. Accepted by ApJ Letters http://arxiv.org/pdf/1509.00316

On the IMF in a Triggered Star Formation Context Tingtao Zhou1,2, Chelsea X. Huang1,3, D.N.C. Lin1,4,5, Matthias Gritschneder4,6, and Herbert Lau7 1 Kavli Institute for Astronomy & Astrophysics and School of Physics, Peking University, Beijing China 2 Department of Physics, MIT, USA 3 Department of Astrophysical Sciences, Princeton University, USA 4 UCO/Lick Observatory, University of California, USA 5 Institute for Advanced Studies, Tsinghua University, Beijing, China 6 University Observatory Munich, Germany 7 Argelander Institute, University of Bonn, Germany E-mail contact: edmondztt at gmail.com The origin of the stellar initial mass function (IMF) is a fundamental issue in the theory of star formation. It is generally fit with a composite power law. Some clues on the progenitors can be found in dense starless cores that have a core mass function (CMF) with a similar shape. In the low-mass end, these mass functions increase with mass, albeit the sample may be somewhat incomplete; in the high-mass end, the mass functions decrease with mass. There is an offset in the turn-over mass between the two mass distributions. The stellar mass for the IMF peak is lower than the corresponding core mass for the CMF peak in the Pipe Nebula by about a factor of three. Smaller offsets are found between the IMF and the CMFs in other nebulae. We suggest that the offset is likely induced during a starburst episode of global star formation which is triggered by the formation of a few O/B stars in the multi-phase media, which naturally emerged through the onset of thermal instability in the cloud-core formation process. We consider the scenario that the ignition of a few massive stars photoionizes the warm medium between the cores, increases the external pressure, reduces their Bonnor-Ebert mass, and triggers the collapse of some previously stable cores. We quantitatively reproduce the IMF in the low-mass end with the assumption of additional rotational fragmentation. Accepted by ApJ http://arxiv.org/pdf/1509.05047

The Structure of Spiral Shocks Excited by Planetary-mass Companions Zhaohuan Zhu1, Ruobing Dong2,3, James M. Stone1 and Roman R. Rafikov1 1 Department of Astrophysical Sciences, 4 Ivy Lane, Peyton Hall, Princeton University, Princeton, NJ 08544, USA 2 Lawrence Berkeley National Lab, Berkeley, CA 94720, USA 3 Department of Astronomy, University of California at Berkeley, Berkeley, CA 94720, USA E-mail contact: zhzhu at astro.princeton.edu Direct imaging observations have revealed spiral structures in protoplanetary disks. Previous studies have suggested that planet-induced spiral arms cannot explain some of these spiral patterns, due to the large pitch angle and high contrast of the spiral arms in observations. We have carried out three dimensional (3-D) hydrodynamical simulations to study spiral wakes/shocks excited by young planets. We find that, in contrast with linear theory, the pitch angle of spiral arms does depend on the planet mass, which can be explained by the non-linear density wave theory. A secondary (or even a tertiary) spiral arm, especially for inner arms, is also excited by a massive planet. With a more massive planet in the disk, the excited spiral arms have larger pitch angle and the separation between the primary and secondary arms in the azimuthal direction is also larger. We also find that although the arms in the outer disk do not exhibit much vertical motion, the inner arms have significant vertical motion, which boosts the density perturbation at the disk atmosphere. Combining hydrodynamical models with Monte-Carlo radiative transfer calculations, we find that the inner spiral arms are considerably more prominent in synthetic near-IR images using full 3-D hydrodynamical models than images based on 2-D models assuming vertical hydrostatic equilibrium, indicating the need to model

46 observations with full 3-D hydrodynamics. Overall, companion-induced spiral arms not only pinpoint the companion’s position but also provide three independent ways (pitch angle, separation between two arms, and contrast of arms) to constrain the companion’s mass. Accepted by ApJ http://arxiv.org/pdf/1507.03599

Abstracts of recently accepted major reviews

Physical processes in protoplanetary disks Philip J. Armitage1 1 JILA, University of Colorado & NIST, Boulder, Colorado, CO 80309-0440, USA E-mail contact: pja at jilau1.colorado.edu This review introduces physical processes in protoplanetary disks relevant to accretion and the initial stages of planet formation. After reprising the elementary theory of disk structure and evolution, I discuss the gas-phase physics of angular momentum transport through turbulence and disk winds, and how this may be related to episodic accretion observed in Young Stellar Objects. Turning to solids, I review the evolution of single particles under aerodynamic forces, and describe the conditions necessary for the development of collective gas-particle instabilities. Observations show that disks are not always radially smooth axisymmetric structures, and I discuss how gas and particle processes can interact to form observable large-scale structure (at ice lines, vortices and in zonal flows). I conclude with disk dispersal. Lectures given at the 45th Saas-Fee Advanced Course “From Protoplanetary Disks to Planet Formation” http://arxiv.org/pdf/1509.06382

47 Dissertation Abstracts

Mathesis of star formation from kpc to parsec scales

Guang-Xing Li Max-Planck Institut fuer Radioastronomie Scheinerstr. 1, D-81679 Mnchen, Germany Address as of Nov. 2014: [email protected] Electronic mail: gxli at usm.lmu.de Ph.D dissertation directed by: Karl Menten, Friedrich Wyrowski, Pavel Kroupa Ph.D degree awarded: Sept. 2014

In this thesis I present a series of studies aiming to understand the formation of stars from gas in the Milky Way. Generally speaking, I will progress from larger to smaller scales. The kilo-parsec scale (∼ 103 parsec ∼ 1021 cm) is the scale at which dynamics of the molecular clouds is coupled to dynamics of the Milky Way disk. Here we present an observational study of molecular gas at 49.5◦ and −5.0 kms < vlsr < 17.4kms . The molecular gas is found in the form of a huge (∼500 pc) filamentary gas wisp. It has a large physical extent and a velocity dispersion of ∼ 5 km s−1. The filamentary gas wisp is composed of two molecular clouds and an expanding bubble. The length of the gas wisp exceeds by much the thickness of the molecular disk of the Milky Way, and this is consistent with the cloud-formation scenario in which gas is cold prior to the formation of molecular clouds. Molecular clouds (1 − 100 parsec) are the nurseries of the stars. There are many indications that molecular clouds are turbulence-dominated objects. However, it is not clear what role gravity plays. We propose a new method (G-virial) to quantify the role of gravity in molecular clouds. Our new method takes the gravitational interactions between all pixels in 3D position-position-velocity data cube into account, and generates maps of the importance of gravity in 3D position-position-velocity space. With our method we demonstrate that gravity plays an importance role in the individual regions in the Perseus and Ophiuchus molecular cloud, and find that high values of G-virial are reached in cluster-bearing regions. We also demonstrate the capability of our method in finding regions and quantifying the properties of the regions in the clouds. Protostellar outflow (∼ 1 parsec) is a prominent process accompanying the formation of stars. In this work, we theoretically investigate the possibility that the outflow results from interaction between the wind and the ambient gas in the form of turbulent entrainment. In our model, the ram-pressure of the wind balances the turbulent ram- pressure of the ambient gas, and the outflow consists of the ambient gas entrained by the wind. We demonstrate that the outflow phenomena can be naturally generated through this process, and discuss the potential usage of outflows as a probes of the dynamical state of the turbulent molecular gas. http://hss.ulb.uni-bonn.de/2015/3817/3817.htm

48 New Jobs

Postdoc position in millimeter observations of protoplanetary disks

One postdoc position is available in the group of Davide Fedele recently established at INAF-Osservatorio Astrofisico di Arcetri (Florence, Italy). The focus of the group of Davide Fedele is the physical structure and chemical composition of protoplanetary disks. The candidate will work on the analysis of submillimeter data with ALMA. Previous experience with submillimeter interferometric data and/or disk modeling with thermo-chemical codes will be a plus in the evaluation. The position will be for an initial period of 2 years with a possible extension of one year dependent on performance. The expected beginning of the position is December 2015/January 2016. Application deadline is October 31 2015. Applications should comprise a cover letter, a CV including publications, a concise statement of previous research and research interests (max 2 pages), and 2 letters of recommendation. Evaluation will start on November 1st and continue until the position has been filled. For inquires, instructions on how to apply, information about salary and benefits, please visit the webpages: http://www.arcetri.astro.it/gare-e-concorsi/182-gare-e-concorsi/concorsi/945-2015-10-02-10-19-51 https://sites.google.com/site/davidefedele/research-1 and/or contact: [email protected]

Postdoctoral Position in Star Formation and Molecular Cloud studies

Applications are invited for a postdoctoral research position in the star formation group at the Astronomy Department at Yale University. We are seeking an astronomer with experience in reducing and analyzing radio/(sub)millimeter interferometer data. The successful candidate will work with large-scale ( 2 square degree) CARMA molecular line maps of nearby molecular clouds. The postdoc will be expected to help with the data reduction and analysis, lead research projects using the CARMA multi-line maps and collaborate with members of the international team. Once combined with single dish data, these maps will probe the kinematics and structure of the molecular gas from 7.2 pc down to 0.012 pc. The size and resolution of the maps will allow for unprecedented analysis of the large-scale structure of molecular clouds. Research topics that may be conducted with these data include molecular cloud structure and kinematics, properties of cores and filaments, stellar feedback processes (outflow, winds, etc.), and turbulence. Conveniently located between New York City and Boston, Yale offers a lively intellectual environment and access to world-class astronomical facilities, including the Keck, Palomar and SMARTS telescopes. Yale is an institutional member of the SDSS-IV collaboration, and the postdoc may develop projects with these data. Applications consisting of a cover letter, curriculum vitae, publication list, and a brief (2-3 page) description of research interests and plans should arrive by December 18. 2015. Applicants should also arrange for three letters of recommendation to arrive by the same date. Email all materials, and have reference letters emailed to Kim Monocchi ([email protected]). Inquiries about the position can be made to Hector Arce ([email protected]). The anticipated start date is September 1, 2016, but earlier start dates are possible.

49 Postdoctoral Researcher in Milky Way High Mass Star Formation

Postdoctoral Fellow - Astronomy (PHYS 15-0123) The West Virginia University Research Corporation (WVURC) invites applications for a postdoctoral researcher in the Department of Physics and Astronomy at West Virginia University (WVU). The applicant will work with Dr. Loren Anderson in studies of global Galactic massive star formation and HII regions. The main research project will be to use a large catalog of Galactic HII regions to link Galactic and extragalactic star formation using studies of the Galactic HII region luminosity function, the Galactic star formation rate, and the star formation rate efficiency. The project will entail Green Bank Telescope, Very Large Array, and Australia Telescope Compact Array spectroscopic and continuum observations. Applicants with experience using these (or similar) facilities are especially encouraged to apply. A PhD in astronomy, astrophysics, or a closely related field is required. Knowledge of web programming including database management is preferred. WVU is a comprehensive land grant university with 29,000 students. WVU is classified by the Carnegie Com- mission on Higher Education as a Research-High Activity Institution. The Department of Physics and Astronomy (http://physics.wvu.edu) consists of 22 tenured and tenure-track faculty, one teaching assistant professor, 15 research faculty and postdoctoral researchers, 72 Ph.D. graduate students, and approximately 80 undergraduate physics ma- jors. The largest research areas are condensed matter physics, astrophysics, plasma physics, and physics education. WVU is located roughly 130 miles from the National Radio Astronomy Observatorys Green Bank Telescope in Green Bank, WV; many astrophysics research and outreach programs make use of the facilities in Green Bank. Competitive salary and benefits package offered. For a complete job description and to apply for this position, please visit http://hr.research.wvu.edu and click on the View Jobs link. Qualified applicants should submit a cover letter, statement of research interests (up to 2 pages), curriculum vitae, and contact information for three references as part of the application process. For questions or additional information, contact Prof. Loren Anderson at 304-293-4884 or [email protected]. The screening process will begin on November 1, 2015 and will continue until the position is filled. The University community of Morgantown offers plentiful educational opportunities as well as recreational outlets, is within easy driving distance of Pittsburgh, PA, and is about 200 miles (3.5 hours driving) northwest of Washington, D.C. WVURC is an AA/EOE/Minorities/Females/Vet/Disability/E-verify compliant employer.

Postdoctoral position in the study of star formation or outflow modeling

Applications are invited for a postdoctoral position in the observational study of massive star formation or MHD modeling of (proto-)stellar outflows at Chalmers University of Technology in Gothenburg, Sweden. The 2-year position will be within the research group of Wouter Vlemmings. This group focusses on radio, millimeter and/or sub-millimeter wavelength observations of evolved stars and star forming regions with instruments such as ALMA, SMA, JVLA, eMERLIN and APEX. The postdoc will work on related topics and will also be able to carry out their own research in collaboration with affiliated group members. The successful candidate will join a research group with close ties to the Nordic ALMA Regional Center (ARC) node. He/She will have access to advanced radiative transfer modeling tools and the possibility to develop MHD simulations. The postdoc will work mainly at Onsala Space Observatory, where Chalmers hosts the Swedish National Facility for Radio Astronomy. A PhD in astrophysics is required at the start of the employment (expected to be early 2016). Experience with (massive) star formation, interferometry or MHD simulations would be an asset. The application deadline is Nov 2nd 2015. For application details please follow the link to the electronic submission form at the following page: http://www.nordic-alma.se/local-links/my-research/projects

50 Postdoctoral position in Astrochemistry and Star/Planet formation

The Center for Astrochemical Studies (CAS; http://www.mpe.mpg.de/CAS) at the Max Planck Institute for Ex- traterrestrial Physics (MPE) in Garching (near Munich), Germany, invites applications for a Postdoctoral position in astrochemistry and observational/theoretical star and planet formation. The overall aim of the project is to study star and planet formation, from the assemblage and earliest phases of pre-stellar cloud cores to the formation and evo- lution of protoplanetary disks, with links to our Solar System, using molecular lines and dust continuum observations as tools to unveil the physical and chemical evolution. This will be done by merging astrochemical with (magneto-) hydro-dynamical models and constraining them with high sensitivity and high angular/spectral resolution observations via the use of radiative transfer codes. Researchers with experience in theory and/or observations of star and planet forming regions are encourage d to apply. The flexible starting date could be as early as Spring 2016, for 2 years guaranteed with the possibility of extension to up to five years and further career within MPE. The salary is paid at German civil service rates (TV¨oD-Bund) depending on your post-doctoral experience. Applicants should have a PhD in astronomy or related field before starting. The post comes with generous travel allowance. Please send a letter of application, a brief description of research interests, a curriculum vitae including bibliography, and three letters of reference by Nov. 15th, 2015 to:

Paola Caselli ([email protected])

Later applications may also be considered in case the post is not filled until Dec. 15th, 2015. The MPE encourages applications from women, minorities and disabled persons.

51 Meetings

2nd Announcement: From Stars to Massive Stars Wed. 6th - Sat. 9th April 2016 University of Florida, Gainesville, FL, USA http://conference.astro.ufl.edu/STARSTOMASSIVE/

From Stars to Massive Stars - Connecting our understanding of massive star & star cluster formation through the universe. Contact: florida.starformation @ gmail.com This conference will bring together researchers from star formation, star cluster evolution and massive star communities to share recent research results and help motivate future projects to improve our understanding of these processes and phenomena. The meeting comes at a time when many exciting results are appearing from surveys of our Galaxys star-forming regions along with detailed follow-up from facilities such as ALMA and SOFIA. Utilization of JWST and TMT-class telescopes is on the horizon, which, along with full-ALMA, will allow unprecedented studies of massive star and star cluster formation across a wide range of cosmic environments. Properties of individual stars and protostars can be determined to build up an accurate statistical census of the star formation activity in entire giant molecular clouds and their star-forming clumps, thus probing the questions: what drives massive star and star cluster formation and how does it proceed in different environments such as the local solar neighborhood, dwarf galaxies, dense starburst regions, around supermassive black holes such as in Galactic center region, and at the very highest redshifts? With increasing computational resources and more sophisticated numerical modeling, theoretical and numerical models are catching up to try to explain these observations. Specific science topics include: 1) Initial Conditions for Massive Star and Star Cluster Formation 2) Astrochemistry in Massive Star and Star Cluster Formation 3) Accretion to Massive Protostars: Infall Envelopes and Disks 4) Outflows from Massive Protostars 5) Hypercompact and Ultracompact HII Regions 6) The Multiplicity, Clustering and Cluster Environment of Massive Star Formation and Young Massive Stars 7) Similarities and Differences of Low-, Intermediate- and High-Mass Star Formation and Young Stars 8) Feedback from Massive Star and Star Cluster Formation 9) Massive Star and StarCluster Formation in Galactic Centers and Starbursts 10) Massive Star and Star Cluster Formation at Low-Metallicity and at High Redshift 11) The Initial Mass Function and Stellar Evolution ofMassive Stars 12) The Initial Cluster Mass Function and the Early Evolution of Star Clusters The conference will be held at the University of Florida in Gainesville, located within 2 hours drive from Orlando, Tampa, Jacksonville, St. Augustine, and the Atlantic and Gulf Coasts. The weather in April is generally dry, sunny and warm. Estimated costs: We expect the registration fee to be less than $200. Hotel rooms in the conference block will be about $100 to $130 per night. Conference activities will start with a reception on Tue. 5th April and there will be a full day of science presentations on the Sat. 9th April, so plan for a 5 night stay. Some financial support, especially for graduate students and junior researchers is available - please indicate if you want to be considered for this support in the comments section of the registration form. If you are interested in attending the conference, please register and submit an abstract by 1st Dec. 2015 for consid- eration by the SOC. Best regards, Jonathan Tan & the SOC

52 Summary of Upcoming Meetings

Exchanging Mass, Momentum and Ideas: Connecting Accretion and Outflows in Young Stellar Objects 27 - 29 October 2015 Noordwijk, The Netherlands http://www.cosmos.esa.int/web/accretion-outflow-workshop Extreme Solar Systems III 29 November - 4 December 2015 Hawaii, USA http://ciera.northwestern.edu/Hawaii2015.php Protoplanetary Discussions 7 - 11 March 2016, Edinburgh, UK http://www-star.st-and.ac.uk/ppdiscs From Stars to Massive Stars 6 - 9 April 2016, Gainesville, Florida, USA http://conference.astro.ufl.edu/STARSTOMASSIVE/ Resolving planet formation in the era of ALMA and extreme AO 16 - 20 May 2016, Santiago, Chile http://www.eso.org/sci/meetings/2016/Planet-Formation2016.html Diffuse Matter in the Galaxy, Magnetic Fields, and Star Formation - A Conference Honoring the Contributions of Richard Crutcher & Carl Heiles 23 - 26 May 2015, Madison, USA no URL yet The 19th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun 6 - 10 June 2016 Uppsala, Sweden http://www.coolstars19.com Cloudy Workshop 20 - 24 June 2016 Weihai, China http://cloudy2016.csp.escience.cn/dct/page/1 EPoS 2016 The Early Phase of Star Formation - Progress after 10 years of EPoS 26 June - 1 July 2016, Ringberg Castle, Germany http://www.mpia.de/homes/stein/EPoS/2016/2016.php Star Formation in Different Environments 25 - 29 July 2016 Quy Nhon, Viet Nam website to be announced Star Formation 2016 21-26 August 2016 Exeter, UK http://www.astro.ex.ac.uk/sf2016 Other meetings: http://www1.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/meetings/

53 Short Announcements

Launch of the AstroChemical Newsletter

We are announcing the launch of the AstroChemical Newsletter, a monthly compilation of recently accepted publica- tions and announcements in the field of astrochemistry (astrophysical observations and modeling as well as theoretical and experimental chemical-physics related to astronomical environments). You can subscribe to the newsletter and submit abstracts by going to the AstroChemical Newsletter website: http://acn.obs.u-bordeaux1.fr/ You can also share your latest astrochemistry news on the AstroChemical Newsletter Facebook page: https://www.facebook.com/AstrochemicalNewsletter and follow @AstroChemNews on Twitter.

Moving ... ??

If you move or your e-mail address changes, please send the editor your new address. If the Newsletter bounces back from an address for three consecutive months, the address is deleted from the mailing list.

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