arXiv:1005.2202v1 [astro-ph.GA] 12 May 2010 il(.. anr ta.12) luso oeua a,wh gas, molecular mate- of obscuring here!”). clouds to sky 1927): due the al. be et to in Barnard known hole (e.g., now a rial are is areas there dark (“Truly These wahrhaft Himmel!” ist im “Hier region exclaim: these Loch to in him faintest reported the Caroline even sister no- d find were first to that Unable Herschel Scorpio . Wilhelm of the Friedrich in sky Sir of C.E. patches ticed 1774 year the In Introduction 1. .Stanke T. otn atcpto rmNASA from participation portant consorti Investigator Principal European-led by provided aelnTlsoe oae tLsCmaa bevtr,C Observatory, Campanas Las at located t Telescopes with Magellan gathered data includes t paper Max-Planck-Inst and This Observatory. Observatory, the Space Southern between European collaboration the a E-2 Radioastronomie, and is E-082.F-9807 APEX proposal 5015). (APEX; Experiment Pathfinder ⋆⋆ coe ,2018 4, October ⋆ Astrophysics & Astronomy .D Francesco Di J. Herschel hspbiainicue aaaqie ihteAtacama the with acquired data includes publication This 15 eelaflxdfii ttelcto ftegoue eestimat We globule. the of location the at deficit flux a reveal 14 13 oerudgoueadpsil ieo mietsa forma star imminent of site possible and globule foreground 12 11 aiyi h aeilpouigteNC19 eeto nebu words. reflection Key 1999 NGC the producing material the in cavity 10 17 16 htaels a less are that eafwtnh oafwM few a to tenths few a be h G 99rflcinnbl etrsadr ac ihasiz a with patch dark a features reflection 1999 NGC The otnu as n aelnPNCna–nrrdiae of images near–infrared the PANIC Magellan and maps, continuum h umliee asapa oso u ersina wel as depression flux a show to appear maps submillimeter the .C Myers C. 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Bal Dr., Martin San 3700 Institute, Science Telescope Space aoaor ’srpyiu eGeol,Universit´e Jos Grenoble, de d’Astrophysique Laboratoire eateto hsc n srnm,Uiest fRochest of University Astronomy, and Physics of Department P,Clfri nttt fTcnlg,Mi tp264767, Stop Mail Technology, of Institute California JPL, ainlRsac oni aaa ezegIsiueo As of Institute Herzberg Canada, Council Research National eateto hsc n srnm,Uiest fVictori of University Astronomy, and Physics of Department ainlOtclAtooyOsraoy 5 .Cer Ave. Cherry N. 950 Observatory, Astronomy Optical National iiino elgcladPaeaySine 5-1 Cali 150-21, Sciences Planetary and Geological of Division eateto hsc n srnm,Uiest fToledo, of University Astronomy, and Physics of Department nttt eAtosc eAdlca SC aioBj eH de Bajo Camino CSIC, Andalucia, de Astrofisica de Instituto NASA eateto srnm,Uiest fMcia,AnArbor Ann Michigan, of University Astronomy, of Department eateto srnm n twr bevtr,Universi Observatory, Steward and Astronomy of Department a-lnkIsiu ¨rAtooi,Koisul1,D-6 K¨onigstuhl 17, f¨ur Astronomie, Max-Planck-Institut S,Kr-cwrshl-tas ,878Grhn e M¨u bei Garching 85748 2, Karl-Schwarzschild-Strasse ESO, Herschel 1 .M Stutz M. A. , sa S pc bevtr ihsineinstruments science with observatory space ESA an is Herschel lbls–IM niiul(G 99 S:jt n outflows and jets ISM: – 1999) (NGC individual ISM: – globules u ermn;frhroeorosrain lc nupper an place observations our furthermore decrement; flux ff 14 ce yetnto nietedr ac hni t surroun its in than patch dark the inside extinction by ected 8 , .Neufeld D. , 9 .J Fischer J. W. , iritwhhfi i ohi Himmel im Loch ein wahrhaftig ist Hier cec etr aionaIsiueo ehooy 7 So 770 Technology, of Institute California Center, Science 2 , 3 .J Tobin J. J. , aucitn.14612 no. manuscript ⊙ nprdb this by Inspired . h G 99dr lbl sntaglobule a not is globule dark 1999 NGC The 15 .Osorio M. , 6 .Furlan E. , 4 .Ali B. , Herschel 16 5 10 n ihim- with and a .T Megeath T. S. , .Pontoppidan K. , .Hartmann L. , e65meter 6.5 he L eOnsala he te othe to etter hile. ttf¨ur itut bevto,w bandAE AOAadSBC submillime SABOCA and LABOCA APEX obtained we observation, gein ig evoid 84.C- ,his s, 17Hiebr,Germany Heidelberg, 9117 in epresent We tion. ABSTRACT p ore,CR,UR51 P5,F301Geol,France Grenoble, F-38041 53, BP 571, UMR CNRS, Fourier, eph ose a xaae ypootla esfo h 8 r multipl Ori 380 V the from jets protostellar by excavated la, 80OkGoeDie aaea A919 USA 91109, CA Pasadena, Drive, Grove Oak 4800 onaIsiueo ehooy aaea A915 USA 91125, CA Pasadena, Technology, of Institute fornia .Frhroe h erifae mgsdtc an back faint detect images near–infrared the Furthermore, l. h lbl asnee opouesc nasrto featu absorption an such produce to needed mass globule the e ioe D228 USA 21218, MD timore, et abig,M 23,USA 02138, MA Cambridge, reet, rpyis 01Ws anc od itraB,VE27 Ca 2E7, V9E BC, Victoria Road, Saanich West 5071 trophysics, ,PO o 5,SNCC itraB,VW36 Canada 3P6, V8W BC, Victoria CSC, STN 355, Box P.O. a, ce,Gray e-mail: Germany; nchen, r ohse,N 42,USA 14627, NY Rochester, er, yo rzn,93NrhCer vne usn Z871 USA 85721, AZ Tucson, Avenue, Cherry North 933 Arizona, of ty 81Ws acotSre,Tld,O 30,USA 43606, OH Toledo, Street, Bancroft West 2801 h ein ed o eetasbilmrsuc ttelocat the at source submillimer a detect not do We region. the usn Z879 USA 85719, AZ Tucson, , I419 USA 48109, MI , t,30 ot hre tet atmr,M 11,USA 21218, MD Baltimore, Street, Charles North 3400 ity, eo 0 -80,Gaaa Spain Granada, E-18008, 50, uetor of e ihPC fa7 n 160 and 70 a of PACS with before. He be detail never (e.g., greater has literature in which formation but studied the star 1980), al. of in et site Warren-Smith described 1960; potential 1946, is and which globule 1), dark a Fig. (see patch dark Mgahe l,i rp) ti luiae yteHri Ae Herbig the by illuminated is 2 It HH 22 prep.). and of in 1 HH driv al., group objects et the small Herbig–Haro (Megeath including prototypical a the protostars, in of and source located stars GMC, sequence A pre–main the Galax of our portion in formation (GMCs) star of clouds sites molecular the giant are globules, from tiny size clo to Dark and stars. mass background in of ranging light the absorbs content dust lca ta.20) G 99faue opc (20–30 199 compact al. a et Hillenbrand features 1997; 1999 NGC al. disk 2009). et Leinert circumsystem al. et (e.g., a Alecian L 100 with lines a system sion is multiple primary the a where Ori, 380 V star 6 4 .Krause O. , .Henning T. , E 17 erpr eetesrniiosadsrrsn detection surprising and serendipitous the here report We G 99i ml eeto euai h D 1641 LDN the in nebula reflection small a is 1999 NGC ∼ ditor .A Poteet A. C. , 000A,wihhsbe nepee sasal dense small, a as interpreted been has which AU, 10,000 ii ntems ftegoueof globule the of mass the on limit ig.W ugs httedr ac si atahl or hole a fact in is patch dark the that suggest We dings. Herschel t isnAe aaea A12,USA CA91125, Pasadena, Ave, Wilson uth nrrd S IM)ds,extinction dust, (ISM:) – ISM infrared: – 2 .Linz H. , 2 ASfrifae 0ad160 and 70 far-infrared PACS .Manoj P. , [email protected] 6 .M Watson M. D. , 2 .Allen L. , 11 µ ⊙ .Maret S. , u ermn ttelocation the at decrement flux m 9sa xiiigsrn emis- strong exhibiting star B9 ⋆⋆ ⋆ 7 .Bergin E. , 11 ∼ 2.4 n .Wilson T. and , 12 · 10 .Muzerolle J. , µ as which maps, m − 2 rudstars ground M system. e 4 ⊙

c Indeed, . .Calvet N. , S 2018 ESO o of ion nada eto re ter 1 13 y. uds, rbig , / ing Be en as ′′ 2; 4 ) , 2 T. Stanke et al.: Hier ist wahrhaftig ein Loch im Himmel

NGC 1999 dark region

HH35 V 380 Ori

HH147 IRS HH1 HH1/2 VLA1 HH2 Fig. 2. NGC 1999/HH1/2 region as seen with Herschel PACS 0.6 pc 10,000 AU at 160 µm (left, the box marks the region shown in Fig.3), and APEX SABOCA at 350 µm (right, smoothed to 10′′ resolution), Fig. 1. NGC1999 and HH1/2 region (DSS, left) and HST all displayed with a logarithmic color stretch. F450W/F555W/F675W true color image of the NGC1999 dark patch.

preserve the extended emission we estimated the sky and the cor- of NGC1999. The maps show a dark patch against the nebu- related signal drifts observed in PACS readouts (Sauvage et al. lous far–IR emission that closely resembles the dark patch seen 2010). To determine the baselines, we removed pixel–to–pixel at visible wavelengths. The MSX, ISO, and Spitzer space tele- electronic offsets using the median of the entire time stream, scopes have detected clouds in absorption at mid–IR (5-30 µm) then calculated the median for each frame/readout. The median wavelengths against the diffuse IR background of the Galaxy values were divided into 500 readout bins, and we took the min- (e.g., Bacmann et al. 2000; Stutz et al. 2008; Tobin et al. 2010; imum value for each bin. This approach preserves the extended Stutzetal. 2009a), in a few cases even at 70 µm (Stutz et al. emission at all spatial scales, but does not remove 1/f noise. The 2009b). However, the detection of the NGC1999 globule by final mosaic was created using the ”photProject” routine. PACS would be the first detection of a dark globule in absorp- Method2: Optimal mapping with MADmap2 to remove the tion at 160 µm. At wavelengths ≥ 160 µm, cold globules are nor- bolometer 1/f noise from the pixel time–line. The initial pro- mally detected through the emission from cold (10–30K) dust. cessing is the same as for Method1. However, instead of ’phot- Furthermore, absorption at these wavelengths requires extinc- Project’, MADmap is used to determine an optimal solution for tions in excess of 100 AV . each sky pixel. This method preserves extended emission and Motivated by the possible discovery of a 160 µm dark cloud, removes the 1/f noise, at the price of a reduced sensitivity. we obtained follow–up ground based submillimeter and near–IR (extinction) observations towards the globule. We did not de- tect the column density or mass of cold dust necessary to pro- 2.2. Other data duce such an absorption feature in the far–IR. We therefore con- APEX SABOCA and LABOCA — We obtained submillimeter clude that the dark globule is actually a cavity in the NGC1999 continuum maps using LABOCA and SABOCA on APEX. cloud carved by outflows from the V380Ori system. Thus, the LABOCA (Siringo et al. 2009) is a ∼250 bolometer array op- Herschel telescope has discovered what truly is a hole in the sky. erating at 870 µm, with a spatial resolution of 19′′. Observations were done on 2009 November 29 and 30 in fair conditions, 2. Observations and processing with precipitable water vapour (PWV) values around 1mm (τzenith,870 ∼ 0.26). We used a combination of spiral and straight 2.1. Herschel PACS observations on–the–fly scans in order to recover extended emission. Data reduction was done with the BOA software (Schuller et al., in NGC1999 was observed with Herschel (Pilbratt et al. 2010) prep.) following standard procedures, including iterative source with the PACS instrument (Poglitsch et al. 2010) at 70 modeling. SABOCA (Siringo et al. 2010) is a 37 bolometer ar- and 160 µm on 2009 October 9 (OBSIDs 1342185551 and ray operating at 350 µm, with a resolution of 7′′. 8. Data were 1342185552) as part of the Science Demonstration Phase ob- taken on 2009 December 1st and 3rd (NGC1999) and on 2008 servations of the Herschel Orion Protostar Survey (HOPS; P.I. October 7 and 8 (HH1/2 area) with PWV<0.5mm (τzenith,350 < S.T.Megeath). The data are presented in Figs.2 and 3 (see also 1). The observing and data reduction procedures were similar to Fischer et al. 2010). They were processed with the Herschel 1 those used for LABOCA. The 350 µm map is presentedin Fig.2, Common Software System (HCSS ) version 3.0 build 919, fol- and both maps in Fig.A.1 (available in electronic form only). lowing standard steps, using v. 4 of the calibration file. After ini- Magellan PANIC — NGC1999 was observed with the PANIC tial processing the two orthogonal scans were combined into a near–IR camera (2′ field of view) at Magellan on 2009 single observation. We used the same HCSS software modules as December 4 in photometric conditions through H, K and H fil- the automatic PACS pipeline. We used two different approaches s 2 ters in 0′′. 3to0′′. 4 seeing. Separate sky exposures were taken for for combining the data into final mosaics: each filter. The data were reduced with standard near–IR routines Method 1: Simple (”naive”) mapping with baseline removal. To in the IRAF UPSQIID package. The photometry is presented in 1 HCSS is a joint development by the Herschel Science Ground Segment Consortium, consisting of ESA, the NASA Herschel Science 2 Microwave Anisotropy Dataset mapper (Cantalupo et al. 2010, see Center, and the HIFI, PACS, and SPIRE consortia Poglitsch et al. (2010) for its implementation in HCSS) T. Stanke et al.: Hier ist wahrhaftig ein Loch im Himmel 3

Appendix B. The Ks and H2 images are shown in Figs.3 and 4, Table 1. Far–infrared optical depth, mass, and column density respectively. estimates

a b c λ f f0 fBG τ Mass N(H+He) ′′ ′′ ′′ −2 µm Jy/⊓⊔ Jy/⊓⊔ Jy/⊓⊔ M⊙ cm 3. Data analysis photProject (method 1) 70 0.002 0.003 0.001 0.23 0.1 1.9 · 1022 3.1. Herschel 70 m and 160 m µ µ 160 0.003 0.007 0.002 0.48 2.5 3.8 · 1023 A cursory inspection of the Herschel data (Figs.2 and 3) im- MADmap (method 2) · 22 mediately reveals a flux decrement in both PACS maps, which 70 0.002 0.003 0.001 0.2 0.1 1.6 10 160 0.004 0.008 0.002 0.45 2.4 3.5 · 1023 closely follows the morphology of the putative dark globule in NGC1999.FollowingStutz et al. (2009b), we determine the col- a Derived in a ∼ 7′′ radius region centered on R.A. = 5h36m24.4s, umn density and mass of the putative globule in the foreground Decl. = −06◦42′56.4′′, indicated in Fig. 3 as the inner most circular of NGC1999, assuming that the observed 70 and 160 µm decre- overlay in the Herschel PACS images. ment is due to extinction. The optical depth is given by b Derived in a ∼ 15′′ to ∼ 30′′ radius half–annulus, excluding bright areas associated with V 380 Ori, indicated in Fig. 3 as well. c Estimated background flux contribution to the PACS maps, esti- τ = −1.0 · ln[( f + fBG)/( f0 + fBG)], (1) mated as 50% of the measurements from IRAS data (interpolated to 70 µm) and the 160 µm ISO Serendipity Survey near NGC 1999. where f is the shadow flux level, f0 is the intrinsic unabsorbed flux level, and fBG is the background contribution to the flux zero–level in the images. We estimate the shadow flux level f thin dust emission, total gas+dust masses can be obtained from as the mean pixel value in a ∼7′′ radius region centered on the submillimeter fluxes as darkest part of NGC1999; the unobscured flux level f0 is esti- 2 MG S νd mated as the median pixel value in a half–annuluswith inner and MG+D = · , (2) outer radii of 15′′ and 30′′, with a southwest orientation chosen MD Bν(TD)κν,D to avoid the bright V380Ori flux. The f and f image regions MG 0 where is the gas–to–dust mass ratio, S ν the flux density, d the MD are over–plotted on the PACS maps in Fig. 3. The fBG flux level distance, Bν(TD) the Planck function, and κν,D the dust opacity. is not present in the Herschel maps because constant flux level With an rms noise level of ∼13mJy in our LABOCA map, pedestals are removed by the data reduction. We estimate the we should be able to detect (3 σ) a 40mJy point source, cor- 70 µm BG flux value by interpolating the IRAS 60 and 100 µm responding to a mass of 0.13M⊙, assuming TD = 10K and images; the 160 µm BG flux values were obtained from the ISO Ossenkopf & Henning (1994) opacities for thick ice mantle Serendipity Survey in the near vicinity of NGC1999. In both grains. Although the 870 µm sensitivity limits are uncertain cases we take 50% of the total measured flux as our estimate due to the surrounding highly structured low surface–brightness for fBG as we are only interested in the missing flux originat- emission, we conclude that a mass around 0.1M⊙ should have ing from behind NGC1999, and not the foreground component. been detected in the LABOCA map. More interestingly, the rms While this assumption is crude, the fBG values are low compared noise on the SABOCA map is around 17mJy, implying a 3σ ff to the f and f0 levels and do not have a large e ect on our anal- point–source detection limit of ∼50 mJy. Due to the steeply ris- ysis. ing Planck function and dust opacity, this limit correspondstoa −2 Following Eq.1, we calculate the mean optical depth per much lower mass detection limit of only 2.4 · 10 M⊙. For com- pixel. Table1 presents the results for the data reduced with both parison, the mass necessary to produce an extinction shadow as methods (which we find to agree well, indicating that both re- derived from the 70 µm map(onthe orderof 0.1M⊙) would pro- cover extended emission equally well). From the resulting op- ∼ ′′ duce a 350 µm source with a flux of 200mJy, i.e., a > 10σ de- tical depth we calculate the column density and mass (in a 7 tection. This result is in stark contradiction with the dense glob- radius aperture) required to cause this flux–decrement at the ule/shadow interpretation of the absorption features observed in two PACS wavelengths; these are presented in Table 1. We use the Herschel data. the extreme Ossenkopf & Henning (1994) model dust opaci- The PANIC images show five faint stars around V380Ori, 2 −1 ties for grains with thick ice mantles: κ70 = 541cm g and marked in Fig. 3 with their source designation as listed in Table κ = 55.7cm2g−1, a gas–to–dust mass–ratio equal to 100, 160 B.1, where we also give their (H − Ks) colors and estimated ex- and a distance of 420pc (e.g., Menten et al. 2007). The result- tinction. Stars 3 and 4 are within the dark patch and have mod- ing column densities and masses for the two wavelength bands erately red colors, implying a mean extinction of AV ∼ 10. In are clearly inconsistent. For example, we derive that masses of comparison, stars 1, 2, and 5 outside the dark patch are slightly 0.1M⊙ and 2.5M⊙ are needed to account for the observed flux redder and have a mean extinction of AV ∼ 12. None of the decrement in the the 70 and 160 µm data, respectively. five stars are apparent in the HST images, indicating that they are background stars (Fig.1). The H − Ks colors show that the 3.2. Ground-based follow-up extinction toward the dark patch is much less than the 100AV needed to attenuate the 160 µm emission and that the extinction Neither the APEX 350 nor 870 µm maps show an emission fea- through the dark patch is slightly less than that through the sur- ture at the location of the Herschel flux decrement. Instead, rounding region. the submillimeter emission bears a strong resemblance to the 160 µm emission, suggestingthat the 160, 350,and 870 µm maps 4. Discussion are all tracing the morphologyof the dust emission (Fig. 3). This morphology is suggestive of a diffuse ring of material, not a hot Optical images of NGC1999 show a dark patch suggestive of region absorbed by a foreground cold cloud. Assuming optically a small, dense globule obscuring the NGC1999 reflection neb- 4 T. Stanke et al.: Hier ist wahrhaftig ein Loch im Himmel

Fig. 3. 1.′75×1.′75 images of the region around NGC1999 (including V380Ori) centered on R.A. = 5h36m24.4s, Decl. = ◦ ′ ′′ ′′ −06 42 56.4 (J2000). The white circle (14 diameter) on the PANIC near-IR Ks image indicates the NGC1999 region; the image is annotated with the source designations for five faint stars in the field as listed in Table B.1, where we give their (H − Ks) colors. The PACS 70 µm and 160 µm maps both show NGC1999 observed as a flux deficit; the overlays represent the pixel masks used for the analysis of the NGC1999 feature. The right-most two panels show the SABOCA and LABOCA maps.

the clearest evidence so far for a collimated flow running north- east to southwest through the cavity. This flow, which likely orig- inates in the V 380 Ori multiple system, could possibly excavate the southern part of the cavity. SMZ6-8 in the southeastern cor- ner of the PANIC image resembles a small bow shock in a flow coming from the northwest; together with HH35, located north- west of V380Ori (Fig.1), it indicates a second, northwest to southeast oriented flow, which could be responsible for digging the northwestern lobe of the cavity. We note a similar flux depression in the 160 µm Herschel image southwest of the protostar HOPS166, which drives the HH147 outflow (Corcoran & Ray 1995). Optical images (e.g., Fig.1) show a circular reflection nebula marking the HH147 Fig. 4. Left: PANIC near-IR H2 narrow-band image of the outflow cavity, coinciding with the far–IR flux depression. The NGC1999; right: the same image with a scaled Ks continuum NGC1999 dark patch may therefore only be a somewhat pe- image subtracted. culiar example of a cavity carved in the ambient medium by an outflow, rendered particularly visible by the illumination and heating of the cavity walls by V 380 Ori. Sensitive far–IR maps taken with Herschel may therefore provide a new tool to assess ula. Surprisingly, our 70 and 160 µm images clearly show a dark the importance of outflow feedback on cloud cores. patch against the bright nebula with a strikingly similar mor- phology to that in visible light images. These Herschel mea- Acknowledgements. We thank Frank Bertoldi and Markus Albrecht for their in- valuable help with BOA, Giorgio Siringo for his help with the SABOCA data, surements, combined with subsequent ground based data, lead Jonathan Williams for encouraging discussions, and the APEX staff for their to the conclusion that the dark feature is a hole in the NGC1999 help wiht taking the data. Based in part on observations made with Herschel, nebula. First, we find that the masses needed to cause the 70 a European Space Agency Cornerstone Mission with significant participation and 160 µm dark patch — 0.1 and 2.5M⊙, respectively — are by NASA. Support for this work was provided by NASA through an award is- inconsistent. Furthermore, the globule is not detected in emis- sued by JPL/Caltech. JJT acknowledges funding through HST-GO-11548.04-A. Fig. 1 produced from data taken with the NASA/ESA , sion at 350 and 870 µm: the SABOCA obervations place an up- and obtained from the Hubble Legacy Archive, which is a collaboration between −2 per limit of 2.4 · 10 M⊙ for a temperature of 10K. This upper the Space Telescope Science Institute (STScI/NASA), the Space Telescope limit is far below the amount of mass needed to cause the ob- European Coordinating Facility (ST-ECF/ESA) and the Canadian Astronomy scuration in the PACS data. Finally, near–IR observations with Data Centre (CADC/NRC/CSA). PANIC detect backgroundstars toward the dark patch; the H−Ks colors of these stars are slightly bluer than stars detected out- References side the globule, suggesting a lower extinction toward the dark patch. Furthermore, the extinctions of the background stars are Alecian, E., Wade, G. A., Catala, C., et al. 2009, MNRAS, 400, 354 less than that required to absorb the 160 µm flux. Taken together, Bacmann, A., Andr´e, P., Puget, J., et al. 2000, A&A, 361, 555 Barnard, E. E., Frost, E. B., & Calvert, M. R. 1927, A photographic atlas of these observation show that the dark patch is not a globule, but selected regions of the Milky way, ed. Barnard, E. E., Frost, E. B., & Calvert, instead a cavity in the nebula. M. R. The presence of a well delineated cavity of the size of Campeggio, L., Strafella, F., Maiolo, B., Elia, D., & Aiello, S. 2007, ApJ, 668, ∼10,000 AU deserves some attention. With the typical turbulent 316 Cantalupo, C. M., Borrill, J. D., Jaffe, A. H., Kisner, T. S., & Stompor, R. 2010, velocities on the order of a few km/s in clouds, such a cav- ApJS, 187, 212 ity should be filled on timescales of at most a few 10,000yrs Corcoran, D. & Ray, T. P. 1995, A&A, 301, 729 and quickly disappear. The PANIC H2 narrow band data (Fig.4) Fischer, W. J., Megeath, S. T., Ali, B., et al. 2010, A&A, this volume deliver important hints about the possible origin and pecu- Herbig, G. H. 1946, PASP, 58, 163 Herbig, G. H. 1960, ApJS, 4, 337 liar shape of the cavity. They reveal a previously unknown, Hillenbrand, L. A., Strom, S. E., Vrba, F. J., & Keene, J. 1992, ApJ, 397, 613 faint H2 bow shock enveloping the SMZ60/HH148 compact Indebetouw, R., Mathis, J. S., Babler, B. L., et al. 2005, ApJ, 619, 931 knots (Stanke et al. 2002; Corcoran & Ray 1995), constituting Leinert, C., Richichi, A., & Haas, M. 1997, A&A, 318, 472 T. Stanke et al.: Hier ist wahrhaftig ein Loch im Himmel 5

Menten, K. M., Reid, M. J., Forbrich, J., & Brunthaler, A. 2007, A&A, 474, 515 Ossenkopf, V. & Henning, T. 1994, A&A, 291, 943 Pilbratt, et, & al. 2010, A&A, this volume Poglitsch, et, & al. 2010, A&A, this volume Sauvage, et, & al. 2010, A&A, this volume Siringo, G., Kreysa, E., de Breuck, C., et al. 2010, The Messenger, 139, 20 Siringo, G., Kreysa, E., Kov´acs, A., et al. 2009, A&A, 497, 945 Stanke, T., McCaughrean, M. J., & Zinnecker, H. 2002, A&A, 392, 239 Stutz, A. M., Rubin, M., Werner, M. W., et al. 2008, ApJ, 687, 389 Stutz, A. M. et al. 2009a, ApJ, 707, 137 Stutz, A. M. et al. 2009b, ApJ, 690, L35 Tobin, J. J., Hartmann, L., Looney, L. W., & Chiang, H. 2010, ApJ, 712, 1010 Warren-Smith, R. F., Scarrott, S. M., King, D. J., et al. 1980, MNRAS, 192, 339 T. Stanke et al.: Hier ist wahrhaftig ein Loch im Himmel , Online Material p 1

Appendix A: SABOCA and LABOCA submillimeter maps

Appendix B: PANIC H and Ks photometry

Five faint stars are visible in the PANIC H and Ks im- ages. Their positions and photometry are listed in Table B.1. Photometric calibration was performed with Two Micron All Sky Survey (2MASS3) photometry of comparison fields con- taining 20 2MASS sources and verified with a 2MASS star in the science field. Photometry was conducted with the IRAF task apphot. The measured (H − KS ) color was used to estimate the ex- tinction AV toward the stars. We assumed an intrinsic (H − KS ) color of 0.17, derived as the median (H−KS ) colorsof stars in an unreddenedcontrol field near Orion (Megeath et al., in prep). We adopted the reddeninglaw of Indebetouw et al. (2005) to convert (H − KS ) excess into K-band extinction AK, from which we ob- tained the optical extinction as AV = 8 · AK, corresponding to a total to selective extinction RV between the diffuse ISM value of 3.1 and the higher values (up to 5) found for dense clouds (e.g. Campeggio et al. 2007).

3 The Two Micron All Sky Survey is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. T. Stanke et al.: Hier ist wahrhaftig ein Loch im Himmel , Online Material p 2

Fig. A.1. Full submillimeter maps. Left: SABOCA, displayed at the original resolution of 7′′. 8; right: LABOCA. Protostars in the field are labeled with their HOPS designations. For both maps a logarithmic color scale is used.

Table B.1. PANIC NGC1999 near–IR colors of background stars

a Source RA (J2000) Decl. (J2000) KS σ(KS ) (H − KS ) σ(H − KS ) (hms) (◦ ′ ′′) mag mag mag mag 1 05 36 27.54 −06 43 22.29 16.08 0.01 0.83 0.01 2 05 36 26.19 −06 42 46.23 15.68 0.01 0.95 0.02 3 05 36 24.78 −06 43 06.72 18.36 0.10 0.67 0.14 4 05 36 24.09 −06 42 51.12 16.62 0.01 0.84 0.02 5 05 36 23.48 −06 42 51.86 16.71 0.02 0.95 0.02

a See Fig. 3 for source designation.