Hier ist wahrhaftig ein Loch im Himmel. The NGC 1999 dark globule is not a globule
Abstract
The NGC 1999 reflection nebula features a dark patch with a size of 10 000 AU, which has been interpreted as a small, dense foreground globule and possible site of imminent star formation. We present Herschel PACS far-infrared 70 and 160 μm maps, which reveal a flux deficit at the location of the globule. We estimate the globule mass needed to produce such an absorption feature to be a few tenths to a few {M}⊙. Inspired by this Herschel observation, we obtained APEX LABOCA and SABOCA submillimeter continuum maps, and Magellan PANIC near-infrared images of the region. We do not detect a submillimer source at the location of the Herschel flux decrement; furthermore our observations place an upper limit on the mass of the globule of 2.4×10-2 {M}⊙. Indeed, the submillimeter maps appear to show a flux depression as well. Furthermore, the near-infrared images detect faint background stars that are less affected by extinction inside the dark patch than in its surroundings. We suggest that the dark patch is in fact a hole or cavity in the material producing the NGC 1999 reflection nebula, excavated by protostellar jets from the V 380 Ori multiple system.
Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASAThis publication includes data acquired with the Atacama Pathfinder Experiment (APEX; proposal E-082.F-9807 and E-284.C-5015). APEX is a collaboration between the Max-Planck-Institut für Radioastronomie, the European Southern Observatory, and the Onsala Space Observatory. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.Appendices A and B are only available in electronic form at http://www.aanda.org- Publication:
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Astronomy and Astrophysics
- Pub Date:
- July 2010
- DOI:
- 10.1051/0004-6361/201014612
- arXiv:
- arXiv:1005.2202
- Bibcode:
- 2010A&A...518L..94S
- Keywords:
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- ISM: clouds;
- ISM: individual objects: NGC 1999;
- ISM: jets and outflows;
- infrared: ISM;
- dust;
- extinction;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- accepted for the A&