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Title: Distributed low-mass star formation in the IRDC G34.43+00.24

We have used deep near-infrared observations with adaptive optics to discover a distributed population of low-mass protostars within the filamentary Infrared Dark Cloud G34.43+00.24. We use maps of dust emission at multiple wavelengths to determine the column density structure of the cloud. In combination with an empirically verified model of the magnitude distribution of background stars, this column density map allows us to reliably determine overdensities of red sources that are due to embedded protostars in the cloud. We also identify protostars through their extended emission in the K band, which comes from excited H{sub 2} in protostellar outflows or reflection nebulosity. We find a population of distributed low-mass protostars, suggesting that low-mass protostars may form earlier than, or contemporaneously with, high-mass protostars in such a filament. The low-mass protostellar population may also produce the narrow line-width SiO emission observed in some clouds without high-mass protostars. Finally, we use a molecular line map of the cloud to determine the virial parameter per unit length along the filament and find that the highest mass protostars form in the most bound portion of the filament, as suggested by theoretical models.
Authors:
 [1] ; ;  [2] ;  [3] ; ;  [4] ;  [5] ;  [6] ; ;  [7] ;  [8] ;  [9]
  1. Yale Center for Astronomy and Astrophysics, New Haven, CT 06520 (United States)
  2. Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States)
  3. W. M. Keck Observatory, 65-1120 Mamalahoa Highway, Kamuela, HI 96743 (United States)
  4. Institute for Astrophysical Research, Boston University, Boston, MA 02215 (United States)
  5. Center for Atmospheric Research, UMASS Lowell, 600 Suffolk Street, Lowell, MA 01854 (United States)
  6. Graduate School of Informatics and Engineering, The University of Electro-Communications, Chofu, Tokyo 182-8585 (Japan)
  7. Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)
  8. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  9. CSIRO Astronomy and Space Science, P.O. Box 76, Epping NSW 1710 (Australia)
Publication Date:
OSTI Identifier:
22365305
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 791; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DENSITY; DISTRIBUTION; DUSTS; EMISSION; HYDROGEN; LINE WIDTHS; MASS; NEAR INFRARED RADIATION; OPTICS; PROTOSTARS; REFLECTION; SILICON OXIDES; SPECTRA; STARS; WAVELENGTHS