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Title: Embedded star formation in S{sup 4}G galaxy dust lanes

Star-forming regions that are visible at 3.6 μm and Hα but not in the u, g, r, i, z bands of the Sloan Digital Sky Survey are measured in five nearby spiral galaxies to find extinctions averaging ∼3.8 mag and stellar masses averaging ∼5 × 10{sup 4} M {sub ☉}. These regions are apparently young star complexes embedded in dark filamentary shock fronts connected with spiral arms. The associated cloud masses are ∼10{sup 7} M {sub ☉}. The conditions required to make such complexes are explored, including gravitational instabilities in spiral-shocked gas and compression of incident clouds. We find that instabilities are too slow for a complete collapse of the observed spiral filaments, but they could lead to star formation in the denser parts. Compression of incident clouds can produce a faster collapse but has difficulty explaining the semi-regular spacing of some regions along the arms. If gravitational instabilities are involved, then the condensations have the local Jeans mass. Also in this case, the near-simultaneous appearance of equally spaced complexes suggests that the dust lanes, and perhaps the arms too, are relatively young.
Authors:
; ;  [1] ;  [2] ; ;  [3] ; ;  [4] ; ; ;  [5] ;  [6] ; ;  [7] ;  [8] ;  [9] ;  [10] ;  [11] ;  [12] ;  [13] more »; « less
  1. Vassar College, Department of Physics and Astronomy, Poughkeepsie, NY 12604 (United States)
  2. IBM Research Division, T.J. Watson Research Center, Yorktown Hts., NY 10598 (United States)
  3. Instituto de Astrofísica de Canarias, Vía Láctea s/n E-38205 La Laguna (Spain)
  4. Aix Marseille Université, CNRS, LAM (Laboratoire d'Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France)
  5. Department of Physical Sciences/Astronomy Division, University of Oulu, FIN-90014 (Finland)
  6. Sternberg Astronomical Institute of the Lomonosov Moscow State University, Moscow 119992 (Russian Federation)
  7. European Southern Observatory, Casilla 19001, Santiago 19 (Chile)
  8. Departamento de Astrofísica, Universidad Complutense de Madrid, E-28040 Madrid (Spain)
  9. MMTO Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
  10. The Observatories, Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
  11. European Space Agency (ESTEC), Keplerlaan 1, 2200 AG Noordwijk (Netherlands)
  12. Observatório do Valongo, Universidade Federal de Rio de Janeiro, Ladeira Pedro Antônio 43, CEP 20080-090, Rio de Janeiro (Brazil)
  13. National Radio Astronomy Observatory/NAASC, 520 Edgemont Road, Charlottesville, VA 22903 (United States)
Publication Date:
OSTI Identifier:
22348326
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 780; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ARMS; COMPRESSION; DUSTS; FILAMENTS; GALAXIES; GRAVITATIONAL INSTABILITY; MASS; SPACE; STAR CLUSTERS; STARS