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Title: THE BOLOCAM GALACTIC PLANE SURVEY. XI. TEMPERATURES AND SUBSTRUCTURE OF GALACTIC CLUMPS BASED ON 350 μM OBSERVATIONS

We present 107 maps of continuum emission at 350 μm from Galactic molecular clumps. Observed sources were mainly selected from the Bolocam Galactic Plane Survey (BGPS) catalog, with three additional maps covering star-forming regions in the outer Galaxy. The higher resolution of the SHARC-II images (8.″5 beam) compared with the 1.1 mm images from BGPS (33″ beam) allowed us to identify a large population of smaller substructures within the clumps. A catalog is presented for the 1386 sources extracted from the 350 μm maps. The color temperature distribution of clumps based on the two wavelengths has a median of 13.3 K and mean of 16.3 ± 0.4 K, assuming an opacity law index of 1.7. For the structures with good determination of color temperatures, the mean ratio of gas temperature, determined from NH{sub 3} observations, to dust color temperature is 0.88 and the median ratio is 0.76. About half the clumps have more than 2 substructures and 22 clumps have more than 10. The fraction of the mass in dense substructures seen at 350 μm compared to the mass of their parental clump is ∼0.19, and the surface densities of these substructures are, on average, 2.2 times those seen inmore » the clumps identified at 1.1 mm. For a well-characterized sample, 88 structures (31%) exceed a surface density of 0.2 g cm{sup −2}, and 18 (6%) exceed 1.0 g cm{sup −2}, thresholds for massive star formation suggested by theorists.« less
Authors:
;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ; ;  [6]
  1. The University of Texas at Austin, Department of Astronomy, 2515 Speedway, Stop C1400, Austin, TX 78712-1205 (United States)
  2. Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
  3. Department of Physics, 4-181 CCIS, University of Alberta, Edmonton, AB T6G 2E1 (Canada)
  4. European Southern Observatory, ESO Headquarters, Karl-Schwarzschild-Strasse 2, D-95748 Garching bei Munchen (Germany)
  5. CASA, University of Colorado, 389-UCB, Boulder, CO 80309 (United States)
  6. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 78, Cambridge, MA 02138 (United States)
Publication Date:
OSTI Identifier:
22520224
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal, Supplement Series; Journal Volume: 218; 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; AMMONIA; CATALOGS; COLOR; COMPARATIVE EVALUATIONS; DENSITY; GALAXIES; IMAGES; MASS; OPACITY; STAR EVOLUTION; STARS; SURFACES; TEMPERATURE DISTRIBUTION