THE BOLOCAM GALACTIC PLANE SURVEY. VII. CHARACTERIZING THE PROPERTIES OF MASSIVE STAR-FORMING REGIONS

Journal Article · Thu Nov 10 04:00:00 EST 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/741/2/110; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21612690

Dunham, Miranda K ^[1]; Rosolowsky, Erik ^[2]; Evans, II, Neal J ^[3]; Cyganowski, Claudia ^[4]

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1. Department of Astronomy, Yale University, New Haven, CT 06520-8101 (United States)
2. Department of Physics and Astronomy, University of British Columbia, Okanagan, Kelowna BC V1V 1V7 (Canada)
3. Department of Astronomy, University of Texas at Austin, Austin, Texas 78712-0259 (United States)
4. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)

We present the results of a Green Bank Telescope survey of NH{sub 3}(1,1), (2,2), (3,3) lines toward 631 Bolocam Galactic Plane Survey (BGPS) sources at a range of Galactic longitudes in the inner Galaxy. We have detected the NH{sub 3}(1,1) line toward 72% of our targets (456), demonstrating that the high column density features identified in the BGPS and other continuum surveys accurately predict the presence of dense gas. We have determined kinematic distances and resolved the distance ambiguity for all BGPS sources detected in NH{sub 3}. The BGPS sources trace the locations of the Scutum and Sagittarius spiral arms, with the number of sources. We measure the physical properties of each source and find that depending on the distance, BGPS sources are primarily clumps, with some cores and clouds. We have examined the physical properties as a function of Galactocentric distance, and find a mean gas kinetic temperature of 15.6 K, and that the NH{sub 3} column density and abundance decrease by nearly an order of magnitude. Comparing sources at similar distances demonstrates that the physical properties are indistinguishable, which suggests a similarity in clump structure across the Galactic disk. We have also compared the BGPS sources to criteria for efficient star formation presented independently by Heiderman et al. and Lada et al., and for massive star formation presented by Kauffmann et al. Forty-eight percent of our sample should be forming stars (including massive stars) with high efficiency, and 87% contain subregions that should be efficiently forming stars. Indeed, we find that 67% of the sample exhibit signs of star formation activity based on an association with a mid-infrared source.

• OSTI ID: 21612690
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 741; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABUNDANCE
AMMONIA
DISTANCE
DUSTS
GALAXIES
HYDRIDES
HYDROGEN COMPOUNDS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
STARS
TELESCOPES