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THE BOLOCAM GALACTIC PLANE SURVEY. XIV. PHYSICAL PROPERTIES OF MASSIVE STARLESS AND STAR-FORMING CLUMPS

We sort 4683 molecular clouds between 10 degrees < l < 65 degrees from the Bolocam Galactic Plane Survey based on observational diagnostics of star formation activity: compact 70 mu m sources, mid-IR color-selected YSOs, H2O and CH3OH masers, and UCH II. regions. We also present a combined NH3-derived gas kinetic temperature and H2O maser catalog for 1788 clumps from our own GBT 100 m observations and from the literature. We identify a subsample of 2223 (47.5%) starless clump candidates (SCCs), the largest and most robust sample identified from a blind survey to date. Distributions of flux density, flux concentration, solid angle, kinetic temperature, column density, radius, and mass show strong (>1 dex) progressions when sorted by star formation indicator. The median SCC is marginally subvirial (alpha similar to 0.7) with >75% of clumps with known distance being gravitationally bound (alpha < 2). These samples show a statistically significant increase in the median clump mass of Delta M similar to 170-370 M-circle dot from the starless candidates to clumps associated with protostars. This trend could be due to (i) mass growth of the clumps at (M) over dot similar to 200-440 M-circle dot Myr(-1) for an average freefall 0.8 Myr timescale, (ii) a systematic factor of two increase in dust opacity from starless to protostellar phases, and/or (iii). a variation in the ratio of starless to protostellar clump lifetime that scales as similar to M-0.4. By comparing to the observed number of CH3OH maser containing clumps, we estimate the phase. lifetime of massive (M > 10(3) M-circle dot) starless clumps to be 0.37 +/- 0.08 Myr (M/10(3) M-circle dot)(-1); the majority (M < 450 M-circle dot) have phase. lifetimes longer than their average freefall time.

Identiferoai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/621258
Date05 May 2016
CreatorsSvoboda, Brian E., Shirley, Yancy L., Battersby, Cara, Rosolowsky, Erik W., Ginsburg, Adam G., Ellsworth-Bowers, Timothy P., Pestalozzi, Michele R., Dunham, Miranda K., Evans II, Neal J., Bally, John, Glenn, Jason
ContributorsUniv Arizona, Steward Observ
PublisherIOP PUBLISHING LTD
Source SetsUniversity of Arizona
LanguageEnglish
Detected LanguageEnglish
TypeArticle
Rights© 2016. The American Astronomical Society. All rights reserved.
Relationhttp://stacks.iop.org/0004-637X/822/i=2/a=59?key=crossref.c041871f89d49e10ef381bb5266a8a5a

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