2016ApJ...822...59S -
Astrophys. J., 822, 59-59 (2016/May-2)
The Bolocam Galactic Plane Survey. XIV. Physical properties of massive starless and star-forming clumps.
SVOBODA B.E., SHIRLEY Y.L., BATTERSBY C., ROSOLOWSKY E.W., GINSBURG A.G., ELLSWORTH-BOWERS T.P., PESTALOZZI M.R., DUNHAM M.K., EVANS II N.J., BALLY J. and GLENN J.
Abstract (from CDS):
We sort 4683 molecular clouds between 10° l µm 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 (α ∼ 0.7) with >75% of clumps with known distance being gravitationally bound (α M ∼ 170-370 M☉ from the starless candidates to clumps associated with protostars. This trend could be due to (i) mass growth of the clumps at {dot}M∼200–440 M☉ M/yr 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 ∼M –0.4. By comparing to the observed number of CH3OH maser containing clumps, we estimate the phase lifetime of massive (M > 103 M☉) starless clumps to be 0.37±0.08 Myr (M/103 M☉)–1; the majority (M M☉) have phase lifetimes longer than their average freefall time.
Abstract Copyright:
© 2016. The American Astronomical Society. All rights reserved.
Journal keyword(s):
ISM: clouds - ISM: molecules - masers - stars: formation - submillimeter: ISM - surveys
VizieR on-line data:
<Available at CDS (J/ApJ/822/59): table1.dat table2.dat table3.dat table5.dat table6.dat>
Nomenclature:
Tables 3, 5-6: [ERG2015] NNNN N=1514 among (Nos 2351-7031) added.
Simbad objects:
4693
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