THE BOLOCAM GALACTIC PLANE SURVEY. XIV. PHYSICAL PROPERTIES of MASSIVE STARLESS and STAR-FORMING CLUMPS

Brian E. Svoboda, Yancy L. Shirley, Cara Battersby, Erik W. Rosolowsky, Adam G. Ginsburg, Timothy P. Ellsworth-Bowers, Michele R. Pestalozzi, Miranda K. Dunham, Neal J. Evans, John Bally, Jason Glenn

Research output: Contribution to journalReview article

38 Scopus citations

Abstract

We sort 4683 molecular clouds between 10° < ℓ < 65° from the Bolocam Galactic Plane Survey based on observational diagnostics of star formation activity: compact 70 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 < 2). These samples show a statistically significant increase in the median clump mass of ΔM ∼ 170-370 M o from the starless candidates to clumps associated with protostars. This trend could be due to (i) mass growth of the clumps at M o 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 ∼M -0.4. By comparing to the observed number of CH3OH maser containing clumps, we estimate the phase lifetime of massive (M > 103 M o) starless clumps to be 0.37 ± 0.08 Myr (M/103 M o)-1; the majority (M < 450 M o) have phase lifetimes longer than their average freefall time.

Original languageEnglish (US)
Article number59
JournalAstrophysical Journal
Volume822
Issue number2
DOIs
StatePublished - May 10 2016

Keywords

  • ISM: clouds
  • ISM: molecules
  • masers
  • stars: formation
  • submillimeter: ISM
  • surveys

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    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, N. J., Bally, J., & Glenn, J. (2016). THE BOLOCAM GALACTIC PLANE SURVEY. XIV. PHYSICAL PROPERTIES of MASSIVE STARLESS and STAR-FORMING CLUMPS. Astrophysical Journal, 822(2), [59]. https://doi.org/10.3847/0004-637X/822/2/59