The Bolocam Galactic Plane Survey. XIV. Physical Properties of Massive Starless and Star Forming Clumps

We sort $4683$ molecular clouds between ${10}^{\circ }<\mathrm{\ell }<{65}^{\circ }$ from the Bolocam Galactic Plane Survey based on observational diagnostics of star formation activity: compact $70$ $\mu \mathrm{m}$ sources, mid-IR color-selected YSOs, ${\mathrm{H}}_2\mathrm{O}$ and $\mathrm{C}{\mathrm{H}}_3\mathrm{O}\mathrm{H}$ masers, and UCHII regions. We also present a combined $\mathrm{N}{\mathrm{H}}_3$-derived gas kinetic temperature and ${\rm H_2O}$masercatalogfor$1788$ clumps from our own GBT 100m observations and from the literature. We identify a subsample of $2223$ ($47.5\mathrm{\%}$) starless clump candidates, 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 starless clump candidate is marginally sub-virial ($\alpha \sim 0.7$) with $>75\mathrm{\%}$ of clumps with known distance being gravitationally bound ($\alpha <2$). These samples show a statistically significant increase in the median clump mass of $\Delta M \sim 170-370$M$_\odot$ from the starless candidates to clumps associated with protostars. This trend could be due to (i) mass growth of the clumps at $\dot{M}\sim 200-440$ Msun Myr${}^{-1}$ for an average free-fall $0.8$ Myr time-scale, (ii) a systematic factor of two increase in dust opacity from starless to protostellar phases, (iii) and/or a variation in the ratio of starless to protostellar clump lifetime that scales as $\sim M^{-0.4}$. By comparing to the observed number of $\mathrm{C}{\mathrm{H}}_3\mathrm{O}\mathrm{H}$ maser containing clumps we estimate the phase-lifetime of massive ($M>{10}^3$ M${}_{\odot }$) starless clumps to be $0.37\pm 0.08\mathrm{M}\mathrm{y}\mathrm{r}(M\mathrm{/}{10}^3{\mathrm{M}}_{\odot }{)}^{-1}$; the majority ($M<450$ M${}_{\odot }$) have phase-lifetimes longer than their average free-fall time.