Star forming cloud-giant molecular cloud complexes

We cross-correlate 5469 giant molecular clouds (GMCs) from a new all-sky catalog with 256 star-forming complexes (SFCs) to build a sample of 191 SFC-GMC complexes-collections of multiple clouds each matched to 191 SFCs. The total mass in stars harbored by these clouds is inferred from WMAP free-free fluxes.

We measure the GMC mass, the virial parameter, the star formation efficiency {epsilon} and the star formation rate per freefall time {epsilon}_ff_. Both {epsilon} and {epsilon}_ff_ range over 3-4 orders of magnitude. We find that 68.3% of the clouds fall within {sigma}_log{epsilon}_=0.79+/-0.22dex and {sigma}_log{epsilon}_ff__=0.91+/-0.22dex about the median.