Astronomy and Astrophysics – Astrophysics – Galaxy Astrophysics
Scientific paper
2010-07-19
Astronomy and Astrophysics
Astrophysics
Galaxy Astrophysics
13 pages, 5 figures, two tables; submitted to ApJ
Scientific paper
We use a sample of the 13 most luminous WMAP Galactic free-free sources, responsible for 33% of the free- free emission of the Milky Way, to investigate star formation. The sample contains 40 star forming complexes; we combine this sample with giant molecular cloud (GMC) catalogs in the literature, to identify the host GMCs of 32 of the complexes. We estimate the star formation efficiency epsilon_GMC and star formation rate per free-fall time epsilon_ff. We find that epsilon_GMC ranges from 0.002 to 0.2, with an ionizing luminosity-weighted average epsilon_GMC = 0.08, compared to the Galactic average = 0.005. Turning to the star formation rate per free-fall time, we find values that range up to epsilon_ff = 1. Weighting by ionizing luminosity, we find an average of epsilon_ff = 0.16 - 0.24 depending on the estimate of the age of the system. Once again, this is much larger than the Galaxy-wide average value epsilon_ff = 0.008. We show that the lifetimes of giant molecular clouds at the mean mass found in our sample is 17 plus or minus 4 Myr, about two free-fall times. The GMCs hosting the most luminous clusters are being disrupted by those clusters. Accordingly, we interpret the range in epsilon_ff as the result of a time-variable star formation rate; the rate of star formation increases with the age of the host molecular cloud, until the stars disrupt the cloud. These results are inconsistent with the notion that the star formation rate in Milky Way GMCs is determined by the properties of supersonic turbulence
No associations
LandOfFree
Star Formation Efficiencies and Lifetimes of Giant Molecular Clouds in the Milky Way does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Star Formation Efficiencies and Lifetimes of Giant Molecular Clouds in the Milky Way, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Star Formation Efficiencies and Lifetimes of Giant Molecular Clouds in the Milky Way will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-124548