The use of extra-galactic star formation tracers on star forming regions in the Milky Way

Abstract

We studied three groups of star forming clouds in the Milky Way: 5 clouds from Spitzer c2d Legacy survey, 10 clouds from Gould Belt survey, and 32 massive dense clumps. We determined the total diffuse 24[Greek letter mu] emission for each cloud and calculated the corresponding SFR using an extragalactic relation. Then the resulting SFRs were compared with SFRs calculated using the method of counting number of YSOs for c2d and Gould Belt clouds and using total infrared luminosity for massive dense clumps. The comparison shows quite a good correlation for the massive dense clumps, which are high-mass star forming regions, with the average ratio of SFR(L_IR)/SFR(25[Greek letter mu]) = 0.896+/-0.663. The result for low-mass star forming clouds (c2d and Gould Belt) shows very little to no correlation between L_24[Greek letter mu] and SFR(YSO count). Comparing 24[Greek letter mu] images with extinction maps shows that a significant portion of 24[Greek letter mu] emission does not come from star-forming regions in the cloud.