Testing 24 micron and Infrared Luminosity as Star Formation Tracers for Galactic Star Forming Regions

TL;DR

This study evaluates the effectiveness of 24 micron and infrared luminosity as tracers for star formation rates within galactic regions, revealing limitations in low-mass regions and better agreement in massive, dense clumps.

Contribution

It provides a comparative analysis of infrared-based star formation rate indicators against direct YSO counts and radio measurements within the Galaxy.

Findings

24 micron emission underestimates SFR in nearby molecular clouds.

Total infrared emission aligns better with radio-based SFR in massive clumps.

Infrared and 24 micron emissions correlate well in both low-mass and high-mass regions.

Abstract

We have tested some relations for star formation rates used in extra-galactic studies for regions within the Galaxy. In nearby molecular clouds, where the IMF is not fully-sampled, the dust emission at 24 micron greatly underestimates star formation rates (by a factor of 100 on average) when compared to star formation rates determined from counting YSOs. The total infrared emission does no better. In contrast, the total far-infrared method agrees within a factor of 2 on average with star formation rates based on radio continuum emission for massive, dense clumps that are forming enough massive stars to have the total infrared luminosity exceed 10^4.5 Lsun. The total infrared and 24 micron also agree well with each other for both nearby, low-mass star forming regions and the massive, dense clumps regions.