Star Formation & Dust Heating in the FIR Bright Sources of M83

TL;DR

This study examines star formation and dust heating in FIR bright sources in M83, revealing their properties, distribution, and the dominant role of local star formation in dust heating, with implications for understanding GMCs.

Contribution

It provides detailed characterization of FIR bright sources in M83, including their physical properties and the role of local star formation in dust heating, using multi-wavelength data and SED fitting.

Findings

Sources are located on spiral arms and are giant molecular associations.

Weak correlation between SFRs and gas masses suggests lower star formation efficiency in more massive clouds.

Local star formation predominantly heats the dust, with other radiation sources also contributing.

Abstract

We investigate star formation and dust heating in the compact FIR bright sources detected in the Herschel maps of M83. We use the source extraction code GETSOURCES to detect and extract sources in the FIR, as well as their photometry in the MIR and H{\alpha}. By performing infrared SED fitting and applying an H{\alpha} based star formation rate (SFR) calibration, we derive the dust masses and temperatures, SFRs, gas masses and star formation efficiencies (SFEs). The detected sources lie exclusively on the spiral arms and represent giant molecular associations (GMAs), with gas masses and sizes of 10^6-10^8 solar masses and 200-300 pc, respectively. The inferred parameters show little to no radial dependence and there is only a weak correlation between the SFRs and gas masses, which suggests that more massive clouds are less efficient at forming stars. Dust heating is mainly due to local star formation. However, although the sources are not optically thick, the total intrinsic young stellar population luminosity can almost completely account for the dust luminosity. This suggests that other radiation sources contribute to the dust heating as well and approximately compensate for the unabsorbed fraction of UV light.