Star formation in M33 (HerM33es)

TL;DR

This study uses multi-wavelength data to analyze star formation and dust properties in M33, revealing the influence of different stellar populations on dust temperature and challenging existing PDR models.

Contribution

It provides high-resolution dust and star formation rate estimations in M33, and highlights limitations of current PDR models in explaining observed emission lines.

Findings

Warm dust temperature is driven by young massive stars.

Cold dust temperature is influenced by evolved stellar populations.

Plane-parallel PDR models do not fully reproduce observed emission maps.

Abstract

Within the key project "Herschel M33 extended survey" (HerM33es), we are studying the physical and chemical processes driving star formation and galactic evolution in the nearby galaxy M33, combining the study of local conditions affecting individual star formation with properties only becoming apparent on global scales. Here, we present recent results obtained by the HerM33es team. Combining Spitzer and Herschel data ranging from 3.6um to 500um, along with HI, Halpha, and GALEX UV data, we have studied the dust at high spatial resolutions of 150pc, providing estimators of the total infrared (TIR) brightness and of the star formation rate. While the temperature of the warm dust at high brightness is driven by young massive stars, evolved stellar populations appear to drive the temperature of the cold dust. Plane-parallel models of photon dominated regions (PDRs) fail to reproduce fully the [CII], [OI], and CO maps obtained in a first spectroscopic study of one 2'x2' subregion of M33, located on the inner, northern spiral arm and encompassing the HII region BCLMP302.