90 GHz continuum observations of Messier 66

摘要: Radio emission at around 90 GHz from star-forming galaxies is expected to be strongly dominated by the free–free component due ionizing radiation massive, short-lived, stars. We present high surface-brightness sensitivity observations of nearby galaxy Messier 66 with resolution about 10 arcsec (corresponding a physical scale 500 pc) and analyse these in combination archival lower frequency radio mid-infrared measurements. detect five regions emission, four which are well fitted models we adopt. For regions, find that indeed dominates 90 GHz, making up 76–90 per cent luminosity. However, data also consistent all being free–free. The estimates luminosities agree, within measurement decomposition errors, star formation rates derived frequencies observations. In our analysis consider both power-law curved spectra for synchrotron but do not evidence support model preference power law.