A global view on star formation: The GLOSTAR Galactic plane survey

Abstract

Class II methanol (CH3OH) masers are amongst the clearest signposts of recent high-mass star formation (HMSF). A complete catalogue outlines the distribution of star formation in the Galaxy, the number of young star-forming cores, and the physical conditions of their environment, made possible by the Global View on Star Formation (GLOSTAR) survey. This blind survey of the radio regime of 4–8 GHz maps the Galactic mid-plane in the radio continuum, 6.7 GHz methanol line, the 4.8 GHz formaldehyde line, and several radio recombination lines. We present an analysis of the observations of the 6.7 GHz CH3OH maser transition using data from the D-configuration of the Very Large Array (VLA). We analysed data covering Galactic longitudes from –2° < l < 60° and Galactic latitudes of |b| < 1°. We detected a total of 554 methanol masers, out of which 84 are new, and we catalogued their positions, velocity components, and integrated fluxes. With a typical noise level of ~18 mJy beam−1, this is the most sensitive unbiased methanol survey for methanol masers to date. We also searched for dust continuum and radio continuum associations, finding that 97% of the sources are associated with dust and 12% are associated with radio continuum emission.