High-velocity-resolution observations of OH main line masers in the M82 starburst

Abstract

Using the Very Large Array, a series of high-velocity-resolution observations have been made of the M82 starburst at 1.6 GHz. These observations follow up on previous studies of the main line OH maser emission in the central kiloparsec of this starburst region, but with far greater velocity resolution, showing significant velocity structure in some of the maser spots for the first time. A total of 13 masers were detected, including all but one of the previously known sources. While some of these masers are still unresolved in velocity, these new results clearly show velocity structure in spectra from several of the maser regions. Position–velocity plots show good agreement with the distribution of H I including interesting velocity structure on the blueward feature in the west of the starburst which traces the velocity distribution seen in the ionized gas.