VLBI observations of the H2O supermaser outburst in the orion nebula

Abstract

We have conducted a campaign of annual VLBI observations of the H2O supermaser region in the Orion-KL. Most of our observations have been conducted with a small number of antennas. Here we report on a seven-station observation taken in 1985. We have produced an image of the supermaser region. Our data indicate that the masers lie along an approximately E-W line, and that there is a significant velocity gradient across the maser region. We suggest that the masers originate in several thin rings in a rotating expanding disk of gas and dust. (Author (revised))