A new sample of OH/IR stars in the Galactic center

Abstract

Two independent, largely overlapping 1612 MHz data sets were searched for OH/IR stars in the Galactic center. One set, taken with the Very Large Array in the period 1988 to 1991, consists of 17 epochs monitoring data of Van Langevelde et al. (1993). The other set was observed in 1994, using the Australia Telescope Compact Array. This article describes the data reduction procedures as well as a different way of searching image cubes for narrow line sources, and lists1 a total of 155 double peak OH maser detections within 18′ or 40 projected parsecs of Sagittarius A*, the compact radio continuum source in the Galactic nucleus. Presented are 65 formerly unseen double peaked 1612 MHz emitters, of which 52 are OH/IR stars. Also given are 3 single peak sources, which we believe to be masers of OH/IR stars. Apart from being less bright in their 1612 MHz OH maser line, the previously unknown OH/IR stars do not seem to be different from the previously known population of OH/IR stars in the Galactic center. We find that the OH/IR star OH maser luminosity distribution peaks at LOH ≈ 1043.4 photons per second. Further physical and kinematical analysis of the new sample will be presented in additional papers.