Gamma-ray observations with the Transient Gamma-Ray Spectrometer (TGRS)

The Transient Gamma-Ray Spectrometer (TGRS), a high-resolution germanium detector, was launched aboard the WIND satellite on November 1, 1994. After similar to 2 years and several deep space orbits the spacecraft will eventually be injected into a halo orbit around the Sun-Earth L(1) point. Although TGRS is primarily designed to perform high resolution spectroscopy of gamma-ray bursts (GRBs) and solar flares, it equally well lends itself to the study of transient X-ray sources and, using an on-board passive occulter, the long-term monitoring of steady sources such as the Crab and the Galactic Center. Since launch, TGRS has been working exceedingly well and has proven to be very stable in its performance. TGRS has been detecting on the average similar to 5 GRBs per month and to date has observed three solar flares. Preliminary analysis of our data also indicates that TGRS is indeed sensitive to sources such as the X-ray transient GRO J1655-40, the Crab, and the Galactic Center.