High Energy Transient Explorer

Abstract

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2002.Includes bibliographical references (p. 135-157).The High Energy Transient Explorer (HETE), was built primarily at MIT and launched in October 2000 with the goal of studying Gamma Ray Bursts (GRBs) at X-ray and gamma-ray energies. A suite of instruments aboard HETE provide broadband sensitivity to GRBs: the French Gamma Telescope (FREGATE; 6 keV to > 400 keV ) instrument provides sensitive detections at gamma-ray energies, the Wide-Field X-Ray Monitor (WXM; 2 to 28 keV) provides detection and localization (5-10' radius) at X-ray energies, and the Soft X-ray Camera (SXC; 1.3 to 14 keV) provides refined localization (< 1' radius) capabiities at soft X-ray energies. GRB positions, determined in-flight, are promptly transmitted to the ground via the Burst Alert Network (BAN), and disseminated to interested observers for X-ray, optical, and radio follow-up observations. The HETE Operations center is located at MIT. This dissertation provides an overview of HETE with a particular focus on the building, testing, and performance of the SXC. To date the WXM has localized 18 GRBs, which have among them a number of interesting properties. Six are X-ray rich, which are of particular interest because they are not as well studied as classical GRBs. Beginning with the discovery of an optical transient at z = 0.45 for GRB 010921, five WXM GRB localizations have led to the identification of an afterglow transient (GRB 010921, GRB 020124, GRB 020305, and GRB 020331 in optical; GRB 020127 in radio). Optical follow-up observations with the Magellan 6.5m Baade Telescope of GRB 011130, GRB 011212, and GRB 020331 are described, including the discovery of the host galaxy of GRB 020331. X-ray observations of GRB 011130 with the Chandra X-ray Observatory at two different epochs have not conclusively revealed an X-ray counterpart among 61 detected X-ray point sources.by Glen Pickslay Monnelly.Ph.D