HETE-2 Mission Goals
The primary goal of HETE-2 is to determine the origin and nature of cosmic
gamma-ray bursts (GRBs).
This is accomplished through the simultaneous, broad-band
observation in the soft X-ray, medium X-ray, and gamma-ray energy ranges,
and the precise localization and identification of cosmic gamma-ray burst
sources (GRBs). HETE-2 carries three science instruments:
(1) a set of wide-field gamma-ray spectrometers
These instruments operate synergistically in order to:
(2) a wide-field X-ray monitor
(3) a set of soft X-ray cameras
Identify the occurrence of a GRB.
Establish precise localizations of gamma-ray bursts. A total of ~16-20 GRBs
per year shall be localized to better than 10 arc-minute accuracy (i.e.,
radial distance from the true burst position) in the medium-energy X-ray
band using the WXM, and ~2-5 gamma-ray bursts per year to better than 10
arc second accuracy in the soft X-ray band using the SXC. These localizations
shall be calculated on board the spacecraft within 10-100 seconds of
burst onset, depending on burst duration and temporal structure
(GRBs have durations ranging from 10 ms to 1000 seconds).
Transmit coordinates of GRBs in near real time (< 10 seconds) through
a network of primary and burst alert stations to the MIT Control Center.
This information is immediately passed to the GCN and from there
to the community of ground-based optical, IR, and radio observers in searches
for GRB counterparts and their after glows.
Establish relative GRB rates and intensities in the soft X-ray, mid X-ray,
and gamma-ray bands by utilizing the unique cross-triggering capabilities
among the three HETE-2 instruments.
Perform spectroscopy of gamma-ray bursts in the energy range 1 - 400 keV,
allowing searches for and studies of X-ray precursors, X-ray afterglows,
and narrow spectral/ cyclotron lines.
Measure the intensities, time histories, and spectra of soft gamma-ray
repeater bursts, which may occur episodically during the HETE-2 mission.
Measure the intensities, time histories, and spectra of X-ray bursts, including
any accompanying bursts in the soft X-ray band due to reprocessing of X-rays
by the accretion disk or companion star in these systems.
Measure the intensities, time histories, and spectra of black hole X-ray