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HETE-2 Mike Corcoran
Overview The High Energy Transient Explorer (HETE-2) is a “University-Class” (small) scientific satellite designed to detect and localize gamma-ray bursts. The coordinates of GRBs detected by HETE are distributed to interested ground-based observers within seconds of burst detection, thereby allowing detailed observations of the initial phases of GRBs. Follow-on to HETE (lost just after launch, Nov 1996). Hete-2 Launched Oct 9, 2000 • Instruments: • French Gamma Telescope (FREGATE): • Instrument type NaI(TI); cleaved • Energy Range 6 to 400 keV • Timing Resolution 10 microseconds • Effective Area 120 cm2 • Sensitivity (10 sigma) 3x10-8 erg cm-2s-1, over 8 keV-1 MeV • Field of View 3 steradians • Wide Field X-ray Monitor (WXM; Riken/LANL) • Instrument type Coded Mask with Position Sensitive Proportional Counter • Energy Range 2 to 25 keV • Timing Resolution 1 ms • Sensitivity (10 sigma) ~8x10 -9 erg cm -2s -1 over the 2-10 keV range • Field of View 1.6 steradians (FWZM) • Angular resolution +-11 arcmin (normal incidence, 8 keV) • Soft X-ray Camera (SXC; MIT/MKI) • Energy Range: 500 eV to 14 keV • Timing Resolution: 1.2 s • Field of View: 0.91 sr • Focal Plane scale: 33" per CCD pixel • Burst Sensitivity: (4 sigma) 0.47 cts cm-2 s-1 • Steady source Sensitivity: (4 sigma) ~700 mCrab t -1/2 • Localization Precision: 80" (systematic + statistical) 90% conf limits Mike Corcoran
Mission Status • All instruments (Fregate, WXM & SXC) currently operating nominally; problems early on • Since last HUG meeting (2004): • 27 refereed publications in ADS • 34 bursts (24 Fregate triggers, 4 WXM triggers, 6 Ground Analysis) • GRB050709: first optical afterglow of a short-hard burst associated with a late-type galaxy at z=0.16. “Solved mystery of short-hard bursts” See Villasenor et al., 2005, Nature 437, 855 Mike Corcoran
Archive Status HEASARC is the primary archive for HETE-2 • ~260 GB of data in IPP format - optimized for efficient burst analysis (not long-term archive) • Fregate 3-band lightcurves for all available GRBs • XSPEC-compatible spectra and response matrices for Fregate bursts • Hete2help: 3 contacts since 2000 • Data transfer to community ~700 MB (mostly in 2005) Mike Corcoran
HETE2 Metadata • Browse tables: • hete2gcn: searchable list of all HETE2 gcn notices with links to data • hete2grb: searchable list of all HETE2 bursts with links to data and to MIT burst pages • hete2tl: searchable HETE2 timeline with data links • xtime: hete2 pointing timeline (like hete2tl) Mike Corcoran
Website & Software • HEASARC Hete2 website contains general information about Hete2, links to burst web pages • /FTP/hete2/ops contains downloadable software (solaris binaries and perl/c-shell scripts): Not user friendly Mike Corcoran
Future status • HETE-2 not involved in current senior review round • NASA 07 budget request Mike Corcoran
Future Plans • MIT funding runs out in Jun 06; operations authorized until Sep 06 • HEASARC will • maintain archive of all IPP data • maintain mirror of MIT HETE2 website • transfer all processing/analysis software from MIT to HEASARC for download • maintain calibration data • Continue to investigate conversion of data into standard format on a best-effort basis Mike Corcoran
Lessons Learned • Primary GRB science goals achieved/exceeded in an exceptionally low-cost mission (<$600K yr-1 for DA) • “Triage decision”: Insufficient funds were provided to PI team to undertake secondary (non-GRB) science analyses • Small missions often have to decide between main mission science vs. long-term archiving: Main mission science (usually) wins Mike Corcoran
Lessons Learned (cont) • Producing data in standard formats readable by software outside of mission-developed tools is essential for broader use. • Projects should incorporate long-term archive plans in their PDMP to maximize long-term usefulness • Adherence to data standards (FITS) from outset is important for long-term archiving & data ease-of-use, but there are (some) mission costs. • Convert telemetry to FITS! • Adherence to software standards is important too (but this isn’t free either) Mike Corcoran
How the HEASARC can Help The HEASARC helps minimize effort for small projects to standardize data: • enabling easy creation/verification of FITS files (cfitsio) • providing well-defined, easy to understand, easy to find data standards (“OGIP Standards”) • Expandable software standards (HEASoft) • Calibration infrastructure (CALDB) Even small missions can find “data attractiveness” Mike Corcoran