# Presentation: 781828

## HETE-2

## 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

## 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

## 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)

## 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)

## 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

## Future status

- HETE-2 not involved in current senior review round
- NASA 07 budget request

## 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

## 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

## 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)

## 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”