HETE2GCN - HETE-2 GCN Triggers Catalog
For more information about HETE-2 please see the HETE-2 archive website: http://heasarc.gsfc.nasa.gov/docs/hete2/
The GCN trigger number.
The Universal Time (UT) of the start of the trigger.
The type of burst notice. Each entry in the table can be one of these types:
S/C_Alert - An S/C alert notifies that HETE has detected a burst, but does not guarantee that the trigger was due to a valid burst, or that a localization will be forthcoming. Strength of burst and timescale are supplied. This is the first Notice for a given trigger; it appears only once for each trigger. On rare occasions when the s/c is out of contact with the Secondary Ground Stations, the S/C will create the S/C_Alert before contact is re-established. This S/C_Alert will have the position determination and so it is possible to have an S/C_Alert with a position. This will happen <10% of the time. S/C_Update - These contain any new burst information and, most importantly, the best localizations to date from the WXM and/or SXC, along with "goodness" indicators for each. Zero to N messages of this type are possible (the 0 case is possible if the burst is over before a Secondary Ground Station comes into view and so only the S/C_Last would be transmitted -- this is rare). It is also possible to have these Updates without any position information. The operations team can (and has) commanded off the position content; this is happening while the s/c is looking at the very active Galactic Center which is producing a high rate of X-ray Burster triggers of very low detection significance (and therefore large position error). S/C_Last - These give a summary of the on-board analyses of the burst. This includes the timescale of the burst, peak brightness, best (if any) localizations by the WXM and SXC, and, if appropriate a "never mind" indicator and the reason for the burst's invalidation (ie a non-GRB trigger). This is the last of the real-time Notices; it appears only once for each trigger. GndAnalysis - contains the best positions available from ground post-processing at the time of the message. Multiple messages of this type are possible, if the ground team conducts even further analysis. Please note that it is possible for a trigger to be classified as "definite GBR" but contain no position. This happens when a burst does not have a large enough signal-to-noise ratio to calculate a reliable position, or when a burst is outside the FOV of the two imaging instruments and is determined to be a burst by looking at the FREGATE light curve or from some external information e.g information from another mission.
The HETE-2 instrument which triggered. Tabulated values are WXM, SXC, TBD if not known yet as in an S/C_Alert Notice, "none" if the s/c decided there was enough to trigger, but not enough events to produce a position, or "neither" as in a GroundAnalysis Notice where it was determined that the trigger was a non-GRB.
The Right Ascension of the burst, if known.
The Declination of the burst, if known.
The Galactic Longitude of the burst, if known.
The Galactic Latitude of the burst, if known.
The error (in arcminutes, includes systematic + statistical uncertainties) in the specified position, if known.
Comment describing the observation results. If a column's information is not available or is not applicable, then that entry is listed as "n/a".
A numerical value that can be used to identify the type of event that caused the trigger. These values are updated manually and are based on the GCN message stored in the `Comments' parameter.
The numerical values have the following meanings:
GRB 10 Possible or Probable GRB 9 SGR 8 GRB or XRB 7 Possible GRB or XRB 6 XRB 5 Not a GRB 4 Invalid Trigger 3 Particle Event 2 Unclear 1
A flag used to indicate whether or not the `ID_Flag' has been verified by a human inspector. If the value is 'N', then the identification has been determined by a simple heuristic that looks for character string matches in the `Comments' parameter. In this case, the identification may be incorrect and some caution should be used. The value is 'Y' if the identification has been confirmed by a human inspector.