Final Number of GRBs

In addition to 894 GRBs automatically caught by means of the multiple rebin off-line quest, other 50 GRBs have been collected according to the following techniques:

1. 35 GRBs have been taken from the on-line detected GRBs from the RAW data (sec. ), for which no FOT data (i.e., the same data, but formatted according to the final archive conventions) were available, when the off-line quests worked;
2. 10 GRBs, missed by the off-line quest (based on the late SWTCs), have been caught thanks to the early SWTCs, which have been used only to limit the number of GRBs missed, because of the vicinity of data gaps (for a detailed discussion of the properties of the early SWTCs, refer to chapter 3); since the reliability of these SWTCs is much lower, only a few GRBs come out from this quest have been accepted;
3. 4 GRBs did trigger both the GRBM on-board logic and BATSE, without triggering the off-line quests: therefore, they have been added ``manually'';
4. 1 WFC GRB triggered the GRBM on-board logic, without triggering the off-line quests.

Thanks to these further GRBs missed by the off-line quest, apart from the 35 for which no archive data are available yet, the total and also final number of GRBs detected so far raises to 894 + 50 = 944. The final situation of the GRB sample is summarized in table .

Table: Final Catalog of GRBs detected with the GRBM

Kind of GRB Quest	# GRBs	Percentage
Off-line Quest (late SWTCs)	894	94.7
On-line Quest on RAW data	35	3.7
Off-line Quest (early SWTCs)	10	1.1
Off-line missed, on-board triggered & BATSE	4	0.4
Off-line missed, on-board triggered & WFC	1	0.1
Total	944	100.0

Table: GRBs detected as a function of the year.

Time Interval	# GRBs	Percentage
Jul-Dec 1996	58	6.1
Jan-Dec 1997	190	20.1
Jan-Dec 1998	199	21.1
Jan-Dec 1999	168	17.8
Jan-Dec 2000	183	19.4
Jan-Oct 2001	146	15.5
Total	944	100.0