==> /universe/htdocs/docs/gamcosray/legr/bacodine/bin_web/tmp/new_gcn3_mesg <== TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3692 SUBJECT: Swift-BAT trigger 147918 is not a real GRB DATE: 05/07/28 02:10:37 GMT FROM: Scott Barthelmy at NASA/GSFC S. Barthelmy (GSFC) and D. Palmer (LANL) on behalf of the Swift-BAT team: The Swift-BAT trigger (trigger=147918) at 06:31:44.34 UT on 27 July 2005 is not due to a real GRB. A retraction Notice was issued at 07:16:16 UT; 45 min after the trigger (appended below in the full email format). We note that the KAIT and RTT150 teams (GCN 3689 and 3691, resp) have issued Circulars on this BAT trigger. We apologize for the inconvenience to these, and any other follow-up observers on this trigger. It will now be Swift-BAT policy to issue retraction Circulars in addition to the retraction Notices to insure the maximum possible distribution of this information. After further analysis, we confirm that the cause of the incorrect BAT trigger was due to a momentary loss in the Star Tracker lock and that this incorrect spacecraft attitude information resulted in the point source found in the BAT image not matching the approrpriate source in the BAT on-board catalog. S. Barthelmy (of GCN) further notes that the retraction Notice was distributed to 228 recipients, whereas the original Notice was distributed to 243 recipients. The difference is due to those sites that have Trigger_ID enabled in their GCN configurations. Since the retraction Notice has the "non-GRB" flag set, the GCN filtering code does not send this Notice to sites with Trigger_ID filtering enabled. The Retraction flag should override the non-GRB flag in these delayed (non-realtime) Notices that are paired with original Notices. This is clearly a mistake in the design of the GCN filtering code and will be rectified soon. We apologise for the inconvenience this has caused on this 147918 trigger and the other retraction Notices the Swift-BAT team has issued in the past. TITLE: GCN/SWIFT NOTICE NOTICE_DATE: Wed 27 Jul 05 07:16:16 UT NOTICE_TYPE: Swift-BAT GRB Position RETRACTION TRIGGER_NUM: 147918, Seg_Num: 0 GRB_RA: 238.256d {+15h 53m 01s} (J2000), 238.338d {+15h 53m 21s} (current), 237.522d {+15h 50m 05s} (1950) GRB_DEC: -21.768d {-21d 46' 04"} (J2000), -21.784d {-21d 47' 02"} (current), -21.620d {-21d 37' 11"} (1950) GRB_ERROR: 4.00 [arcmin radius, statistical only] GRB_INTEN: 0 [cnts] Image_Peak=1308 [image_cnts] TRIGGER_DUR: 64.000 [sec] TRIGGER_INDEX: 20000 E_range: 15-50 keV BKG_INTEN: 0 [cnts] BKG_TIME: 0.00 SOD {00:00:00.00} UT BKG_DUR: 0 [sec] GRB_DATE: 13578 TJD; 208 DOY; 05/07/27 GRB_TIME: 23504.34 SOD {06:31:44.34} UT GRB_PHI: 57.31 [deg] GRB_THETA: 34.52 [deg] SOLN_STATUS: 0x33 RATE_SIGNIF: 0.00 [sigma] IMAGE_SIGNIF: 7.98 [sigma] MERIT_PARAMS: +1 +0 +0 +6 +1 -2 +0 +0 +44 +1 SUN_POSTN: 126.67d {+08h 26m 41s} +19.17d {+19d 10' 27"} SUN_DIST: 116.47 [deg] MOON_POSTN: 21.77d {+01h 27m 06s} +9.68d {+09d 40' 47"} MOON_DIST: 142.90 [deg] MOON_ILLUM: 59 [%] GAL_COORDS: 349.43, 24.29 [deg] galactic lon,lat of the burst (or transient) ECL_COORDS: 240.74, -1.50 [deg] ecliptic lon,lat of the burst (or transient) COMMENTS: SWIFT-BAT GRB Coordinates. COMMENTS: This is an image trigger. (The RATE_SIGNIF & BKG_{INTEN, TIME, DUR} are undefined.) COMMENTS: A point_source was found. COMMENTS: This does not match any source in the on-board catalog. COMMENTS: This does not match any source in the ground catalog. COMMENTS: This is not a GRB. COMMENTS: This is a RETRACTION of a previous notice that identified this as a GRB -- it is NOT a GRB. COMMENTS: This Notice was ground-reprocessed from flight-data. COMMENTS: COMMENTS: This is NOT a real GRN, nor is it a Transient. COMMENTS: The s/c attitude information was not valid at the time of the trigger. COMMENTS: So it is very likely this is a known source misidentified due to incorrect pointing information.