TITLE: GCN CIRCULAR NUMBER: 43502 SUBJECT: GRB 260122B: Swift detection of a burst DATE: 26/01/22 23:49:28 GMT FROM: Mike Siegel at PSU/Swift MOC <siegel@swift.psu.edu> A. Mei (INAF-OAB), R. Brivio (INAF-OAB), R. Gupta (NASA GSFC), A. Y. Lien (U Tampa) and M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 23:13:10 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 260122B (trigger=1443066). Swift did not slew immediately to the burst due to observing constraint. The BAT on-board calculated location is RA, Dec 336.079, -59.167 which is RA(J2000) = 22h 24m 19s Dec(J2000) = -59d 10' 02" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 15 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~0 sec after the trigger. We note that the burst occurred during the high background interval near the SAA. Therefore, at this moment we cannot completely rule out the possibility that the event is due to background fluctuation. However, given that the image significance is 9.35 sigma, we believe this is likely a real burst. Further ground data is required to determine the nature of the burst. Due to a Sun observing constraint, Swift cannot slew to the BAT position until 2026 February 16. There will thus be no XRT or UVOT data for this trigger. Burst Advocate for this burst is A. Mei (alessio.mei AT inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/) View this GCN Circular online at https://gcn.nasa.gov/circulars/43502. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...