TITLE: GCN CIRCULAR NUMBER: 36604 SUBJECT: GRB 240603B: Swift detection of a possible burst DATE: 24/06/03 07:29:50 GMT FROM: K.L. Page at U Leicester <klp5@leicester.ac.uk> A. P. Beardmore (U Leicester), A. Y. Lien (U Tampa) and K. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift Observatory Team: At 06:57:43 UT, the Swift Burst Alert Telescope (BAT) triggered and located on a possible GRB 240603B (trigger=1232755). Swift did not slew immediately to the location. The BAT on-board calculated location is RA, Dec 36.054, -50.944 which is RA(J2000) = 02h 24m 13s Dec(J2000) = -50d 56' 38" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve did not show any significant structures, despite the light curve fluctuated greatly from ~4000 ct/s to ~10000 ct/s. Also, the source was detected with marginal significance (7.0 sigma) in the image, but the source is no longer detected in the scaled map from ground analysis. Therefore, the trigger may be due to a noisy detector. However, further ground data and XRT/UVOT observation is required to confirm the nature of the trigger. Due to an observing constraint, Swift will not slew until T0+54.8 minutes. There will be no XRT or UVOT data until this time. Burst Advocate for this burst is A. P. Beardmore (apb AT star.le.ac.uk). 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/36604. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...