TITLE: GCN CIRCULAR NUMBER: 40903 SUBJECT: GRB 250702D, C, E: Swift/BAT-GUANO localization skymap of a burst or galactic transient DATE: 25/07/03 01:29:21 GMT FROM: Jimmy DeLaunay at Penn State <delauj2@gmail.com> James DeLaunay (PSU), Samuele Ronchini (PSU), Aaron Tohuvavohu (Caltech), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC), Maia Williams (PSU) report: Fermi/GBM triggered on four possible GRBs with similar localizations (GCN 40891) that may all have a common origin. Three of these bursts (GRB 250702D GCN 40886, GRB 250702C GCN 40885, GRB 250702E GCN 40890) have been detected in Swift/BAT-GUANO data. GRB 250702D (T0: 2025-07-02T13:09:02.03 UTC, Fermi/GBM trig 773154547) was detected by the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169) with a sqrt(TS) of 14.6 in a 8.192 s analysis time bin, starting at T0 - 6.144 s. The localization resulted in a 90% credible area of 5,318 deg2, a 50% credible area of 1,192 deg2, and an integrated probability of 5% inside the coded field of view. GRB 250702C (T0: 2025-07-02T14:49:31.91 UTC, Fermi/GBM trig 773160576) was detected by the NITRATES analysis with a sqrt(TS) of 7.5 in a 16.384 s analysis time bin, starting at T0 - 4.096 s. The localization resulted in a 90% credible area of 13,685 deg2, a 50% credible area of 4,087 deg2, and an integrated probability of 7% inside the coded field of view. GRB 250702E (T0: 2025-07-02T16:21:33.07 UTC, Fermi/GBM trig 773166098) was detected by the NITRATES analysis with a sqrt(TS) of 12.3 in a 8.192 s analysis time bin, starting at T0 - 4.096 s. The localization resulted in a 90% credible area of 8,604 deg2, a 50% credible area of 2,099 deg2, and an integrated probability of 3% inside the coded field of view. The localizations of all three bursts are consistent with the combined GBM skymap (GCN 40891). When the three NITRATES localizations are combined with the combined GBM skymap there is a slight improvement, with a 90% credible region of 142 deg2 centered at, RA, Dec = 285.820, -4.182 deg More details about these bursts and their skymaps can be found here: GRB 250702D https://guano.swift.psu.edu/trigger_report?id=773154577 GRB 250702C https://guano.swift.psu.edu/trigger_report?id=773160607 GRB 250702E https://guano.swift.psu.edu/trigger_report?id=773166128 The combined NITRATES and Fermi GBM skymap localization can be found here: https://zenodo.org/records/15795079 Additionally, imaging was performed to search for persistent emission while the source was in the coded field of view from ~13:28 to 13:48 UTC and from ~17:50 to 18:06 UTC, but nothing significant was found. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/ View this GCN Circular online at https://gcn.nasa.gov/circulars/40903. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...