TITLE: GCN CIRCULAR NUMBER: 43137 SUBJECT: GRB 251215A: Swift-XRT observations DATE: 25/12/16 08:06:33 GMT FROM: Phil Evans at U of Leicester <pae9@star.le.ac.uk> J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), A. D'Ai (INAF-IASFPA), S. Campana (INAF-OAB), A. Melandri (INAF-OAR), S. Lanava (PSU), S. Dichiara (PSU), J.A. Kennea (PSU) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the Swift/BAT-detected burst GRB 251215A, collecting 5.2 ks of Photon Counting (PC) mode data between T0+32.0 ks and T0+49.6 ks. Four uncatalogued X-ray sources have been detected within the estimated 3-sigma Swift/BAT error region (493 arcsec), however none of them is above historical upper limits, or shows definitive signs of fading. Therefore, at the present time we cannot identify which, if any, is the afterglow. Details of these sources are given below: Source 2: RA (J2000.0): 122.5523 = 08h 10m 12.54s Dec (J2000.0): -36.6697 = -36d 40' 10.8" Error: 3.9 arcsec (radius, 90% conf. [Enhanced position]) Count-rate: (9.7 [+1.8, -1.7])e-3 ct s^-1 Distance: 383 arcsec from Swift/BAT position. Flux: (4.47 [+0.81, -0.77])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV) Source 5: RA (J2000.0): 122.6189 = 08h 10m 28.54s Dec (J2000.0): -36.7427 = -36d 44' 33.6" Error: 5.7 arcsec (radius, 90% conf. [Enhanced position]) Count-rate: (5.0 [+1.3, -1.2])e-3 ct s^-1 Distance: 97 arcsec from Swift/BAT position. Flux: (1.96 [+0.50, -0.47])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV) Source 6: RA (J2000.0): 122.6954 = 08h 10m 46.90s Dec (J2000.0): -36.6198 = -36d 37' 11.5" Error: 7.1 arcsec (radius, 90% conf. [Enhanced position]) Count-rate: (3.44 [+1.20, -0.99])e-3 ct s^-1 Distance: 448 arcsec from Swift/BAT position. Flux: (2.87 [+1.00, -0.83])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV) Source 8: RA (J2000.0): 122.6662 = 08h 10m 39.88s Dec (J2000.0): -36.6483 = -36d 38' 53.8" Error: 5.9 arcsec (radius, 90% conf.) Count-rate: (1.81 [+0.92, -0.72])e-3 ct s^-1 Distance: 330 arcsec from Swift/BAT position. Flux: (3.7 [+1.9, -1.5])e-10 erg cm^-2 s^-1 (observed, 0.3-10 keV) A catalogued source was also detected within the estimated 3-sigma Swift/BAT error region (493 arcsec). Two uncatalogued sources were also detected too far from the GRB position to be likely afterglow candidates. The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/ToO_GRBs/00021894. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/43137. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...