TITLE: GCN CIRCULAR NUMBER: 43671 SUBJECT: GRB 260208B: Swift-XRT observations DATE: 26/02/09 16:03:40 GMT FROM: Phil Evans at U of Leicester <pae9@star.le.ac.uk> A.P. Beardmore (U. Leicester), J.P. Osborne (U. Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA), J.A. Kennea (PSU), D.N. Burrows (PSU), S. Lanava (PSU) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the Fermi/LAT-detected burst GRB 260208B, collecting 1.6 ks of Photon Counting (PC) mode data between T0+33.1 ks and T0+44.4 ks. One uncatalogued X-ray source has been detected within the estimated 3-sigma Fermi/LAT error region (354 arcsec), it is below the RASS limit and shows no definitive signs of fading. Details of this source are given below: Source 1: RA (J2000.0): 99.6189 = 06h 38m 28.55s Dec (J2000.0): -13.7743 = -13d 46' 27.4" Error: 3.1 arcsec (radius, 90% conf. [Enhanced position]) Count-rate: 0.0338 +/- 0.0067 ct s^-1 Distance: 238 arcsec from Fermi/LAT position. Flux: (1.63 +/- 0.32)e-12 erg cm^-2 s^-1 (observed, 0.3-10 keV) The flux reported by EP-WXT for this source at 74.7 ks after the trigger (GCN Circ. 43663) is about a factor of 10 fainter than this XRT measurement, however, which suggests it is indeed the GRB afterglow. 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/00021909. We note that the large number of spurious sources was due to unusually high background. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/43671. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...