TITLE: GCN CIRCULAR NUMBER: 42983 SUBJECT: GRB 251203B: Swift-XRT observations DATE: 25/12/03 22:35:55 GMT FROM: Phil Evans at U of Leicester <pae9@star.le.ac.uk> S. Lanava (PSU), P.A. Evans (U. Leicester), J.A. Kennea (PSU), E. Ambrosi (INAF-IASFPA) , A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), R. Brivio (INAF-OAB), D.N. Burrows (PSU), S. Campana (INAF-OAB), M. Capalbi (INAF-OAR), A. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB), V. D'Elia (SSDC & INAF-OAR), S. Dichiara (PSU), M. Ferro (INAF-OAB), A. Melandri (INAF-OAR), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), M. Perri (SSDC & INAF-OAR), C. Salvaggio (INAF-OAB), T. Sbarrato (INAF-OAB), B. Sbarufatti (INAF-OAB), M.A. Williams (PSU) report on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the SVOM/ECLAIRs-detected source sb25120304, collecting 972 s of Photon Counting (PC) mode data between T0+4.6 ks and T0+5.7 ks after the trigger. A candidate counterpart has been found. The details of this source are: Source 1 (SWIFT J011326.9+000111): ================================== RA (J2000.0): 18.3625 = 01 13 27.00 Dec (J2000.0): +0.0198 = +00 01 11.3 Error: 3.5 (arcsec, radius, 90% confidence). Detect flag: GOOD Distance: 5.9 arcmin from the SVOM/ECLAIRs position. Mean rate: 1.785 +/- 0.088 ct s^-1 Mean flux: (5.76 +/- 0.28)e-11 erg cm^-2 s^-1 Peak rate: 2.72 +/- 0.62 ct s^-1 Peak flux: (8.8 +/- 2.0)e-11 erg cm^-2 s^-1 ECF: 3.23e-11 erg cm^-2 ct^-1 assuming NH=1.00e+21 cm^-2, gamma=2.03 determined from a spectral fit. This matches a catalogued X-ray source 4XMM J011326.8+000107 in the XMM-NEWTON/XMMSSC catalogue. Details: Separation: 3.3" from the XRT source Cat Rate: 2.7e-01 +/- 1.0e-02 ct s^-1 Cat Flux: 2.4e-12 +/- 8.9e-14 erg cm^-2 s^-1 (0.3-10 keV) so the source is 4.3-sigma above the catalogued flux. The source may be fading, at the 0.3-sigma level. A SIMBAD object `Gaia DR3 2534635509050352256' is 4.2" away. There is 1 2MASS object within the source's 3-sigma error radius. As pointed out by Malesani et al. (GCNs 42979), Brunet et al. (GCN 42981) and Perez-Garcia at al. (GCN 42982) this suggest that the transient is due to flaring activity from this star. We have detected a total of 4 sources. These have been automatically classified as follows: * 0 likely counterparts * 1 candidate counterpart * 3 uncatalogued X-ray sources * 0 known X-ray sources Uncatalogued X-ray sources -------------------------- Source 2 (SWIFT J011329.9-000900): ================================== RA (J2000.0): 18.3746 = 01 13 29.90 Dec (J2000.0): -0.1502 = -00 09 00.7 Error: 7.9 (arcsec, radius, 90% confidence). Detect flag: POOR Distance: 10.3 arcmin from the SVOM/ECLAIRs position. Mean rate: (6.9 [+4.4, -3.1])e-3 ct s^-1 Mean flux: (3.0 [+1.9, -1.3])e-13 erg cm^-2 s^-1 Peak rate: (6.9 [+4.4, -3.1])e-3 ct s^-1 Peak flux: (3.0 [+1.9, -1.3])e-13 erg cm^-2 s^-1 XMM UL: 1.8e-14 erg cm^-2 s^-1, (0.3-10 keV) so the source is not above this 3-sigma upper limit. There is no evidence for fading. Source 3 (SWIFT J011422.6+000036): ================================== RA (J2000.0): 18.5945 = 01 14 22.68 Dec (J2000.0): +0.0102 = +00 00 36.7 Error: 8.3 (arcsec, radius, 90% confidence). Detect flag: POOR Distance: 8.1 arcmin from the SVOM/ECLAIRs position. Mean rate: (6.2 [+4.0, -2.8])e-3 ct s^-1 Mean flux: (2.6 [+1.7, -1.2])e-13 erg cm^-2 s^-1 Peak rate: (6.2 [+4.0, -2.8])e-3 ct s^-1 Peak flux: (2.6 [+1.7, -1.2])e-13 erg cm^-2 s^-1 XMM UL: 1.1e-14 erg cm^-2 s^-1, (0.3-10 keV) so the source is not above this 3-sigma upper limit. There is no evidence for fading. Source 4 (SWIFT J011327.9-000300): ================================== RA (J2000.0): 18.3663 = 01 13 27.91 Dec (J2000.0): -0.0501 = -00 03 00.4 Error: 9.4 (arcsec, radius, 90% confidence). Detect flag: POOR Distance: 6.4 arcmin from the SVOM/ECLAIRs position. Mean rate: (-1.0 +/- -1.0)e0 ct s^-1 Mean flux: (-4.3 +/- -4.3)e-11 erg cm^-2 s^-1 Peak rate: (4.0 [+3.3, -2.3])e-3 ct s^-1 Peak flux: (1.7 [+1.4, -1.0])e-13 erg cm^-2 s^-1 XMM UL: 3.6e-14 erg cm^-2 s^-1, (0.3-10 keV) so the source is not above this 3-sigma upper limit. There is no evidence for fading. There is 1 2MASS object within the source's 3-sigma error radius. All fluxes are 0.3-10 keV, observed. For all flux conversions and comparisons with catalogues and upper limits from other missions, we assumed a power-law spectrum with NH=3x10^20 cm^-2 and photon index (Gamma)=1.7 unless otherwise stated. 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/SVOM/SVOM_FIELD00054. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/42983. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...