{
  "eventId": "GRB 251027A",
  "subject": "GRB 251027A: Swift-XRT observations",
  "submittedHow": "email",
  "bibcode": "2025GCN.42486....1E",
  "submitter": "Phil Evans at U of Leicester <pae9@star.le.ac.uk>",
  "body": "P.A. Evans (U. Leicester), J.A. Kennea (PSU), E. Ambrosi  (INAF-IASFPA) , A.P.\nBeardmore (U. Leicester), M.G. Bernardini (INAF-OAB), R. Brivio (INAF-OAB), D.N.\nBurrows (PSU), S. Campana (INAF-OAB), M. Capalbi (INAF-OAR), A. D'Ai (INAF-IASFPA),\nP. D'Avanzo (INAF-OAB), V. D'Elia (SSDC & INAF-OAR), S. Dichiara (PSU), M. Ferro\n(INAF-OAB), A. Melandri (INAF-OAR), J.P. Osborne (U. Leicester), K.L. Page (U.\nLeicester), M. Perri (SSDC & INAF-OAR), C. Salvaggio (INAF-OAB), T. Sbarrato\n(INAF-OAB), B. Sbarufatti (INAF-OAB), M.A. Williams (PSU) report on behalf of the\nSwift-XRT team:\n\nSwift-XRT has performed follow-up observations of the SVOM/ECLAIRs-detected source\nGRB 251027A, collecting 1.6 ks of Photon Counting (PC) mode data between T0+4.5 ks\nand T0+12 ks after the trigger. We have detected 2 sources.  These have been\nautomatically classified as follows:\n  * 0 likely counterparts\n  * 0 candidate counterparts\n  * 2 uncatalogued X-ray sources\n  * 0 known X-ray sources\n\nUncatalogued X-ray sources\n--------------------------\n\n  Source 1 (SWIFT J062052.1+114644):\n  ==================================\n    RA (J2000.0):   95.2175  =\t06 20 52.20\n    Dec (J2000.0):  +11.7792  =  +11 46 45.1\n    Error:\t    7.5 (arcsec, radius, 90% confidence).\n    Detect flag:    GOOD\n    Distance:\t    5.8 arcmin from the SVOM/ECLAIRs position.\n    Mean rate:\t    (5.4 [+2.7, -2.0])e-3 ct s^-1\n    Mean flux:\t    (1.90 [+0.95, -0.72])e-10 erg cm^-2 s^-1\n    Peak rate:\t    (5.4 [+2.7, -2.0])e-3 ct s^-1\n    Peak flux:\t    (1.90 [+0.95, -0.72])e-10 erg cm^-2 s^-1\n    ECF:\t    3.52e-08 erg cm^-2 ct^-1\n\t\t      assuming NH=1.86e+24 cm^-2, gamma=-3.00\n\t\t      determined from a spectral fit.\n    XMM UL:\t    2.1e-12 erg cm^-2 s^-1, (0.3-10 keV)\n\t\t      so the source is 2.2-sigma above this 3-sigma upper limit.\n    There is no evidence for fading.\n    A SIMBAD object `NVSS J062052+114645' is 0.1\" away.\n    There are 4 2MASS objects within the source's 3-sigma error radius.\n\n  Source 3 (SWIFT J062105.2+112959):\n  ==================================\n    RA (J2000.0):   95.2720  =\t06 21 05.28\n    Dec (J2000.0):  +11.4998  =  +11 29 59.3\n    Error:\t    8.8 (arcsec, radius, 90% confidence).\n    Detect flag:    POOR\n    Distance:\t    12.3 arcmin from the SVOM/ECLAIRs position.\n    Mean rate:\t    (5.7 [+3.5, -2.5])e-3 ct s^-1\n    Mean flux:\t    (2.4 [+1.5, -1.1])e-13 erg cm^-2 s^-1\n    Peak rate:\t    (5.7 [+3.5, -2.5])e-3 ct s^-1\n    Peak flux:\t    (2.4 [+1.5, -1.1])e-13 erg cm^-2 s^-1\n    XMM UL:\t    3.3e-12 erg cm^-2 s^-1, (0.3-10 keV)\n\t\t      so the source is not above this 3-sigma upper limit.\n    There is no evidence for fading.\n    There are 5 2MASS objects within the source's 3-sigma error radius.\n\nAll fluxes are 0.3-10 keV, observed. For all flux conversions and comparisons with\ncatalogues and upper limits  from other missions, we assumed a power-law spectrum\nwith NH=3x10^20 cm^-2 and photon index (Gamma)=1.7 unless otherwise stated.\n\nThe results of the XRT-team automatic analysis of the XRT observations, including a\nposition-specific upper limit calculator, are available at\nhttps://www.swift.ac.uk/SVOM/SVOM_FIELD00046.\n\nThis circular is an official product of the Swift-XRT team.\n\n\n",
  "circularId": 42486,
  "createdOn": 1761582986049
}