{
  "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\nsb25061207, collecting 2.6 ks of Photon Counting (PC) mode data between T0+8.8 ks\nand T0+20 ks after the trigger. We have detected 4 sources. These have been\nautomatically classified as follows:\n  * 0 likely counterparts\n  * 0 candidate counterparts\n  * 4 uncatalogued X-ray sources\n  * 0 known X-ray sources\n\nUncatalogued X-ray sources\n--------------------------\n\n  Source 1 (SWIFT J131222.8+000431):\n  ==================================\n    RA (J2000.0):  198.0954  =\t13h 12m 22.90s\n    Dec (J2000.0): +0.0753  =  +00d 04' 31.1\"\n    Error:\t   6.4 (arcsec, radius, 90% confidence).\n    Detect flag:   GOOD\n    Distance:\t   7.2 arcmin from the SVOM/ECLAIRs position; \n\t 4.6 arcsec from SVOM/VT counterpart (GCN 40707).\n    Mean rate:\t   0.0133 [+0.0031, -0.0028] ct s^-1\n    Mean flux:\t   (6.0 [+1.4, -1.3])e-13 erg cm^-2 s^-1\n    Peak rate:\t   0.0147 +/- 0.0037 ct s^-1\n    Peak flux:\t   (6.6 +/- 1.7)e-13 erg cm^-2 s^-1\n    ECF:\t   4.50e-11 erg cm^-2 ct^-1, assuming NH=2.24e+20 cm^-2,\n\t\t   gamma=1.42; determined from a spectral fit.\n    XMM UL:\t   2.7e-12 erg cm^-2 s^-1, (0.3-10 keV)\n\t so the source is 12.4-sigma above this 3-sigma upper limit.\n    The source may be fading, at the 0.6-sigma level.\n\n  Source 2 (SWIFT J131136.2+000123):\n  ==================================\n    RA (J2000.0):  197.9010  =\t13h 11m 36.24s\n    Dec (J2000.0): +0.0233  =  +00d 01' 23.9\"\n    Error:\t   5.9 (arcsec, radius, 90% confidence).\n    Detect flag:   GOOD\n    Distance:\t   5.2 arcmin from the SVOM/ECLAIRs position.\n    Mean rate:\t   (7.2 +/- 2.1)e-3 ct s^-1\n    Mean flux:\t   (7.4 +/- 2.1)e-13 erg cm^-2 s^-1\n    Peak rate:\t   (7.2 +/- 2.1)e-3 ct s^-1\n    Peak flux:\t   (7.4 +/- 2.1)e-13 erg cm^-2 s^-1\n    ECF:\t   1.03e-10 erg cm^-2 ct^-1, assuming NH=2.41e+21 cm^-2,\n\t\t   gamma=0.47; determined from a spectral fit.\n    XMM UL:\t   4.4e-12 erg cm^-2 s^-1, (0.3-10 keV)\n\t so the source is 17.2-sigma above this 3-sigma upper limit.\n    There is no evidence for fading.\n    A SIMBAD object `MGC 42939' is 5.7\" away.\n\n  Source 3 (SWIFT J131139.2-000814):\n  ==================================\n    RA (J2000.0):  197.9134  =\t13h 11m 39.22s\n    Dec (J2000.0): -0.1375  =  -00d 08' 15.0\"\n    Error:\t   7.3 (arcsec, radius, 90% confidence).\n    Detect flag:   GOOD\n    Distance:\t   10.5 arcmin from the SVOM/ECLAIRs position.\n    Mean rate:\t   (6.3 [+2.4, -1.9])e-3 ct s^-1\n    Mean flux:\t   (1.36 [+0.52, -0.42])e-18 erg cm^-2 s^-1\n    Peak rate:\t   (6.3 [+2.4, -1.9])e-3 ct s^-1\n    Peak flux:\t   (1.36 [+0.52, -0.42])e-18 erg cm^-2 s^-1\n    ECF:\t   2.14e-16 erg cm^-2 ct^-1, assuming NH=4.37e+21 cm^-2,\n\t\t   gamma=96.83; determined from a spectral fit.\n    XMM UL:\t   2.7e-12 erg cm^-2 s^-1, (0.3-10 keV)\n\t so the source is 5817530.8-sigma above this 3-sigma upper limit.\n    There is no evidence for fading.\n\n  Source 4 (SWIFT J131140.3-000120):\n  ==================================\n    RA (J2000.0):  197.9181  =\t13h 11m 40.34s\n    Dec (J2000.0): -0.0225  =  -00d 01' 21.0\"\n    Error:\t   6.1 (arcsec, radius, 90% confidence).\n    Detect flag:   REASONABLE\n    Distance:\t   4.9 arcmin from the SVOM/ECLAIRs position.\n    Mean rate:\t   (2.6 [+1.5, -1.2])e-3 ct s^-1\n    Mean flux:\t   (1.61 [+0.96, -0.73])e-13 erg cm^-2 s^-1\n    Peak rate:\t   (2.6 [+1.5, -1.2])e-3 ct s^-1\n    Peak flux:\t   (1.61 [+0.96, -0.73])e-13 erg cm^-2 s^-1\n    ECF:\t   6.23e-11 erg cm^-2 ct^-1, assuming NH=3.65e+22 cm^-2,\n\t\t   gamma=2.45; determined from a spectral fit.\n    XMM UL:\t   4.8e-12 erg cm^-2 s^-1, (0.3-10 keV)\n\t so the source is 55.2-sigma above this 3-sigma upper limit.\n    There is no evidence for fading.\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.\n\nThis circular is an official product of the Swift-XRT team.\n\n\n",
  "subject": "sb25061207: Swift-XRT observations",
  "bibcode": "2025GCN.40711....1E",
  "submitter": "Phil Evans at U of Leicester <pae9@star.le.ac.uk>",
  "submittedHow": "email",
  "circularId": 40711,
  "createdOn": 1749762748458,
  "eventId": "sb25061207"
}