{
  "editedBy": "Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov>",
  "eventId": "EP-WXT trigger 01709176612",
  "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), M. Capalbi (INAF-IASFPA), A. D'Ai (INAF-IASFPA), P. D'Avanzo\n(INAF-OAB), V. D'Elia (SSDC & INAF-OAR), S. Dichiara (PSU), M. Ferro (INAF-OAB), A.\nMelandri (INAF-OAR), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), M. Perri\n(SSDC & INAF-OAR), C. Salvaggio (INAF-OAB), T. Sbarrato (INAF-OAB), B. Sbarufatti\n(INAF-OAB), M.A. Williams (PSU) report on behalf of the Swift-XRT team:\n\nSwift-XRT has performed follow-up observations of the Einstein Probe/WXT-detected\nsource EP#01709176612, collecting 2.0 ks of Photon Counting (PC) mode data between\nT0+4.2 ks and T0+9.7 ks after the trigger. A candidate counterpart has been found.\nThe details of this source are:\n\n  Source 1 (SWIFT J122501.5-521613):\n  ==================================\n    RA (J2000.0):  186.2566  =\t12h 25m 01.58s\n    Dec (J2000.0): -52.2705  =\t-52d 16' 13.8\"\n    Error:\t   3.5 (arcsec, radius, 90% confidence).\n    Detect flag:   GOOD\n    Distance:\t   23 arcsec from the Einstein Probe/WXT position.\n    Mean rate:\t   2.883 +/- 0.078 ct s^-1\n    Mean flux:\t   (9.45 +/- 0.26)e-11 erg cm^-2 s^-1\n    Peak rate:\t   5.3 +/- 1.1 ct s^-1\n    Peak flux:\t   (1.74 +/- 0.37)e-10 erg cm^-2 s^-1\n    ECF:\t   3.28e-11 erg cm^-2 ct^-1, assuming NH=2.18e+21 cm^-2,\n\t\t   gamma=2.19; determined from a spectral fit.\n\n    This matches a catalogued X-ray source XMMSL3 J122501.2-521616\n    in the XMM-NEWTON/XMMSLEWCLN catalogue. Details:\n\n      Separation:  2.9\" from the XRT source\n      Cat Rate:    6.3e-01 +/- 2.6e-01 ct s^-1 \n      Cat Flux:    5.5e-12 +/- 2.3e-12 erg cm^-2 s^-1 (0.3-10 keV)\n\t     so the source  is 4.5-sigma above the catalogued flux.\n    \n    The source may be fading, at the 1.0-sigma level.\n    A SIMBAD object `WISEA J122501.45-521614.6' is 1.5\" away.\n    There are 2 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\nThis is most likely a stellar flare of a Young Stellar Object Candidate Gaia DR3\n6077506855610363648 (GCN 40523, Song et al.)\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/EP.\n\nThis circular is an officicial product of the Swift-XRT team.\n\n\n",
  "editedOn": 1748525404720,
  "version": 2,
  "subject": "EP#01709176612: Swift-XRT counterpart detection of flaring star",
  "format": "text/plain",
  "circularId": 40528,
  "createdOn": 1747941422002,
  "bibcode": "2025GCN.40528....1E",
  "submitter": "Phil Evans at U of Leicester <pae9@star.le.ac.uk>",
  "submittedHow": "email"
}