GCN Circular 42486

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
GRB 251027A, collecting 1.6 ks of Photon Counting (PC) mode data between T0+4.5 ks
and T0+12 ks after the trigger. We have detected 2 sources.  These have been
automatically classified as follows:
  * 0 likely counterparts
  * 0 candidate counterparts
  * 2 uncatalogued X-ray sources
  * 0 known X-ray sources

Uncatalogued X-ray sources
--------------------------

  Source 1 (SWIFT J062052.1+114644):
  ==================================
    RA (J2000.0):   95.2175  =	06 20 52.20
    Dec (J2000.0):  +11.7792  =  +11 46 45.1
    Error:	    7.5 (arcsec, radius, 90% confidence).
    Detect flag:    GOOD
    Distance:	    5.8 arcmin from the SVOM/ECLAIRs position.
    Mean rate:	    (5.4 [+2.7, -2.0])e-3 ct s^-1
    Mean flux:	    (1.90 [+0.95, -0.72])e-10 erg cm^-2 s^-1
    Peak rate:	    (5.4 [+2.7, -2.0])e-3 ct s^-1
    Peak flux:	    (1.90 [+0.95, -0.72])e-10 erg cm^-2 s^-1
    ECF:	    3.52e-08 erg cm^-2 ct^-1
		      assuming NH=1.86e+24 cm^-2, gamma=-3.00
		      determined from a spectral fit.
    XMM UL:	    2.1e-12 erg cm^-2 s^-1, (0.3-10 keV)
		      so the source is 2.2-sigma above this 3-sigma upper limit.
    There is no evidence for fading.
    A SIMBAD object `NVSS J062052+114645' is 0.1" away.
    There are 4 2MASS objects within the source's 3-sigma error radius.

  Source 3 (SWIFT J062105.2+112959):
  ==================================
    RA (J2000.0):   95.2720  =	06 21 05.28
    Dec (J2000.0):  +11.4998  =  +11 29 59.3
    Error:	    8.8 (arcsec, radius, 90% confidence).
    Detect flag:    POOR
    Distance:	    12.3 arcmin from the SVOM/ECLAIRs position.
    Mean rate:	    (5.7 [+3.5, -2.5])e-3 ct s^-1
    Mean flux:	    (2.4 [+1.5, -1.1])e-13 erg cm^-2 s^-1
    Peak rate:	    (5.7 [+3.5, -2.5])e-3 ct s^-1
    Peak flux:	    (2.4 [+1.5, -1.1])e-13 erg cm^-2 s^-1
    XMM UL:	    3.3e-12 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 are 5 2MASS objects 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_FIELD00046.

This circular is an official product of the Swift-XRT team.