GCN Circular 42721

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 251116C, collecting 1.7 ks of Photon Counting (PC) mode data between T0+10 ks
and T0+26 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 J222122.5-102045):
  ==================================
    RA (J2000.0):   335.3441  =  22 21 22.58
    Dec (J2000.0):  -10.3459  =  -10 20 45.2
    Error:	    6.9 (arcsec, radius, 90% confidence).
    Detect flag:    GOOD
    Distance:	    6.1 arcmin from the SVOM/ECLAIRs position.
    Mean rate:	    (7.3 [+3.1, -2.5])e-3 ct s^-1
    Mean flux:	    (4.4 [+1.9, -1.5])e-13 erg cm^-2 s^-1
    Peak rate:	    (7.3 [+3.1, -2.5])e-3 ct s^-1
    Peak flux:	    (4.4 [+1.9, -1.5])e-13 erg cm^-2 s^-1
    ECF:	    6.06e-11 erg cm^-2 ct^-1
		      assuming NH=4.81e+20 cm^-2, gamma=0.94
		      determined from a spectral fit.
    XMM UL:	    4.1e-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 is 1 2MASS object within the source's 3-sigma error radius.

  Source 2 (SWIFT J222052.1-102849):
  ==================================
    RA (J2000.0):   335.2172  =  22 20 52.13
    Dec (J2000.0):  -10.4803  =  -10 28 49.1
    Error:	    5.8 (arcsec, radius, 90% confidence).
    Detect flag:    POOR
    Distance:	    5.1 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:	    (2.4 [+1.9, -1.3])e-3 ct s^-1
    Peak flux:	    (1.03 [+0.80, -0.57])e-13 erg cm^-2 s^-1
    XMM UL:	    4.7e-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.

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_FIELD00051.

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