GCN Circular 42733

S. Dichiara (PSU), J.A. Kennea (PSU), K.L. Page (U. Leicester), A.P.
Beardmore (U. Leicester), T. Sbarrato (INAF-OAB), P. D'Avanzo
(INAF-OAB), M.G. Bernardini (INAF-OAB), D.N. Burrows (PSU) and P.A.
Evans (U. Leicester) reports on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the
Fermi/LAT-detected burst GRB 251115A in a series of observations tiled
on the sky.  The total exposure time is  4.9 ks, distributed over 5
tiles; the maximum exposure at a single sky location in the tiling was
2.1 ks. The data were collected between T0+35.6 ks and T0+80.1 ks, and
are entirely in Photon Counting (PC) mode. 

Six uncatalogued X-ray sources have been detected, however none of them
is above the RASS limit or shows definitive signs of fading. Therefore,
at the present time we cannot identify which, if any, is the afterglow.
Details of these sources are given below:

Source 1:
  RA (J2000.0):  330.1753  =  22h 00m 42.06s
  Dec (J2000.0): -9.3644  =  -09d 21' 51.7"
  Error: 8.5 arcsec (radius, 90% conf.)
  Count-rate: (3.7 [+2.2, -1.6])e-3 ct s^-1   
  Distance: 660 arcsec from Fermi/LAT position.

Source 2:
  RA (J2000.0):  330.0683  =  22h 00m 16.38s
  Dec (J2000.0): -9.4681  =  -09d 28' 05.0"
  Error: 8.6 arcsec (radius, 90% conf.)
  Count-rate: (6.2 [+3.9, -2.8])e-3 ct s^-1   
  Distance: 1100 arcsec from Fermi/LAT position.

Source 3:
  RA (J2000.0):  330.0530  =  22h 00m 12.72s
  Dec (J2000.0): -9.1976  =  -09d 11' 51.3"
  Error: 5.8 arcsec (radius, 90% conf.)
  Count-rate: (4.3 [+2.3, -1.7])e-3 ct s^-1   
  Distance: 437 arcsec from Fermi/LAT position.
  Flux: (2.26 [+1.23, -0.91])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 4:
  RA (J2000.0):  330.2127  =  22h 00m 51.06s
  Dec (J2000.0): -9.1608  =  -09d 09' 38.9"
  Error: 14.1 arcsec (radius, 90% conf.)
  Count-rate: (9.6 [+4.4, -3.4])e-3 ct s^-1   
  Distance: 152 arcsec from Fermi/LAT position.
  Flux: (3.6 [+1.6, -1.2])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 6:
  RA (J2000.0):  329.7737  =  21h 59m 05.69s
  Dec (J2000.0): -8.8965  =  -08d 53' 47.2"
  Error: 5.6 arcsec (radius, 90% conf.)
  Count-rate: 0.0113 [+0.0055, -0.0042] ct s^-1   
  Distance: 1756 arcsec from Fermi/LAT position.
  Flux: (4.5 [+2.2, -1.7])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 7:
  RA (J2000.0):  329.8892  =  21h 59m 33.40s
  Dec (J2000.0): -8.9944  =  -08d 59' 39.8"
  Error: 6.6 arcsec (radius, 90% conf.)
  Count-rate: 0.0101 [+0.0049, -0.0038] ct s^-1   
  Distance: 1218 arcsec from Fermi/LAT position.
  Flux: (2.63 [+1.28, -0.99])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

A catalogued source was also detected.

The results of the XRT-team automatic analysis of the tiled XRT
observations, including a position-specific upper limit calculator, are
available at https://www.swift.ac.uk/xrt_products/TILED_GRB00140.

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