GCN Circular 42768

J.A. Kennea (PSU), A.P. Beardmore (U. Leicester), J.P. Osborne (U.
Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E.
Ambrosi  (INAF-IASFPA) , D.N. Burrows (PSU), S. Lanava (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/GBM-detected burst GRB 251117A in a series of observations tiled
on the sky.  The total exposure time is  6.5 ks, distributed over 7
tiles; the maximum exposure at a single sky location in the tiling was
2.0 ks. The data were collected between T0+48.9 ks and T0+81.8 ks, and
are entirely in Photon Counting (PC) mode. 

Thirteen 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):  331.2065  =  22h 04m 49.57s
  Dec (J2000.0): +5.5085  =  +05d 30' 30.6"
  Error: 8.0 arcsec (radius, 90% conf.)
  Count-rate: (7.5 [+4.2, -3.1])e-3 ct s^-1   
  Distance: 401 arcsec from Fermi/GBM position.
  Flux: (2.8 [+1.5, -1.1])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 2:
  RA (J2000.0):  331.2121  =  22h 04m 50.90s
  Dec (J2000.0): +5.6862  =  +05d 41' 10.4"
  Error: 18.7 arcsec (radius, 90% conf.)
  Count-rate: (4.4 [+2.7, -1.9])e-3 ct s^-1   
  Distance: 523 arcsec from Fermi/GBM position.

Source 3:
  RA (J2000.0):  331.1150  =  22h 04m 27.61s
  Dec (J2000.0): +5.1842  =  +05d 11' 03.0"
  Error: 8.5 arcsec (radius, 90% conf.)
  Count-rate: (7.0 [+4.5, -3.2])e-3 ct s^-1   
  Distance: 1539 arcsec from Fermi/GBM position.

Source 6:
  RA (J2000.0):  331.1130  =  22h 04m 27.12s
  Dec (J2000.0): +5.7560  =  +05d 45' 21.6"
  Error: 7.8 arcsec (radius, 90% conf.)
  Count-rate: (8.2 [+4.5, -3.4])e-3 ct s^-1   
  Distance: 947 arcsec from Fermi/GBM position.
  Flux: (2.8 [+1.5, -1.2])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 7:
  RA (J2000.0):  331.5308  =  22h 06m 07.38s
  Dec (J2000.0): +5.4134  =  +05d 24' 48.2"
  Error: 6.5 arcsec (radius, 90% conf.)
  Count-rate: (4.9 [+2.6, -1.9])e-3 ct s^-1   
  Distance: 1000 arcsec from Fermi/GBM position.

Source 8:
  RA (J2000.0):  331.7897  =  22h 07m 09.54s
  Dec (J2000.0): +5.6746  =  +05d 40' 28.6"
  Error: 7.8 arcsec (radius, 90% conf.)
  Count-rate: (7.1 [+4.4, -3.1])e-3 ct s^-1   
  Distance: 1794 arcsec from Fermi/GBM position.

Source 9:
  RA (J2000.0):  330.9021  =  22h 03m 36.49s
  Dec (J2000.0): +5.4483  =  +05d 26' 54.0"
  Error: 8.3 arcsec (radius, 90% conf.)
  Count-rate: (7.3 [+4.4, -3.3])e-3 ct s^-1   
  Distance: 1491 arcsec from Fermi/GBM position.
  Flux: (3.5 [+2.1, -1.6])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 10:
  RA (J2000.0):  331.7481  =  22h 06m 59.54s
  Dec (J2000.0): +5.3975  =  +05d 23' 51.1"
  Error: 8.5 arcsec (radius, 90% conf.)
  Count-rate: 0.0109 [+0.0053, -0.0040] ct s^-1   
  Distance: 1721 arcsec from Fermi/GBM position.

Source 11:
  RA (J2000.0):  330.8986  =  22h 03m 35.66s
  Dec (J2000.0): +5.4101  =  +05d 24' 36.5"
  Error: 8.6 arcsec (radius, 90% conf.)
  Count-rate: (8.4 [+4.7, -3.5])e-3 ct s^-1   
  Distance: 1549 arcsec from Fermi/GBM position.

Source 12:
  RA (J2000.0):  330.9379  =  22h 03m 45.11s
  Dec (J2000.0): +5.3847  =  +05d 23' 05.0"
  Error: 7.1 arcsec (radius, 90% conf.)
  Count-rate: (9.1 [+4.8, -3.5])e-3 ct s^-1   
  Distance: 1458 arcsec from Fermi/GBM position.

Source 13:
  RA (J2000.0):  330.8498  =  22h 03m 23.95s
  Dec (J2000.0): +5.4122  =  +05d 24' 44.0"
  Error: 9.1 arcsec (radius, 90% conf.)
  Count-rate: (5.8 [+4.2, -2.8])e-3 ct s^-1   
  Distance: 1710 arcsec from Fermi/GBM position.

Source 14:
  RA (J2000.0):  330.7987  =  22h 03m 11.70s
  Dec (J2000.0): +5.6452  =  +05d 38' 42.7"
  Error: 9.8 arcsec (radius, 90% conf.)
  Count-rate: (6.7 [+4.2, -3.0])e-3 ct s^-1   
  Distance: 1816 arcsec from Fermi/GBM position.

Source 15:
  RA (J2000.0):  330.9250  =  22h 03m 42.01s
  Dec (J2000.0): +5.4456  =  +05d 26' 44.0"
  Error: 32.4 arcsec (radius, 90% conf.)
  Count-rate: (5.7 [+4.1, -3.1])e-3 ct s^-1   
  Distance: 1416 arcsec from Fermi/GBM position.
  Flux: (1.79 [+1.29, -0.96])e-12 erg cm^-2 s^-1 (observed, 0.3-10 keV)

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_GRB00141.

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