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GCN Circular 29202

Subject
GRB 201227A: Swift-XRT observations
Date
2020-12-30T00:59:11Z (3 years ago)
From
Aaron Tohuvavohu at U Toronto <aaron.tohu@gmail.com>
V. D'Elia (SSDC & INAF-OAR), A. D'Ai (INAF-IASFPA), A. Tohuvavohu (U.
Toronto), B. Sbarufatti (PSU), D.N. Burrows (PSU), K.L. Page (U.
Leicester), A.P. Beardmore (U. Leicester), A. Melandri (INAF-OAB) and
P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the IPN-detected
burst GRB 201227A (Ursi et al. GCN Circ. 29179) in a series of
observations tiled on the sky. The total exposure time is 7.5 ks,
distributed over 4 tiles; the maximum exposure at a single sky location
was 5.3 ks. The data were collected between T0+51.6 ks and T0+80.7 ks,
and are entirely in Photon Counting (PC) mode. 

Four 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):  170.6083  =  11:22:25.99
  Dec (J2000.0): -73.4880  =  -73:29:16.9
  Error: 7.4 arcsec (radius, 90% conf.)
  Count-rate: (4.4 [+1.7, -1.4])e-3 ct s^-1   
  Distance: 670 arcsec from IPN position.
  Flux: (9.0 [+3.5, -2.8])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 2:
  RA (J2000.0):  170.6190  =  11:22:28.57
  Dec (J2000.0): -73.4798  =  -73:28:47.2
  Error: 4.8 arcsec (radius, 90% conf.)
  Count-rate: (3.6 [+1.6, -1.3])e-3 ct s^-1   
  Distance: 698 arcsec from IPN position.
  Flux: (1.34 [+0.60, -0.47])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 3:
  RA (J2000.0):  169.8508  =  11:19:24.19
  Dec (J2000.0): -73.5866  =  -73:35:11.9
  Error: 5.6 arcsec (radius, 90% conf.)
  Count-rate: (2.8 [+1.4, -1.1])e-3 ct s^-1   
  Distance: 290 arcsec from IPN position.

Source 4:
  RA (J2000.0):  171.2953  =  11:25:10.87
  Dec (J2000.0): -73.6326  =  -73:37:57.4
  Error: 4.4 arcsec (radius, 90% conf.)
  Count-rate: (4.2 [+2.6, -1.9])e-3 ct s^-1   
  Distance: 1194 arcsec from IPN position.

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_GRB00096.

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