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GCN Circular 27500

Subject
GRB 200405B: Swift-XRT observations
Date
2020-04-06T15:18:06Z (4 years ago)
From
Andy Beardmore at U Leicester <ab271@leicester.ac.uk>
B. Sbarufatti (PSU), D.N. Burrows (PSU), J. D. Gropp (PSU), K.L. Page
(U. Leicester), A.P. Beardmore (U. Leicester), A. Melandri (INAF-OAB),
T. Sbarrato (INAF-OAB), P. D'Avanzo (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 INTEGRAL/SPI-ACS
and Swift-BAT GUANO detected possible short burst GRB 200405B (James
DeLaunay et al. GCN Circ. 27497Not found
 
 
), collecting 5.0 ks of Photon Counting
(PC) mode data between T0+66.6 ks and T0+80.0 ks. 

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. We note that Source 2 lies within the 4 arcmin BAT error
region reported in GCN Circ. 27497Not found
 
 
. Details of these sources are given
below:

Source 1:
  RA (J2000.0):  62.6009  =  04:10:24.21
  Dec (J2000.0): -51.4435  =  -51:26:36.5
  Error: 5.5 arcsec (radius, 90% conf.)
  Count-rate: (1.87 [+0.90, -0.69])e-3 ct s^-1	 
  Distance: 530 arcsec from BAT position.
  Flux: (1.15 [+0.55, -0.43])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)


Source 2:
  RA (J2000.0):  62.8248  =  04:11:17.95
  Dec (J2000.0): -51.5687  =  -51:34:07.5
  Error: 6.5 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (3.31 [+1.13, -0.93])e-3 ct s^-1	 
  Distance: 152 arcsec from BAT position.
  Flux: (4.1 [+1.4, -1.1])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 3:
  RA (J2000.0):  62.5137  =  04:10:3.28
  Dec (J2000.0): -51.4509  =  -51:27:03.3
  Error: 4.6 arcsec (radius, 90% conf.)
  Count-rate: (1.96 [+0.97, -0.73])e-3 ct s^-1	 
  Distance: 684 arcsec from BAT position.

Source 4:
  RA (J2000.0):  62.6146  =  04:10:27.49
  Dec (J2000.0): -51.5329  =  -51:31:58.3
  Error: 4.3 arcsec (radius, 90% conf.)
  Count-rate: (3.74 [+1.18, -0.99])e-3 ct s^-1	 
  Distance: 391 arcsec from BAT position.
  Flux: (1.20 [+0.38, -0.32])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)


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/ToO_GRBs/00020979.

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