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GCN Circular 36226

Subject
GRB 240415B: Swift-XRT observations
Date
2024-04-22T07:23:17Z (3 months ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), J.P. Osborne (U.
Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), E.
Ambrosi  (INAF-IASFPA) , M. Capalbi (INAF-IASFPA), M. Perri (SSDC &
INAF-OAR), 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
Swift/BAT-detected burst GRB 240415B, collecting 3.4 ks of Photon
Counting (PC) mode data between T0+86.1 ks and T0+115.2 ks. 

Four uncatalogued X-ray sources have been detected consistent with
being within 493 arcsec of the Swift/BAT position, 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 2:
  RA (J2000.0):  132.2001  =  08:48:48.03
  Dec (J2000.0): -27.0714  =  -27:04:17.2
  Error: 6.4 arcsec (radius, 90% conf.)
  Count-rate: (9.5 [+10.4, -8.3])e-4 ct s^-1   
  Distance: 374 arcsec from Swift/BAT position.

Source 3:
  RA (J2000.0):  132.3176  =  08:49:16.23
  Dec (J2000.0): -27.1553  =  -27:09:19.0
  Error: 6.6 arcsec (radius, 90% conf.)
  Count-rate: (2.6 [+1.6, -1.3])e-3 ct s^-1   
  Distance: 306 arcsec from Swift/BAT position.
  Flux: (1.32 [+0.83, -0.68])e-12 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 6:
  RA (J2000.0):  132.3018  =  08:49:12.44
  Dec (J2000.0): -27.1242  =  -27:07:27.0
  Error: 5.5 arcsec (radius, 90% conf.)
  Count-rate: (3.4 [+1.6, -1.3])e-3 ct s^-1   
  Distance: 200 arcsec from Swift/BAT position.
  Flux: (4.6 [+2.2, -1.8])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 7:
  RA (J2000.0):  132.4111  =  08:49:38.66
  Dec (J2000.0): -27.0674  =  -27:04:02.8
  Error: 5.6 arcsec (radius, 90% conf.)
  Count-rate: (3.6 [+1.8, -1.5])e-3 ct s^-1   
  Distance: 301 arcsec from Swift/BAT position.
  Flux: (8.8 [+4.5, -3.6])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Three uncatalogued sources were also detected too far from the GRB
position to be likely afterglow candidates.

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/00021684.

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


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