[vsnet-grb-info 28043] GRB 210605B: Swift-XRT observations

GCN Circulars gcncirc at capella2.gsfc.nasa.gov
Tue Jun 8 03:30:21 JST 2021


TITLE:   GCN CIRCULAR
NUMBER:  30146
SUBJECT: GRB 210605B: Swift-XRT observations
DATE:    21/06/07 18:29:21 GMT
FROM:    Boris Sbarufatti at PSU  <bxs60 at psu.edu>

A. D'Ai (INAF-IASFPA), A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU),
D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester), A.P. Beardmore (U. Leicester), A. Melandri (INAF-OAB), T.
Sbarrato (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
Swift/BAT-detected burst GRB 210605B (James DeLaunay et al. GCN Circ.
30130), collecting 5.0 ks of Photon Counting (PC) mode data between
T0+74.2 ks and T0+96.6 ks. 

One uncatalogued X-ray sources has been detected, however it is not
above the RASS limit or shows definitive signs of fading. Therefore, at
the present time we cannot confirm if this source is the afterglow.
Details of the source are given below:

Source 1:
  RA (J2000.0):  15.7456  =  01:02:58.95
  Dec (J2000.0): -6.4290  =  -06:25:44.3
  Error: 5.7 arcsec (radius, 90% conf.)
  Count-rate: (2.94 [+1.05, -0.86])e-3 ct s^-1	 
  Distance: 145 arcsec from Swift/BAT position.
  Flux: (9.3 [+3.3, -2.7])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)

The field has been previously observed by XRT for the Swift
Gravitational Wave Galaxy Survey (https://www.swift.ac.uk/SGWGS/). No
source was detected at this position on a 5.3 ks integrated exposure,
down to a 3-σ upper limit of 2.7 e-3 ct s^-1.

A catalogued source and a spurious source caused by Earth limb
contamination were also detected.

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/00021450.

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



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