GCN Circular 25473
Subject
GRB 190816A: Swift-XRT afterglow detection
Date
2019-08-25T04:57:43Z (5 years ago)
From
Kim Page at U.of Leicester <klp5@leicester.ac.uk>
A. D'Ai (INAF-IASFPA), D.N. Burrows (PSU), J. D. Gropp (PSU), A.
Tohuvavohu (PSU), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB) and P.A.
Evans (U. Leicester) report on behalf of the Swift-XRT team:
Swift-XRT has conducted further observations of the field of the
Swift/BAT-detected burst GRB 190816A (Ukwatta et al. GCN Circ. 25405).
The observations now extend from T0+141.7 ks to T0+723.4 ks. The source
previously reported by D'Ai et al. (GCN Circ. 25399), "Source 4", is
fading with 3-sigma significance, and is therefore likely the GRB
afterglow. Using 267 s of PC mode data and 1 UVOT image, we find an
enhanced XRT position (using the XRT-UVOT alignment and matching UVOT
field sources to the USNO-B1 catalogue): RA, Dec = 341.18949, -29.75761
which is equivalent to:
RA (J2000): 22h 44m 45.48s
Dec(J2000): -29d 45' 27.4"
with an uncertainty of 4.9 arcsec (radius, 90% confidence). This
position is 64 arcsec from the Swift/BAT position. The source is
fading with alpha >0.5.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00920783.
The results of the full analysis of the XRT observations are available
at https://www.swift.ac.uk/ToO_GRBs/00920783.
This circular is an official product of the Swift-XRT team.