GCN Circular 19481
Subject
GRB 160530A: Swift follow-up and X-ray afterglow candidate
Date
2016-06-01T16:58:01Z (8 years ago)
From
Valerio D'Elia at ASDC <delia@asdc.asi.it>
V. D���Elia (ASDC), L. Izzo (IAA-CSIC), P. A. Evans (U. Leicester), A.
A. Breeveld (UCL-MSSL), J.A. Kennea (PSU), D. Malesani (DARK/NBI), C.
B. Markwardt (NASA/GSFC) report on behalf of the Swift team:
Swift has performed follow-up observations of the COSI-detected burst
GRB 160530A (Tomsick, GCN Circ. 19473) in a series of observations
tiled on the sky. The total exposure time is 24 ks, distributed over
46 tiles; the maximum exposure at a single sky location was 1.4 ks.
The data were collected between T0+19.0 ks and T0+158 ks, and are
entirely in Photon Counting (PC) mode.
One uncatalogued X-ray source has been detected by XRT in the
intersection of the COSI and the IPN error regions (Svinkin et al.,
GCN Circ. 19476), however, this source is below the RASS limit at its
location, and we cannot currently determine whether it is fading.
Therefore, at the present time we cannot state if it is the afterglow.
The source was imaged and detected in the time interval T0+145 ks to
T0+158 ks and comprises 920 s of exposure time. More XRT data are
expected in the forthcoming days. Further details of this source are
given below:
RA (J2000.0): 118.9741 = 07:55:53.77
Dec (J2000.0): -25.4638 = -25:27:49.7
Error: 6.6 arcsec (radius, 90% conf.)
Count-rate: 0.0222 +/- 0.0070 ct s^-1
Flux: (6.3 +/- 2.0)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)
No optical afterglow consistent with the XRT source position is
detected in the initial UVOT exposures. The preliminary 3-sigma upper
limit for the summed U-band exposures (926 s) is 20.8 mag.