Skip to main content
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 16661

GRB 140801A: Swift-XRT observations
2014-08-02T14:20:53Z (10 years ago)
Alessandro Maselli at INAF/IASF Palermo <>
A. Maselli and M. De Pasquale (INAF-IASFPA) report on behalf of the 
Swift-XRT team:

We have analysed 2.0 ks of XRT data for the FERMI/GBM detected burst GRB 
140801A (Pelassa, GCN Circ. 16658), from 36.4 ks to 48.0 ks after the 
GBM trigger. The data are entirely in Photon Counting (PC) mode. An 
X-ray source is found at the position of the optical transient detected 
by MASTER (Gorbovskoy et al.,  GCN Circ. 16653). Using 1893 s of PC mode 
data and 2 UVOT images, we find an enhanced XRT position (using the 
XRT-UVOT alignment and matching UVOT  field sources to the USNO-B1 
catalogue): RA, Dec = 44.06877, +30.93799 which is equivalent to:

RA (J2000): 02h 56m 16.50s
Dec(J2000): +30d 56' 16.8"

with an uncertainty of 2.5 arcsec (radius, 90% confidence). This 
position is 0.8 arcsec from the MASTER position. We believe that this 
source, which has a mean count rate of 2.3e-02 ct/sec, is the X-ray 
afterglow of GRB 140801A but further observations are needed to 
determine a decaying behaviour.

The results of the XRT-team automatic analysis are available at

This circular is an official product of the Swift-XRT team.
Looking for U.S. government information and services? Visit