[vsnet-grb-info 15381] GRB 140808A: Swift-XRT observations

GCN Circulars gcncirc at capella2.gsfc.nasa.gov
Sat Aug 9 03:47:45 JST 2014


TITLE:   GCN CIRCULAR
NUMBER:  16670
SUBJECT: GRB 140808A: Swift-XRT observations
DATE:    14/08/08 18:47:37 GMT
FROM:    Kim Page at U.of Leicester  <klp5 at leicester.ac.uk>

K.L. Page, P.A. Evans (U. Leicester) and S.B. Cenko (GSFC) report on
behalf of the Swift-XRT team:

We have analysed 3.0 ks of XRT data for the GBM-detected burst: GRB
140808A (Zhang, GCN Circ. 16669), from 41.9 ks to 52.0 ks after the GBM
trigger. The data are entirely in Photon Counting (PC) mode.  An X-ray
source is detected within the XRT field of view. Using 1513 s of PC
mode data and 1 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 = 221.22196, +49.21463 which is equivalent to:

RA (J2000): 14h 44m 53.27s
Dec(J2000): +49d 12' 52.7"

with an uncertainty of 3.3 arcsec (radius, 90% confidence). This
position is 1.6 arcsec from the iPTF position (Singer et al., GCN CIrc.
16668).  The source has a mean count rate of 1.5e-02 ct/sec; we cannot
determine at the present time whether it is fading. We note that this
count rate is just below the ROSAT All Sky Survey detection limit, so
this source would not have been listed in the RASS. However, given the
transient nature of the iPTF optical candidate, it seems likely this is
a new X-ray source. 

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020403.

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


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