[vsnet-grb-info 15986] Swift J123205.1-105602: XRT and UVOT observations of soft short burst source

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17268
SUBJECT: Swift J123205.1-105602: XRT and UVOT observations of soft short burst source
DATE:    15/01/03 19:06:28 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings at nasa.gov>

J. R. Cummings, M. Gropp (PSU), K. L. Page (U. Leicester), M. Siegel (PSU)

We report on Swift followup observations of the source of the ground-detected
short, soft burst reported on Jan 1, 2015 by Cummings (GCN Circ. 17267).

We have analysed 3.3 ks of XRT data from 139.2 ks to 155.5 ks after the burst.
The data are entirely in Photon Counting (PC) mode.  An X-ray source is
detected within the BAT error circle. Using 2057 s of PC mode data and 3 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 = 188.02119, -10.93389 which is equivalent to:

RA (J2000): 12h 32m 05.09s
Dec(J2000): -10d 56' 02.0"

with an uncertainty of 2.4 arcsec (radius, 90% confidence). This position is
111 arcsec from the BAT position.  The source has a mean count rate of
1.4e-02 ct/sec; we cannot determine at the present time whether it is fading.

The spectrum is not well-determined.  However, the best fit results from the
data collected so far are:  Gamma = 2.5 ± 0.5, with no evidence for NH above
the Galactic value of 3.5e20 cm^-2.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020464.

There is an optical source in the DSS consistent with the XRT source.  The
source is detected in UVOT with a white magnitude of 18.44 +- 03.  It shows no
significant variability over the 15 ks spanned by the observations.

A followup Swift TOO has been requested with the target number 20464, in order
to observe any fading and to refine the spectrum.