[vsnet-grb-info 16376] GRB 150323B: Swift-XRT afterglow detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17657
SUBJECT: GRB 150323B: Swift-XRT afterglow detection
DATE:    15/03/30 14:10:10 GMT
FROM:    Alex Amaral-Rogers at U.of Leicester  <aar14 at leicester.ac.uk>

P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), M. de Pasquale (INAF-IASFPA),
D.N. Burrows (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU),
J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U.
Leicester) 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 150323B (Cummings et al. GCN Circ. 17619).
The observations now extend from T0+40.4 ks to T0+483.5 ks. 

Of the sources reported by D'Avanzo et al. (GCN Circ. 17634), "Source
1" is fading with 3-sigma significance, and is therefore likely the GRB
afterglow.  The position of this source is RA, Dec=260.4534, +38.3179
which is equivalent to:

RA (J2000): 17:21:48.83
Dec(J2000): +38:19:04.6

with an uncertainty of 4.3 arcsec (radius, 90% confidence).  This
position is 18 arcsec from the Swift/BAT position.  The source is
fading with alpha >0.3.

The results of the XRT-team automatic analysis of the likely afterglow
are at http://www.swift.ac.uk/ToO_GRBs/00020485/index_1.php.
The results of the full analysis of the XRT observations are available
at http://www.swift.ac.uk/ToO_GRBs/00020485.

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