[vsnet-grb-info 18500] XRT refined analysis for GRB 160925A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19948
SUBJECT: XRT refined analysis for GRB 160925A  
DATE:    16/09/27 15:01:49 GMT
FROM:    Boris Sbarufatti at INAF-OAB/IASFPA  <boris.sbarufatti at brera.inaf.it>

J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), V. D’Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), T.G.R. Roegiers (PSU), L.M. McCauley (PSU), J.A. Kennea (PSU), B. Mingo (U. Leicester) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the Fermi/GBM-detected burst GRB 160925A, pointing towards the direction of the MASTER variable optical source (Lipunov et al., GCN 19938), collecting 3.0 ks of Photon Counting (PC) mode data between T0+122.7 ks and T0+133.6 ks. 

No X-ray sources have been detected consistent with being within 9.9 arcsec of the MASTER position. The 3-sigma upper limit in the field is 0.003 ct  s^-1, corresponding to a 0.3-10 keV observed flux of 1.1e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum).

The lack of X-ray detection is consistent with the classification of the optical source as a dwarf nova (Steele et al., GCN 19944).

The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at http://www.swift.ac.uk/ToO_GRBs/00020701.

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