TITLE:   GCN CIRCULAR
NUMBER:  43412
SUBJECT: GRB 260114A: Swift-XRT refined Analysis
DATE:    26/01/15 11:55:38 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>

A.P. Beardmore (U. Leicester), B. Sbarufatti (INAF-OAB), C. Salvaggio
(INAF-OAB), M. Ferro (INAF-OAB), J.A. Kennea (PSU), D.N. Burrows (PSU),
S. Lanava (PSU), J.P. Osborne (U. Leicester) and P.A. Evans report on
behalf of the Swift-XRT team:

We have analysed 4.9 ks of XRT data for GRB 260114A, from 107 s to 33.3
ks after the   trigger. The data comprise 9 s in Windowed Timing (WT)
mode (taken while Swift was slewing), with the remainder in Photon
Counting (PC) mode. The best available XRT position  (using the
promptly downlinked event data, the XRT-UVOT alignment and matching
UVOT field sources to the USNO-B1 catalogue) is RA, Dec = 74.59789,
-8.01441 which is equivalent to:

RA (J2000): 04h 58m 23.49s
Dec(J2000): -08d 00' 51.9"

with an uncertainty of 3.2 arcsec (radius, 90% confidence).

The light curve can be modelled with a power-law decay with a decay
index of alpha=2.9 (NaN, NaN).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.7 (+0.8, -0.6). The
best-fitting absorption column is  4.9 (+8.1, -3.9) x 10^21 cm^-2, in
excess of the Galactic value of 5.7 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 4.9 x 10^-11 (6.9 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     4.9 (+8.1, -3.9) x 10^21 cm^-2
Galactic foreground: 5.7 x 10^20 cm^-2
Excess significance: 1.9 sigma
Photon index:	     1.7 (+0.8, -0.6)

If the light curve continues to decay with a power-law decay index of
2.9, the count rate at T+24 hours will be 1.2 x 10^-8 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.9 x
10^-19 (8.2 x 10^-19) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
https://www.swift.ac.uk/xrt_products/01440319.

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