Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 15739

GRB 140114A: Swift-XRT refined Analysis
2014-01-15T00:23:05Z (10 years ago)
Phil Evans at U of Leicester <>
V. Mangano (PSU), M.C. Stroh (PSU), P.A. Evans (U. Leicester), B.P.
Gompertz (U. Leicester), J.P. Osborne (U. Leicester), B. Sbarufatti
(INAF-OAB/PSU), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), D.N. Burrows
(PSU) and E. Troja report on behalf of the Swift-XRT team:

We have analysed 11 ks of XRT data for GRB 140114A (Troja  et al. GCN
Circ. 15728),  from 118 s to 24.7 ks after the	BAT trigger. The data
comprise 449 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Beardmore et al. (GCN. Circ 15733).

The late-time light curve (from T0+5.0 ks) can be modelled with  a
power-law decay with a decay index of alpha=0.50 (+/-0.15).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index	of 2.22 (+/-0.03). The
best-fitting absorption column is  1.53 (+/-0.07) x 10^21 cm^-2, in
excess of the Galactic value of 1.6 x 10^20 cm^-2 (Kalberla et al.
2005). The PC mode spectrum has a photon index of 2.33 (+0.21, -0.20)
and a best-fitting absorption column of 1.3 (+0.5, -0.4) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 3.1 x 10^-11 (4.8 x 10^-11) erg cm^-2

A summary of the PC-mode spectrum is thus:
Total column:	     1.3 (+0.5, -0.4) x 10^21 cm^-2
Galactic foreground: 1.6 x 10^20 cm^-2
Excess significance: 4.5 sigma
Photon index:	     2.33 (+0.21, -0.20)

If the light curve continues to decay with a power-law decay index of
0.50, the count rate at T+24 hours will be 0.020 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.2 x
10^-13 (9.6 x 10^-13) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at

This circular is an official product of the Swift-XRT team.
Looking for U.S. government information and services? Visit