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GCN Circular 18166

Subject

GRB 150818A: Swift-XRT update, correction to GCN 18162

Date

2015-08-19T07:17:42Z (9 years ago)

From

Phil Evans at U of Leicester <pae9@leicester.ac.uk>

P.A. Evans (U, Leicester) reports on behalf of the Swift-XRT team:

Due to a computer error, the light curve decay index was missing in GCN 
18162Not found
 
 
.

At the present time, we have analysed 7.6 ks of XRT data for GRB 150818A 
(D'Elia et al. GCN Circ. 18152Not found
 
 
), from 74 s to 44.1 ks after the BAT trigger.

The XRT light curve can be modelled as a broken power-law, with an 
initial decay index of 2.36 (+0.08, -0.06), a break at T0 + 3600 
(+/-500) s, and a subsequent shallow decay of 0.66 (+0.16, -0.15).

If the decay continues at alpha=0.66, the predicted count-rate at T0+24 
hrs is 8.9e-3 ct/sec, which corresponds to an observed (unabsorbed) 
0.3-10 keV flux of 2.97e-13 (3.56e-13) erg/cm^2/s.

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