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GCN Circular 30012

Subject
GRB 210514A: Swift-XRT refined Analysis
Date
2021-05-15T08:29:00Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester), M.G. Bernardini (INAF-OAB), M. Capalbi (INAF-IASFPA), A.
Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), D.N. Burrows (PSU) and E.
Ambrosi report on behalf of the Swift-XRT team:

We have analysed 6.7 ks of XRT data for GRB 210514A (Ambrosi et al. GCN
Circ. 30008), from 60 s to 23.8 ks after the  BAT trigger. The data
comprise 1.4 ks in Windowed Timing (WT) mode (the first 8 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Osborne et
al. (GCN Circ. 30011). We cannot determine at the present time whether
the source is fading.

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index	of 2.06 (+/-0.04). The
best-fitting absorption column is  4.79 (+/-0.22) x 10^21 cm^-2, in
excess of the Galactic value of 2.0 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.95 (+0.12, -0.11)
and a best-fitting absorption column of 4.7 (+0.7, -0.6) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 4.1 x 10^-11 (6.5 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     4.7 (+0.7, -0.6) x 10^21 cm^-2
Galactic foreground: 2.0 x 10^20 cm^-2
Excess significance: 12.2 sigma
Photon index:	     1.95 (+0.12, -0.11)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01048372.

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