TITLE:   GCN CIRCULAR
NUMBER:  36502
SUBJECT: GRB 240516A: Swift-XRT refined Analysis
DATE:    24/05/17 06:58:50 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>

K.L. Page (U. Leicester) reports on behalf of the Swift-XRT team:

We have analysed 6.7 ks of XRT data for GRB 240516A. Following the
prompt detection of an X-ray source reported in GCN Circ. 36493
(Parsotan et al.), Swift passed into the South Atlantic Anomaly, and so
no further data were collected until 1.6 ks after the BAT trigger.
Combining all the Photon Counting (PC) mode data collected after this
time (6.7 ks, from 1.6 to 45.5 ks post-trigger), the source is no
longer detected, with a 3-sigma upper limit of 2.2 x 10^-3 count s^-1.

Assuming a typical GRB spectrum with a photon spectral index of 1.9 and
the Galactic absorption column of 1.29 x 10^22 cm^-2 (Willingale et al.
2013), the counts to observed (unabsorbed) 0.3-10 keV flux conversion
deduced from this spectrum is 5.6 x 10^-11 (1.0 x 10^-10) erg cm^-2
count^-1. The observed (unabsorbed) flux upper limit for the X-ray
source is thus 1.2 x 10^-13 (2.2 x 10^-13) erg cm^-2 s^-1.

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