TITLE:   GCN CIRCULAR
NUMBER:  37553
SUBJECT: GRB 240910A: further Swift observations and confirmation of afterglow
DATE:    24/09/19 07:02:34 GMT
FROM:    K.L. Page at U Leicester <klp5@leicester.ac.uk>

P.A. Evans (U. Leicester), M.H. Siegel (PSU) and K.L. Page (U. Leicester)
report on behalf of the Swift-XRT and UVOT teams:

Swift has re-observed the putative afterglow of GRB 240910A, first
reported by Julakanti et al. (GCN Circ. 37459) at two additional epochs.
2.8 ks of data were taken between T0+282 ks and T0+329 ks, and a further
4.2 ks between T0+679 ks and T0+708 ks. The X-ray counterpart (D'Ai et
al., GCN Circ. 37461) clearly fades between epochs. The light curve can be
modelled with a power-law decay with a decay index of alpha=1.1 (+0.4,
-0.3).

UVOT observed the field in the u, v and white filters. A faint source was
detected in the first epoch at the XRT position with a u magnitude of
20.65 +/- 0.28 with a significance of 3.8 sigma. The second epoch detected
no counterpart to a 3 sigma upper limit of 21.51.

We therefore confirm that GOTO24fvl/AT2024vfp is the afterglow of GRB
240910A.

This circular is an official product of the Swift-XRT and UVOT teams.