TITLE: GCN CIRCULAR NUMBER: 36981 SUBJECT: GRB 240715A: Swift-XRT afterglow detection DATE: 24/07/30 16:04:49 GMT FROM: Chiara Salvaggio at INAF OABrera chiara.salvaggio@inaf.it

C. Salvaggio (INAF-OAB), K. L. Page (U. Leicester) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:

Swift-XRT has performed further follow-up observations of the IPN-detected burst GRB 240715A (Kozyrev et al., GCN Circ. 36872). The data were collected between T0+36.0 ks ks and T0+1270 ks, for a total exposure time of 17.7 ks.

The uncatalogued X-ray source reported by D'Elia et al. ("Source 3"; GCN Circ. 36890), with a count-rate of 4.0 [+1.4, -1.2]e-3 ct s^-1, is no more detected: we derive an upper limit of 1.4e-3 ct s^-1. Source 3 shows significant signs of fading, and is therefore likely the GRB afterglow.

The X-ray afterglow light curve can be modelled with a power-law with no breaks and decay index alpha > 0.63.

The results of the XRT-team automatic analysis are available at https://www.swift.ac.uk/xrt_products/00021699.

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

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