TITLE: GCN CIRCULAR NUMBER: 37311 SUBJECT: GRB 240819A: Swift afterglow confirmation DATE: 24/08/27 16:41:54 GMT FROM: Antonino D'Ai' at IASF-PA antonino.dai@inaf.it

Antonino D’Ai, Elena Ambrosi (INAF/IASF-PA) report on behalf of the Swift-XRT team:

Swift performed a second epoch follow-up observation for Source2 (D’Avanzo et al., GCN 37218), the likely counterpart for the SVOM/Eclairs-detected X-ray transient GRB 240819A (Coleiro et al., GCN 37208). We collected 3.4 ks of Photon Counting (PC) mode data between T0+6.01 days and T0+7.67 days.

At the position of Source2 (previously detected at rate 11(+3.5, -2.9) x 10^-3 ct/sec), no source is detected with a 3-sigma upper limit of 3.5 x 10^-3 ct/sec.

The upper limit is evidence for the lightcurve fading of this source, confirming the afterglow association with GRB 240819A.

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

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