TITLE: GCN CIRCULAR NUMBER: 36721 SUBJECT: GRB 240619A: Swift-XRT probable afterglow detection DATE: 24/06/21 08:07:28 GMT FROM: Phil Evans at U of Leicester <pae9@star.le.ac.uk> M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), S. Dichiara (PSU), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), A.P. Beardmore (U. Leicester), J.P. Osborne (U. Leicester) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the Fermi/GBM-detected burst GRB 240619A (GCN Circ. 36694), collecting 1.7 ks of Photon Counting (PC) mode data between T0+174.0 ks and T0+175.7 ks at the location of the GOTO afterglow candidate AT 2024lw (Gompertz et al., GCN Circ. 36715). An uncatalogued X-ray source is detected at RA, Dec=162.3944, +17.2829 which is equivalent to: RA (J2000): 10:49:34.66 Dec(J2000): +17:16:58.5 with an uncertainty of 4.3 arcsec (radius, 90% confidence). This position is 0.7 arcsec from the GOTO position and thus we suggest it is related to that object and likely the GRB afterglow. The source has a mean count rate of 2.5e-02 ct/sec; we cannot determine at the present time whether it is fading. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00021697. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/00021697. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/36721. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...