TITLE: GCN CIRCULAR NUMBER: 35963 SUBJECT: X-ray transient EP 240315a: Chandra observations DATE: 24/03/19 11:31:23 GMT FROM: Andrew Levan at Radboud University <a.levan@astro.ru.nl> A.J. Levan (Radboud & Warwick), P.G. Jonker (Radboud), D.B. Malesani (DAWN/NBI & Radboud), N.R. Tanvir (Leicester), B.P. Gompertz (Birmingham), A. Saccardi (GEPI/Obs. de Paris), A. de Ugarte Postigo (CNRS/OCA & LAM), A. Martin-Carrillo (UCD), D. Perley (LJMU), D. Xu (NAOC), G. Tagliaferri (INAF, Brera), J. Palmerio (GEPI/Obs. de Paris)), K.E. Heintz (DAWN/NBI), K. Wiersema (Hertfordshire), M. Grazia Bernardini (INAF, Brera), M. Ferro (INAF, Brera), P. Jakobbson (U. Iceland), P. D’Avanzo (INAF, Brera), R. Salvaterra (INAF, Milan), S. Vergani (GEPI/Obs. de Paris), G. Pugliese (API, Amsterdam), Y. Julakanti (Leicester) report for the Stargate collaboration: We obtained observations of EP240315a (Zhang et al., GCN 35931) with the Chandra X-ray observatory. Observations began at 20:13 on 18 March 2024, 72 hours after the flare detection. The source was placed at the default aim point on the S3 chip for a total exposure time of 10 ks. At the location of AT2024eju (Srivastav et al., GCN 35932) we clearly detect an X-ray counterpart with a source flux of (3.3+/- 0.5)e-3 cps. For the same spectral parameters inferred from the EP follow-up telescope observations, and at z = 4.859 (Saccardi et al., GCN 35936; Quirola-Vásquez et al., GCN 35960) the source has an X-ray luminosity of L_X ~ 2e46 erg/s . The decay from the EP follow-up telescope observations at t+42 hours (Chen et al. GCN 35951) to the Chandra exposure at t+72 hours post burst is ~t^-1.6. Both of these are typical of the properties seen in long GRBs, although the luminosity is towards the higher end. We thank Pat Slane, Vinay Kashyap and the staff of the CXC for their excellent support and rapid scheduling of these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/35963. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...