TITLE: GCN CIRCULAR NUMBER: 40459 SUBJECT: GRB 250502A: TESS observations DATE: 25/05/14 20:02:36 GMT FROM: Rahul Jayaraman at MIT rjayaram@mit.edu

R. Jayaraman (MIT), M.M. Fausnaugh (TTU), S. Chastain (TTU), R. Vanderspek (MIT), and G.R. Ricker (MIT) report:

The Transiting Exoplanet Survey Satellite (TESS; Ricker et al., JATIS 1 2015) observed GRB 250502A (Wang et al., GCN 40313) during Sector 91 of its scheduled sky survey.

We performed forced difference-imaging photometry at the location of the confirmed X-ray afterglow (Dichiara et al., GCN 40336) using the full-frame images from the publicly-available TICA data archived at MAST (https://archive.stsci.edu/hlsp/tica). Our data reduction routine is described in Fausnaugh et al. 2023 (ApJ 956(2):108).

The light curve shows a rapidly rising afterglow in the three 200s exposures from after the trigger. The light curve peaks roughly ~700 s after the burst at a magnitude of 16.44 ± 0.14 (uncorrected for Galactic extinction), followed by a decay to the detection limit of 17.6 (3-sigma) over ~4 x 10^3 s. These results are consistent with measurements of the early afterglow from Rakotondrainibe et al. (GCN 40315), Xu et al. (GCN 40319), and Li et al. (GCN 40320).

This circular includes data collected with the TESS mission, obtained from the MAST data archive at the Space Telescope Science Institute (STScI). Funding for the TESS mission is provided by the NASA Explorer Program. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

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