TITLE:   GCN CIRCULAR
NUMBER:  33453
SUBJECT: TESS Detection of the Optical Afterglow of GRB230307A
DATE:    23/03/11 16:52:38 GMT
FROM:    Roland Vanderspek at MIT  <roland@space.mit.edu>

R. Vanderspek, M.M. Fausnaugh, R. Jayaraman, G.R. Ricker (MIT), K. Colon and A. Youngblood (GSFC), on behalf of the TESS Team, report:

The Transiting Exoplanet Survey Satellite (TESS; Ricker et al. 2015) observed the location of the bright gamma-ray burst GRB230307A during the second orbit of Observation Sector 62.  Images of the burst region, located in TESS Camera 4, CCD 4, were captured in the TESS full-frame images (FFIs). The observations of the field were made at a cadence of 200 seconds and were continuous from 3 days before the trigger to 3 days after the trigger.

Analysis of the TESS FFIs using TICA (Fausnaugh et al. 2020; doi:10.3847/2515-5172/abd63a <https://ui.adsabs.harvard.edu/link_gateway/2020RNAAS...4..251F/doi:10.3847/2515-5172/abd63a>) data confirms the existence of the optical counterpart reported by Levan et al. (GCN Circular 33439), Lipunov et al. (GCN Circular 33441), O'Conner et al. (GCN Circular 33447), and Im et al. (GCN Circular 33449). The signal is seen as a point source brighter than 15th magnitude in a single 200s FFI.  The measured position is 4:03:26.5, -75:22:45 with an estimated 1-sigma error of 4”, consistent with previously-reported localizations.   

TICA data can be found at https://archive.stsci.edu/hlsp/tica.