GCN Circular 37675
Subject
EP trigger ID 01709064214: GOTO confirms detection as a flare star
Date
2024-10-02T10:51:34Z (6 months ago)
From
Amit Kumar at Royal Holloway - U. of London/U. of Warwick, UK <amitkundu515@gmail.com>
Via
Web form
G. Ramsay, A. Kumar, D. O'Neill, B. P. Gompertz, R. Starling, K. Ackley, M. J. Dyer, J. Lyman, K. Ulaczyk, F. Jimenez-Ibarra, D. Steeghs, D. K. Galloway, V. Dhillon, P. O'Brien, K. Noysena, R. Kotak, R. P. Breton, L. K. Nuttall, E. Palle and D. Pollacco report on behalf of the GOTO collaboration:
We report on observations with the Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022, Dyer et al. 2024) in response to EP-WXT trigger ID 01709064214, which is suggested as a possible stellar flare (Mao et al. GCN 37669). Targeted observations were obtained using the GOTO North on 2024-10-01 between 21:18:35 and 23:34:24 UT (from 2.307 to 4.571 hours pots-trigger). Each observation consisted of 4x90s exposures in the GOTO L-band (400-700 nm).
Images were processed immediately after acquisition using the GOTO pipeline. Difference imaging was performed using deeper template observations of the same pointings. Source candidates were initially filtered using a classifier (Killestein et al. 2021) and cross-matched against a variety of contextual and minor planet catalogues. Human vetting was carried out in real time on any candidates that passed the above checks.
We identify an optical transient at RA (J2000) = 23:30:11.43, Dec (J2000) = -02:37:23.9, detected at 2024-10-01 21:18:35 UT with a brightness of L = 14.28 ± 0.01 mag, approximately 1.37 mag brighter than the mean quiescent magnitude of 15.65 ± 0.09 mag sampled over the last year. This is consistent with the position of the star 2MASS J23301129-0237227/2RXS J233013.0-023738, noted as a possible source of the X-ray emission in GCN 37669. We therefore show that the X-ray transient was also detected in the optical and confirm it originated from a flare star.
GOTO (https://goto-observatory.org) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester and the Instituto de Astrofisica de Canarias (IAC).