Orphan optical flare as SOSS emission afterglow, localization in time

Authors :: Lipunov, V.
Kornilov, V.
Zhirkov, K.
Tyurina, N.
Gorbovskoy, E.
Vlasenko, D.
Simakov, S.
Topolev, V.
Francile, C.
Podesta, R.
Podesta, F.
Svinkin, D.
Budnev, N.
Gress, O.
Balanutsa, P.
Kuznetsov, A.
Chasovnikov, A.
Serra-Ricart, M.
Gabovich, A.
Minkina, E.
Antipov, G.
Svertilov, S.
Tlatov, A.
Senik, V.
Tselik, Yu.
Kechin, Ya.
Yurkov, V.
Source :: MNRAS 514, 4, 4980-4987 (2022)
Publication Year :: 2023
Abstract: We report on MASTER optical observations of an afterglow-like optical and X-ray transient AT2021lfa/ZTF21aayokph. We detected the initial steady brightening of the transient at 7{\sigma} confidence level. This allowed us to use smooth optical self-similar emission of GRBs model to constrain the explosion time to better than 14 min as well as to estimate its initial Lorentz factor {\Gamma}0 = 20 +/- 10. Taking into consideration the low {\Gamma}0 and non-detection in gamma-rays, we classify this transient as the first failed GRB afterglow.<br />Comment: 8 pages, 5 figures, accepted for publication in MNRAS