Multiband analyses of the bright GRB 230812B and the associated SN2023pel

Authors

T. Hussenot-Desenonges, Université Paris-Saclay
T. Wouters, FOM-Institute of Subatomic Physics - NIKHEF
N. Guessoum, American University of Sharjah
I. Abdi, American University of Sharjah
A. Abulwfa, National Research Institute of Astronomy and Geophysics, Cairo
C. Adami, Laboratoire d'Astrophysique de Marseille
J. F. Agüí Fernández, CSIC - Instituto de Astrofísica de Andalucía (IAA)
T. Ahumada, California Institute of Technology
V. Aivazyan, E. Kharadze Georgian National Astrophysical Observatory
D. Akl, American University of Sharjah
S. Anand, California Institute of Technology
C. M. Andrade
S. Antier, Observatoire de la Côte d'Azur
S. A. Ata, National Research Institute of Astronomy and Geophysics, Cairo
P. D'Avanzo, Osservatorio Astronomico di Brera
Y. A. Azzam, National Research Institute of Astronomy and Geophysics, Cairo
A. Baransky, Taras Shevchenko National University of Kyiv
S. Basa, Laboratoire d'Astrophysique de Marseille
M. Blazek, Institute of Physics of the Czech Academy of Sciences
P. Bendjoya, Laboratoire Joseph-Louis Lagrange
S. Beradze, E. Kharadze Georgian National Astrophysical Observatory
P. Boumis, National Observatory of Athens
M. Bremer, IRAM Institut de RadioAstronomie Millimétrique
R. Brivio, Osservatorio Astronomico di Brera
V. Buat, Laboratoire d'Astrophysique de Marseille
M. Bulla, University of Ferrara
O. Burkhonov, Ulugh Beg Astronomical Institute Uzbekistan Academy of Sciences
E. Burns, Louisiana State University
S. B. Cenko, NASA Goddard Space Flight Center
M. W. Coughlin
W. Corradi, Laboratório Nacional de Astrofísica
F. Daigne, Institut d’Astrophysique de Paris
T. Dietrich, Universität Potsdam

Document Type

Article

Publication Date

5-1-2024

Abstract

GRB 230812B is a bright and relatively nearby (z = 0.36) long gamma-ray burst (GRB) that has generated significant interest in the community and has thus been observed over the entire electromagnetic spectrum. We report over 80 observations in X-ray, ultraviolet, optical, infrared, and submillimetre bands from the GRANDMA (Global Rapid Advanced Network for Multimessenger Addicts) network of observatories and from observational partners. Adding complementary data from the literature, we then derive essential physical parameters associated with the ejecta and external properties (i.e. the geometry and environment) of the GRB and compare with other analyses of this event. We spectroscopically confirm the presence of an associated supernova, SN2023pel, and we derive a photospheric expansion velocity of v ∼ 17 × 10³ km s^-1. We analyse the photometric data first using empirical fits of the flux and then with full Bayesian inference. We again strongly establish the presence of a supernova in the data, with a maximum (pseudo-)bolometric luminosity of 5.75 × 10⁴² erg s^-1, at 15.76⁺-1^0.21⁸¹ d (in the observer frame) after the trigger, with a half-max time width of 22.0 d. We compare these values with those of SN1998bw, SN2006aj, and SN2013dx. Our best-fitting model favours a very low density environment (log10(nISM/cm^-3) = -2.38⁺-1^1.60⁴⁵) and small values for the jet's core angle θcore = 1.54⁺-0^1.81⁰² deg and viewing angle θobs = 0.76⁺-0^1.76²⁹ deg. GRB 230812B is thus one of the best observed afterglows with a distinctive supernova bump.

Publication Source (Journal or Book title)

Monthly Notices of the Royal Astronomical Society

First Page

1

Last Page

19

Recommended Citation

Hussenot-Desenonges, T., Wouters, T., Guessoum, N., Abdi, I., Abulwfa, A., Adami, C., Agüí Fernández, J., Ahumada, T., Aivazyan, V., Akl, D., Anand, S., Andrade, C., Antier, S., Ata, S., D'Avanzo, P., Azzam, Y., Baransky, A., Basa, S., Blazek, M., Bendjoya, P., Beradze, S., Boumis, P., Bremer, M., Brivio, R., Buat, V., Bulla, M., Burkhonov, O., Burns, E., Cenko, S., Coughlin, M., Corradi, W., Daigne, F., & Dietrich, T. (2024). Multiband analyses of the bright GRB 230812B and the associated SN2023pel. Monthly Notices of the Royal Astronomical Society, 530 (1), 1-19. https://doi.org/10.1093/mnras/stae503