Please use this identifier to cite or link to this item: http://hdl.handle.net/2248/8774
Title: The nature of optical afterglows without Gamma-ray bursts: Identification of AT2023lcr and multiwavelength modeling
Authors: Li, Maggie L
Ho, Anna Y. Q
Ryan, Geoffrey
Perley, Daniel A
Lamb, Gavin P
Nayana, A. J
Andreoni, Igor
Anupama, G. C
Bellm, Eric C
Berger, E
Bloom, Joshua S
Burns, Eric
Caiazzo, Ilaria
Chandra, P
Coughlin, Michael W
El-Badry, Kareem
Graham, Matthew J
Kasliwal, Mansi M
Keating, Garrett K
Kulkarni, S. R
Kumar, Harsh
Masci, Frank J
Perley, Richard A
Ramprasad Rao
Rodriguez, Antonio C
Rusholme, Ben
Sarin, Nikhil
Sollerman, Jesper
Srinivasaragavan, Gokul P
Swain, Vishwajeet
Vanderbosch, Zachary
Keywords: Gamma-ray bursts
Transient sources
Surveys
Sky surveys
Radio transient sources
X-ray transient sources
Issue Date: 20-May-2025
Publisher: American Astronomical Society
Citation: The Astrophysical Journal, Vol. 985, No. 1, 124
Abstract: In the past few years, the improved sensitivity and cadence of wide-field optical surveys have enabled the discovery of several afterglows without associated detected gamma-ray bursts (GRBs). We present the identification, observations, and multiwavelength modeling of a recent such afterglow (AT2023lcr), and model three literature events (AT2020blt, AT2021any, and AT2021lfa) in a consistent fashion. For each event, we consider the following possibilities as to why a GRBwas not observed: (1) the jet was off-axis; (2) the jet had a low initial Lorentz factor; and (3) the afterglow was the result of an on-axis classical GRB (on-axis jet with physical parameters typical of the GRB population), but the emission was undetected by gamma-ray satellites. We estimate all physical parameters using afterglowpy and Markov Chain Monte Carlo methods from emcee. We find that AT2023lcr, AT2020blt, and AT2021any are consistent with on-axis classical GRBs, and AT2021lfa is consistent with both on-axis low Lorentz factor (Γ0 ≈ 5–13) and off-axis (θobs = 2θjet) high Lorentz factor (Γ0 ≈ 100) jets.
Description: Open Access
Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI
URI: http://hdl.handle.net/2248/8774
ISSN: 1538-4357
Appears in Collections:IIAP Publications



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