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| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Preprint |
| Published: |
2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2411.07973 |
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| _version_ | 1866916668186296320 |
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| author | 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, Edo Bloom, Joshua S. Burns, Eric Caiazzo, Ilaria Chandra, Poonam Coughlin, Michael W. El-Badry, Kareem Graham, Matthew J. Kasliwal, Mansi Keating, Garrett K. Kulkarni, S. R. Kumar, Harsh Masci, Frank J. Perley, Richard A. Purdum, Josiah Rao, Ramprasad Rodriguez, Antonio C. Rusholme, Ben Sarin, Nikhil Sollerman, Jesper Srinivasaragavan, Gokul P. Swain, Vishwajeet Vanderbosch, Zachary |
| author_facet | 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, Edo Bloom, Joshua S. Burns, Eric Caiazzo, Ilaria Chandra, Poonam Coughlin, Michael W. El-Badry, Kareem Graham, Matthew J. Kasliwal, Mansi Keating, Garrett K. Kulkarni, S. R. Kumar, Harsh Masci, Frank J. Perley, Richard A. Purdum, Josiah Rao, Ramprasad Rodriguez, Antonio C. Rusholme, Ben Sarin, Nikhil Sollerman, Jesper Srinivasaragavan, Gokul P. Swain, Vishwajeet Vanderbosch, Zachary |
| contents | 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 GRB was 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 ($Γ_0 \approx 5 - 13$) and off-axis ($θ_\text{obs}=2θ_\text{jet}$) high Lorentz factor ($Γ_0 \approx 100$) jets. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2411_07973 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | The Nature of Optical Afterglows Without Gamma-ray Bursts: Identification of AT2023lcr and Multiwavelength Modeling 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, Edo Bloom, Joshua S. Burns, Eric Caiazzo, Ilaria Chandra, Poonam Coughlin, Michael W. El-Badry, Kareem Graham, Matthew J. Kasliwal, Mansi Keating, Garrett K. Kulkarni, S. R. Kumar, Harsh Masci, Frank J. Perley, Richard A. Purdum, Josiah Rao, Ramprasad Rodriguez, Antonio C. Rusholme, Ben Sarin, Nikhil Sollerman, Jesper Srinivasaragavan, Gokul P. Swain, Vishwajeet Vanderbosch, Zachary High Energy Astrophysical Phenomena 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 GRB was 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 ($Γ_0 \approx 5 - 13$) and off-axis ($θ_\text{obs}=2θ_\text{jet}$) high Lorentz factor ($Γ_0 \approx 100$) jets. |
| title | The Nature of Optical Afterglows Without Gamma-ray Bursts: Identification of AT2023lcr and Multiwavelength Modeling |
| topic | High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2411.07973 |