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| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Preprint |
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2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2509.22784 |
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| _version_ | 1866915601311596544 |
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| author | Carney, Jonathan Andreoni, Igor O'Connor, Brendan Freeburn, James Skobe, Hannah Westcott, Lewi Busmann, Malte Palmese, Antonella Hall, Xander J. Gill, Ramandeep Beniamini, Paz Coughlin, Eric R. Kilpatrick, Charles D. Anumarlapudi, Akash Law, Nicholas M. Corbett, Hank Ahumada, Tomas Chen, Ping Conselice, Christopher Damke, Guillermo Das, Kaustav K. Gal-Yam, Avishay Gruen, Daniel Heathcote, Steve Hu, Lei Karambelkar, Viraj Kasliwal, Mansi Labrie, Kathleen Pasham, Dheeraj Riffeser, Arno Schmidt, Michael Sharma, Kritti Wilke, Silona Zang, Weicheng |
| author_facet | Carney, Jonathan Andreoni, Igor O'Connor, Brendan Freeburn, James Skobe, Hannah Westcott, Lewi Busmann, Malte Palmese, Antonella Hall, Xander J. Gill, Ramandeep Beniamini, Paz Coughlin, Eric R. Kilpatrick, Charles D. Anumarlapudi, Akash Law, Nicholas M. Corbett, Hank Ahumada, Tomas Chen, Ping Conselice, Christopher Damke, Guillermo Das, Kaustav K. Gal-Yam, Avishay Gruen, Daniel Heathcote, Steve Hu, Lei Karambelkar, Viraj Kasliwal, Mansi Labrie, Kathleen Pasham, Dheeraj Riffeser, Arno Schmidt, Michael Sharma, Kritti Wilke, Silona Zang, Weicheng |
| contents | GRB 250702B was the longest gamma-ray burst ever detected, with a duration that challenges standard collapsar models and suggests an exotic progenitor. We collected a rich set of optical and infrared follow-up observations of its rapidly fading afterglow using a suite of telescopes including the W. M. Keck Observatory, the Gemini telescopes, the Magellan Baade Telescope, the Victor M. Blanco 4-meter telescope, and the Fraunhofer Telescope at Wendelstein Observatory. Our analysis reveals that the afterglow emission is well described by forward shock emission from a highly obscured relativistic jet. Deep photometric observations of the host galaxy reveal a massive (10^10.66 solar masses), dusty, and extremely asymmetric system that is consistent with two galaxies undergoing a major merger. The galactocentric offset, host galaxy properties, and jet characteristics disfavor a jetted TDE around a supermassive black hole but do not definitively distinguish between competing progenitor scenarios. We find that the afterglow and host are consistent with a range of progenitors including an atypical collapsar, a merger between a helium star and a stellar mass black hole, the disruption of a star by a stellar mass compact object (micro-TDE), and the tidal disruption of a star by an off-nuclear intermediate mass black hole. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2509_22784 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Optical/infrared observations of the extraordinary GRB 250702B: a highly obscured afterglow in a massive galaxy consistent with multiple possible progenitors Carney, Jonathan Andreoni, Igor O'Connor, Brendan Freeburn, James Skobe, Hannah Westcott, Lewi Busmann, Malte Palmese, Antonella Hall, Xander J. Gill, Ramandeep Beniamini, Paz Coughlin, Eric R. Kilpatrick, Charles D. Anumarlapudi, Akash Law, Nicholas M. Corbett, Hank Ahumada, Tomas Chen, Ping Conselice, Christopher Damke, Guillermo Das, Kaustav K. Gal-Yam, Avishay Gruen, Daniel Heathcote, Steve Hu, Lei Karambelkar, Viraj Kasliwal, Mansi Labrie, Kathleen Pasham, Dheeraj Riffeser, Arno Schmidt, Michael Sharma, Kritti Wilke, Silona Zang, Weicheng High Energy Astrophysical Phenomena GRB 250702B was the longest gamma-ray burst ever detected, with a duration that challenges standard collapsar models and suggests an exotic progenitor. We collected a rich set of optical and infrared follow-up observations of its rapidly fading afterglow using a suite of telescopes including the W. M. Keck Observatory, the Gemini telescopes, the Magellan Baade Telescope, the Victor M. Blanco 4-meter telescope, and the Fraunhofer Telescope at Wendelstein Observatory. Our analysis reveals that the afterglow emission is well described by forward shock emission from a highly obscured relativistic jet. Deep photometric observations of the host galaxy reveal a massive (10^10.66 solar masses), dusty, and extremely asymmetric system that is consistent with two galaxies undergoing a major merger. The galactocentric offset, host galaxy properties, and jet characteristics disfavor a jetted TDE around a supermassive black hole but do not definitively distinguish between competing progenitor scenarios. We find that the afterglow and host are consistent with a range of progenitors including an atypical collapsar, a merger between a helium star and a stellar mass black hole, the disruption of a star by a stellar mass compact object (micro-TDE), and the tidal disruption of a star by an off-nuclear intermediate mass black hole. |
| title | Optical/infrared observations of the extraordinary GRB 250702B: a highly obscured afterglow in a massive galaxy consistent with multiple possible progenitors |
| topic | High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2509.22784 |