_version_ 1866929661480534016
author Srinivasaragavan, Gokul P.
Perley, Daniel A.
Ho, Anna Y. Q.
O'Connor, Brendan
Postigo, Antonio de Ugarte
Sarin, Nikhil
Cenko, S. Bradley
Sollerman, Jesper
Rhodes, Lauren
Green, David A.
Svinkin, Dmitry S.
Bhalerao, Varun
Waratkar, Gaurav
Nayana, A. J.
Chandra, Poonam
Miller, M. Coleman
Malesani, Daniele B.
Ryan, Geoffrey
Srijan, Suryansh
Bellm, Eric C.
Burns, Eric
Titterington, David J.
Stone, Maria B.
Purdum, Josiah
Ahumada, Tomás
Anupama, G. C.
Barway, Sudhanshu
Coughlin, Michael W.
Drake, Andrew
Fender, Rob
Fernández, José F. AgüÍ
Frederiks, Dmitry D.
Geier, Stefan
Graham, Matthew J.
Kasliwal, Mansi M.
Kulkarni, S. R.
Kumar, Harsh
Li, Maggie L.
Laher, Russ R.
Lysenko, Alexandra L.
Parwani, Gopal
Perley, Richard A.
Ridnaia, Anna V.
Salgundi, Anirudh
Smith, Roger
Sravan, Niharika
Swain, Vishwajeet
Thöne, Christina C.
Tsvetkova, Anastasia E.
Ulanov, Mikhail V.
Vail, Jada
Wise, Jacob L.
Wold, Avery
author_facet Srinivasaragavan, Gokul P.
Perley, Daniel A.
Ho, Anna Y. Q.
O'Connor, Brendan
Postigo, Antonio de Ugarte
Sarin, Nikhil
Cenko, S. Bradley
Sollerman, Jesper
Rhodes, Lauren
Green, David A.
Svinkin, Dmitry S.
Bhalerao, Varun
Waratkar, Gaurav
Nayana, A. J.
Chandra, Poonam
Miller, M. Coleman
Malesani, Daniele B.
Ryan, Geoffrey
Srijan, Suryansh
Bellm, Eric C.
Burns, Eric
Titterington, David J.
Stone, Maria B.
Purdum, Josiah
Ahumada, Tomás
Anupama, G. C.
Barway, Sudhanshu
Coughlin, Michael W.
Drake, Andrew
Fender, Rob
Fernández, José F. AgüÍ
Frederiks, Dmitry D.
Geier, Stefan
Graham, Matthew J.
Kasliwal, Mansi M.
Kulkarni, S. R.
Kumar, Harsh
Li, Maggie L.
Laher, Russ R.
Lysenko, Alexandra L.
Parwani, Gopal
Perley, Richard A.
Ridnaia, Anna V.
Salgundi, Anirudh
Smith, Roger
Sravan, Niharika
Swain, Vishwajeet
Thöne, Christina C.
Tsvetkova, Anastasia E.
Ulanov, Mikhail V.
Vail, Jada
Wise, Jacob L.
Wold, Avery
contents We present multi-wavelength analysis of ZTF23abelseb (AT 2023sva), an optically discovered fast-fading ($Δm_r = 2.2$ mag in $Δt = 0.74 $ days), luminous ($M_r \sim -30.0$ mag) and red ($g-r = 0.50$ mag) transient at $z = 2.28$ with accompanying luminous radio emission. AT 2023sva does not possess a $γ$-ray burst (GRB) counterpart to an isotropic equivalent energy limit of $E_{\rm{γ, \, iso}} < 1.6 \times 10^{52}$ erg, determined through searching $γ$-ray satellite archives between the last non-detection and first detection, making it the sixth example of an optically-discovered afterglow with a redshift measurement and no detected GRB counterpart. We analyze AT 2023sva's optical, radio, and X-ray observations to characterize the source. From radio analyses, we find the clear presence of strong interstellar scintillation (ISS) 72 days after the initial explosion, allowing us to place constraints on the source's angular size and bulk Lorentz factor. When comparing the source sizes derived from ISS of orphan events to those of the classical GRB population, we find orphan events have statistically smaller source sizes. We also utilize Bayesian techniques to model the multi-wavelength afterglow. Within this framework, we find evidence that AT 2023sva possesses a shallow power-law structured jet viewed slightly off-axis ($θ_{\rm{v}} = 0.07 \pm 0.02$) just outside of the jet's core opening angle ($θ_{\rm{c}} = 0.06 \pm 0.02$). We determine this is likely the reason for the lack of a detected GRB counterpart, but also investigate other scenarios. AT 2023sva's evidence for possessing a structured jet stresses the importance of broadening orphan afterglow search strategies to a diverse range of GRB jet angular energy profiles, to maximize the return of future optical surveys.
format Preprint
id arxiv_https___arxiv_org_abs_2501_03337
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Multi-Wavelength Analysis of AT 2023sva: a Luminous Orphan Afterglow With Evidence for a Structured Jet
Srinivasaragavan, Gokul P.
Perley, Daniel A.
Ho, Anna Y. Q.
O'Connor, Brendan
Postigo, Antonio de Ugarte
Sarin, Nikhil
Cenko, S. Bradley
Sollerman, Jesper
Rhodes, Lauren
Green, David A.
Svinkin, Dmitry S.
Bhalerao, Varun
Waratkar, Gaurav
Nayana, A. J.
Chandra, Poonam
Miller, M. Coleman
Malesani, Daniele B.
Ryan, Geoffrey
Srijan, Suryansh
Bellm, Eric C.
Burns, Eric
Titterington, David J.
Stone, Maria B.
Purdum, Josiah
Ahumada, Tomás
Anupama, G. C.
Barway, Sudhanshu
Coughlin, Michael W.
Drake, Andrew
Fender, Rob
Fernández, José F. AgüÍ
Frederiks, Dmitry D.
Geier, Stefan
Graham, Matthew J.
Kasliwal, Mansi M.
Kulkarni, S. R.
Kumar, Harsh
Li, Maggie L.
Laher, Russ R.
Lysenko, Alexandra L.
Parwani, Gopal
Perley, Richard A.
Ridnaia, Anna V.
Salgundi, Anirudh
Smith, Roger
Sravan, Niharika
Swain, Vishwajeet
Thöne, Christina C.
Tsvetkova, Anastasia E.
Ulanov, Mikhail V.
Vail, Jada
Wise, Jacob L.
Wold, Avery
High Energy Astrophysical Phenomena
We present multi-wavelength analysis of ZTF23abelseb (AT 2023sva), an optically discovered fast-fading ($Δm_r = 2.2$ mag in $Δt = 0.74 $ days), luminous ($M_r \sim -30.0$ mag) and red ($g-r = 0.50$ mag) transient at $z = 2.28$ with accompanying luminous radio emission. AT 2023sva does not possess a $γ$-ray burst (GRB) counterpart to an isotropic equivalent energy limit of $E_{\rm{γ, \, iso}} < 1.6 \times 10^{52}$ erg, determined through searching $γ$-ray satellite archives between the last non-detection and first detection, making it the sixth example of an optically-discovered afterglow with a redshift measurement and no detected GRB counterpart. We analyze AT 2023sva's optical, radio, and X-ray observations to characterize the source. From radio analyses, we find the clear presence of strong interstellar scintillation (ISS) 72 days after the initial explosion, allowing us to place constraints on the source's angular size and bulk Lorentz factor. When comparing the source sizes derived from ISS of orphan events to those of the classical GRB population, we find orphan events have statistically smaller source sizes. We also utilize Bayesian techniques to model the multi-wavelength afterglow. Within this framework, we find evidence that AT 2023sva possesses a shallow power-law structured jet viewed slightly off-axis ($θ_{\rm{v}} = 0.07 \pm 0.02$) just outside of the jet's core opening angle ($θ_{\rm{c}} = 0.06 \pm 0.02$). We determine this is likely the reason for the lack of a detected GRB counterpart, but also investigate other scenarios. AT 2023sva's evidence for possessing a structured jet stresses the importance of broadening orphan afterglow search strategies to a diverse range of GRB jet angular energy profiles, to maximize the return of future optical surveys.
title Multi-Wavelength Analysis of AT 2023sva: a Luminous Orphan Afterglow With Evidence for a Structured Jet
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2501.03337