Files and links (1)
Preprint (Author's original)arXiv.org - Non-exclusive license to distribute, Open
Preprint
Multi-Wavelength Analysis of AT 2023sva: a Luminous Orphan Afterglow With Evidence for a Structured Jet
06 Jan 2025
Abstract
We present multi-wavelength analysis of ZTF23abelseb (AT 2023sva), an
optically discovered fast-fading ($\Delta m_r = 2.2$ mag in $\Delta t = 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 $\gamma$-ray burst (GRB) counterpart to an isotropic equivalent
energy limit of $E_{\rm{\gamma, \, iso}} < 1.6 \times 10^{52}$ erg, determined
through searching $\gamma$-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
($\theta_{\rm{v}} = 0.07 \pm 0.02$) just outside of the jet's core opening
angle ($\theta_{\rm{c}} = 0.06 \pm 0.02$). 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.
Metrics
1 Record Views
Details
- Title
- Multi-Wavelength Analysis of AT 2023sva: a Luminous Orphan Afterglow With Evidence for a Structured Jet
- Creators
- Gokul P SrinivasaragavanDaniel A PerleyAnna Y. Q HoBrendan O'ConnorAntonio de Ugarte PostigoNikhil SarinS. Bradley CenkoJesper SollermanLauren RhodesDavid A GreenDmitry S SvinkinVarun BhaleraoGaurav WaratkarA. J NayanaPoonam ChandraM. Coleman MillerDaniele B MalesaniGeoffrey RyanSuryansh SrijanEric C BellmEric BurnsDavid J TitteringtonMaria B StoneJosiah PurdumTomás AhumadaG. C AnupamaSudhanshu BarwayMichael W CoughlinAndrew DrakeRob FenderJosé F. AgüÍ FernándezDmitry D FrederiksStefan GeierMatthew J GrahamMansi M KasliwalS. R KulkarniHarsh KumarMaggie L LiRuss R LaherAlexandra L LysenkoGopal ParwaniRichard A PerleyAnna V RidnaiaAnirudh SalgundiRoger SmithNiharika SravanVishwajeet SwainChristina C ThöneAnastasia E TsvetkovaMikhail V UlanovJada VailJacob L WiseAvery Wold
- Resource Type
- Preprint
- Language
- English
- Academic Unit
- Physics
- Other Identifier
- 991022016381704721