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Published in

Oxford University Press, Monthly Notices of the Royal Astronomical Society, 3(527), p. 7672-7680, 2023

DOI: 10.1093/mnras/stad3717

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An off-axis relativistic jet seen in the long lasting delayed radio flare of the TDE AT 2018hyz

This paper was not found in any repository, but could be made available legally by the author.
This paper was not found in any repository, but could be made available legally by the author.

Full text: Unavailable

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Preprint: archiving allowed
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Postprint: archiving allowed
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Published version: archiving allowed
Data provided by SHERPA/RoMEO

Abstract

ABSTRACT The Tidal Disruption Event (TDE) AT 2018hyz exhibited a delayed radio flare almost three years after the stellar disruption. Here, we report new radio observations of the TDE AT 2018hyz with the AMI-LA and ATCA spanning from a month to more than four years after the optical discovery and 200 d since the last reported radio observation. We detected no radio emission from 30–220 d after the optical discovery in our observations at 15.5 GHz down to a 3σ level of <0.14 mJy. The fast-rising, delayed radio flare is observed in our radio data set and continues to rise almost ∼1580 d after the optical discovery. We find that the delayed radio emission, first detected 972 d after optical discovery, evolves as t4.2 ± 0.9, at 15.5 GHz. Here, we present an off-axis jet model that can explain the full set of radio observations. In the context of this model, we require a powerful narrow jet with an isotropic equivalent kinetic energy Ek, iso ∼ 1055 erg, an opening angle of ∼7°, and a relatively large viewing angle of ∼42°, launched at the time of the stellar disruption. Within our framework, we find that the minimal collimated energy possible for an off-axis jet from AT 2018hyz is Ek ≥ 3 × 1052 erg. Finally, we provide predictions based on our model for the light curve turnover time, and for the proper motion of the radio emitting source.