Sun, N.-C., Maund, J.R., Crowther, P.A. et al. (1 more author) (2022) A hot and luminous source at the site of the fast transient AT2018cow at 2–3 years after its explosion. Monthly Notices of the Royal Astronomical Society: Letters, 512 (1). L66-L70. ISSN 1745-3933
Abstract
We report the discovery of a luminous late-time source at the position of the fast blue optical transient (FBOT) AT2018cow on images taken by the Hubble Space Telescope (HST) at 714 d and 1136 d after its explosion. This source is detected at both UV and optical wavelengths and has prominent Hα emission. It has a very stable brightness between the two epochs and a very blue spectral energy distribution (SED) consistent with fλ ∝ λ−4.1 ± 0.1, i.e. the Rayleigh-Jeans tail of a hot blackbody with a very high temperature of log(T/K) > 4.6 and luminosity of log(L/L⊙) > 7.0. This late-time source is unlikely to be an unrelated object in chance alignment, or due to a light echo of AT2018cow. Other possible scenarios also have some difficulties in explaining this late-time source, including companion star(s), star cluster, the survived progenitor star, interaction with circumstellar medium (CSM), magnetar, or delayed accretion in a tidal disruption event (TDE). Long-term and multi-wavelength monitoring will help to resolve its nature and finally reveal the origin of the ‘Cow’.
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Copyright, Publisher and Additional Information: | © 2022 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This is an author-produced version of a paper subsequently published in Monthly Notices of the Royal Astronomical Society: Letters. Uploaded in accordance with the publisher's self-archiving policy. | ||||
Keywords: | stars: massive; supernovae: general; supernovae: individual: AT2018cow | ||||
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Institution: | The University of Sheffield | ||||
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Physics and Astronomy (Sheffield) | ||||
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Depositing User: | Symplectic Sheffield | ||||
Date Deposited: | 21 Mar 2022 15:12 | ||||
Last Modified: | 10 Feb 2023 15:46 | ||||
Status: | Published | ||||
Publisher: | Oxford University Press (OUP) | ||||
Refereed: | Yes | ||||
Identification Number: | https://doi.org/10.1093/mnrasl/slac023 | ||||
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