AT 2018cow at ~5 years: additional evidence for a tidal disruption origin

Fuente: arXiv
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Main Authors: Inkenhaag, Anne, Levan, Andrew J., Mummery, Andrew, Jonker, Peter G.
Format: Preprint
Published: 2025
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author Inkenhaag, Anne
Levan, Andrew J.
Mummery, Andrew
Jonker, Peter G.
author_facet Inkenhaag, Anne
Levan, Andrew J.
Mummery, Andrew
Jonker, Peter G.
contents The Luminous Fast Blue Optical Transient (LFBOT) AT 2018cow is the prototype of its class with an extensive set of multi-wavelength observations. Despite a rich data set there is, still, no consensus about the physical nature and origin of this event. AT 2018cow remained UV bright 2-4 years after the explosion, which points at an additional energy injection source, most likely from an accretion disk. We present additional late time UV data obtained with the Hubble Space Telescope, to show there is no significant fading in the optical since the last epoch and only marginal fading in the UV. The new UV data points match the predictions of previously published accretion disk models, where the disk is assumed to form from the tidal disruption of a low mass star by an intermediate mass black hole. This consistency provides evidence that AT 2018cow could indeed be a tidal disruption event. The marginal decay is in contrast with the predictions of light curves produced by interacting supernovae. The difference between expectations for disc emission and interacting supernovae will further increase with time, making data at even later times a route to robustly rule out interaction between supernova ejecta and circumstellar material.
format Preprint
id arxiv_https___arxiv_org_abs_2510_08505
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle AT 2018cow at ~5 years: additional evidence for a tidal disruption origin
Inkenhaag, Anne
Levan, Andrew J.
Mummery, Andrew
Jonker, Peter G.
High Energy Astrophysical Phenomena
Solar and Stellar Astrophysics
The Luminous Fast Blue Optical Transient (LFBOT) AT 2018cow is the prototype of its class with an extensive set of multi-wavelength observations. Despite a rich data set there is, still, no consensus about the physical nature and origin of this event. AT 2018cow remained UV bright 2-4 years after the explosion, which points at an additional energy injection source, most likely from an accretion disk. We present additional late time UV data obtained with the Hubble Space Telescope, to show there is no significant fading in the optical since the last epoch and only marginal fading in the UV. The new UV data points match the predictions of previously published accretion disk models, where the disk is assumed to form from the tidal disruption of a low mass star by an intermediate mass black hole. This consistency provides evidence that AT 2018cow could indeed be a tidal disruption event. The marginal decay is in contrast with the predictions of light curves produced by interacting supernovae. The difference between expectations for disc emission and interacting supernovae will further increase with time, making data at even later times a route to robustly rule out interaction between supernova ejecta and circumstellar material.
title AT 2018cow at ~5 years: additional evidence for a tidal disruption origin
topic High Energy Astrophysical Phenomena
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2510.08505