A likely decade-long sustained tidal disruption event
Abstract
Multiwavelength flares from tidal disruption and accretion of stars can be used to find and study otherwise dormant massive black holes in galactic nuclei. Previous well-monitored candidate flares are short-lived, with most emission confined to within ~1 year. Here we report the discovery of a well observed super-long (>11 years) luminous soft X-ray flare from the nuclear region of a dwarf starburst galaxy. After an apparently fast rise within ~4 months a decade ago, the X-ray luminosity, though showing a weak trend of decay, has been persistently high at around the Eddington limit (when the radiation pressure balances the gravitational force). The X-ray spectra are generally soft (steeply declining towards higher energies) and can be described with Comptonized emission from an optically thick low-temperature corona, a super-Eddington accretion signature often observed in accreting stellar-mass black holes. Dramatic spectral softening was also caught in one recent observation, implying either a temporary transition from the super-Eddington accretion state to the standard thermal state or the presence of a transient highly blueshifted (~0.36c) warm absorber. All these properties in concert suggest a tidal disruption event of an unusually long super-Eddington accretion phase that has never been observed before.
Cite
@article{arxiv.1702.00792,
title = {A likely decade-long sustained tidal disruption event},
author = {Dacheng Lin and James Guillochon and S. Komossa and Enrico Ramirez-Ruiz and Jimmy A. Irwin and W. Peter Maksym and Dirk Grupe and Olivier Godet and Natalie A. Webb and Didier Barret and B. Ashley Zauderer and Pierre-Alain Duc and Eleazar R. Carrasco and Stephen D. J. Gwyn},
journal= {arXiv preprint arXiv:1702.00792},
year = {2017}
}
Comments
Published in Nature Astronomy on Feb 6. Including supplementary materials