A concordance scenario for the observed neutrino from a tidal disruption event
Abstract
During a tidal disruption event, a star is torn apart by the tidal forces of a supermassive black hole, with about 50% of the star's mass eventually accreted by the black hole. The resulting flare can, in extreme cases of super-Eddington mass accretion, result in a relativistic jet1-4. While tidal disruption events have been theoretically proposed as sources of high-energy cosmic rays5,6 and neutrinos7-14, stacking searches indicate that their contribution to the diffuse extragalactic neutrino flux is very low15. However, a recent association of a track-like astrophysical neutrino (IceCube-191001A16) with a tidal disruption event (AT2019dsg17) indicates that some tidal disruption events can accelerate cosmic rays to petaelectronvolt energies. Here we introduce a phenomenological concordance scenario with a relativistic jet to explain this association: an expanding cocoon progressively obscures the X-rays emitted by the accretion disk, while at the same time providing a sufficiently intense external target of backscattered X-rays for the production of neutrinos via proton-photon interactions. We also reproduce the delay (relative to the peak) of the neutrino emission by scaling the production radius with the black-body radius. Our energetics and assumptions for the jet and the cocoon are compatible with expectations from numerical simulations of tidal disruption events.
- Publication:
-
Nature Astronomy
- Pub Date:
- May 2021
- DOI:
- 10.1038/s41550-021-01305-3
- arXiv:
- arXiv:2005.06097
- Bibcode:
- 2021NatAs...5..472W
- Keywords:
-
- Astrophysics - High Energy Astrophysical Phenomena;
- High Energy Physics - Phenomenology
- E-Print:
- LaTeX, 25 pages, 3 figures. One figure and various clarifications added. Title and text modified to meet journal requirements. Results unchanged. Version accepted for publication in Nature Astronomy