Optical polarization from colliding stellar stream shocks in a tidal disruption event

Abstract

A tidal disruption event (TDE) occurs when a supermassive black hole rips apart a passing star. Part of the stellar material falls toward the black hole, forming an accretion disk that in some cases launches a relativistic jet. We performed optical polarimetry observations of a TDE, AT 2020mot. We find a peak linear polarization degree of $25\pm 4$%, consistent with highly polarized synchrotron radiation, as is typically observed from relativistic jets. However, our radio observations, taken up to 8 months after the optical peak, do not detect the corresponding radio emission expected from a relativistic jet. We suggest that the linearly polarized optical emission instead arises from shocks that occur during accretion disk formation, as the stream of stellar material collides with itself.

41 pages, 10 figures, 4 tables, published in Science

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Cited by in corpus (6)

• The Large Array Survey Telescope -- Science Goals
• Spin-induced offset stream self-crossing shocks in tidal disruption events
• Optical polarization of stellar-fed active and quiescent supermassive black holes
• Revisiting the unification of tidal disruption events with polarimetry
• Science with a large field-of-view polarization survey: The Large Array Survey Telescope Polarization Node (LAST-P)
• Fast giant flares in discs around supermassive black holes