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Optical polarization from colliding stellar stream shocks in a tidal disruption event
I Liodakis1, K I I Koljonen1,2,3, D Blinov4,5
1Finnish Center for Astronomy with the European Southern Observatory, University of Turku, FI-20014 Turku, Finland.
Science (New York, N.Y.)
|May 11, 2023
Summary
We studied a tidal disruption event (TDE) and found highly polarized optical light. This polarization likely originates from accretion disk shocks, not a relativistic jet, as radio observations were negative.
Area of Science:
- Astronomy and Astrophysics
- Black Hole Physics
- Observational Cosmology
Background:
- Tidal disruption events (TDEs) involve supermassive black holes (SMBHs) destroying stars.
- Accretion disks formed from stellar debris can launch relativistic jets.
- Understanding TDE emission mechanisms is crucial for SMBH studies.
Purpose of the Study:
- Investigate the emission properties of the TDE AT 2020mot.
- Determine the origin of the observed high optical polarization.
- Test the hypothesis of relativistic jet formation in TDEs.
Main Methods:
- Conducted optical polarimetry observations of AT 2020mot.
- Analyzed polarization data to measure linear polarization degree.
- Performed radio observations to search for jet emission up to 8 months post-optical peak.
Main Results:
- Observed a peak linear polarization of 25 ± 4% in optical light.
- This polarization is consistent with synchrotron radiation.
- No corresponding radio emission from a relativistic jet was detected.
Conclusions:
- The high optical polarization likely originates from accretion disk shocks.
- The absence of radio emission challenges the typical jet model for TDEs.
- Accretion disk formation processes may be responsible for polarized optical emission in TDEs.
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