Tidal Disruption Events in Polarized Light

Tidal disruption events (TDEs) occur when a star is torn apart by a supermassive black hole, producing a powerful multiwavelength flare. They offer a unique laboratory for studying the formation of accretion disks and jets, complementing studies of active galactic nuclei. Yet two central mysteries still remain: what powers their optical emission? Are jets intrinsically rare, or simply undetected? I will present results from the Black hOle Optical polarization TimE-domain Survey (BOOTES), the first systematic optical polarization survey of TDEs, using the Nordic Optical Telescope, the Calar Alto 2.2 m telescope, the Skinakas Observatory 1.3 m telescope, and the Very Large Telescope. I will also discuss plans to incorporate VSTPOL, whose large field of view and depth will make it particularly valuable for serendipitous polarization measurements of both TDEs during their flares and their host galaxies. Across our observations, we uncover diverse polarization behavior, including variability in both polarization degree and angle, pointing to evolving, asymmetric structures. Combined with multiwavelength observations, these measurements probe the geometry of the disrupted debris and help distinguish between shock-powered and reprocessing-dominated emission. A particularly striking case is AT2024tvd, the first optically identified off-nuclear TDE. We measure strong optical polarization of around 25% together with delayed radio and X-ray emission, supporting a non-thermal optical component consistent with a previously unrecognized, emerging jet. This finding raises the possibility that jets in TDEs are more common than current detections suggest, demonstrating how polarimetry can expose hidden activity during the earliest stages of accretion.