Decoding the clockwork of repeating nuclear transients: unveiling black hole environments with optical polarimetry

Repeating nuclear transients are quasi-periodic outbursts occurring in galactic nuclei, driven by episodic accretion onto supermassive black holes (SMBHs). These events provide unique laboratories for advancing our understanding of accretion physics, yet the innermost regions of most galactic nuclei remain inaccessible to direct imaging. More routinely observational approaches are therefore required to uncover the geometry and physical mechanisms governing these extreme environments.

In this talk, I will present optical polarimetry as a powerful tool to probe the hidden structures surrounding SMBHs. I will show how polarimetric observations reveal the geometry of two different classes of repeating nuclear transients: ASASSN-14ko, the most regularly repeating periodic nuclear transient known to date and a repeating partial tidal disruption event candidate, and GSN069, the prototype source of quasi-periodic eruptions. These results are part of POLTerDEIST, a target-of-opportunity observational program combining data from OSN, CAHA, NOT, and VLT, which I will also introduce.

Fecha y lugar: 16/06/2026 – 12:30 | Salón de Actos
Beatriz Agís González
Institute of Astrophysics at FORTH