ABSTRACT

A tidal disruption event (TDE) occurs when an ill-fated star wanders too close to a supermassive black hole (SMBH) and is torn apart by tidal forces. TDE observations offer a unique laboratory to measure SMBH masses and to study super-Eddington accretion and associated outflows. In radio wavelengths, observations can allow us to probe the environment around previously-dormant SMBHs, as well as the physical properties of the outflow itself. To date, ~100 TDEs are known, the majority of which are discovered by optical surveys and then followed-up at other wavelengths. Recently, it has become apparent that some TDEs can indeed exhibit delayed onset of radio emission, which may be due to the long-elusive off-axis jets, or to a previously unknown delayed phase of TDE accretion and outflows. For example, in the recent case of AT2018hyz, the outflow began several hundred days post-disruption, at mildly relativistic speeds. In this talk, I will first give an overview of the TDE phenomenon and observations to date. I will also discuss the phenomenon of late-time radio emission, including results from a radio survey using the VLA and MeerKAT of ~25 TDEs >2 years post-disruption, which did not exhibit radio emission at early times. I will discuss the rate of radio-bright TDEs at late times, and implications for the density profile surrounding SMBHs.

About the Speaker:

Yvette Cendes is a postdoctoral fellow at the Center for Astrophysics | Harvard & Smithsonian, whose research focuses on radio transients. This has covered a diverse range of topics, from TDEs to supernovae to radio emission from exoplanets. Recently named one of the "Top 25 Rising Stars in Astronomy" by Astronomy magazine, Yvette is also interested in science outreach, which has covered writing for publications such as Astronomy and Discover, and she is the astronomy editor for the 2023 Guinness Book of World Records. Yvette is also known for her profile, /u/Andromeda321, on the website Reddit, where her "astronomer here!" comments are read by millions of people around the world.