ELT Contributions to Tidal Disruption Events
J. Craig Wheeler, Rafaella Margutti, Ryan Chornock, Dan Milisavljevic, Maryam Modjaz, Sung-Chul Yoon
EELT Contributions to Tidal Disruption Events A Whitepaper Submitted to the Astro 2020 Decadal Survey Committee
J. Craig Wheeler (The University of Texas at Austin) Rafaella Margutti (Northwestern University) Ryan Chornock (Ohio University) Dan Milisavljevic (Purdue University) Maryam Modjaz (New York University) Sung-Chul Yoon (Seoul National University)
Contact information for Primary Author: J. Craig Wheeler Department of Astronomy, The University of Texas at Austin 2515 Speedway, C1400 Austin, TX 78712-1205 512-471-6407 [email protected] Adapted from a chapter in the 2018 edition of the Science Book of the Giant Magellan Telescope Project.
An ELT system with its large aperture and sensitive optical and near infrared imager spectrographs will make major contributions to the study of stars ripped apart by supermassive black holes.
Stars that pass too close to supermassive black-holes (SMBHs) at the cores of their host galaxies can encounter death and be completely ripped apart by the SMBH tidal forces (Figure 1). The result of the tidal encounter is a flare of luminous radiation across the electromagnetic spectrum (X-ray to radio) powered by partial accretion of the stellar material onto the SMBH. Theoretically predicted in the seventies (e.g. Hills 1975, Frank & Rees 1976), these flares of radiation are now routinely observed and are known as Tidal Disruption Events (TDEs).
Figure 1. Thanks to the spectroscopic sensitivity, spatial resolution, and spectral coverage it enables, ELT system observations will be able to reach a range of distances and masses that are inaccessible today in the study of supermassive black holes (SMBHs). Tidal disruption events (TDE) are luminous transients that originate from the disruption of stars by supermassive black holes (and perhaps intermediate mass black holes) in the cores of their host galaxies. This figure presents the current state of photometric and spectroscopic follow up (Chornock et al. 2014). An ELT system will greatly expand the fidelity of such data and the cosmic volume over which such systems can be studied.
TDEs are interesting for many reasons. First, TDEs can be used as a marker for SMBHs that otherwise lie dormant and undetected in the centers of distant galaxies (>100 Mpc away), where they are too far away for the orbits of gas and stars around them to be resolved. Furthermore, TDEs are excellent probes of relativistic effects in regimes of strong gravity and provide a new means to measure SMBH masses and spins. Finally, TDEs are signposts of intermediate-mass BHs, binary BHs and recoiling BHs. The first TDE candidates were detected in the nineties at X-ray wavelengths (by
ROSAT ), and later in UV (mainly by
GALEX ). TDEs are now routinely detected by current optical transient surveys (e.g.