Shocks Power Tidal Disruption Events
Accretion of debris seems to be the natural mechanism to power the radiation emitted during a tidal disruption event (TDE), in which a supermassive black hole tears apart a star. However, this requires the prompt formation of a compact accretion disk. Here, using a fully relativistic global simulati...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2023-01-01
|
| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/acf5de |
| _version_ | 1797654237367238656 |
|---|---|
| author | Taeho Ryu Julian Krolik Tsvi Piran Scott C. Noble Mark Avara |
| author_facet | Taeho Ryu Julian Krolik Tsvi Piran Scott C. Noble Mark Avara |
| author_sort | Taeho Ryu |
| collection | DOAJ |
| description | Accretion of debris seems to be the natural mechanism to power the radiation emitted during a tidal disruption event (TDE), in which a supermassive black hole tears apart a star. However, this requires the prompt formation of a compact accretion disk. Here, using a fully relativistic global simulation for the long-term evolution of debris in a TDE with realistic initial conditions, we show that at most a tiny fraction of the bound mass enters such a disk on the timescale of observed flares. To “circularize” most of the bound mass entails an increase in the binding energy of that mass by a factor of ∼30; we find at most an order-unity change. Our simulation suggests it would take a timescale comparable to a few tens of the characteristic mass fallback time to dissipate enough energy for “circularization.” Instead, the bound debris forms an extended eccentric accretion flow with eccentricity ≃0.4–0.5 by ∼two fallback times. Although the energy dissipated in shocks in this large-scale flow is much smaller than the “circularization” energy, it matches the observed radiated energy very well. Nonetheless, the impact of shocks is not strong enough to unbind initially bound debris into an outflow. |
| first_indexed | 2024-03-11T16:56:31Z |
| format | Article |
| id | doaj.art-9df268c4ca744f17bf9fcdf20df50867 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-11T16:56:31Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-9df268c4ca744f17bf9fcdf20df508672023-10-20T17:19:06ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0195711210.3847/1538-4357/acf5deShocks Power Tidal Disruption EventsTaeho Ryu0https://orcid.org/0000-0003-2012-5217Julian Krolik1https://orcid.org/0000-0002-2995-7717Tsvi Piran2https://orcid.org/0000-0002-7964-5420Scott C. Noble3https://orcid.org/0000-0003-3547-8306Mark Avara4https://orcid.org/0000-0001-9562-9677Max Planck Institute for Astrophysics , Karl-Schwarzschild-Strasse 1, D-85748 Garching, Germany ; tryu@mpa-garching.mpg.de; Physics and Astronomy Department, Johns Hopkins University , Baltimore, MD 21218, USAPhysics and Astronomy Department, Johns Hopkins University , Baltimore, MD 21218, USARacah Institute of Physics, Hebrew University , Jerusalem 91904, IsraelGravitational Astrophysics Laboratory, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USAInstitute of Astronomy, University of Cambridge , Madingley Road, Cambridge CB3 0HA, UK; Center for Computational Relativity and Gravitation, Rochester Institute of Technology , Rochester, NY 14623, USAAccretion of debris seems to be the natural mechanism to power the radiation emitted during a tidal disruption event (TDE), in which a supermassive black hole tears apart a star. However, this requires the prompt formation of a compact accretion disk. Here, using a fully relativistic global simulation for the long-term evolution of debris in a TDE with realistic initial conditions, we show that at most a tiny fraction of the bound mass enters such a disk on the timescale of observed flares. To “circularize” most of the bound mass entails an increase in the binding energy of that mass by a factor of ∼30; we find at most an order-unity change. Our simulation suggests it would take a timescale comparable to a few tens of the characteristic mass fallback time to dissipate enough energy for “circularization.” Instead, the bound debris forms an extended eccentric accretion flow with eccentricity ≃0.4–0.5 by ∼two fallback times. Although the energy dissipated in shocks in this large-scale flow is much smaller than the “circularization” energy, it matches the observed radiated energy very well. Nonetheless, the impact of shocks is not strong enough to unbind initially bound debris into an outflow.https://doi.org/10.3847/1538-4357/acf5deBlack hole physicsGalaxy nucleiGravitationHydrodynamicsStellar dynamics |
| spellingShingle | Taeho Ryu Julian Krolik Tsvi Piran Scott C. Noble Mark Avara Shocks Power Tidal Disruption Events The Astrophysical Journal Black hole physics Galaxy nuclei Gravitation Hydrodynamics Stellar dynamics |
| title | Shocks Power Tidal Disruption Events |
| title_full | Shocks Power Tidal Disruption Events |
| title_fullStr | Shocks Power Tidal Disruption Events |
| title_full_unstemmed | Shocks Power Tidal Disruption Events |
| title_short | Shocks Power Tidal Disruption Events |
| title_sort | shocks power tidal disruption events |
| topic | Black hole physics Galaxy nuclei Gravitation Hydrodynamics Stellar dynamics |
| url | https://doi.org/10.3847/1538-4357/acf5de |
| work_keys_str_mv | AT taehoryu shockspowertidaldisruptionevents AT juliankrolik shockspowertidaldisruptionevents AT tsvipiran shockspowertidaldisruptionevents AT scottcnoble shockspowertidaldisruptionevents AT markavara shockspowertidaldisruptionevents |