Tidal Disruption Event

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The term Tidal disruption event ( English for tidal -Sternzerrissereignis ) in describing astronomy the close encounter a star with a super massive black hole in the core of a galaxy , whereby a part of the material of the star leaves his gravitational field and accretion forms around the black hole. This process should convert calm galactic nuclei back into active galactic nuclei and be a comparatively common occurrence at a rate of 0.0001 per galaxy per year.

The S stars have been found around the center of the Milky Way Sagittarius A * . The S-stars are early massive blue giants with an orbital period of a few years. By scattering due to close encounters, every 100 to 10,000 years a star will come so close to the supermassive black hole that parts of the star are within the Roche boundary of the black hole. This matter leaves the star's gravitational influence and forms an accretion disk around the black hole. In addition to capturing gas clouds , this represents a second variant in which matter is transported into a black hole in the center of a galaxy and thus converts it into an active galactic core. Due to the viscosity of the material in the accretion disk, a tidal disruption event leads to an outbreak in the ultraviolet and X-ray range , which is known as tidal flare .

A tidal flare should have blackbody temperatures between 0.04 and 0.12  keV and last on the order of months to years. The luminosity may be up to 10 47  erg / s reach. The increase in luminosity is on the order of days to weeks depending on the mass of the black hole, with lower masses leading to a steeper increase in the light curve . In addition to the mass, the period of rotation of the black holes can also be examined with the help of the tidal flares. The decrease in brightness should decrease with a power law of −5/3 and this decrease should be able to be used to identify tidal disruption events, since no other known event leads to such a decrease in luminosity.

Candidates for Tidal Disruption Events or Tidal Flares are:

  • WINGS J1348 in Abell 1795
  • PS1-10jh
  • Swift J1644 + 57
  • ASASSN-15lh in 2015 during the All-Sky Automated Survey for SuperNovae (ASAS-SN) observation program

Individual evidence

  1. ^ Susana Frech, Stefan Frech: Specialized dictionary astronomy. Books on Demand, Norderstedt 2011, ISBN 3-8423-1963-0 , page 45, Google books.
  2. ↑ Chenwei Yang, Tinggui Wang, Gary Ferland, Weimin Yuan, Hongyan Zhou, Peng Jiang: Long Term Spectral Evolution of Tidal Disruption Candidates Selected by Strong Coronal Lines . In: Astrophysics. Solar and Stellar Astrophysics . 2013, arxiv : 1307.3313v1 .
  3. ↑ Peter Jonker et al: The Hot and Energetic Universe: Luminous extragalactic transients . In: Astrophysics. Solar and Stellar Astrophysics . 2013, arxiv : 1306.2336v1 .
  4. ↑ Jonah Kanner et al: X-ray Transients in the Advanced LIGO / Virgo Horizon . In: Astrophysics. Solar and Stellar Astrophysics . 2013, arxiv : 1305.5874v1 .
  5. ↑ Ildar Khabibullin, Sergey Sazonov, Rashid Sunyaev: SRG / eROSITA prospects for the detection of stellar tidal disruption flares . In: Astrophysics. Solar and Stellar Astrophysics . 2013, arxiv : 1304.3376v1 .
  6. ^ WP Maksym, MP Ulmer, MC Eracleous, L. Guennou, LC Ho: A Tidal Flare Candidate in Abell 1795 . In: Astrophysics. Solar and Stellar Astrophysics . 2013, arxiv : 1307.6556v1 .
  7. ↑ Tamara Bogdanovic et al: Disruption of a Red Giant Star by a Supermassive Black Hole and the Case of PS1-10jh . In: Astrophysics. Solar and Stellar Astrophysics . 2013, arxiv : 1307.6176v1 .
  8. ↑ Morgan MacLeod, Enrico Ramirez-Ruiz, Sean Grady, James Guillochon: Spoon-Feeding Giant Stars to Supermassive Black Holes: Episodic Roche Lobe Overflow from Evolving Stars and Their Contribution to the Quiescent Activity of Galactic Nuclei . In: Astrophysics. Solar and Stellar Astrophysics . 2013, arxiv : 1307.2900v1 .
  9. ↑ G. Leloudas, M. Fraser et al: The superluminous transient ASASSN-15lh as a tidal disruption event from a Kerr black hole. In: Nature Astronomy. 1, Article 2 (2016), doi: 10.1038 / s41550-016-0002 .
  10. ↑ Brighter than 500 billion suns: The flash of light was probably not a supernova after all. In: heise online. Retrieved December 14, 2016 .