Compact Symmetric Object

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Compact Symmetric Objects ( German  compact symmetric objects ) are bipolar radio galaxies that have a diameter of less than 1000 parsecs in the area of radio radiation . They are interpreted as precursor objects of active galaxy nuclei .

Properties and interpretations

As with other radio galaxies, the morphology of Compact Symmetric Objects (CSO for short) is characterized by two jets emanating from the center of the galaxy . In the center of the CSOs, as in other active galaxies, a supermassive black hole is suspected. The relativistic jets end on both sides of the galaxy at a distance of less than 1000 parsecs in hotspots due to a collision with the interstellar medium , while with active galaxy nuclei the jets can be observed over several 100,000 parces and interact with the intergalactic medium .

The radio emission of the Compact Symmetric Objects is dominated by the hot spots, which often show the greatest intensity in the collision zone. The diameter of the CSO increases by up to 0.1 c per year and from this the kinematic age of the CSO can be calculated to be 20 to 2000 years. The CSOs could be detected in the X-ray range, whereas previously the theoretically assumed emission in the gamma-ray range could only be observed in one CSO. Polarization in the range of radio waves could only be measured in a few CSOs .

In general, Compact Symmetric Objects in the so-called youth model are interpreted as eruptions in the galactic core with an age of less than 2000 years. In the frustation model, however, the small diameter is interpreted as a consequence of a dense interstellar medium in the galaxy that the jets cannot pierce.

Examples

  • J10351 + 5628
  • OQ 208
  • PKS 1718-649

literature

  • Giulia Migliori, Aneta Siemiginowska, Malgorzata Sobolewska, Alan Loh, Stéphane Corbel, Luisa Ostorero, Łukasz Stawarz: First detection in gamma-rays of a young radio galaxy: Fermi-LAT observations of the Compact Symmetric Object PKS 1718-649 . In: Astrophysics. Solar and Stellar Astrophysics . 2016, arxiv : 1604.01987v1 .
  • SE Tremblay, GB Taylor, AA Ortiz, CD Tremblay, JF Helmboldt, RW Romani: Compact Symmetric Objects and Supermassive Binary Black Holes in the VLBA Imaging and Polarimetry Survey . In: Astrophysics. Solar and Stellar Astrophysics . 2016, arxiv : 1603.03094v1 .
  • Fang Wu, Tao An, Willem A. Baan, Xiao-Yu Hong, Carlo Stanghellini, Sandor Frey, Hai-Guang Xu, Xiang Liu, Jingying Wang: Kinematics of the Compact Symmetric Object OQ 208 revisited . In: Astrophysics. Solar and Stellar Astrophysics . 2012, arxiv : 1211.4287v2 .
  • KV Sokolovsky, YY Kovalev, AB Pushkarev, P. Mimica, M. Perucho: Close neighbors of Markarian galaxies. I. Optical database . In: Astrophysics. Solar and Stellar Astrophysics . 2011, arxiv : 1107.0719v3 .