Radio galaxy

This article is about the type of galaxy. For the UK radio network, see The Galaxy Network.
Alcyoneus, a giant radio galaxy with lobed structures spanning 5 megaparsecs (16×106 ly).

A radio galaxy is a galaxy with giant regions of radio emission extending well beyond its visible structure. These energetic radio lobes are powered by jets from its active galactic nucleus.[1] They have luminosities up to 1039 W at radio wavelengths between 10 MHz and 100 GHz.[2] The radio emission is due to the synchrotron process. The observed structure in radio emission is determined by the interaction between twin jets and the external medium, modified by the effects of relativistic beaming. The host galaxies are almost exclusively large elliptical galaxies. Radio-loud active galaxies can be detected at large distances, making them valuable tools for observational cosmology. Recently, much work has been done on the effects of these objects on the intergalactic medium, particularly in galaxy groups and clusters.

The term "radio galaxy" is often used to refer to the entire jet system, rather than solely to its host galaxy. Some scientists consider the term "black hole jet system" more accurate and less confusing.[3][4] Radio galaxies that reach the size of around 0.7 megaparsecs or more, are commonly called "giant radio galaxies".[5]

  1. ^ David J. Adams; David John Adams; Alan Cayless; Anthony W. Jones (2004). Mark H. Jones; David J. Adams; Robert J. Lambourne (eds.). An Introduction to Galaxies and Cosmology. Cambridge University Press. pp. 142–144. ISBN 978-0-521-54623-2.
  2. ^ "9.3 Fanaroff-Riley Classification". NASA/IPAC Extragalactic Database (NED). California Institute of Technology. Retrieved 24 March 2022.
  3. ^ Oei, Martijn S. S. L.; Hardcastle, Martin J.; Timmerman, Roland; Gast, Aivin R. D. J. G. I. B.; Botteon, Andrea; Rodriguez, Antonio C.; Stern, Daniel; Calistro Rivera, Gabriela; Van Weeren, Reinout J.; Röttgering, Huub J. A.; Intema, Huib T.; De Gasperin, Francesco; Djorgovski, S. G. (2024-09-18). "Black hole jets on the scale of the cosmic web". Nature. 633: 537–541. doi:10.1038/s41586-024-07879-y.
  4. ^ "Somerville Student Discovers Black Hole Jet Systems". Somerville College, Oxford. 19 September 2024.
  5. ^ Oei, Martijn S. S. L.; van Weeren, Reinout J.; Gast, Aivin R. D. J. G. I. B.; Botteon, Andrea; Hardcastle, Martin J.; Dabhade, Pratik; Shimwell, Tim W.; Röttgering, Huub J. A.; Drabent, Alexander (2023). "Measuring the giant radio galaxy length distribution with the LoTSS". Astronomy & Astrophysics. 672: A163. arXiv:2210.10234. doi:10.1051/0004-6361/202243572. ISSN 0004-6361. Retrieved 19 September 2024 – via cdsarc.cds.unistra.fr.