Astronomers have discovered a dying radio galaxy

Watching the area ELAIS N1 in the constellation of the Dragon with GMRT (Giant Metrewave Radio Telescope), the South African and Indian astronomers discovered a dying radio galaxy with a redshift of 0.33. Its linear size is about 100 kiloparsec. A Preprint of the article published on

The radio galaxies are called galaxies, which have a much greater radio emission compared to the other — power of radiation can reach 1045 erg/s, while normal galaxies, including the milky Way, it is 1037-1038 erg/s In the active phase of evolution, which continues from 10 to 100 million years, these galaxies allocated core, “blades” and the jets — that says a continuous ejection of relativistic electrons.

This evolutionary stage is the stage of dying — the activity nucleus decays, “blade”, and the jets gradually disappear. The search for the remains of the nuclei of radio galaxies based on the detection of the spectrum to the low frequencies. For the first time such a dying galaxy was discovered in 1987. The study of these objects is of interest for understanding the life cycle of radio galaxies.

Randriamandrato Zara (Zara Randriamanakoto) of the South African astronomical Observatory and her colleagues from India have analyzed archival observational data in the Indian radio telescope GMRT (Giant Metrewave Radio Telescope) at frequencies of 150 and 325 MHz, and the data obtained by means of a system of radio telescopes VLA (Very Large Array) at a frequency of 1400 megahertz. In the field ELAIS-N1 (European Large-Area ISO Survey-North 1) in the constellation of the Dragon they found a new dying galaxy with a redshift of 0.33, which was called J1615+5452. It is assumed that, in its active phase, it was an elliptical galaxy.

According to the researchers, the size of this object is about 100 kiloparsec. Galaxy is an amorphous radio source without any hints to the kernel, “vane” or the jets. The observations of this region at high resolution using the VLA did not reveal other compact detail visible in the radio. Most likely, J1615+5452, at least thirty percent of his life spent in the stages of dying.

Earlier we talked about how the astronomers found the most distant radio galaxy, and also unusual microquasar Z-shaped structure, and how in the most famous radio source Cygnus A was discovered the second black hole.

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