(ORDO NEWS) — An international team of astronomers has observed a giant radio galaxy known as GRG-J223301+131502. The results of the study are reported in an article published September 26.
Giant radio galaxies (GRGs) are radio galaxies with a total projected linear length greater than at least 2.3 million light-years. They are rare objects that grow in a rarefied medium.
GRG-J223301+131502 (abbreviated as GRG-J2233+1315) is a giant radio galaxy first discovered in 2017 by the Associated Nucleus GRG Search and Analysis (SAGAN) project.
Its total predicted linear size is almost 5.57 million light years. It is part of SDSSJ223301.30+131502.5, an S0-a type galaxy with a large diffuse stellar halo.
Previous studies of GRG-J2233+1315 showed that this galaxy is in a dense cluster environment, which contradicts current theories that GRGs are usually found in a rarefied environment.
Therefore, to verify this, a team of astronomers conducted deep multi-frequency radio observations of GRG-J2233+1315 using the Giant Metrowave Radio Telescope (GMRT) and the Low Frequency Array (LOFAR). Spectroscopic observations were also made with the William Herschel Telescope (WHT).
High-resolution deep radio images have revealed a huge jet about 772,000 light-years across, emanating from the radio core of GRG-J2233+1315 and leading to a “kink” that extends for about 326,000 light-years.
The images also show that the galaxy has lobes without any noticeable hotspots. It turned out that these detected lobes have a spectral age of 110 to 200 million years.
Observations have shown that the galaxy has a redshift of approximately 0.99, and that its linear size is larger than previously thought – almost 6 million light years.
The results show that the parent galaxy has a relatively low star formation rate of about 0.001 solar masses per year.
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