Using Giant Metrewave Radio Telescope (GMRT), a team led by Indian radio astronomers has identified 34 new giant radio sources (GRSs) from the TIFR GMRT Sky Survey Alternative Data Release 1 (TGSS ADR1) at 150 MHz.
Giant Radio Sources (GRS) are among the biggest structures in the universe. At their centers are supermassive black holes, which are millions to billions of times heavier than the Sun. These black holes push out powerful jets of hot plasma, creating huge radio-emitting lobes that stretch far beyond the visible parts of the galaxy.
Astronomers think that Giant Radio Sources (GRSs) are the last stage of a radio galaxy’s life because they are so large. Their huge size makes them useful for studying how radio galaxies evolve and the space between their lobes. However, finding GRSs is difficult because the connection between the lobes is often faint. Low-frequency radio surveys are better at spotting them.
Low-frequency radio surveys are better at finding Giant Radio Sources because the aged plasma shines brighter at these lower frequencies than higher ones.
From 2010 to 2012, the TIFR GMRT Sky Survey (TGSS) used the GMRT to map 90% of the radio sky at 150 MHz. The recently discovered GRS are among the most distant objects of this type.
Two of these objects (J0843+0513 and J1138+4540) defy the widely accepted notion about their low-density environments.
Researchers noted, “The environment alone does not play a major role in the exceptionally large size of GRGs.”
Journal Reference:
- Netai Bhukta, Souvik Manik, Sabyasachi Pal, and Sushanta K. Mondal. Discovery of Giant Radio Sources from TGSS Alternative Data Release 1: Radio, Optical, and Infrared Properties. Astrophysical Journal Supplement Series (ApJS). DOI 10.3847/1538-4365/ad5184