A team of international astronomers has used the Giant Metrewave Radio Telescope (GMRT), located 80 km away from Pune, to discover the biggest pair of plasma jets to emanate from a supermassive black hole, spanning a size of 23 million light years from end to end.
The size of the jets is more than a hundred times that of the Milky Way and the discovery has recently been published in Naturethe foremost science journal.
Prof. Yogesh Wadadekar from the Pune-based National Centre for Radio Astrophysics-Tata Institute of Fundamental Research (NCRA-TIFR) told The Indian Express that the discovery of a jet spanning a prodigious length of 23 million light years is the largest discovered so far.
“The GMRT telescope located in Khodad, 80 km from Pune, played a crucial role in this discovery,” Prof Wadadekar said.
“Giant jets of fast-moving plasma emanate from the supermassive black holes at the centre of galaxies. These can be observed with radio telescopes. However, only a few jets are very long. Hence this jet discovered is the largest so far,” Prof Wadadekar explained.
To determine the length of the jets, a powerful radio telescope was needed that could trace the jets back to the galaxy from which they emerged. This is where the GMRT comes in. Once the host was identified using the GMRT, the researchers used the Keck I optical telescope in Hawaii, US, to obtain the distance.
Martijn Oei, a postdoctoral scholar at the California Institute of Technology (Caltech) and the lead author of the new Nature paper, said that sensitive, high-resolution GMRT observations were used to identify the host galaxy that spawns the jets. The jet megastructure, nicknamed Porphyrion after a giant in Greek mythology, dates to a time when the universe was 6.3 billion years old.
Without the precise position provided by the GMRT observations, it would have been impossible to identify the optical host galaxy and to determine the giant extent of the radio megastructure, researchers have written in Nature.
The study of supermassive black hole jets in radio galaxies has been an area of research where the GMRT has made several important contributions over the last two decades. The discovery of Porphyrion is another achievement for it in this active area of research in astrophysics.
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