An international team of astronomers led by India has detected a mysterious object in the sky using the Giant Vaulted Wave Radio Telescope (GMRT). The GMRT, the world’s largest and most powerful radio telescope in the low frequency range of 150-1500 MHz from the Tata Institute for Fundamental Research’s National Center for Radio Astrophysics (NCRA-TIFR), is widely used by astronomers around the world.
Observing at low radio frequencies with GMRT is like conducting a deeper archaeological dig to uncover the past history of black hole jet activity. The various evolutionary processes that drive the evolution of galaxies and galaxy clusters were discovered by the team using GMRT.
Ananda Hota of the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), Taiwan, discovered a strange galaxy containing a combination of properties never seen before and called it SPECA (Spiral Host, Tracking Accumulative Radio Galaxies Spiral Host). SPECA is only a second spiral galaxy, unlike elliptical galaxies which are known to produce jets of heavy subatomic particles that travel close to the speed of light. These potentially more exotic black hole galaxies have the potential to provide new lessons on how galaxies and galaxy clusters formed in the early universe.
It is also one of only two galaxies to show this activity occurs in three separate rings. The reason behind the black hole’s intermittent activity to produce the emission is unknown.
“The ongoing TIFR GMRT Sky Survey (TGSS) will find more SPECA-like galaxies, and Dr Hota’s discovery is a potential clue,” said NCRA-TIFR’s Dr Sandeep Sirothia.
“This type of reborn radio galaxy is a laboratory for understanding the many enigmatic aspects of black holes,” said Dr. Chirangib Kunar of Asia.
SPECA is a “missing link”, rare in the nearby universe, but it should be common in the early universe when black holes, galaxies and clusters were very young in their formation, said Dr. Hota.
This is perhaps the first evidence of a process of growth and organization of galaxy clusters by supersonic material falling from cosmic webs and black holes to control them by means of powerful jet streams.
“This is an exciting and very important discovery of the clustering model and highlights the importance of meter wavelength sensitive observations provided by GMRT,” said Professor Govind Swarup, Padmashri Award winner, FRS , considered the “father” of Indian radio astronomy. . and Chief Architect at GMTT.
Apart from Dr. Hota, Dr. Sirothia, and Dr. Konar, the research group that includes Dr. Yuichi Ohiyama, Dr. Satoki Matsushita from Asia, Suk Kim, Professor Soo Chang-ri from National Chungnam University in Korea, NCRA Professor DJ Saikya, and Dr. Judith. H Croston of the University of Southampton, United Kingdom.
