A class of blazars known as BL Lacerate objects emits the whole electromagnetic spectrum, a rather uncommon phenomenon requiring extreme physical conditions and such blazars helps to understand how matter behaves in extreme gravitational fields where it is difficult for even light to escape from the vicinity of the black hole.
New Delhi: A team of Indian astronomers has found an active galaxy five billion light-years from earth away that promises to help in better understanding of the formation, interaction, and evolution of galaxies in the early universe.
Every galaxy in the Universe is believed to host a supermassive black hole (SMBH) at its centre. Some of these black holes are actively devouring a large amount of material and shooting jets of plasma almost at the speed of light.
These are called blazars. A class of blazars known as BL Lacerate objects emits the whole electromagnetic spectrum, a rather uncommon phenomenon requiring extreme physical conditions. The study of such blazars helps to understand how matter behaves in extreme gravitational fields where it is difficult for even light to escape from the vicinity of the black hole.
Astronomers at Aryabhatta Research Institute of Observational Sciences (ARIES), an autonomous institute of the Department of Science & Technology (DST), Government of India, have been monitoring one such black hole system named OJ 287 since 2015.
This shows a repeated optical brightness enhancement almost every 12 years. This makes it very intriguing as this class of sources normally does not show repeating features in flux variations. The repeated optical enhancement made the researchers believe that the system perhaps hosts a binary black hole.
Last year, the source was bright at optical and X-ray bands with X-ray flux more than ten times the normal (non-active phase) flux. This flare was unique.
It is not expected in models proposed for BL Lacerate object blazars. This indicated a more complex system and physical conditions. The astronomers conducted detailed studies and found that the blazar got into a completely new spectral state.
The researchers, who have reported their finding in the publication, ‘The Astrophysical Journal’, said “This change of state could hold the clue to understand how matter behaves in very strong gravity and how it accelerates the particle to almost the speed of light–a feat that is out of the scope of even the most advanced CERN accelerator. Multi-wavelength studies of such sources can perhaps establish the role of strong gravity and acceleration of particles to the speed of light and in the formation, interaction, and evolution of galaxies in the early universe.
The study was conducted by Dr. Pankaj Kushwaha and Prof Alok C. Gupta from ARIES in association with Dr. Main Pal from Jamia Milia Islamia University, Neeraj Kumari–a PhD student with Prof Sachindra Naik from PRL, Ahmedabad, Prof. Elisabete M. de Gouveia Dal Pino from University of Sao Paulo Brazil, Nibediate Kalita, a former PhD student of ARIES with Prof Minfeng Gu from the Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, China.
The study was conducted using data recorded by the Ahmedabad-based Physical Research Laboratory’s Mount Abu observing facility in near-infra-red bands and the space-based NASA’s satellites–the Niels Gherel Swift satellite and Fermi satellite.
Courtesy: India Science Wire
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