“Changing Look” Blazar spotted 6.3 billion light years away | Astronomy

Astronomers have made photometric and spectroscopic observations of B2 1420 + 32, a blazar with a collection of “look change” features.

Blazars are powerful active galactic nuclei (AGNs) with relativistic jets pointing towards the observer.

Their jets cover distances of the order of a million light years and are known to impact the evolution of galaxies and galaxy clusters in which they reside via radiation.

These characteristics make blazars ideal environments for studying jet physics and their role in the evolution of galaxies.

“The Blazars are a unique type of AGN with very powerful jets,” said lead author Hora Mishra, a PhD. student in the Homer L. Dodge Department of Physics and Astronomy at the University of Oklahoma.

“Jets are a mode of radio feedback and because of their scales, they enter the galaxy in their large-scale environment.”

“The origin of these jets and the processes leading to the radiation are not well known. Thus, the study of blazars allows us to better understand these jets and how they are connected to other components of the AGN, such as the accretion disk.

“These jets can heat and move gas in their environment affecting, for example, star formation in the galaxy.”

In the research, Mishra and his colleagues studied the evolution of B2 1420 + 32, a blazar located 6.3 billion light-years away in the constellation Boötes.

At the end of 2017, this blazar exhibited a huge optical flare, a phenomenon captured by the All Sky Automated Survey for SuperNovae (ASAS-SN) telescope array.

“We followed this by observing the evolution of its spectrum and light curve over the next two years and also retrieved the archival data available for this object,” Mishra said.

“The campaign, with data spanning over a decade, has yielded some of the most exciting results.”

“We are seeing for the first time dramatic variability in the spectrum and multiple transformations between the two subclasses of blazars, which has earned it the blazar name of ‘change of look’. “

Astronomers have concluded that this behavior is caused by the dramatic changes in continuous flow, which supports a long-proposed theory that separates blazars into two main categories.

“In addition, we are seeing several very large multiband flares in the optical and gamma bands at different time scales and new spectral characteristics,” Mishra said.

“Such extreme variability and spectral characteristics require dedicated research for more blazars, which will allow us to use the dramatic spectral changes observed to reveal AGN / jet physics, including how dust particles around supermassive black holes are destroyed by the enormous radiation from the central motor and how the energy of a relativistic jet is transferred into the dust clouds, providing a new channel connecting the evolution of the supermassive black hole to its host galaxy.

“We are very excited by the results of discovering a changing-looking blazar that transforms not once, but three times, between its two subclasses, from the dramatic changes in its continuous show. “

“In addition, we are seeing new spectral characteristics and unprecedented optical variability. These results open the door to further studies of this type on highly variable blazars and their importance in understanding the physics of AGNs.

“It is really interesting to see the emergence of a forest of iron emission lines, suggesting that the nearby dust particles were evaporated by the strong radiation of the jet and released free iron ions in the clouds. Transmitters, a phenomenon predicted by theoretical models and confirmed in this blazar explosion, ”said Dr. Xinyu, also from the Homer L. Dodge Department of Physics and Astronomy at the University of Oklahoma.

the study was published in the Astrophysics Journal.

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Hora D. Mishra et al. 2021. The Blazar with a changing look B2 1420 + 32. ApJ 913, 146; doi: 10.3847 / 1538-4357 / abf63d