Astronomers have performed photometric and spectroscopic observations of B2 1420+32, a blazar with a collection of changing-look features.<\/p>\n
Sloan Digital Sky Survey archival image from March 2004 (left) and the image from the observation campaign of B2 1420+32 taken by Mishra et al. in January 2020 using ASAS-SN (right); the blazars brightness increased by a factor of 100. Image credit: SDSS \/ Mishra et al., doi: 10.3847\/1538-4357\/abf63d.<\/p>\n
Blazars are powerful active galactic nuclei (AGN) with relativistic jets pointing toward the observer.<\/p>\n
Their jets span distances on the million light-year scales and are known to impact the evolution of galaxies and galaxy clusters in which they reside via the radiation.<\/p>\n
These features make blazars ideal environments in which to study the physics of jets and their role in galaxy evolution.<\/p>\n
Blazars are a unique kind of AGN with very powerful jets, said lead author Hora Mishra, a Ph.D. student in the Homer L. Dodge Department of Physics and Astronomy at the University of Oklahoma.<\/p>\n
Jets are a radio mode of feedback and because of their scales, they penetrate the galaxy into their large-scale environment.<\/p>\n
The origin of these jets and processes driving the radiation are not well-known. Thus, studying blazars allows us to understand these jets better and how they are connected to other components of the AGN, like the accretion disk.<\/p>\n
These jets can heat up and displace gas in their environment affecting, for example, the star formation in the galaxy.<\/p>\n
In the research, Mishra and her colleagues investigated the evolution of B2 1420+32, a blazar located 6.3 billion light-years away in the constellation of Botes.<\/p>\n
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 network.<\/p>\n
We followed this up by observing the evolution of its spectrum and light curve over the next two years and also retrieved archival data available for this object, Mishra said.<\/p>\n
The campaign, with data spanning over a decade, has yielded some most exciting results.<\/p>\n
We see dramatic variability in the spectrum and multiple transformations between the two blazar sub-classes for the first time for a blazar, thus giving it the name changing-look blazar.<\/p>\n
The astronomers concluded that this behavior is caused by the dramatic continuum flux changes, which confirm a long-proposed theory that separates blazars into two major categories.<\/p>\n
In addition, we see several very large multiband flares in the optical and gamma-ray bands on different timescales and new spectral features, Mishra said.<\/p>\n
Such extreme variability and the spectral features demand dedicated searches for more such blazars, which will allow us to utilize the dramatic spectral changes observed to reveal AGN\/jet physics, including how dust particles around supermassive black holes are destructed by the tremendous radiation from the central engine and how energy from a relativistic jet is transferred into the dust clouds, providing a new channel linking the evolution of the supermassive black hole with its host galaxy.<\/p>\n
We are very excited by the results of discovering a changing-look blazar that transforms itself not once, but three times, between its two sub-classes, from the dramatic changes in its continuum emission.<\/p>\n
In addition, we see new spectral features and optical variability that is unprecedented. These results open the door to more such studies of highly variable blazars and their importance in understanding AGN physics.<\/p>\n
It is really interesting to see the emergence of a forest of iron emission lines, suggesting that nearby dust particles were evaporated by the strong radiation from the jet and released free iron ions into the emitting clouds, a phenomenon predicted by theoretical models and confirmed in this blazar outburst, said Dr. Xinyu, also from the Homer L. Dodge Department of Physics and Astronomy at the University of Oklahoma.<\/p>\n
The study was published in the Astrophysical Journal.<\/p>\n
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Hora D. Mishra et al. 2021. The Changing-look Blazar B2 1420+32. ApJ 913, 146; doi: 10.3847\/1538-4357\/abf63d<\/p>\n
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Read more: <\/p>\n
'Changing-Look' Blazar Spotted 6.3 Billion Light-Years Away | Astronomy - Sci-News.com<\/a><\/p>\n","protected":false},"excerpt":{"rendered":" Astronomers have performed photometric and spectroscopic observations of B2 1420+32, a blazar with a collection of changing-look features. Sloan Digital Sky Survey archival image from March 2004 (left) and the image from the observation campaign of B2 1420+32 taken by Mishra et al. in January 2020 using ASAS-SN (right); the blazars brightness increased by a factor of 100. Continue reading