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A group of astronomers from around the world, including from Raman Research Institute (RRI) in Bengaluru, has spotted the brightest flare of the blazar called PG 1553+113 and said the analysis would pave the way for understanding the process of galaxy mergers in the early universe.
Researchers from RRI, along with collaborators from all over the world, captured this flare using the 1.3m JC Bhattacharya telescope (JCBT), Kavalur, India. The astronomers then studied for 76 nights at a stretch the said blazar using nine different telescopes around the globe.
A blazar is an active galactic nucleus (AGN) — that is a compact region at the center of a galaxy. A flare in a blazar is a sudden flash of brightness, just as we know of solar flares.
The PG 1553+113, which is a primary candidate for a binary supermassive black hole system, has lately intrigued scientists because of its repetitive gamma-ray emissions which are quasi-periodic, the astronomers said.
RRI is an autonomous institute of the Department of Science and Technology (DST). The DST, while pointing out that galaxies merge frequently throughout cosmic times, said that whenever two galaxies harbour a supermassive blackhole (SMBH) at their centers, the formation of a binary SMBH is inevitable.
“SMBHs, cannot be spatially spotted with current techniques. Therefore, to search for them, scientists have to rely on indirect methods. One of these indirect search strategies is based on the detection of periodicity in the source. A few recent candidates displaying quasi-periodic light curve variability have emerged from large-sky surveys and long-term monitoring programmes. The PG 1553+113 is one of them which enters an outburst and produces very high energy emission,” the DST said.
The research has been published in the journal ‘Astronomy and Astrophysics’. The astronomers said in the paper: “We analysed the light curves using various statistical tests, fitting and cross-correlation techniques, and methods for the search for periodicity. We examined the colour-magnitude diagrams before and after the corresponding light curves were corrected for the long-term variations.”
The researchers studied the multiband flux and spectral variability of the blazar on diverse timescales, the DST said, and added that they estimated the periodicity, radius, size of the emission region, the magnetic field strength, and the electron energy for the blazar.
“Besides, having recorded the flare, they have found that the accelerated particles cool off by synchrotron radiation (popularly known as synchrotron cooling) and is the dominant emission mechanism. These findings which can help explore the binary black hole nature of PG 1553+113 can facilitate understanding the process of galaxy mergers in the early universe,” the DST said.
It added that the analysis also provides interesting targets for observation of multi-messengers like light, neutrinos, and gravity waves which help us in studying the cosmos.
Researchers from RRI, along with collaborators from all over the world, captured this flare using the 1.3m JC Bhattacharya telescope (JCBT), Kavalur, India. The astronomers then studied for 76 nights at a stretch the said blazar using nine different telescopes around the globe.
A blazar is an active galactic nucleus (AGN) — that is a compact region at the center of a galaxy. A flare in a blazar is a sudden flash of brightness, just as we know of solar flares.
The PG 1553+113, which is a primary candidate for a binary supermassive black hole system, has lately intrigued scientists because of its repetitive gamma-ray emissions which are quasi-periodic, the astronomers said.
RRI is an autonomous institute of the Department of Science and Technology (DST). The DST, while pointing out that galaxies merge frequently throughout cosmic times, said that whenever two galaxies harbour a supermassive blackhole (SMBH) at their centers, the formation of a binary SMBH is inevitable.
“SMBHs, cannot be spatially spotted with current techniques. Therefore, to search for them, scientists have to rely on indirect methods. One of these indirect search strategies is based on the detection of periodicity in the source. A few recent candidates displaying quasi-periodic light curve variability have emerged from large-sky surveys and long-term monitoring programmes. The PG 1553+113 is one of them which enters an outburst and produces very high energy emission,” the DST said.
The research has been published in the journal ‘Astronomy and Astrophysics’. The astronomers said in the paper: “We analysed the light curves using various statistical tests, fitting and cross-correlation techniques, and methods for the search for periodicity. We examined the colour-magnitude diagrams before and after the corresponding light curves were corrected for the long-term variations.”
The researchers studied the multiband flux and spectral variability of the blazar on diverse timescales, the DST said, and added that they estimated the periodicity, radius, size of the emission region, the magnetic field strength, and the electron energy for the blazar.
“Besides, having recorded the flare, they have found that the accelerated particles cool off by synchrotron radiation (popularly known as synchrotron cooling) and is the dominant emission mechanism. These findings which can help explore the binary black hole nature of PG 1553+113 can facilitate understanding the process of galaxy mergers in the early universe,” the DST said.
It added that the analysis also provides interesting targets for observation of multi-messengers like light, neutrinos, and gravity waves which help us in studying the cosmos.
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