The Indian Astronomical Observatory in Hanle, Ladakh, has collaborated with ten other global telescopes to examine the brightening of BL Lacertae (BL Lac), a blazar situated approximately 950 million light years from Earth.
A blazar is a type of galaxy that is fueled by a massive black hole and is one of the universe’s brightest and most powerful phenomena. They are known to emit high-energy particles and radiation, such as gamma rays, X-rays, and radio waves.
A team lead by Raman Research Institute postdoctoral fellow Aditi Agarwal has recently analysed the brightening of BL Lac, which was found almost a century ago and has been progressively approaching the maxima. These are compact formations that exhibit sporadic abnormal brightness.
According to the researchers, the difference in their brightness levels might fluctuate and continue for a few hours, days, weeks, or even months. The researchers employed a global network of telescopes to detect electromagnetic emissions observable at radio, microwave, infrared, optical, ultra-violet, X-ray, and gamma wavelengths.
In July 2020, astronomers feared that BL Lac was about to flare up, and 11 telescopes, including the Himalayan Chandra Telescope in Ladakh’s Hanle, were directed at the blazar for 84 days.
“As time passed, it was noticed that the flare became brighter and brighter, indicating that BL Lac was becoming more active.” On August 21, 2020, the brightness of BL Lac reached its maximum for the first time. This was well captured by the Modified Dall-Kirkham telescope in Krak3w, Poland,” said Agarwal, the paper’s principal author.
The observations revealed that the brightness of BL Lac increased from magnitude 14 to 11.8 and the international team of researchers calculated the source’s magnetic field, which was found to range from 7.5 Gauss to 76.3 Gauss during the flare.
According to a statement from the Ministry of Science and Technology, the computations were only possible because of the availability of Terabytes of datasets obtained from the telescope’s batteries.
“These new parameters will serve as the foundation for future multispectral studies of BL Lac,” Agarwal said.
