A team of astronomers from the Russian Academy of Sciences, utilizing the Spektr-RG (SRG) space observatory, has identified 11 new active galactic nuclei (AGNs) through an investigation of X-ray sources across the sky. This discovery, outlined in a study published in Astronomy Letters (2024), marks a significant expansion in the catalog of these powerful cosmic phenomena. The research, titled “New Active Galactic Nuclei Detected by the ART-XC and eROSITA Telescopes During the First Five SRG All-Sky X-ray Surveys”, sheds light on previously unknown AGNs, deepening our understanding of galaxy centers and their extreme energetic behavior.
This groundbreaking work was made possible by the ART-XC telescope aboard the SRG observatory, which allowed astronomers to identify new sources that had not been classified before. The findings hold potential for advancing our knowledge of galaxy evolution and the role of supermassive black holes.
Seyfert Galaxies: A New Window into AGNs
The newly discovered 11 AGNs are predominantly classified as Seyfert galaxies, a category of active galaxies known for their unique emission characteristics. Out of these, seven were identified as type 1 Seyferts, three as type 1.9, and one as type 2. Seyfert galaxies are often characterized by broad optical emission lines, though their appearances vary depending on their type. Type 1 Seyfert galaxies have broad optical emission lines, while type 2 galaxies display narrower emission lines, offering a glimpse into the complex structure of the universe’s most luminous sources.
The newly detected AGNs are situated relatively close to Earth, with redshifts ranging from 0.028 to 0.258. Their X-ray luminosities span a wide range, from 2 to 300 tredecillion erg/s, which is typical for AGNs at the present epoch. This range is an important factor, as it provides insight into the energy output of these galaxies, which are among the most luminous persistent sources of electromagnetic radiation in the universe.
The Role of Black Holes in AGN Activity
A significant aspect of this study was the calculation of black hole masses for the seven Seyfert galaxies. These mass estimates varied from 4.68 million to 150 million solar masses, offering a glimpse into the scale of the supermassive black holes at the centers of these galaxies. Understanding the mass of black holes is critical to understanding their influence on the surrounding galaxy, as well as the dynamics of AGN behavior.
This data highlights the immense gravitational pull of these black holes, which is believed to power the intense radiation output of AGNs. The larger the mass of the black hole, the more gravitational energy it can extract from surrounding material, fueling the active galactic nucleus. The researchers’ findings underscore the diverse range of black hole sizes and their associated AGN activity.
The Power of the SRG/ART-XC Telescope
The ART-XC telescope on the Spektr-RG observatory played a central role in the discovery of these 11 new AGNs. This cutting-edge X-ray telescope is designed to capture high-resolution X-ray data from across the sky, revealing sources that were previously unidentified. The importance of the SRG mission cannot be overstated, as it provides astronomers with an unprecedented view of the X-ray universe, enabling them to uncover cosmic phenomena like AGNs that are often hidden from optical telescopes.
“In this paper we present the results of our optical identification and classification of another 11 AGNs from the ARTSS1-5 catalog,” the researchers wrote, detailing their methods for classifying these newfound AGNs. The study has significantly expanded the list of AGNs cataloged by the SRG observatory, providing valuable data for future studies of these energetic cosmic objects.
What’s Next for AGN Research?
Despite these exciting discoveries, the team of astronomers has much more work ahead. The researchers plan to conduct more detailed X-ray observations of specific AGNs to better understand their physical properties. In particular, they are focused on the AGN SRGA J000132.9+240237, which exhibited a distinctive spectrum that suggests strong absorption and significant radiation reflection from the galaxy’s dusty torus.
“We are planning to take a higher-quality X-ray spectrum of this source in the pointing mode with the SRG/ART-XC telescope to study in detail its physical properties,” the scientists wrote. This focused approach will likely yield crucial insights into the behavior and composition of these extreme cosmic objects, and will continue to expand our understanding of the role of supermassive black holes in AGN activity.
