Active Galactic Nuclei
Recent investigations by astronomers from the Russian Academy of Sciences using the Spektr-RG (SRG) space observatory have led to the identification of 11 new active galactic nuclei (AGNs). AGNs are regions at the centre of galaxies that emit immense amounts of light and energy, often due to black holes or intense star formation.
About Active Galactic Nuclei (AGNs)
AGNs are among the most luminous sources of electromagnetic radiation in the universe. They are characterised by their brightness and energy, which surpass that of the surrounding galaxy. The light emitted by AGNs comes from dust and gas swirling around a supermassive black hole or intense star formation. Their study provides vital information about galaxy evolution and the behaviour of matter in extreme conditions.
The Role of Seyfert Galaxies
The newly identified AGNs are classified as Seyfert galaxies. Seyfert galaxies are a type of AGN that appear similar to regular galaxies in visible light but emit infrared radiation. They are divided into two main types – Type 1 Seyfert galaxies have broad optical emission lines, while Type 2 Seyfert galaxies exhibit narrower lines. The identification of these AGNs contributes to the understanding of galaxy types and their characteristics.
Findings from the SRG Observations
The research team used the ART-XC telescope to explore both new and previously known X-ray sources. They reported discovering over 50 AGNs, with the latest findings comprising 11 new AGNs. The redshifts of these newly identified AGNs range from 0.028 to 0.258, indicating they are relatively nearby in cosmic terms. Their X-ray luminosities vary from 2 to 300 tredecillion erg/s, typical for AGNs.
Black Hole Masses and Characteristics
The study also calculated the masses of black holes in seven of the Seyfert galaxies. These masses ranged from 4.68 to 150 million solar masses. This measurement is crucial for understanding the relationship between black hole mass and the properties of host galaxies. The spectrum of one AGN, SRGA J000132.9+240237, suggested strong absorption and radiation reflection from the galaxy’s dusty torus, necessitating further observation.
Future Research Directions
The researchers noted the need for longer X-ray observations to better understand the physical properties of the new AGNs. They plan to conduct higher-quality X-ray spectral studies using the SRG/ART-XC telescope. This continued research aims to deepen our knowledge of AGNs and their role in the universe.
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