\n<\/p>\n
Using the T\u00dcB\u0130TAK National Observatory, astronomers from Turkey and India have observed a bright blazar known as S5 0716+714. Results of the observational campaign, published July 12 on the pre-print server arXiv<\/i>, yield essential information regarding the optical variability of this blazar.<\/p>\n
Blazars are very compact quasars associated with supermassive black holes (SMBHs) at the centers of active, giant elliptical galaxies. They belong to a larger group of active galaxies that host active galactic nuclei (AGN), and are the most numerous extragalactic gamma-ray sources. Their characteristic features are relativistic jets pointed almost exactly toward the Earth.<\/p>\n
Based on their optical emission properties, astronomers divide blazars into two classes: flat-spectrum radio quasars (FSRQs) that feature prominent and broad optical emission lines, and BL Lacertae objects (BL Lacs), which do not.<\/p>\n
S5 0716+714 is a blazar at a redshift of 0.23, first discovered in 1979 as part of a survey of extragalactic radio sources. It is one of the brightest and most active BL Lacs so far detected.<\/p>\n
S5 0716+714 showcases extreme optical variability, and due to this, it has been the subject of several optical monitoring campaigns. The most recent of them has been conducted by a group of astronomers led by Erg\u00fcn Ege of Istanbul University. For this purpose, they employed T\u00dcB\u0130TAK National Observatory’s T60 and T100 telescopes.<\/p>\n
“We present the results of the observational study of the blazar S5 0716+714 in the optical bands B, V, R, and I between March 2019 and August 2023 to investigate its variability on diverse timescales,” the researchers wrote.<\/p>\n
The observations found that the brightness of S5 0716+714 varied between 12.11 and 14.58 in the optical R-band. Moreover, the long-term light curve shows that the blazar had a variability amplitude of approximately 256.12, 247.08, 247.04, 230.21 percent in the B, V, R, I bands, respectively.<\/p>\n
When it comes to the intraday variability (IDV), the results indicate that S5 0716+714 was significantly variable in the R-band on 12 out of 21 observing nights. On those days, the blazar had a significant IDV with a magnitude change of approximately 0.1 mag and a variability amplitude between 4.41 and 11.23 in the BVRI bands.<\/p>\n
The study found that S5 0716+714 likely has quasi-periods of about 186 and 532 days in the R-band light curve. The astronomers assume that the 186-day quasi-period oscillation (QPO) points to two outbursts of the blazar that may have taken place in May and October 2021.<\/p>\n
Based on the collected data, the authors of the paper were also able to calculate that the size of the emission region in S5 0716+714 is some 67 AU and that the mass of the blazar’s SMBH is at a level of 569 million solar masses.<\/p>\n
More information:<\/strong> \n\t\t\t\t\t\t\t\t\t\t\t\t\tJournal information:<\/strong> \t\t\t\t\t\t\t\t\t\t\t\t\t\t\t
\n\t\t\t\t\t\t\t\t\t\t\t\tErg\u00fcn Ege et al, Investigating Optical Variability of the Blazar S5 0716+714 On Diverse Time-scales, arXiv<\/i> (2024). DOI: 10.48550\/arxiv.2407.09419<\/p>\n
\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tarXiv<\/cite><\/p>\n