Optical identification of active galactic nucleus candidates detected by the Mikhail Pavlinsky ART-XC telescope aboard the SRG observatory during the all-sky X-ray survey

• Published in: arXiv.org 2021-04
• Main Authors: Zaznobin, I A, Uskov, G S, S Yu Sazonov, Burenin, R A, Medvedev, P S, Khorunzhev, G A, Lyapin, A R, Krivonos, R A, Filippova, E V, Gilfanov, M R, Sunyaev, R A, Eselevich, M V, Bikmaev, I F, Irtuganov, E N, Nikolaeva, E A
• Format: Article
• Language: English
• Subjects: Active galactic nuclei; Deposition; Energy bands; Luminosity; Object recognition; Observatories; Seyfert galaxies; Sky surveys (astronomy); Soft x rays; X ray sources; X-ray astronomy; X-rays; Zidovudine
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2104.09390

We present the results of our identification of eight objects from a preliminary catalogue of X-ray sources detected in the 4-12 keV energy band by the Mikhail Pavlinsky ART-XC telescope aboard the SRG observatory during its first all-sky survey. Three of them (SRGAJ005751.0+210846,SRGAJ014157.0-032915, SRGAJ232446.8+440756) have been discovered by ART-XC, while five were already known previously as X-ray sources, but their nature remained unknown. The last five sources have also been detected in soft X-rays by the eROSITA telescope of the SRG observatory. Our optical observations were carried out at the 1.6-m AZT-33IK telescope of the Sayan Observatory and the 1.5-m Russian-Turkish telescope (RTT-150). All of the investigated objects have turned out to be active galactic nuclei (AGNs) at redshifts from 0.019 to 0.283. Six of them are Seyfert 2 galaxies(including one Seyfert 1.9 galaxy), one (SRGAJ005751.0+210846) is a "hidden" AGN (in an edge-on galaxy), and one (SRGAJ224125.9+760343) is a narrow-line Seyfert 1 galaxy. The latter object is characterized by a high X-ray luminosity (~(2-13)*10^44 erg/s in the 4-12 keV band) and,according to our black hole mass estimate (~2*10^7 M_sun), an accretion rate close to the Eddington limit. All three AGNs discovered by the ART-XC telescope (which are not detected by the eROSITA telescope) are characterized by a high absorption column density (N_H > 3*10^23 cm^-2). The results obtained confirm the expectations that the ART-XC telescope is an efficient instrument for searches of heavily obscured and other interesting AGNs in the nearby (z