Abstract

We report the results of optical spectroscopy of eight highly variable X-ray sources—AGN candidates from all-sky survey of the eROSITA telescope of the Spectrum-Roentgen-Gamma Space Observatory—performed with the TDS spectrograph (3600–7500 Å, \(R\approx 2000\)) attached to the 2.5-m telescope of the Caucasian Mountain Observatory of Sternberg Astronomical Institute of M.V. Lomonosov Moscow State University. We determined the redshifts of the sources from the emission and absorption lines in their spectra. At least five objects can be classified as Seyfert galaxies. We performed pilot infrared photometry of three distant quasars with \(z>5\) using the ASTRONIRCAM camera and show that on the ‘‘\((z-J){-}(J-W1)\)’’ diagram the distant quasars studied can be confidently distinguished from Galactic red and brown dwarfs. This result proves the possibility of preliminary classification of distant X-ray quasar candidates by their IR colors for further detailed spectroscopic study on large telescopes.

中文翻译：

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SRG/eROSITA 巡天中选定的活动星系核：2021 年和 2022 年使用 SAI MSU 高加索山天文台的 2.5 米望远镜进行的光学和红外观测

摘要

我们报告了八个高度可变的 X 射线源（来自光谱伦琴伽马空间天文台 eROSITA 望远镜的全天巡天候选 AGN）的光谱结果，这些 X 射线源是使用 TDS 摄谱仪（3600-7500 Å，\ （ R\约2000\)）附属于MV罗蒙诺索夫莫斯科国立大学斯滕伯格天文研究所高加索山天文台的2.5米望远镜。我们根据光谱中的发射线和吸收线确定了光源的红移。至少有五个天体可以被归类为塞弗特星系。我们使用 ASTRONIRCAM 相机对三个遥远类星体\(z>5\)进行了试点红外光度测量，并显示在“ \((zJ){-}(J-W1)\) ”图上研究了遥远类星体可以自信地将其与银河系红矮星和褐矮星区分开来。这一结果证明了通过红外颜色对遥远的 X 射线类星体候选者进行初步分类的可能性，以便在大型望远镜上进行进一步详细的光谱研究。