AI 中文总结
本研究利用随机森林分类器从 eRASS1 中筛选并确认 156 个激变变星，明确其特性与演化相关问题，新方法优于传统手段，成果助力银道面 X 射线辐射等研究。
AI 中文摘要
研究目的：我们旨在从 SRG/eROSITA 巡天中选取大量激变变星（CV）样本，以解决关于双星演化、磁场在 CV 演化中的作用以及它们对银道面 X 射线辐射（GRXE）的贡献等基础问题。研究方法：我们基于 X 射线和光学的组合特性训练了随机森林（RF）分类器，从第一期 eROSITA 全天 X 射线巡天（eRASS1）中选取 CV 候选体；对部分候选体使用南北半球的望远镜进行后续光谱观测以确认天体身份；还通过专门的后续测光、光谱及档案资源对新确认的 CV 进行分析，确定其可能的子类型。研究结果：我们确认了 156 个几乎涵盖所有子类型的 CV，它们的距离范围为 170 秒差距至数千秒差距，绝对星等 G=4.5-12，X 射线光度 log LX（0.2-2.3 keV）=29.6-33.3 erg/s；其中大多数 CV 的身份为首次报道，40 个天体被确定了可能的轨道周期，范围从 CV 最短周期 79.2 分钟到近 22 小时；发现 7 个食双星系统，由于目前缺乏专门的后续观测，这是实际数量的下限；另有 5 个天体显示出回旋或塞曼特征，可用于确定其磁场强度；14 个 CV 中发现了软 X 射线成分，均被认为是磁型 CV；该样本包含 X 射线明亮的天体，是新中间偏振星（Intermediate Polars）的极佳候选体，这类天体被认为是 GRXE 的主要贡献者；研究发现，从 eRASS1 中选取 CV 的新方法优于文献中描述的其他方法。
英文摘要
(abridged) Aims. We aim to generate large samples of CVs selected from the SRG/eROSITA surveys to address fundamental questions about binary evolution, the role of magnetic fields in CV evolution and their contribution to the Galactic Ridge X-ray Emission (GRXE). Methods. We have trained a Random Forest (RF) classifier based on combined X-ray and optical properties to select CV candidates from the first eROSITA X-ray all-sky survey (eRASS1). Follow-up spectroscopy to securly identify the objects was performed on a subset of the selected candidates using telescopes at the Northern and the Southern hemisphere. Newly identified CVs were further analyzed to determine their likely subtype with the help of dedicated follow-up photometry, spectroscopy and archival resources. Results. We have identified 156 CVs of almost all subtypes covering a wide range of distances (between 170 pc and several kpc), absolute magnitudes (G= 4.5-12) and X-ray luminosities (log LX (0.2-2.3 keV)= 29.6-33.3 erg/s). For most objects, the nature as a CV is reported here for the first time. For 40 objects periods were determined, which were regarded as their likely orbital periods. These range from 79.2 min, at the CV minimum period, to almost 22 hours. Seven objects were found to be eclipsing, a lower limit to the actual number due to the current lack of dedicated follow-up observations. A further five objects show cyclotron or Zeeman features, that allowed to determine their field strengths. A soft component was found in 14 CVs, all were regarded being magnetic. The sample comprises X-ray luminous objects, excellent candidates for being new Intermediate Polars, that are thought to be main contributors to the GRXE. The new method of selecting CVs from eRASS1 was found to be superior to other methods described in the literature ...
CommentsAccepted for publication in A&A
