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arXiv 2202.05809astro-ph.HE
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激变变星的硬X射线光度函数:结合Swift/BAT与Gaia数据

Hard X-ray luminosity functions of cataclysmic variables: Joint Swift/BAT and Gaia data

Institut für Astronomie und Astrophysik, Kepler Center for Astro and Particle Physics, Universität Tübingen(蒂宾根大学天文与天体物理研究所、开普勒天文与粒子物理中心);Kazan (Volga region) Federal University(喀山(伏尔加地区)联邦大学);Space Research Institute, Russian Academy of Sciences(俄罗斯科学院空间研究所)

Valery F. Suleimanov, Victor Doroshenko, Klaus Werner

AI总结:

本研究结合Swift/BAT与Gaia数据,推导激变变星的硬X射线光度函数,证实其存在两个族群,二者对观测到的硬X射线光度贡献几乎相当。

摘要:

激变变星(CVs)是银河系硬X射线辐射天体中数量最多的一类,很可能是银道面延伸硬X射线辐射以及银心区域硬X射线辐射的来源。本研究选取在全天硬X射线Swift/BAT巡天中被探测到、同时也被Gaia探测到(因此拥有可靠距离估计)的激变变星样本,利用这些数据推导样本天体每太阳质量的局部数密度(ρ_M = 1.37^{+0.3}_{-0.16} × 10^{-5} M_⊙^{-1})和每太阳质量的光度密度(ρ_L = 8.95^{+0.15}_{-0.1} × 10^{26} erg·s^{-1}·M_⊙^{-1})的精确估计值。这些数值与银道面积分X射线辐射、核星团光度吻合良好。对微分光度函数dρ_M/d(log₁₀ L_x)和dρ_L/d(log₁₀ L_x)的分析证实,硬X射线辐射激变变星存在两个族群:中间偏振星在光度L > 10^{33} erg·s^{-1}时占主导,而非磁激变变星和偏振星数量多得多,但平均光度更低;因此,这两个族群对观测到的硬X射线光度的贡献几乎相当。

英文摘要:

Cataclysmic variables (CVs) are the most numerous population among the Galactic objects emitting in hard X-rays. Most probably, they are responsible for the extended hard X-ray emission of the Galactic ridge and the central Galactic regions. Here we consider the sample of CVs detected in the all-sky hard X-ray Swift/BAT survey which were also detected by Gaia and thus have reliable distance estimates. Using these data, we derive accurate estimates for local number density per solar mass ($ρ_M = 1.37^{+0.3}_{-0.16} \times 10^{-5} M_\odot^{-1}$) and luminosity density per solar mass ($ρ_L = 8.95^{+0.15}_{-0.1} \times 10^{26} erg\, s^{-1} M_\odot^{-1}$) for objects in the sample. These values appear to be in good agreement with the integrated Galactic ridge X-ray emission and Nuclear Stellar Cluster luminosities. Analysis of the differential luminosity functions $dρ_M/d(\log_{10} L_x)$ and $dρ_L/d(\log_{10} L_x)$ confirms that there are two populations of hard X-ray emitting CVs. Intermediate polars dominate at luminosities $L > 10^{33} erg\, s^{-1}$, whereas non-magnetic CVs and polars are much more numerous but have lower luminosities on average. As a consequence, the contribution of these populations to the observed hard X-ray luminosity is almost equivalent.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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