论文标题
高质量X射线二进制光度函数的金属依赖性
The Metallicity Dependence of the High-Mass X-ray Binary Luminosity Function
论文作者
论文摘要
我们对高质量X射线二进制（HMXB）X射线光度函数（XLF）的金属性依赖性（XLF）提出了详细的约束。我们分析了〜5 ms的Chandra数据，以d <30 mpc的55个积极形成的星系，具有12 + log（O/H）= 7-9.2的气相金属度。在银河足迹中，我们的样本总共包含1311 X射线点源，其中约49％的预计为HMXB，其余来源可能是低质量X射线二进制文件（LMXBS; 〜22％）和无关的背景来源（约29％）。我们构建了一个模型，该模型成功地表征了整个金属性范围内平均HMXB XLF。我们证明，SFR标准化的HMXB XLF显示出具有金属性的清晰趋势，并稳步增加了数量的发光和超X射线源（Logl（ERG/S）= 38-40.5），金属性下降。但是，我们发现低亮度（logl（erg/s）= 36-38）HMXB XLF似乎显示出几乎恒定的SFR缩放率和具有金属性的斜率。我们的模型提供了整合的LX/SFR与12 + log（O/H）的修订缩放关系，并提供了其SFR依赖性随机散布的新表征。这种关系的总体趋势与基于综合星系发射的过去研究广泛一致。但是，我们的模型表明，这种关系主要是由HMXB XLF的高光度端驱动的。我们的结果对二进制种群合成模型，超级埃德丁顿物体的性质（例如，超X射线源）的性质，最近识别矮人星系中活跃的银河核候选物以及X射线辐射场的最新努力，在Z> 10> 10> 10> 10的宇宙供热期间的X射线辐射场。
We present detailed constraints on the metallicity dependence of the high mass X-ray binary (HMXB) X-ray luminosity function (XLF). We analyze ~5 Ms of Chandra data for 55 actively star-forming galaxies at D < 30 Mpc with gas-phase metallicities spanning 12 + log(O/H) = 7-9.2. Within the galactic footprints, our sample contains a total of 1311 X-ray point sources, of which ~49% are expected to be HMXBs, with the remaining sources likely to be low-mass X-ray binaries (LMXBs; ~22%) and unrelated background sources (~29%). We construct a model that successfully characterizes the average HMXB XLF over the full metallicity range. We demonstrate that the SFR-normalized HMXB XLF shows clear trends with metallicity, with steadily increasing numbers of luminous and ultraluminous X-ray sources (logL(erg/s) = 38-40.5) with declining metallicity. However, we find that the low-luminosity (logL(erg/s) = 36-38) HMXB XLF appears to show a nearly constant SFR scaling and slope with metallicity. Our model provides a revised scaling relation of integrated LX/SFR versus 12 + log(O/H) and a new characterization of its the SFR-dependent stochastic scatter. The general trend of this relation is broadly consistent with past studies based on integrated galaxy emission; however, our model suggests that this relation is driven primarily by the high-luminosity end of the HMXB XLF. Our results have implications for binary population synthesis models, the nature of super-Eddington accreting objects (e.g., ultraluminous X-ray sources), recent efforts to identify active galactic nucleus candidates in dwarf galaxies, and the X-ray radiation fields in the early Universe during the epoch of cosmic heating at z > 10.
