X-ray luminosity function of high-mass X-ray binaries: Studying the signatures of different physical processes using detailed binary evolution calculations
X-ray luminosity function of high-mass X-ray binaries: Studying the signatures of different physical processes using detailed binary evolution calculations
复制标题
高质量X射线双星的X射线光度函数：使用详细的双星演化计算研究不同物理过程的特征
DOI：
10.1051/0004-6361/202244929
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发表时间：
2023
影响因子：
6.5
通讯作者：
Andrews, Jeff J.
中科院分区：
文献类型：
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作者：
Misra, Devina;Kovlakas, Konstantinos;Fragos, Tassos;Lazzarini, Margaret;Bavera, Simone S.;Lehmer, Bret D.;Zezas, Andreas;Zapartas, Emmanouil;Xing, Zepei;Andrews, Jeff J.
背景双星系统演化过程中发生的许多物理过程仍然知之甚少。不断扩大的 X 射线双星 (XRB) 观测样本使它们成为约束双星演化理论的优秀实验室。通过研究各种物理假设对合成 X 射线光度函数 (XLF) 的影响并将其与观测到的 XLF 进行比较，可以获得此类约束和有用的见解。目的在这项工作中，我们重点关注高质量 X 射线双星 (HMXB)，并研究有关物理过程的各种约束不良的假设对 XLF 的影响，例如共同包络相、核心塌陷和风馈吸积。方法我们使用了新的方法双星总体合成代码 POSYDON，采用详细恒星结构和双星演化模型的广泛预计算网格来模拟双星的整个演化。我们生成了 96 个合成 XRB 群，对应于模型假设的不同组合，包括超新星冲击、超新星残余质量、共同包络演化、罗希瓣溢出开始时的环化以及可观测的风馈吸积的不同规定。结果生成的 HMXB XLF 特征丰富，偏离了通常假设的单一幂律。我们发现合成 XLF 在光度 ∼1038erg s−1 处出现断点，与观察到的 XLF 类似。然而，我们还发现 XRB 普遍过多（对于某些模型参数组合，XRB 最多可达 10 倍），这主要是由带有黑洞增殖子的 XRB 驱动的。关于 Be XRB 瞬态行为、不对称超新星爆发和共包络物理的假设可以显着影响我们合成 XLF 的形状和标准化。我们发现，关于罗希瓣溢出开始时轨道圆化的假设以及在吸积风黑洞周围形成 X 射线发射吸积盘的标准，研究较少的假设也可能影响我们的合成 XLF 并减少与观测的差异。结论我们的合成 XLF 并不总是与观测相符，特别是在中间 X 射线光度下，这可能是由于所采用的物理假设的不确定性。虽然某些模型参数会在合成 XLF 的形状上留下明显的印记并且可以减少这种偏差，但其他模型参数总体上没有显着影响。我们的研究揭示了大规模参数研究的重要性，强调了 XRB 在约束二元演化理论中的力量。
ContextMany physical processes taking place during the evolution of binary stellar systems remain poorly understood. The ever-expanding observational sample of X-ray binaries (XRBs) makes them excellent laboratories for constraining binary evolution theory. Such constraints and useful insights can be obtained by studying the effects of various physical assumptions on synthetic X-ray luminosity functions (XLFs) and comparing them with observed XLFs.AimsIn this work we focus on high-mass X-ray binaries (HMXBs) and study the effects on the XLF of various, poorly constrained assumptions regarding physical processes, such as the common-envelope phase, core collapse, and wind-fed accretion.MethodsWe used the new binary population synthesis code POSYDON, which employs extensive precomputed grids of detailed stellar structure and binary evolution models, to simulate the entire evolution of binaries. We generated 96 synthetic XRB populations corresponding to different combinations of model assumptions, including different prescriptions for supernova kicks, supernova remnant masses, common-envelope evolution, circularization at the onset of Roche-lobe overflow, and observable wind-fed accretion.ResultsThe generated HMXB XLFs are feature-rich, deviating from the commonly assumed single power law. We find a break in our synthetic XLF at luminosity ∼1038erg s−1, similar to observed XLFs. However, we also find a general overabundance of XRBs (up to a factor of ∼10 for certain model parameter combinations) driven primarily by XRBs with black hole accretors. Assumptions about the transient behavior of Be XRBs, asymmetric supernova kicks, and common-envelope physics can significantly affect the shape and normalization of our synthetic XLFs. We find that less well-studied assumptions regarding the circularization of the orbit at the onset of Roche-lobe overflow and criteria for the formation of an X-ray-emitting accretion disk around wind-accreting black holes can also impact our synthetic XLFs and reduce the discrepancy with observations.ConclusionsOur synthetic XLFs do not always agree well with observations, especially at intermediate X-ray luminosities, which is likely due to uncertainties in the adopted physical assumptions. While some model parameters leave distinct imprints on the shape of the synthetic XLFs and can reduce this deviation, others do not have a significant effect overall. Our study reveals the importance of large-scale parameter studies, highlighting the power of XRBs in constraining binary evolution theory.