The recurring transient outbursts in low-mass X-ray binaries (LMXBs) provide us with strong test-beds for constraining the poorly understood accretion process. While impossible to image directly, phase-resolved spectroscopy can provide a powerful diagnostic to study their highly complex, time-dependent accretion discs. We present an 8-month long multi-wavelength (UV, optical, X-ray) monitoring campaign of the new candidate black hole LMXB MAXI J0637$-$430 throughout its 2019/2020 outburst, using the {\em Neil Gehrels Swift Observatory}, as well as three quasi-simultaneous epochs of Gemini/GMOS optical spectroscopy. We find evidence for the existence of a correlation between the X-ray irradiation heating the accretion disc and the evolution of the He {\sc ii} 4686 \AA emission line profiles detected in the optical spectra. Our results demonstrate a connection between the line emitting regions and physical properties of the X-ray irradiation heating the discs during outburst cycles of LMXBs. Further, we are able to show that changes in the physical properties of the irradiation heating the disc in outburst can be imprinted within the H/He emission line profiles themselves in these systems.

中文翻译：

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使用光谱法绘制低质量 X 射线双星中辐照吸积盘的几何形状和结构：MAXI J0637−430 的试点研究

低质量 X 射线双星 (LMXB) 中反复出现的瞬态爆发为我们提供了强大的测试平台，以限制人们对吸积过程知之甚少。虽然无法直接成像，但相位分辨光谱可以提供强大的诊断方法来研究其高度复杂的、与时间相关的吸积盘。我们使用 {\em Neil Gehrels Swift Observatory} 在整个 2019/2020 年爆发期间对新候选黑洞 LMXB MAXI J0637 进行了为期 8 个月的多波长（紫外线、光学、X 射线）监测活动 - 430 美元，以及 Gemini/GMOS 光谱的三个准同时时期。我们发现了 X 射线辐射加热吸积盘与光谱中检测到的 He {\sc ii} 4686 \AA 发射谱线的演化之间存在相关性的证据。我们的结果证明了线发射区域与 X 射线辐射在 LMXB 爆发循环期间加热圆盘的物理特性之间存在联系。此外，我们能够证明，在这些系统中，加热圆盘的辐射物理特性的变化可以印在 H/He 发射谱线本身中。