利用阴影高度去除地冕Hα的方法
Method on Using Shadow Altitude to Remove Geocoronal H$α$
AI总结：
本文提出利用阴影高度去除地冕Hα发射的方法，通过建立经验关系提高银河系Hα观测的可靠性。
摘要：
光谱巡天允许对星系进行空间分辨光谱学研究，以研究其星际介质（ISM）。然而，银河系Hα发射的观测受到地冕Hα发射的污染。后者已知依赖于阴影高度，这是一个与视线到地球阴影锥的关系的几何参数。利用SDSS-IV/MaStar巡天中的空白天空上的光纤，我们建立了地冕Hα发射与阴影高度之间的经验关系，其均方根分数散射为23.52%。这种关系可用于预测地冕Hα发射，从而从观测光谱中去除。这种去除方法在观测目标在天空中广泛分布时具有优势，并且不需要观测目标与本地标准休息之间有较大的速度分离。这将使在中等光谱分辨率积分场光谱学巡天中可靠地研究银河系Hα成为可能。我们还发现地冕发射对太阳活动和地球与太阳之间距离的依赖性存在初步证据。
英文摘要：
Spectroscopic surveys allow spatially resolved spectroscopy of galaxies to study their interstellar medium (ISM). However, observations of Galactic H$α$ emission are contaminated by geocoronal H$α$ emission. The latter is known to depend on the shadow altitude, a geometric parameter relating the line of sight to Earth's shadow cone. Using fibres on blank skys from the SDSS-IV/MaStar survey, we established an empirical relation between the geocoronal H$α$ emission and the shadow altitude, with a root mean square fractional scatter of 23.52$\%$. This relation can be used to predict geocoronal H$α$ emission so that it can be removed from observed spectra. This removal method is advantageous when the observed targets are extensive in the sky, and it does not require a large velocity separation between the observed target and the local standard of rest. This will enable reliable studies of Galactic H$α$ in intermediate spectral resolution integral field spectroscopic surveys. We also find tentative evidences for the dependences of geocoronal emission on solar activity and the distance between the Earth and the Sun.
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。
