AI 中文总结
本文研究钱德拉X射线天文台ACIS污染层2010-2026年的演化，用最新校准观测评估当前污染模型性能，确认其可充分预测截至2026年中期的额外吸收。
AI 中文摘要
钱德拉X射线天文台（CXO）已发射超过27年，在任务期间取得了出色的科学成果。高级CCD成像光谱仪（ACIS）是该卫星的主要仪器，承担了超过90%的观测任务。这些CCD工作在-120℃的温度下，而位于CCD前方的光学阻挡滤光片（OBF）温度约为-60℃。由于OBF是航天器内部暴露于外部的最冷表面，在任务期间其表面积累了一层污染。我们一直在表征污染层的厚度、化学成分和空间分布随任务时间的变化。随着污染层特性的变化和我们对其理解的加深，污染模型在任务期间已多次修订。在本文中，我们使用2023年至2026年开展的最新校准观测，评估当前污染模型（2025年12月16日发布于CalDB 4.12.3的N0016）的性能，所用数据包括国际高能天文学联合会（IACHEC）开发的超新星遗迹1E 0102.2-7219（E0102）的标准模型光谱、星系团Abell 1795的光谱数据以及Mrk 421的高分辨率X射线光谱。由于低能段观测计数减少，该评估变得复杂，尤其是E0102的O VII Heα线系和O VIII Lyα线已不再适用于此目的。对E0102、Abell 1795和Mrk 421数据的分析表明，当前的污染模型能够充分预测截至2026年中期的额外吸收情况。
英文摘要
The Chandra X-ray Observatory (CXO) was launched over 27 years ago and has been delivering spectacular science over the course of its mission. The Advanced CCD Imaging Spectrometer (ACIS) is the prime instrument on the satellite, conducting over 90% of the observations. The CCDs operate at a temperature of $-$120$^\circ$C and the optical blocking filter (OBF) in front of the CCDs is at a temperature of approximately $-$60$^\circ$C. The surface of the OBF has accumulated a layer of contamination over the course of the mission, as it is the coldest surface exposed to the interior to the spacecraft. We have been characterizing the thickness, chemical composition, and spatial distribution of the contamination layer as a function of time over the mission. The contamination model has required several revisions over the course of the mission as the properties of the contamination layer have changed and our understanding of the layer has improved. In this paper, we evaluate the performance of the current contamination model (N0016 released in CalDB 4.12.3 on 16 December 2025) using the most recent calibration observations conducted from 2023 to 2026 by using the standard model spectrum for the supernova remnant 1E 0102.2-7219 (E0102) developed by the International Astronomical Consortium for High Energy (IACHEC), spectral data from the cluster of galaxies known as Abell 1795, and high resolution X-ray spectra of Mrk 421. This evaluation has been complicated by the decreasing observed counts at low energies, especially the O VII He$α$ line complex and the O VIII Ly$α$ line from E0102 which are no longer useful for this purpose. The analyses of the E0102, Abell 1795, and Mrk 421 data show that the current model of the contamination adequately predicts the additional absorption through mid-2026.
Comments17 pages, 15 figures, proceeding of SPIE Astronomical Telescopes + Instrumentation 2026 (Paper No. 14146-298)
