An X-ray spectroscopic search for dark matter and unidentified line signatures in the Perseus cluster with Hitomi
An X-ray spectroscopic search for dark matter and unidentified line signatures in the Perseus cluster with Hitomi
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DOI：
10.1093/pasj/psz023
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发表时间：
2018-11
影响因子：
2.3
通讯作者：
T. Tamura;A. Fabian;P. Gandhi;L. Gu;Ayuki Kamada;T. Kitayama;M. Loewenstein;Y. Maeda;K. Matsushita;D. McCammon;K. Mitsuda;S. Nakashima;S. Porter;C. Pinto;Kosuke Sato;F. Tombesi;N. Yamasaki
中科院分区：
文献类型：
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作者：
T. Tamura;A. Fabian;P. Gandhi;L. Gu;Ayuki Kamada;T. Kitayama;M. Loewenstein;Y. Maeda;K. Matsushita;D. McCammon;K. Mitsuda;S. Nakashima;S. Porter;C. Pinto;Kosuke Sato;F. Tombesi;N. Yamasaki
我们展示了从英仙座星团核心区域观测中提取的 2-12keV 能带光谱中寻找未识别的线发射和吸收信号的结果，该观测是使用 5eV 能量分辨率 Hitomi 软 X 射线光谱仪获得的。没有发现明显的未识别线发射或吸收。线通量上限（每个分辨率元素 1 西格玛）随光子能量和假设的固有宽度而变化，从 2keV 时的 100 个光子 cm$^{-2}$ s$^{-1}$ sr $^{-1}$ 减少到高斯 5-10 keV 能量范围内的 $<10$ cm$^{-2}$ s$^{-1}$ sr $^{-1}$与 640 km/s 的多普勒展宽一致。较窄和较宽线的极限具有类似的能量依赖性，并且分别系统地更小和更大。这些线通量限制用于约束假设的暗物质候选者的衰变率。对于惰性中微子衰变率，获得了 4-24 keV 质量范围的新约束，其质量分辨率优于以前的任何 X 射线分析。此外，还评估了相关热谱模型和原子数据的准确性。英仙座星团光谱可以通过多温度热和 AGN 幂律连续体的复合来描述。叠加在这些信号上，一些可能源自未建模原子过程（包括 Si XIV 和 Fe XXV）的线发射信号被少量检测到并制成表格。讨论了与以前的 X 射线上限的比较以及使用高能分辨率光谱搜索暗物质的未来前景。
We present results of a search for unidentified line emission and absorption signals in the 2-12keV energy band of spectra extracted from Perseus Cluster core region observations obtained with the 5eV energy resolution Hitomi Soft X-ray Spectrometer. No significant unidentified line emission or absorption is found. Line flux upper limits (1 sigma per resolution element) vary with photon energy and assumed intrinsic width, decreasing from 100 photons cm$^{-2}$ s$^{-1}$ sr $^{-1}$ at 2keV to $<10$ cm$^{-2}$ s$^{-1}$ sr $^{-1}$ over most of the 5-10 keV energy range for a Gaussian line with Doppler broadening of 640 km/s. Limits for narrower and broader lines have a similar energy dependence and are systematically smaller and larger, respectively. These line flux limits are used to constrain the decay rate of hypothetical dark matter candidates. For the sterile neutrino decay rate, new constraints over the the mass range of 4-24 keV with mass resolution better than any previous X-ray analysis are obtained. Additionally, the accuracy of relevant thermal spectral models and atomic data are evaluated. The Perseus cluster spectra may be described by a composite of multi-temperature thermal and AGN power-law continua. Superposed on these, a few line emission signals possibly originating from unmodeled atomic processes (including Si XIV and Fe XXV) are marginally detected and tabulated. Comparisons with previous X-ray upper limits and future prospects for dark matter searches using high-energy resolution spectroscopy are discussed.