arXiv 2209.016982022-09-04astro-ph.GAastro-ph.HE

朱雀Ⅰ号软X射线背景。Milky Way光环

The soft X-ray background with Suzaku: I. Milky Way halo

Masaki Ueda, Hayato Sugiyama, Shogo B. Kobayashi, Kotaro Fukushima, Noriko Y. Yamasaki, Kosuke Sato, Kyoko Matsushita

备注：: 20 pages, 16 figures, Accepted for publication in PASJ
DOI：: 10.1093/pasj/psac077

摘要：

我们提供了从2005年到2015年在$75^\circ<l < 285^\circ$和$|b|>15^\circ$获得的130个朱雀观测数据的软X射线背景发射测量，覆盖了近一个太阳周期。除了标准的软X射线背景模型组成的本地热泡和银河系晕（MWH），我们包括一个热的碰撞电离平衡组件的温度为$\sim 0.8$ keV重现光谱的一个显着的分数的视线。然后，减少了MWH部件的排放测量与温度之间的关系的分散。在这里，我们排除了具有高计数率的时间范围，以最大限度地减少太阳风电荷交换（SWCX）的影响。然而，几乎相同的视线的光谱是不一致的。日光层SWCX排放可能会污染，并在MWH的温度和排放测量中产生偏差。排除太阳活动极大期附近的数据，并使用2009年底之前在$|b|>35^\circ$和$105^\circ<l<255^\circ$获得的数据，MWH的温度（0.22 keV）和排放测量（$2\times 10^{-3}~\rm{cm^{-6}pc}$）相当一致。在$|b|<35^\circ$，朝向银河系低纬度的发射测量的增加表明存在盘状形态成分。一个复合模型，其中包括盘状和球形形态组件也再现了观测到的排放量分布的MWH。在这种情况下，距离银河系中心几十千秒差距处的流体静力质量与银河系的引力质量一致。具有维里温度的等离子体可能以接近流体静力学平衡的方式填充银河系晕。假设气体的金属丰度为0.3太阳能，则在250 kpc或维里半径范围内，球形组分的气体质量上限为几个$\times 10^{10}~ M_\odot$。

英文摘要：

We present measurements of the soft X-ray background emission for 130 Suzaku observations at $75^\circ<l < 285^\circ$ and $|b|>15^\circ$ obtained from 2005 to 2015, covering nearly one solar cycle. In addition to the standard soft X-ray background model consisting of the local hot bubble and the Milky Way Halo (MWH), we include a hot collisional-ionization-equilibrium component with a temperature of $\sim 0.8$ keV to reproduce spectra of a significant fraction of the lines of sight. Then, the scatter in the relation between the emission measure vs. temperature of the MWH component is reduced. Here, we exclude time ranges with high count rates to minimize the effect of the solar wind charge exchange (SWCX). However, the spectra of almost the same lines of sight are inconsistent. The heliospheric SWCX emissions likely contaminate and gives a bias in measurements of temperature and the emission measure of the MWH. Excluding the data around the solar maximum and using the data taken before the end of 2009, at $|b|>35^\circ$ and $105^\circ<l<255^\circ$, the temperature (0.22 keV) and emission measure ($2\times 10^{-3}~\rm{cm^{-6}pc}$) of the MWH are fairly uniform. The increase of the emission measure toward the lower Galactic latitude at $|b|<35^\circ$ indicates a presence of a disk-like morphology component. A composite model which consists of disk-like and spherical-morphology components also reproduces the observed emission measure distribution of MWH. In this case, the hydrostatic mass at a few tens of kpc from the Galactic center agrees with the gravitational mass of the Milky Way. The plasma with the virial temperature likely fills the Milky Way halo in nearly hydrostatic equilibrium. Assuming the gas metallicity of 0.3 solar, the upper limit of the gas mass of the spherical component out to 250 kpc, or the virial radius, is $\sim$ a few $\times 10^{10}~ M_\odot$.

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。

摘要：

英文摘要：

相关论文