Low-mass stars dominate the hot (0.7 keV) Galactic X-ray emission
Osservatorio Astronomico di Brera, (INAF)（布雷拉天文台（意大利国家天体物理研究所））；Max-Planck-Institut für extraterrestrische Physik（马克斯·普朗克地外物理学研究所）；Como Lake Center for Astrophysics (CLAP), DiSAT, Università degli Studi dell’Insubria（因苏布里亚大学DiSAT系科莫湖天体物理学中心）；Institut für Astronomie & Astrophysik, Eberhard Karls Universität Tübingen（蒂宾根大学天文与天体物理研究所）；Dr. Karl Remeis Observatory, Erlangen（埃尔朗根卡尔·雷梅斯观测站）
G. Ponti, M. C. H. Yeung, G. Stel, N. Locatelli, X. Zheng, B. Stelzer, A. Merloni, M. Caramazza, E. Magaudda, M. Sasaki, K. Dennerl, T. H. Reiprich, A. Schwope,… 展开作者
G. Ponti, M. C. H. Yeung, G. Stel, N. Locatelli, X. Zheng, B. Stelzer, A. Merloni, M. Caramazza, E. Magaudda, M. Sasaki, K. Dennerl, T. H. Reiprich, A. Schwope, W. Becker, M. Freyberg
The circumgalactic medium (CGM) of the Milky Way is composed of a tenuous atmosphere filled with multi-phase plasma, including a warm-hot virialised component. Recent studies suggest a much hotter (~0.7 keV) super-virial component detected in both absorption and emission. We want to shed light on the nature of this putative super-virial component. We analysed the X-ray background as observed by SRG/eROSITA over the entire western Galactic hemisphere. We show that low-mass stars provide a large fraction of the 0.7 keV emission. Indeed, a tight correlation is found between the surface brightness of the 0.7 keV emission and the mass distribution of the Milky Way across a large portion of the western Galactic hemisphere. The correlation coefficient implies an X-ray luminosity per unit of stellar mass comparable to that of the average low-mass stars within 10 pc of the Sun, suggesting that unresolved M dwarfs and F, G, and K type stars dominate the 0.7 keV emission. This emission is asymmetric with respect to the Galactic plane, influenced by the asymmetric distribution of nearby star-forming regions, and broadly consistent with the known offset of the Sun above the Galactic midplane. The remaining signal might be produced by the cumulative emission of stars of different types or ages, in addition to other sources (e.g. hot interstellar medium, Galactic corona, etc.). Assuming that the putative residual hot super-virial atmosphere is homogeneous and has a spherical beta profile with slope $β=0.4$, we constrain its density at 10 kpc to be $n_e<4\times10^{-4}$~cm$^{-3}$. Our findings may help refine models of the circumgalactic medium around external galaxies, advancing our understanding of hot baryon flows and galaxy evolution.
Global Hot Gas Excess in (U)LIRGs: Replicating Galactic Nuclei Scaling Relations between Diffuse X-ray Emission and Star Formation on Galaxy-Wide Scales
Particle Propagation in the Galactic Center and Spatial Distribution of Non-Thermal X-rays
我们表明，如果在14-40 keV范围内的银河系中心的非热辐射是由于逆韧致辐射的亚相对论质子，它们与热和冷馏分的星际介质的相互作用是同样重要的。我们的估计表明，在14-40 keV的范围内，从GC的总非热通量的约30%是在冷气体区域产生的，而其余的是由质子与热等离子体相互作用产生的。从6.7keV铁谱线的空间分布可以看出，热等离子体的空间分布具有很强的非均匀性，在分析质子在气相色谱中的传输时应考虑到这一点。从朱雀实验数据中我们得到了GC中次相对论质子扩散系数的独立估计值，其范围为$ 10^{26} - 10^{27}$ cm $^2$ s $^{-1}$
Elevated Hot Gas and High-Mass X-ray Binary Emission in Low Metallicity Galaxies: Implications for Nebular Ionization and Intergalactic Medium Heating in the Early Universe
Deep XMM-Newton observation reveals hot gaseous outflow in NGC 5746
Dr. Karl Remeis-Observatory, Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg（弗里德里希·亚历山大大学埃尔朗根天体粒子物理中心卡尔·雷米斯天文台）
Measuring the Temperature of Extremely Hot Shock-Heated Gas in the Major Merger MACS J0717.5+3745 With Relativistic Corrections to the Sunyaev-Zel'dovich Effect
Rochester Institute of Technology（罗切斯特理工学院）；Cornell University（康奈尔大学）；California Institute of Technology（加州理工学院）；University of Lethbridge（莱斯布里奇大学）；Jet Propulsion Laboratory（喷气推进实验室）；Berkeley Center for Cosmological Physics, University of California, Berkeley（加州大学伯克利分校宇宙学物理中心）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）
