We present a detailed analysis of the galaxy and group distributions around three reported X-ray absorption line systems in the spectrum of the quasar H2356-309. Previous studies associated these absorbers with known large-scale galaxy structures (i.e., walls and filaments) along the line of sight. Such absorption lines typically trace 10^{5-7} K gas, and may be evidence of the elusive warm-hot intergalactic medium (WHIM) thought to harbor the bulk of the low-redshift "missing baryons;" alternatively, they may be linked to individual galaxies or groups in the filaments. Here we combine existing galaxy survey data with new, multi-object Magellan spectroscopy to investigate the detailed galaxy distribution near each absorber. All of these three absorption systems are within the projected virial radii of nearby galaxies and/or groups, and could therefore arise in these virialized structures rather than (or in addition to) the WHIM. However, we find no additional galaxies near a fourth "void" absorber recently found in the spectrum, suggesting that this system may indeed trace gas unassociated with any individual halo. Though the number of known systems is still small, spatial coincidences suggest that some X-ray absorbers lie in galaxy and/or group environments, though others could still trace the large-scale filamentary WHIM gas predicted by simulations.
For the first time, we present the simultaneous detection and characterization of three distinct phases at $>10^5$ K in $z=0$ absorption, using deep $\it{Chandra}$ observations toward Mrk 421. The extraordinarily high signal-to-noise ratio ($\geqslant60$) of the spectra has allowed us to detect a $\it{hot}$ phase of the Milky Way circumgalactic medium (CGM) at 3.2$^{+1.5}_{-0.5}\times$ 10$^7$ K, coexisting with a $\textit{warm-hot}$ phase at 1.5$\pm$0.1$\times$10$^6$ K and a $\textit{warm}$ phase at 3.0$\pm$0.4$\times$10$^5$ K. The $\textit{warm-hot}$ phase is at the virial temperature of the …
Using Suzaku data, we had found a $3.4σ$ evidence for the X-ray emitting warm-hot circumgalactic medium (CGM) in the L$^\star$ galaxy NGC 3221. Here we present XMM-Newton data and outline an efficient, rigorous and well-defined method to extract the faint CGM signal. We confirm the CGM detection at $4σ$ significance within 30-200 kpc of the galaxy. We claim with $99.62\%$ confidence that the CGM is extended beyond $150$ kpc. The average temperature of the CGM is 2.0$^{+0.2}_{-0.3} \times 10^6$ K, but it is not isothermal. We find suggestive evidence for a declining temperature gradient out to …
Today, the majority of the cosmic baryons in the Universe are not observed directly, leading to an issue of "missing baryons" at low redshift. Cosmological hydrodynamical simulations have indicated that a significant portion of them will be converted into the so-called Warm-Hot Intergalactic Medium (WHIM), with gas temperature ranging between 10$^5$-10$^7$K. While the cooler phase of this gas has been observed using O VI and Ne VIII absorbers at UV wavelengths, the hotter fraction detection relies mostly on observations of O VII and O VIII at X-ray wavelengths. Here, we target the forbidden li…
Warm absorbers in X-rays (WAX), a comprehensive high resolution grating spectral study of a sample of Seyfert galaxies: I. A global view and frequency of occurrence of warm absorbers
我们提出的结果从均匀分析的宽带0.3-10 keV的CCD分辨率,以及软X射线高分辨率光栅光谱的硬X射线通量有限的样品26塞弗特星系观测XMM-牛顿。我们的目标是沿着活动核的视线来研究热吸收体(WA)的性质。我们在样本源的$65\%$中显著检测到WA。我们的研究结果是一致的WAs存在于至少一半的塞弗特星系在附近的宇宙中,与以前的估计。我们发现在$0.5<\logξ<1.5$的范围内,我们解释为WA云的热不稳定区域的电离参数的分布的差距。这可能表明,暖吸收流可能是由离散云的clusterical分布,而不是一个连续的介质。具有宽的Fe K $α$线的源的WA柱密度的分布类似于那些没有加宽的发射线的源。因此,检测到的宽Fe K $α$发射线是真实的,而不是软X射线中电离吸收的伪影。WA参数显示它们之间没有相关性,除了电离参数与柱密度。$\logξ$与$\log v_{\rm out}$线性回归($0.12\pm 0.03$)的浅斜率与辐射或磁流体动力驱动风预测的标度律不一致。我们的研究结果还表明,WA和超快速外流(UFO)并不代表同一天体物理系统的极端表现。
X-Ray Absorption by the Warm-Hot Intergalactic Medium in the Hercules Supercluster
“失踪重子”,在温暖的热星系际介质(WHIM)的形式,预计将驻留在宇宙的附属结构,可以跟踪的路标,如大规模的星系超级结构。在雕塑者墙中清晰地探测到X射线吸收线,证明了利用星系上层结构作为寻找WHIM的路标的成功。在这里,我们提出了一个XMM-牛顿反射光栅光谱仪(RGS)观测的耀变体MKN 501,位于武仙座超星系团。我们在前景武仙座超星系团的红移处探测到一条O VII K $α$吸收线($2.5σ$),能级为98.7%.所得到的吸收体的性质与WHIM的理论预期是一致的。我们讨论的含义,我们的检测寻找“失踪的重子”。虽然这一检测再次表明,使用路标是一个非常有效的策略来搜索WHIM,后续观察是至关重要的,既要加强检测的统计意义,并排除其他解释。一个本地的,$z\sim0$ O VII K $α$吸收线也清楚地检测到在$4σ$水平,我们讨论了它的影响,我们的理解我们的银河系的热气含量。
The problem of missing baryons in the local universe remains an open question. One propose alternative is that at low redshift missing baryons are in the form of the Warm Hot Intergalactic Medium (WHIM). In order to test this idea, we present a detailed analysis of X-ray high-resolution spectra of six extragalactic sources, Mrk 421, 1ES 1028+511, 1ES 1553+113, H2356-309, PKS 0558-504 and PG 1116+215, obtained with the XMM-Newton Reflection Grating Spectrometer to search for signals of WHIM and/or circumgalactic medium (CGM) X-ray absorbing gas. We fit the X-ray absorption with the IONeq model,…
The current observational status of the hot (log T(K) > 5.5) warm-hot intergalactic medium (WHIM) remains incomplete. While recent observations from stacking large numbers of Cosmic Web filaments have yielded statistically significant detections, direct measurements of single objects remain scarce. The lack of such a sample currently prevents a robust analysis of the cosmic baryon content composed of the hot WHIM, which could help solve the cosmological missing baryons problem. To improve the search for the missing baryons, we used the EAGLE simulation. Our aim is to understand the metal enric…
We used dedicated SRG/eROSITA X-ray, ASKAP/EMU radio, and DECam optical observations of a 15 sq.deg region around the interacting galaxy cluster system A3391/95 to study the warm-hot gas in cluster outskirts and filaments, the surrounding large-scale structure and its formation process. We relate the observations to expectations from cosmological hydrodynamic simulations from the Magneticum suite. We trace the irregular morphology of warm-hot gas of the main clusters from their centers out to well beyond their characteristic radii, $r_{200}$. Between the two main cluster systems, we observe an…