Related papers: Evidence for an X-ray Emitting Galactic Bulge: Sha…
A mosaic of 5 \ros~PSPC pointed observations in the Galactic plane ($l\sim25^{\circ}$) reveals X-ray shadows in the $0.5-2.0$ keV band cast by distant molecular clouds. The observed on-cloud and off-cloud X-ray fluxes indicate that…
The diffuse X-ray background (DXB) emission near the Galactic plane ($l,b \sim 25.6^{\circ},0.78^{\circ}$) has been observed with $ASCA$. The observed region is toward a Galactic molecular cloud which was recently reported to cast a deep…
Cosmological simulations predict that a large fraction of the baryonic mass of the Universe exists as 10^5-10^7 K diffuse, X-ray emitting gas, tracing low density filament and sheet-like structures exterior to massive clusters of galaxies.…
(Abridged) The inner couple hundred pcs of our Galaxy is characterized by significant amount of synchrotron-emitting gas, which appears to co-exist with a large reservoir of molecular gas. The spatial correlation between fluorescent Fe…
We investigate the X-ray emission from the Galactic Centre (GC) region, focusing on the 6.4 keV fluorescent line of neutral or weakly ionised iron, which is commonly attributed to X-ray reflection from dense molecular clouds. Our goal is to…
We searched for X-ray shadowing toward two infrared dark clouds (IRDCs) using the MOS detectors on XMM-Newton to learn about the Galactic distribution of X-ray emitting plasma. IRDCs make ideal X-ray shadowing targets of 3/4 kev photons due…
The origin of the X-ray emission from the central region of the Galaxy has remained a mystery, despite extensive study over the past two decades. A fundamental question is the relative contribution of the point-source and diffuse components…
The galactic diffuse $\gamma$-ray emission, as seen by Fermi Large Area Telescope (LAT), shows a sharp peak in the region around 4 kpc from the Galactic center, which can be interpreted either as due to an enhanced density of cosmic-ray…
We use Chandra deep observations of the Galactic Center (GC) region to improve the constraints on the unresolved fraction of the Galactic X-ray background (also known as the Galactic ridge X-ray emission). We emphasize the importance of…
The Galactic center region near l$\approx0.2^0$ hosts a mixture of nonthermal linear filaments and thermal radio continuum features associated with the radio Arc. Chandra observations of this region reveal an X-ray filament and diffuse…
The Nuclear Stellar Disk (NSD), together with the Nuclear Stellar Cluster and the supermassive black hole Sgr A*, forms the central region of the Milky Way. Galactic X-ray background emission is known to be associated with the old stellar…
ROSAT observations indicate that approximately half of all nearby groups of galaxies contain spatially extended X-ray emission. The radial extent of the X-ray emission is typically 50-500 kpc or approximately 10-50% of the virial radius of…
Based on new and archival Chandra observations of the Sombrero galaxy (M 104), we study the diffuse X-ray emission in and around its massive stellar bulge. The 2-6 keV unresolved emission from the bulge region closely follows the K-band…
It is believed that the observed diffuse gamma ray emission from the galactic plane is the result of interactions between cosmic rays and the interstellar gas. Such emission can be amplified if cosmic rays penetrate into dense molecular…
We present a method to derive positions of molecular clouds along the lines of sight from a quantitative comparison between 2.6 mm CO emission lines and 18 cm OH absorption lines, and apply it to the central kiloparsecs of the Milky Way.…
The intensity of the soft X-Ray background is correlated with the distribution of galaxies. To demonstrate this, magnitude limited galaxy samples extracted from bright galaxy catalogues and the Lick counts are utilized. Significant…
Similarly to the larger Galactic ridge, the Galactic center region presents a hard diffuse emission whose origin has been strongly debated for the past two decades: does this emission result from the contribution of numerous, yet…
Archival Chandra observations are used to study the X-ray emission associated with star formation in the central region of the nearby SAB(s)cd galaxy NGC 2403. The distribution of X-ray emission is compared to the morphology visible at…
We use ROSAT PSPC data to study the X-ray properties of a sample of twelve poor groups that have extensive membership information (Zabludoff and Mulchaey 1997; Paper I). Diffuse X-ray emission is detected in nine of these groups. In all but…
The soft X-ray background shows a general enhancement toward the inner region of the Galaxy. But whether this enhancement is a local feature (e.g., a superbubble within a distance of <= 200 pc) and/or a phenomenon related to energetic…