Related papers: Soft and hard X-ray excess emission in Abell 3112 …
We have used a 50.4 ksec Chandra obsffervation to examine the galaxy cluster Abell 115 (z=0.1971). The X-ray surface brightness distribution shows a merger of 2 sub-clusters with substantial off-axis motion. The northern sub-cluster moves…
We present the results of a Chandra observation of the galaxy cluster Abell 689 (z=0.279). Abell 689 is one of the most luminous clusters detected in the ROSAT All Sky Survey (RASS), but was flagged as possibly including significant point…
We present results based on the systematic analysis of \textit{Chandra} archive data on the X-ray bright Abell Richness class-I type cluster Abell 1991 with an objective to investigate properties of the X-ray cavities hosted by this system.…
After confirmation of the presence of a nonthermal hard X-ray excess with respect to the thermal emission in the Coma cluster from two independent observations, obtained using the Phoswich Detection System onboard BeppoSAX, we present in…
In this paper we report on the analysis of a deep ROSAT HRI image of the moderately-rich cluster, Abell 2634, by which we have been able to detect the X-ray emission from the galaxies in the cluster. The ICM of Abell 2634 is an order of…
We report on the imaging analysis of 200 ks sub-arcsecond resolution Chandra ACIS-S observations of the nearby Seyfert 1 galaxy NGC 4151. Bright, structured soft X-ray emission is observed to extend from 30 pc to 1.3 kpc in the south-west…
The temperature and abundance structure in the intracluster medium (ICM) of the Hydra-A cluster of galaxies is studied with ASCA and ROSAT. The effect of the large extended outskirts in the point-spread function of the X-Ray Telescope on…
The cluster A3627 was recently recognized to be a very massive, nearby cluster in a galaxy survey close to the galactic plane. We are reporting on ROSAT PSPC observations of this object which confirm that the cluster is indeed very massive.…
We study the X-ray emission in a sample of galaxy clusters using the BeppoSAX PDS instrument in the 20 -- 80 keV energy band. The non-thermal hard X-ray cluster emission (HXR) is detected at a 2 sigma level in 50% of the non-significantly…
We report the first X-ray detection of a proto-supermassive binary black hole at the centre of Abell 400. Using the Chandra ACIS, we are able to clearly resolve the two active galactic nuclei in 3C 75, the well known double radio source at…
We report a detailed spectroscopic study of the gas dynamics and hydrostatic mass bias of the galaxy cluster Abell 2029, utilizing high-resolution observations from XRISM Resolve. Abell 2029, known for its cool core and relaxed X-ray…
Galaxy clusters are among the most massive gravitationally bound systems in the Universe and are considered major reservoirs of high-energy cosmic rays, yet no conclusive $\gamma$-ray detection from them has been achieved. This…
As part of the Chandra GTO program we are monitoring and surveying M31 using the HRC and ACIS cameras. These observations have resolved the nuclear X-ray source into five separate sources, one of which is very soft and may (or may not!) be…
The origin of the diffuse extragalactic, high-energy gamma-ray background (EGRB) filling the Universe remains unknown. The spectrum of this extragalactic radiation, as measured by the EGRET on-board CGRO, is well-fit by a power law across…
An anomalous gamma-ray excess emission has been found in Fermi Large Area Telescope data covering the centre of the Galaxy. Several theories have been proposed for this `Galactic Centre Excess'. They include self-annihilation of dark matter…
AIMS: A peculiar morphology of the hot gas was discovered at the center of IC1262 with the ROSAT HRI. Sensitive Chandra and XMM-Newton data were requested to investigate the characteristics of this structure to understand its nature.…
We present the results of a spatially-resolved spectroscopic analysis of the galaxy cluster Abell 496 with the S3 chip on-board the Chandra satellite. We confirm the presence of a central positive temperature gradient consistent with a…
We report the first localization of diffuse, non-thermal, X-ray emission from a nearby galaxy cluster. Using Chandra data, we have isolated a diffuse non-thermal X-ray component with a photon index, Gamma_ X = 2.21 +0.14 -0.15 and a flux of…
We have used a high resolution Chandra observation to examine the core mass distribution of the unusually regular cD cluster Abell 2029. This system is especially well-suited for analysis of its mass distribution under the assumption of…
Clusters of galaxies are strong emitters of EUV and soft X-rays substantially in excess of the contribution from the hot intra-cluster medium at X-ray temperatures. After the initial discovery of EUV excess emission in the Virgo cluster,…