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We present Chandra observations of the galaxy cluster AC114, which shows a strongly irregular morphology, with signs of multiple merging activity. We report the discovery of a soft X-ray filament originating close to the core of the cluster. We confirm that X-ray emission is associated with two of three mass concentrations identified in previous gravitational lensing studies of this object. These two mass concentrations are located at opposite ends of the soft filament, evidence for interaction between them. In the northern part, the cluster shows two sharp discontinuities, both in surface brightness and in temperature, evincing another, more recent merger event which took place in, or close, to the cluster core. In spite of the merger activity, a combined mass and lensing analysis shows remarkably good agreement between lensing and X-ray masses. We therefore advocate for the robustness of the X-ray mass estimates, and conclude that the assumption of hydrostatic equilibrium can yield accurate mass estimates even in clusters as dynamically active as AC 114, once the gas density distribution is properly mapped.
We have analyzed the Chandra, BeppoSax, and ROSAT observations of Abell 754 and report evidence of a soft, diffuse X-ray component. The emission is peaked in the cluster center and is detected out to 8 from the X-ray center. Fitting a thermal model t
We analyze the first X-ray observations with XMM-Newton of RXS J070407.9+262501 and 1RXS 180340.0+401214, in order to characterize their broad-band temporal and spectral properties, also in the UV/optical domain, and to confirm them as Intermediate P
Galaxy clusters grow primarily through the continuous accretion of group-scale haloes. Group galaxies experience preprocessing during their journey into clusters. A star-bursting compact group, the Blue Infalling Group (BIG), is plunging into the nea
We present here a combined analysis of four high spectral resolution observations of the Diffuse X-ray Background (DXRB), made using the University of Wisconsin-Madison/Goddard Space Flight Center X-ray Quantum Calorimeter (XQC) sounding rocket paylo
Transition-edge sensors (TESs) are used as very sensitive thermometers in microcalorimeters aimed at detection of different wavelengths. In particular, for soft X-ray astrophysics, science goals require very high resolution microcalorimeters which ca