相关论文: Nonthermal hard X-ray excess in the cluster Abell …
We report the hard X-ray spectrum of the Coma cluster obtained using the PDS data of two independent BeppoSAX observations performed with a time interval of about three years. In both the spectra a non thermal excess with respect to the…
The detection of a nonthermal excess in the Coma cluster spectrum by two BeppoSAX observations analyzed with the XAS package (Fusco-Femiano et al.) has been disavowed by an analysis (Rossetti & Molendi) performed with a different software…
We review all the BeppoSAX results relative to the search for additional nonthermal components in the spectra of clusters of galaxies. In particular, our MECS data analysis of A2199 does not confirm the presence of the nonthermal excess…
After the positive detection by BeppoSAX of hard X-ray radiation up to ~80 keV in the Coma cluster spectrum, we present evidence for nonthermal emission from A2256 in excess of thermal emission at a 4.6sigma confidence level. In addition to…
We report the results of a long BeppoSAX observation of Abell 3667, one of the most spectacular galaxy cluster in the southern sky. A clear detection of hard X-ray radiation up to ~ 35 keV is reported, while a hard excess above the thermal…
The Supermodel provides an accurate description of the thermal contribution by the hot intracluster plasma which is crucial for the analysis of the hard excess. In this paper the thermal emissivity in the Coma cluster is derived starting…
Clusters of galaxies are among the best candidates for particle acceleration sources in the universe, a signature of which is non-thermal hard X-ray emission from the accelerated relativistic particles. We present early results on Suzaku…
We present a long BeppoSAX observation of Abell 754 that reports a nonthermal excess with respect to the thermal emission at energies greater than ~45 keV. A VLA radio observation at 1.4 GHz definitely confirms the existence of diffuse…
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 detection of both soft and hard excess X-ray emission in the cluster of galaxies A 2199, based upon spatially resolved spectroscopy with data from the BeppoSAX, EUVE and ROSAT missions. The excess emission is visible at radii…
We present results from a BeppoSAX observation of the rich cluster Abell 3266. The broad band spectrum (2-50 keV) of the cluster, when fitted with an optically thin thermal emission model, yields a temperature of 8.1 +/- 0.2 keV and a metal…
We present results on the spectroscopic analysis of XMM-Newton EPIC data of the central 0.5/h_50 Mpc regions of the clusters of galaxies Coma, A1795 and A3112. The temperature of the hot intracluster gas as determined by modeling the 2 - 7…
We report X-ray observations of two galaxy clusters Abell 1555 and Abell 1558 with Suzaku, which are included in a large scale filamentary structure and a supercluster, to search for non-thermal emission driven by shocks produced in…
We present the results of our study of the X-ray emission from the Ophiuchus galaxy cluster based on INTEGRAL/IBIS data in the energy range 20-120 keV. Our goal is the search for a nonthermal emission component from the cluster. Using the…
We present results from a spatially resolved spectral analysis of the merging cluster Abell 2256. The long integration time (135 ks) and the good spatial resolution of the MECS onboard BeppoSAX allow us to derive a new and substantially…
Hard X-ray radiation has been detected for the first time in the Coma cluster by BeppoSAX. Thanks to the unprecedented sensitivity of the Phoswich Detection System (PDS) instrument, the source has been detected up to ~80 keV. There is clear…
We present an analysis of BeppoSAX observations of the IC1262 galaxy cluster and report the first temperature and abundance measurements, along with preliminary indications of diffuse, nonthermal emission. By fitting a 6' (~360 h_50^-1 kpc)…
We report the observation of the Intra-Cluster Medium (ICM) of Abell 85 by the X-ray satellite BeppoSAX. We have both analysed the spectrum obtained in the central 8 arcmin circular region centred on the Very Steep Spectrum Radio Source…
We present results of X-ray observations of the Coma cluster with multiple instruments over a broad energy band. Using the data from INTEGRAL, RXTE and ROSAT observatories, we find that the Coma spectrum in the 0.5-107 keV energy band can…
We present an analysis of the hard X-ray emission from the central region of Abell 3667 using deep NuSTAR observations. While previous studies on the nature of the hard X-ray excess have been controversial, our analysis of the central…