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Various independent ways of constraining the Hubble constant and the baryonic content of the universe finally converged at a consensus range of values which indicates that at the present epoch the bulk of the universe's baryons is in the…

Astrophysics · Physics 2007-05-23 Richard Lieu , Massimiliano Bonamente , Jonathan P. D. Mittaz

Since all of the five clusters of galaxies observed by the Extreme Ultraviolet Explorer deep survey telescope are found to possess a diffuse EUV emitting component which is unrelated to the virial gas at X-ray temperatures, the question…

Astrophysics · Physics 2009-10-31 Richard Lieu , Massimiliano Bonamente , Jonathan P. D. Mittaz

Among the models proposed to account for the new component of diffuse EUV and soft X-ray emission from clusters of galaxies (first discovered in Virgo) are two key contestants: the non-thermal scenario which postulates a population of…

Astrophysics · Physics 2007-05-23 Massimiliano Bonamente , Richard Lieu

The discovery of EUV and soft X-ray excess emission in clusters of galaxies (the cluster soft-excess phenomenon) challenged the notion of the hot ($\sim 10^{7-8}$ K) gas as the only dominant thermal component of the intracluster medium…

Astrophysics · Physics 2009-10-31 Max Bonamente , Richard Lieu , Jonathan P. D. Mittaz

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,…

Astrophysics · Physics 2016-11-03 Max Bonamente , Richard Lieu

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…

Observations with the Extreme Ultraviolet Explorer satellite are purported to show extreme ultraviolet (EUV) and soft X-ray excesses in several clusters of galaxies (Bonamente, Lieu & Mittaz 2001). If interpreted as thermal emission, this…

Astrophysics · Physics 2009-11-06 Philip R. Maloney , J. Bland-Hawthorn

The detection of excess of soft X-ray or Extreme Ultraviolet (EUV) radiation, above the thermal contribution from the hot intracluster medium (ICM), has been a controversial subject ever since the initial discovery of this phenomenon. We…

Several authors (S. Bowyer, T. Berghoeffer, and E. Korpela, hereinafter abbreviated as BBK) recently announced that the luminous extended EUV radiation from the clusters Abell 1795 and Abell 2199, which represents the large scale presence…

With tantalizing evidence of the recent e-Rosita mission, re-discovering very soft X-rays and EUV radiation from a cluster of galaxies or its environment, the question of the origin of cluster EUV excess is revisited in this work. It will…

High Energy Astrophysical Phenomena · Physics 2023-05-03 Richard Lieu , Chun-Hui Shi

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…

Astrophysics · Physics 2009-11-07 J. Nevalainen , R. Lieu , M. Bonamente , D. Lumb

An extremely soft X-ray excess throughout galaxy clusters has been claimed as a new feature of these sytems, with important physical implications. We have reexamined this feature in the five clusters for which it has been discussed, using…

Astrophysics · Physics 2009-10-31 John S. Arabadjis , Joel N. Bregman

The observational and theoretical status of the search for missing cosmological baryons is summarized, with a discussion of some indirect methods of detection. The thermal interpretation of the cluster soft X-ray and EUV excess phenomenon…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-11 Richard Lieu , Max Bonamente

The nearby ($z=0.03015$) cluster of galaxies Abell~2199 was observed by Suzaku in X-rays, with five pointings for $\sim 20$ ks each. From the XIS data, the temperature and metal abundance profiles were derived out to $\sim 700$ kpc (0.4…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Madoka Kawaharada , Kazuo Makishima , Takao Kitaguchi , Sho Okuyama , Kazuhiro Nakazawa , Yasushi Fukazawa

The Virgo and A1795 clusters of galaxies were re-observed by EUVE with {\it in situ} background measurements by pointing at small offsets. Earlier, a similar re-observational strategy applied to the cluster A2199 revealed that the…

Astrophysics · Physics 2009-10-31 Max Bonamente , Richard Lieu , Jonathan P. D. Mittaz

The initial results from XMM-Newton observations of the rich cluster of galaxies Abell 1795 are presented. The spatially-resolved X-ray spectra taken by the European Photon Imaging Cameras (EPIC) show a temperature drop at a radius of $\sim…

We report new EUV data on the cluster of galaxies Abell 1795. These data were taken well away from a detector defect which could have compromised earlier results on this cluster. Our new observations confirm the validity of the original…

Astrophysics · Physics 2009-10-31 Stuart Bowyer , Thomas Berghoefer , Eric Korpela

We present a detailed analysis of the thermal X-ray emission from the intracluster medium (ICM) in the cool-core galaxy cluster Abell 2667 ($z=0.23$). Our goal is to detect low-temperature ($<2$ keV) X-ray emitting gas, potentially…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-12 M. Lepore , C. Pinto , P. Tozzi , M. Gaspari , F. Gastaldello , A. Liu , P. Rosati , R. van Weeren , G. Cresci , E. Iani , G. Rodighiero

Using the X-ray data from \ASCA, spectral and spatial properties of the intra-cluster medium (ICM) of the cD cluster Abell 1795 are studied, up to a radial distance of $\sim 12'$ ($\sim 1.3$ $h_{50}^{-1}$ kpc). The ICM temperature and…

Astrophysics · Physics 2009-10-30 H. Xu , K. Makishima , Y. Fukazawa , Y. Ikebe , K. Kikuchi , T. Ohashi , T. Tamura

The EUV excess emission from the clusters A2199 and A1795 remains an unexplained astrophysical phenomenon. There has been many unsuccessful attempts to `trivialize' the findings. In this Letter we present direct evidence to prove that the…

Astrophysics · Physics 2009-10-31 R. Lieu , M. Bonamente , J. P. D. Mittaz , F. Durret , S. Dos Santos , J. Kaastra
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