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Related papers: The GEMS project: X-ray analysis and statistical p…

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X-ray observations of hot, intergalactic gas in galaxy groups provide a useful means of characterizing the global properties of groups. However, X-ray studies of large group samples have typically involved very shallow X-ray exposures or…

Galaxy groups have been under-studied relative to their richer counterparts -- clusters. The Group Evolution Multiwavelength Study (GEMS) aims to redress some the balance. Here we describe the GEMS sample selection and resulting sample of…

We have used the ROSAT PSPC to study the properties of a sample of 24 X-ray bright galaxy groups, representing the largest sample examined in detail to date. Hot plasma models are fitted to the spectral data to derive temperatures, and…

Astrophysics · Physics 2009-10-31 S. F. Helsdon , T. J. Ponman

Here we present an investigation of the properties of 16 nearby galaxy groups and their constituent galaxies. The groups are selected from the Group Evolution Multi-wavelength Study (GEMS) and all have X-ray as well as wide-field neutral…

Astrophysics · Physics 2009-11-11 Sarah Brough , Duncan Forbes , Virginia Kilborn , Warrick Couch

We consider a sample of 22 nearby clusters of galaxies observed with the Medium Energy Concentrator Spectrometer (MECS) on board of BeppoSAX. They cover the range in gas temperature between 3 and 10 keV, with bolometric X-ray luminosity…

Astrophysics · Physics 2009-11-07 S. Ettori , S. De Grandi , S. Molendi

Properties of the hot intracluster and intragroup medium are mostly set by the underlying gravitational potential well, although complex astrophysical processes at play during their buildup may leave a significant imprint. Observational…

We use gas-dynamical simulations of galaxy clusters to compare their X-ray and strong lensing properties. Special emphasis is laid on mass estimates. The cluster masses range between 6 x 10^14 solar masses and 4 x 10^15 solar masses, and…

Astrophysics · Physics 2015-06-24 Matthias Bartelmann , Matthias Steinmetz

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…

Astrophysics · Physics 2009-10-31 John S. Mulchaey

We present results from a systematic investigation of the X-ray properties of a sample of moderate redshift (0.3<z<0.6) galaxy groups. These groups were selected not by traditional X-ray or optical search methods, but rather by an…

We report the results of an almost complete survey of the X-ray properties of Hickson's compact galaxy groups with the ROSAT PSPC. Diffuse X-ray emission is detected from 22 groups. We infer that hot intragroup gas is present in $\gtsimm…

Astrophysics · Physics 2015-06-24 T. J. Ponman , P. D. Bourner , H. Ebeling , H. Bohringer

We investigate the properties of 232 optical spectroscopically selected groups from the Galaxy And Mass Assembly (GAMA) survey that overlap the XXL X-ray cluster survey. X-ray aperture flux measurements combined with GAMA group data…

We have undertaken a multiwavelength project to study the relatively unknown properties of groups and poor clusters of galaxies at intermediate redshifts. In this paper, we describe the XMM-Newton observations of six X-ray selected groups…

Astrophysics · Physics 2008-11-26 T. E. Jeltema , J. S. Mulchaey , L. M. Lubin , P. Rosati , H. Bohringer

We used archival ROSAT observations to investigate the X-ray surface brightness profiles of a sample of 26 clusters in the redshift range (0.04-0.06). For 15 of these clusters accurate temperature (kT>3.5 keV) were available from the…

Astrophysics · Physics 2007-05-23 Doris M. Neumann , Monique Arnaud

We present an analysis of 39 X-ray luminous early-type galaxies observed with the ROSAT PSPC. Using multi-component spectral and spatial fits to these data we have measured halo abundance, temperature, luminosity and surface brightness…

Astrophysics · Physics 2009-11-07 Ewan O'Sullivan , Trevor J. Ponman , Ross S. Collins

Combining X-ray data from the ROSAT PSPC and optical data drawn from the literature, we examine in detail the relationship between the X-ray and optical properties of X-ray bright galaxy groups. We find a relationship between optical…

Astrophysics · Physics 2009-11-07 Stephen F. Helsdon , Trevor J. Ponman

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…

Astrophysics · Physics 2009-10-30 John S. Mulchaey , Ann I. Zabludoff

We examine the relationship between the group x-ray luminosity in the 0.3-3.5 keV band and the measured velocity dispersion, and galaxy surface number density. We find definite correlations. Richer groups follow the same relation as rich…

Astrophysics · Physics 2009-10-22 I. P. Dell'Antonio , M. J. Geller , D. G. Fabricant

This study examines the average X-ray properties of massive halos at z< 0.2, covering the largest halo mass range to date, from Milky Way-like halos to massive clusters. The analysis is based on stacking in the eFEDS area of the GAMA galaxy…

We study the substructure statistics of a representative sample of galaxy clusters by means of two currently popular substructure characterisation methods, power ratios and centroid shifts. We use the 31 clusters from the REXCESS sample,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 H. Boehringer , G. W. Pratt , M. Arnaud , S. Borgani , J. H. Croston , T. J. Ponman , S. Ameglio , R. F. Temple , K. Dolag

The study of soft X-ray emission of 38 X-ray selected galaxy clusters observed by ROSAT PSPC indicates that the soft excess phenomenon may be a common occurrence in galaxy clusters. Excess soft X-ray radiation, above the contribution from…

Astrophysics · Physics 2015-06-24 M. Bonamente , R. Lieu , M. K. Joy , J. H. Nevalainen
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