Two-Phased Intra-Cluster Medium in the Centaurus Cluster of Galaxies

ASCA and ROSAT data of the Centaurus cluster were analyzed. A central excess in the radial brightness profile is found in the hard energy band up to 10keV. This requires a deeper central potential than a King-type one. A double-beta brightness distribution gives a good account of the data. A deprojected energy spectrum within a spherical region of radius 30 kpc at the cluster center indicates that the ICM cannot be isothermal there. Simultaneous fitting of the three (PSPC, GIS, and SIS) energy spectra extracted from the central 3' region showed that a two-temperature model that has temperatures of 1.4keV and 4.4keV and a common metallicity of 1.0 solar with the Galactic absorption gives the best description to the spectra. A cooling-flow spectral model did not give satisfactory fit. A 3-dimensional cluster model incorporating the two-phase picture, the double-beta brightness distribution, and the central metallicity increase reproduced the overall ASCA and ROSAT data successfully. The derived spatial distribution of the dark matter deviates from a King-type profile exhibiting a central excess, which is consistent with the Navvaro-Frenk-White model. The iron is revealed to be more widely spread than stars, which may have been caused by energetic supernovae and the motion of the cD galaxy. Since the derived characteristics of the cool phase including the temperature, angular extent, gas mass, and metallicity, are on a smooth extension of those of inter-stellar medium (ISM) of elliptical galaxies, the cool phase can be regarded as the ISM associated with the cD galaxy. The cool-phase X-ray emission is presumably sustained by energies dissipated by infalling mass to the cD galaxy in the course of cluster evolution.Comment: accepted for publication in Ap

Gravitino and goldstino at colliders

We consider theories with spontaneously broken global or local supersymmetry where the pseudo-goldstino or the gravitino is the lightest superparticle (LSP). Assuming that the long-lived next-to-lightest superparticle (NSP) is a charged slepton, we study several supergravity predictions: the NSP lifetime, angular and energy distributions in 3-body NSP decays. The characteristic couplings of the gravitino, or goldstino, can be tested even for very small masses. (orig.)Available from TIB Hannover: RA 8919(04-043) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

The scaling of the redshift power spectrum: observations from the Las Campanas Redshift Survey

SIGLEAvailable from TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Scaling properties of the redshift power spectrum: theoretical models

SIGLEAvailable from TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Spatial correlation functions and the pairwise peculiar velocity dispersion of galaxies in the PSCz survey: implications for the galaxy biasing in cold dark matter models

SIGLEAvailable from TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Curvatons in supersymmetric models

We study the curvaton scenario in supersymmetric framework paying particular attention to the fact that scalar fields are inevitably complex in supersymmetric theories. If there are more than one scalar fields associated with the curvaton mechanism, isocurvature (entropy) fluctuations between those fields in general arise, which may significantly affect the properties of the cosmic density fluctuations. We examine several candidates for the curvaton in the supersymmetric framework, such as moduli fields, Affleck-Dine field, F- and D-flat directions, and right-handed sneutrino. We estimate how the isocurvature fluctuations generated in each case affect the cosmic microwave background angular power spectrum. With the use of the recent observational result of the WMAP, stringent constraints on the models are derived and, in particular, it is seen that large fraction of the parameter space is excluded if the Affleck-Dine field plays the role of the curvaton field. Natural and well-motivated candidates of the curvaton are also listed. (orig.)SIGLEAvailable from TIB Hannover: RA 2999(03-097) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Spatial and dynamical biases in velocity statistics of galaxies

SIGLEAvailable from TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Spatial correlation function and pairwise velocity dispersion of galaxies: CDM models versus the Las Campanas Survey

We show, with the help of large N-body simulations, that the real-space two-point correlation function and pairwise velocity dispersion of galaxies can both be measured reliably from the Las Campanas Redshift Survey. The real-space correlation function is well fitted by the power law #xi#(r)=(r_0/r)"#gamma# with r_0=(5.06#+-#0.12) h"-"1 Mpc and #gamma#=1.862#+-#0.034, and the pairwise velocity dispersion at 1 h"-"1 Mpc is (570#+-#80) km s"-"1. A detailed comparison between these observational results and the predictions of current CDM cosmogonies is carried out. We construct 60 mock samples for each theoretical model from a large set of high resolution N-body simulations, which allows us to include various observational selection effects in the analyses and to use exactly the same methods for both real and theoretical samples. We demonstrate that such a procedure is essential in the comparison between models and observations. The observed two-point correlation function is significantly flatter than the mass correlation function in current CDM models on scales <or#approx#1 h"-"1 Mpc. The observed pairwise velocity dispersion is also lower than that of dark matter particles in these models. We propose a simple antibias model to explain these discrepancies. This model assumes that the number of galaxies per unit dark matter mass, N/M, decreases with the mass of dark haloes. The predictions of CDM models with #sigma#_8#OMEGA#_0"0"."6#propor to#0.4-0.5 and #GAMMA##propor to#0.2 are in agreement with the observational results, if the trend of N/M with M is at the level already observed for rich clusters of galaxies. Thus CDM models with #GAMMA##propor to#0.2 and with cluster-abundance normalization are consistent with the observed correlation function and pairwise velocity dispersion of galaxies. A high level of velocity bias is not required in these models. (orig.)Available from FIZ Karlsruhe / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Probing intracluster magnetic fields with cosmic microwave background polarization

SIGLEAvailable from: http://www.mpa-garching.mpg.de / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman