Sensitivity of galaxy cluster dark energy constraints to halo modeling uncertainties (2009)
Cunha, Carlos E., Evrard, August E.
We perform a sensitivity study of dark energy constraints from galaxy cluster surveys to uncertainties in the halo mass function, bias and the mass-observable relation. For a set of idealized...
Cosmological Constraints from the SDSS maxBCG Cluster Catalog (2009)
Rozo, Eduardo, Wechsler, Risa H., Rykoff, Eli S., Annis, James T., Becker, Matthew R., Evrard, August E., ...
We use the abundance and weak lensing mass measurements of the SDSS maxBCG cluster catalog to simultaneously constrain cosmology and the richness--mass relation of the clusters. Assuming a flat...
Accretion Shocks in Clusters of Galaxies and their SZ Signature from Cosmological Simulations (2009)
Molnar, Sandor M., Hearn, Nathan, Haiman, Zoltán, Bryan, Greg, Evrard, August E., Lake, Georg
Cold dark matter (CDM) hierarchical structure formation models predict the existence of large-scale accretion shocks between the virial and turnaround radii of clusters of galaxies. Kocsis et al....
The X-ray Cluster Normalization of the Matter Power Spectrum (2008)
Henry, J. Patrick, Evrard, August E., Hoekstra, Henk, Babul, Arif, Mahdavi, Andishieh
The number density of galaxy clusters provides tight statistical constraints on the matter fluctuation power spectrum normalization, traditionally phrased in terms of sigma_8, the root mean square...
Evrard, August E., Bialek, James, Busha, Michael T., White, Martin, Habib, Salman, Heitmann, Katrin, ...
Abstract not available.
Evrard, August E., Bialek, James, Busha, Michael T., White, Martin, Habib, Salman, Heitmann, Katrin, ...
Abstract not available.
Evrard, August E., Bialek, James, Busha, Michael T., White, Martin, Habib, Salman, Heitmann, Katrin, ...
Abstract not available.
Evrard, August E., Bialek, James, Busha, Michael T., White, Martin, Habib, Salman, Heitmann, Katrin, ...
Abstract not available.
Evrard, August E., Bialek, James, Busha, Michael T., White, Martin, Habib, Salman, Heitmann, Katrin, ...
Abstract not available.
Johnston, David E., Sheldon, Erin S., Wechsler, Risa H., Rozo, Eduardo, Koester, Benjamin P., Frieman, Joshua A., ...
We interpret and model the statistical weak lensing measurements around 130,000 groups and clusters of galaxies in the Sloan Digital Sky Survey presented by Sheldon et al. 2007 (Paper I). We present...
The Merger in Abell 576: A Line of Sight Bullet Cluster? (2007)
Dupke, Renato A., Mirabal, Nestor, Bregman, Joel N., Evrard, August E.
Using a combination of Chandra and XMM observations, we confirmed the presence of a significant velocity gradient along the NE/E-W/SW direction in the intracluster gas of the cluster Abell 576. The...
Cosmological Constraints from SDSS maxBCG Cluster Abundances (2007)
Rozo, Eduardo, Wechsler, Risa H., Koester, Benjamin P., McKay, Timothy A., Evrard, August E., Johnston, David, ...
We perform a maximum likelihood analysis of the cluster abundance measured in the SDSS using the maxBCG cluster finding algorithm. Our analysis is aimed at constraining the power spectrum...
Optically-Selected Cluster Catalogs as a Precision Cosmology Tool (2007)
Rozo, Eduardo, Wechsler, Risa H., Koester, Benjamin P., Evrard, August E., McKay, Timothy A.
We introduce a framework for describing the halo selection function of optical cluster finders. We treat the problem as being separable into a term that describes the intrinsic galaxy content of a...
MaxBCG: A Red Sequence Galaxy Cluster Finder (2007)
Koester, Benjamin P., McKay, Timothy A., Annis, James, Wechsler, Risa H., Evrard, August E., Rozo, Eduardo, ...
Measurements of galaxy cluster abundances, clustering properties, and mass to- light ratios in current and future surveys can provide important cosmological constraints. Digital wide-field imaging...
The Asymptotic Form of Cosmic Structure: Small Scale Power and Accretion History (2006)
Busha, Michael T., Evrard, August E., Adams, Fred C.
We explore the effects of small scale structure on the formation and equilibrium of dark matter halos in a universe dominated by vacuum energy. We present the results of a suite of four N-body...
Cluster-Supercluster Alignments (2006)
Lee, Jounghun, Evrard, August E.
We study correlations in spatial orientation between galaxy clusters and their host superclusters using a Hubble Volume N-body realization of a concordance cosmology and an analytic model for...
Dark Energy Studies: Challenges to Computational Cosmology (2005)
Annis, James, Castander, Francisco J., Evrard, August E., Frieman, Joshua A., Gaztanaga, Enrique, Jain, Bhuvnesh, ...
The ability to test the nature of dark mass-energy components in the universe through large-scale structure studies hinges on accurate predictions of sky survey expectations within a given world...
Constraining Dark Energy with the Dark Energy Survey: Theoretical Challenges (2005)
Annis, James, Bridle, Sarah, Castander, Francisco J., Evrard, August E., Fosalba, Pablo, Frieman, Joshua A., ...
The Dark Energy Survey (DES) will use a new imaging camera on the Blanco 4-m telescope at CTIO to image 5000 square degrees of sky in the South Galactic Cap in four optical bands, and to carry out...
Effects of Mergers and Core Structure on the Bulk Properties of Nearby Galaxy Clusters (2005)
O'Hara, Timothy B., Mohr, Joseph J., Bialek, John J., Evrard, August E.
We use morphological measurements and the scatter of clusters about observed and simulated scaling relations to examine the impact of merging and core-related phenomena on the structure of galaxy...
Detecting Intracluster Gas Motion in Galaxy Clusters: Mock Astro-E2 Observations (2005)
Pawl, Andrew, Evrard, August E., Dupke, Renato A.
We explore the detectability of bulk motions in the X-ray emitting intracluster medium (ICM) using a catalog of 1,836 mock Astro-E2 observations of simulated clusters of galaxies. We generate high...
The C4 clustering algorithm: clusters of galaxies in the sloan digital sky survey (2005)
Miller, Christopher J., Nichol, Robert C., Reichart, Daniel, Wechsler, Risa H., Evrard, August E., Annis, James, ...
The C4 clustering algorithm: Clusters of galaxies in the Sloan Digital Sky Survey (2005)
Miller, Christopher J., Nichol, Robert C., Reichart, Daniel, Wechsler, Risa H., Evrard, August E., Annis, James, ...
We present the C4 Cluster Catalog, a new sample of 748 clusters of galaxies identified in the spectroscopic sample of the Second Data Release (DR2) of the Sloan Digital Sky Survey (SDSS). The C4...
The Ultimate Halo Mass in a LCDM Universe (2004)
Busha, Michael T., Evrard, August E., Adams, Fred C., Wechsler, Risa H.
In the far future of an accelerating LCDM cosmology, the cosmic web of large-scale structure consists of a set of increasingly isolated halos in dynamical equilibrium. We examine the approach of...
The Asymptotic Structure of Space-Time (2003)
Adams, Fred C., Busha, Michael T., Evrard, August E., Wechsler, Risa H.
Astronomical observations strongly suggest that our universe is now accelerating and contains a substantial admixture of dark vacuum energy. Using numerical simulations to study this newly...
Future Evolution of Structure in an Accelerating Universe (2003)
Busha, Michael T., Adams, Fred C., Wechsler, Risa H., Evrard, August E.
Current cosmological data indicate that our universe contains a substantial component of dark vacuum energy that is driving the cosmos to accelerate. We examine the immediate and longer term...
Studying Dark Energy with Galaxy Cluster Surveys (2002)
Mohr, Joseph J., OShea, Brian, Evrard, August E., Bialek, John, Haiman, Zoltan
Galaxy cluster surveys provide a powerful means of studying the density and nature of the dark energy. The redshift distribution of detected clusters in a deep, large solid angle SZE or X-ray survey...
A Cold Front in a Preheated Galaxy Cluster (2002)
Bialek, John J., Evrard, August E., Mohr, Joseph J.
We present a simulated cluster of galaxies, modeled with a pre-heated intracluster medium, that exhibits X-ray features similar to the `cold fronts' seen in Chandra observations. Mock observations at...
Hamana, Takashi, Yoshida, Naoki, Suto, Yasushi, Evrard, August E.
We develop a phenomenological model to predict the clustering of dark matter halos on the light-cone by combining several existing theoretical models. Assuming that the velocity field of halos on...
Confusion of Diffuse Objects in the X-ray Sky (2000)
Voit, G. Mark, Evrard, August E., Bryan, Greg L.
Most of the baryons in the present-day universe are thought to reside in intergalactic space at temperatures of 10^5-10^7 K. X-ray emission from these baryons contributes a modest (~10%) fraction of...
Effects of Preheating on X-ray Scaling Relations in Galaxy Clusters (2000)
Bialek, John J., Evrard, August E., Mohr, Joseph J.
The failure of purely gravitational models of X-ray cluster formation to reproduce basic observed properties of the local cluster population suggests the need for one or more additional physical...
Mathiesen, Benjamin F., Evrard, August E.
We employ an ensemble of hydrodynamic cluster simulations to create spatially and spectrally resolved images of quality comparable to Chandra's expected performance. Emission from simulation mass...
The X-ray Size-Temperature Relation for Intermediate Redshift Galaxy Clusters (2000)
Mohr, Joseph J., Reese, Erik D., Ellingson, E., Lewis, Aaron D., Evrard, August E.
We present the first measurements of the X-ray size-temperature (ST) relation in intermediate redshift (z~0.30) galaxy clusters. We interpret the local ST relation (z~0.06) in terms of underlying...
Expectations For an Interferometric Sunyaev-Zel'dovich Effect Survey for Galaxy Clusters (1999)
Holder, Gilbert P., Mohr, Joseph J., Carlstrom, John E., Evrard, August E., Leitch, Erik M.
Non-targeted surveys for galaxy clusters using the Sunyaev-Zel'dovich effect (SZE) will yield valuable information on both cosmology and evolution of the intra-cluster medium (ICM). The redshift...
Radial Temperature Profiles of X-Ray--Emitting Gas Within Clusters of Galaxies (1999)
Irwin, Jimmy A., Bregman, Joel N., Evrard, August E.
Previous analyses of ASCA data of clusters of galaxies have found conflicting results regarding the slope of the temperature profile of the hot X-ray gas within clusters, mainly because of the large,...
Simulating Large-scale Structure (1998)
After two decades of direct dynamical simulation of large-scale structure in the universe, it is safe to say the subject is now mature. Still, there are parts of the problem that are less well...
Galaxy Clusters in the Hubble Volume Simulations (1998)
Colberg, Joerg M., White, Simon D. M., MacFarland, Thomas J., Jenkins, Adrian, Frenk, Carlos S., Pearce, F. R., ...
We report on analyses of cluster samples obtained from the Hubble Volume Simulations. These simulations, an $\Omega=1$ model named $\tau$CDM and a flat low $\Omega$ model with a cosmological constant...
The Lx-T Relation and Intracluster Gas Fractions of X-ray Clusters (1998)
Arnaud, Monique, Evrard, August E.
We re-examine the X-ray luminosity-temperature relation using a nearly homogeneous data set of 24 clusters selected for statistically accurate temperature measurements and absence of strong cooling...
Simulations Of Galaxy Clusters With And Without Winds: I. The Structure Of Clusters (1997)
Metzler, Christopher A., Evrard, August E.
We use gas dynamic simulations to explore the effects of galactic winds on galaxy clusters. Two ensembles of 18 realizations, spanning a decade in temperature, are evolved with and without winds in...
An X-ray Size-Temperature Relation for Galaxy Clusters: Observation and Simulation (1997)
Mohr, Joseph J., Evrard, August E.
We show that galaxy clusters conform to a tight relation between X-ray isophotal size R_I and emission weighted intracluster medium (ICM) temperature T_X. The best fit relation for 41 members of an...
Cosmological Simulations with Scale-Free Initial Conditions I: Adiabatic Hydrodynamics (1997)
Owen, J. Michael, Weinberg, David H., Evrard, August E., Hernquist, Lars, Katz, Neal
We analyze hierarchical structure formation based on scale-free initial conditions in an Einstein-de Sitter universe, including a baryonic component. We present three independent, smoothed particle...
The Tully--Fisher Relation : A Numerical Simulator's Perspective (1997)
In this brief contribution, I outline hopes of understanding the origin of galaxy scaling relations using numerical simulations as a tool to gain understanding. The case of the Tully--Fisher relation...
The Intracluster Gas Fraction in X-ray Clusters : Constraints on the Clustered Mass Density (1997)
The mean intracluster gas fraction of X-ray clusters within their hydrostatic regions is derived from recent observational compilations of David, Jones & Forman and White & Fabian. At radii...
Properties of Simulated Compact Groups of Galaxies (1996)
Pildis, Rachel A., Evrard, August E., Bregman, Joel N.
We analyze compact groups of galaxies appearing in a galaxy formation simulation dominated by cold dark matter (omega_0=1, omega_{baryon}=0.1). The simulation uses an N-body code to model the...
Mass Estimates of X-Ray Clusters (1995)
Evrard, August E., Metzler, Christopher A., Navarro, Julio F.
We use cosmological gas dynamic simulations to investigate the accuracy of galaxy cluster mass estimates based on X-ray observations. The experiments follow the formation of clusters in different...
Galaxy Tracers and Velocity Bias (1995)
Summers, F J, Davis, Marc, Evrard, August E.
This paper examines several methods of tracing galaxies in N-body simulations and their effects on the derived galaxy statistics, especially measurements of velocity bias. Using two simulations with...
ROSAT Observations of Compact Groups of Galaxies (1995)
Pildis, Rachel A., Bregman, Joel N., Evrard, August E.
We have systematically analyzed a sample of 13 new and archival ROSAT PSPC observations of compact groups of galaxies: 12 Hickson Compact Groups plus the NCG 2300 group. We find that approximately...
Simulations of Clusters of Galaxies (1994)
The degree of complexity and, to a somewhat lesser degree, realism in simulations has advanced rapidly in the past few years. The simplest approach - modeling a cluster as collisionless dark matter...
The Cosmological Dependence of Cluster Density Profiles (1994)
Crone, Mary M., Evrard, August E., Richstone, Douglas O.
We use N-body simulations to study the shape of mean cluster density and velocity profiles formed via gravitational instability. The dependence of the final structure on both cosmology and initial...
A Comparison of Cosmological Hydrodynamic Codes (1994)
Kang, Hyesung, Ostriker, Jeremiah P., Cen, Renyue, Ryu, Dongsu, Hernquist, Lars, Evrard, August E., ...
We present a detailed comparison of the simulation results of various cosmological hydrodynamic codes. Starting with identical initial conditions based on the Cold Dark Matter scenario for the growth...
Dynamics of Clusters of Galaxies (1993)
The abundance and internal characteristics of rich clusters of galaxies can provide useful constraints on models of large--scale structure formation. This article will review some recent three...
A Simulation of the Intracluster Medium with Feedback from Cluster Galaxies (1993)
Metzler, Christopher A., Evrard, August E.
The formation and evolution of an X--ray cluster is studied using a 3--D N-body + hydrodynamical simulation which includes feedback of energy and iron from cluster galaxies. The differences in...
Structure in a Loitering Universe (1992)
Feldman, Hume A., Evrard, August E.
We study the formation of structure for a universe that undergoes a recent loitering phase. We compare the nonlinear mass distribution to that in a standard, matter dominated cosmology. The...
Dark matter and the dynamics of galaxy clustering /--by August E. Evrard. (1986)
Thesis (Ph. D.)--State University of New York at Stony Brook, 1986.
Real or virtual large-scale structure?
Modeling the development of structure in the universe on galactic and larger scales is the challenge that drives the field of computational cosmology. Here, photorealism is used as a simple, yet...
Real or virtual large-scale structure?
Modeling the development of structure in the universe on galactic and larger scales is the challenge that drives the field of computational cosmology. Here, photorealism is used as a simple, yet...