Extending Recovery of the Primordial Matter Power Spectrum (2008)
Yoo, Jaiyul, Weinberg, David H., Tinker, Jeremy L., Zheng, Zheng, Warren, Michael S.
The shape of the primordial matter power spectrum Plin(k) encodes critical information on cosmological parameters. At large scales, the observable galaxy power spectrum Pobs(k) is expected to follow...
ABSTRACT The Space Simulator: Modeling the Universe from Supernovae to Cosmology (2008)
Michael S. Warren, Chris L. Fryer, M. Patrick Goda
The Space Simulator is a 294-processor Beowulf cluster with theoretical peak performance just below 1.5 Teraflop/s. It is based on the Shuttle XPC SS51G mini chassis. Each node consists of a 2.53 GHz...
Toward a halo mass function for precision cosmology: the limits of universality (2008)
Tinker, Jeremy L, Kravtsov, Andrey V, Klypin, Anatoly, Abazajian, Kevork, Warren, Michael S, Yepes, Gustavo, ...
We measure the mass function of dark matter halos in a large set of collisionless cosmological simulations of flat LCDM cosmology and investigate its evolution at z
Abate, Alexandra, Bridle, Sarah, Teodoro, Luis F. A., Warren, Michael S., Hendry, Martin
We investigate methods to best estimate the normalisation of the mass density fluctuation power spectrum (sigma_8) using peculiar velocity data from a survey like the Six degree Field Galaxy Velocity...
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.
Astrophysical N-body Simulations Using Hierarchical Tree Data Structures (2007)
Michael S. Warren, John K. Salmon
We report on recent large astrophysical N-body simulations executed on the Intel Touchstone Delta system. We review the astrophysical motivation, and the numerical techniques, and discuss steps taken...
Avalon: An Alpha/Linux Cluster Achieves 10 Gflops for $150k (2007)
Submitted For The, Michael S. Warren, Timothy C. Germann, Peter S. Lomdahl, David M. Beazley, John K. Salmon
We present two calculations from the disciplines of condensed matter physics and astrophysics. The simulations were performed on a 70 processor DEC Alpha cluster (Avalon) constructed entirely from...
Michael S. Warren, John K. Salmon, Donald J. Becker, M. Patrick Goda, Thomas Sterling, Grgoire S. Winckelmans
: As an entry for the 1997 Gordon Bell performance prize, we present results from two methods of solving the gravitational N-body problem on the Intel Teraflops system at Sandia National Laboratory...
Avalon: An Alpha/Linux Cluster Achieves 10 Gflops for $150k (2007)
Finalist For, Michael S. Warren, Timothy C. Germann, Peter S. Lomdahl, David M. Beazley, John K. Salmon
As an entry for the 1998 Gordon Bell price/performance prize, we present two calculations from the disciplines of condensed matter physics and astrophysics. The simulations were performed on a 70...
Gravitational Waves Chris, Chris L. Fryer, Daniel E. Holz, Scott A. Hughes, Michael S. Warren
The new generation of gravitational wave (GW) detectors have the potential to open a novel window onto the violent dynamics of core collapse. Although it is certain that core collapse events generate...
Tinker, Jeremy L., Conroy, Charlie, Norberg, Peder, Patiri, Santiago G., Weinberg, David H., Warren, Michael S.
We use measurements of the projected galaxy correlation function w_p and galaxy void statistics to test whether the galaxy content of halos of fixed mass is systematically different in low density...
The Cosmic Code Comparison Project (2007)
Heitmann, Katrin, Lukic, Zarija, Fasel, Patricia, Habib, Salman, Warren, Michael S., White, Martin, ...
Current and upcoming cosmological observations allow us to probe structures on smaller and smaller scales, entering highly nonlinear regimes. In order to obtain theoretical predictions in these...
Close Pairs as Proxies for Galaxy Cluster Mergers (2007)
Wetzel, Andrew R., Schulz, A. E., Holz, Daniel E., Warren, Michael S.
Galaxy cluster merger statistics are an important component in understanding the formation of large-scale structure. Unfortunately, it is difficult to study merger properties and evolution directly...
Simulations of Baryon Oscillations (2006)
Huff, Eric, Schulz, A. E., White, Martin, Schlegel, David J., Warren, Michael S.
The coupling of photons and baryons by Thomson scattering in the early universe imprints features in both the Cosmic Microwave Background (CMB) and matter power spectra. The former have been used to...
The Clustering of Massive Halos (2006)
Wetzel, Andrew R., Cohn, J. D., White, Martin, Holz, Daniel E., Warren, Michael S.
The clustering properties of dark matter halos are a firm prediction of modern theories of structure formation. We use two large volume, high-resolution N-body simulations to study how the...
On the Luminosity Dependence of the Galaxy Pairwise Velocity Dispersion (2006)
Tinker, Jeremy L., Norberg, Peder, Weinberg, David H., Warren, Michael S.
(Abridged) We make predictions for the pairwise velocity dispersion (PVD) of galaxies with models that are constrained to match the projected correlation function and luminosity function of galaxies...
Cosmic Voids and Galaxy Bias in the Halo Occupation Framework (2006)
Tinker, Jeremy L., Weinberg, David H., Warren, Michael S.
(Abridged) We investigate the power of void statistics to constrain galaxy bias and the amplitude of dark matter fluctuations. We use the halo occupation distribution (HOD) framework to describe the...
Berlind, Andreas A., Frieman, Joshua A., Weinberg, David H., Blanton, Michael R., Warren, Michael S., Abazajian, Kevork, ...
We identify galaxy groups and clusters in volume-limited samples of the SDSS redshift survey, using a redshift-space friends-of-friends algorithm. We optimize the friends-of-friends linking lengths...
Fast Parallel Tree Codes for Gravitational and Fluid Dynamical N-Body Problems (2006)
Salmon, John K., Warren, Michael S., Winckelmans, Gregoire S.
We discuss two physical systems from separate disciplines that make use of the same algorithmic and mathematical structures to reduce the number of operations necessary to complete a realistic...
Very small scale clustering and merger rate of Luminous Red Galaxies (2006)
Masjedi, Morad, Hogg, David W., Cool, Richard J., Eisenstein, Daniel J., Blanton, Michael R., Zehavi, Idit, ...
We present the small-scale (0.01 Mpc
Very Small-Scale Clustering and Merger Rate of Luminous Red Galaxies (2005)
Masjedi, Morad, Hogg, David W., Cool, Richard J., Eisenstein, Daniel J., Blanton, Michael R., Zehavi, Idit, ...
We present the small-scale (0.01
Precision Determination of the Mass Function of Dark Matter Halos (2005)
Warren, Michael S., Abazajian, Kevork, Holz, Daniel E., Teodoro, Luis
The predicted mass function of dark matter halos is essential in connecting observed galaxy cluster counts and models of galaxy clustering to the properties of the primordial density field. We...
Robustness of Cosmological Simulations I: Large Scale Structure (2004)
Heitmann, Katrin, Ricker, Paul M., Warren, Michael S., Habib, Salman
The gravitationally-driven evolution of cold dark matter dominates the formation of structure in the Universe over a wide range of length scales. While the longest scales can be treated by...
The Distribution of Dark Matter in the Universe on Scales of 10^10 M_sun to 10^15 M_sun (2004)
Teodoro, Luis, Warren, Michael S.
The use of parallel computers and increasingly sophisticated software has allowed us to perform a large suite of N-body simulations using from $10^8$,to $10^9$ particles. We will report on our recent...
Large scale bias and stochasticity of halos and dark matter (2004)
Seljak, Uros, Warren, Michael S.
On large scales galaxies and their halos are usually assumed to trace the dark matter with a constant bias and dark matter is assumed to trace the linear density field. We test these assumption using...
Colgate, Stirling A., Cen, Renyue, Li, Hui, Currier, Nathan, Warren, Michael S.
A scenario is put forth for the formation of supermassive black holes at the centers of galaxies. It depends upon the formation of a Mestel disk with a flat rotation curve, where the mass is...
Diffuse X-Rays from the Inner 3 Parsecs of the Galaxy (2003)
Rockefeller, Gabriel, Fryer, Chris L., Melia, Fulvio, Warren, Michael S.
Recent observations with the Chandra X-ray Observatory have provided us with the capability to discriminate point sources, such as the supermassive black hole Sgr A*, from the diffuse emission within...
Stellar collapse and gravitational waves (2002)
Fryer, Chris L., Holz, Daniel E., Hughes, Scott A., Warren, Michael S.
The new generation of gravitational wave (GW) detectors have the potential to open a novel window onto the violent dynamics of core collapse. Although it is certain that core collapse events generate...
Michael S. Warren, Chris Fryer, M. Patrick Goda
this paper we describe the design, implementation and performance of the cluster, as well as some scientific application results obtained with the machine
Parallel, Out-of-core methods for N-body Simulation (1997)
John Salmon, Michael S. Warren
Hierarchical treecodes have, to a large extent, converted the compute-bound N-body problem into a memory-bound problem. The large ratio of DRAM to disk pricing suggests use of out-of-core techniques...
A Parallel, Portable and Versatile Treecode (1995)
Michael S. Warren, John K. Salmon
yz Portability and versatility are important characteristics of a computer program which is meant to be generally useful. We describe how we have developed a parallel N-body treecode to meet these...
A portable parallel particle program (1995)
Michael S. Warren, John K. Salmon
We describe our implementation of the parallel hashed oct-tree (HOT) code, and in particular its application to neighbor finding in a smoothed particle hydrodynamics (SPH) code. We also review the...
Wojciech H. Zurek, Peter J. Quinn, John K. Salmon, Michael S. Warren
Large N-body simulations on parallel supercomputers allow one to simultaneously investigate large scale structure and the formation of galactic halos with unprecedented resolution. Our study shows...
Skeletons from the Treecode Closet (1994)
John K. Salmon, Michael S. Warren
We consider treecodes (N-body programs which use a tree data structure) from the standpoint of their worst-case behavior. That is, we derive upper bounds on the largest possible errors that are...
Fast Parallel Tree Codes for Gravitational and Fluid Dynamical N-Body Problems (1994)
Submitted To, John K. Salmon, Michael S. Warren, Gregoire S. Winckelmans
We discuss two physical systems from separate disciplines that make use of the same algorithmic and mathematical structures to reduce the number of operations necessary to complete a realistic...
Theoretical Astrophysics, Los Alamos National Laboratory, Los Alamos, NM 87545 (1994)
Wojciech H. Zurek, Peter Quinn, John K. Salmon, Michael S. Warren
Large N-body simulations on parallel supercomputers allow one to simultaneously investigate large scale structure and the formation of galactic halos with unprecedented resolution. Our study shows...
A parallel hashed oct-tree N-body algorithm (1993)
Michael S. Warren, John K. Salmon
We report on an efficient adaptive N-body method which we have recently designed and implemented. The algorithm computes the forces on an arbitrary distribution of bodies in a time which scales as N...
A Parallel Hashed Oct-Tree N-Body Algorithm (1993)
Michael S. Warren, John K. Salmon
We report on an efficient adaptive N-body method which we have recently designed and implemented. The algorithm computes the forces on an arbitrary distribution of bodies in a time which scales as N...
A parallel hashed oct-tree N-body algorithm (1993)
Michael S. Warren, John K. Salmon
We report on an efficient adaptive N-body method which we have recently designed and implemented. The algorithm computes the forces on an arbitrary distribution of bodies in a time which scales as ยข...
Dark halos formed via dissipationless collapse: I. Shapes and alignment of angular momentum (1992)
Michael S. Warren, Peter J. Quinn, John K. Salmon, Wojciech H. Zurek
We use N-body simulations on highly parallel supercomputers to study the structure of galactic dark matter halos. The systems form by gravitational collapse from scale-free and more general Gaussian...
N-body Methods on MIMD Supercomputers: Astrophysics on the Intel Touchstone Delta. (1992)
David P. Fullagar, Peter J. Quinn, Carl J. Grillmair, Mount Stromlo, Siding Spring Observatories, John K. Salmon, ...
We have used hierarchical N-body methods running on a MIMD parallel supercomputer to follow the evolution of systems with large numbers of particles (N ? 10 6 ). The nonlinear gravitational collapse...
Astrophysical N-body simulations using hierarchical tree data structures (1992)
Michael S. Warren, John K. Salmon
We report on recent large astrophysical N-body simulations executed on the Intel Touchstone Delta system. We review the astrophysical motivation, and the numerical techniques, and discuss steps taken...
Fast Parallel Tree Codes for Gravitational and Fluid Dynamical N-Body Problems (1986)
John K. Salmon, Michael S. Warren, Gregoire S. Winckelmans
We discuss two physical systems from separate disciplines that make use of the same algorithmic and mathematical structures to reduce the number of operations necessary to complete a realistic...