Shen, Sijing, Wadsley, James, Stinson, Gregory
A study of IGM metal enrichment using a series of SPH simulations is presented, employing metal cooling and the turbulent diffusion of metals and thermal energy. Stellar feedback naturally drives...
A Numerical Study of Brown Dwarf Formation via Encounters of Protostellar Disks (2009)
Shen, Sijing, Wadsley, James, Hayfield, Tristen, Ellens, Nicholas
The formation of brown dwarfs (BDs) due to the fragmentation of proto-stellar disks undergoing pairwise encounters was investigated. High resolution allowed the use of realistic initial disk models...
The nature of HI absorbers in GRB afterglows: clues from hydrodynamic simulations (2009)
Pontzen, Andrew, Deason, Alis, Governato, Fabio, Pettini, Max, Wadsley, James, Quinn, Thomas, ...
In recent work, we have shown that it is possible to link quantitatively many aspects of damped Lyman alpha (DLA) absorbers in the spectra of quasars to high resolution simulations of galaxy...
Feedback and the Formation of Dwarf Galaxy Stellar Halos (2009)
Stinson, Greg, Dalcanton, Julianne, Quinn, Tom, Gogarten, Stephanie, Kaufmann, Tobias, Wadsley, James
Stellar population studies show that low mass galaxies in all environments exhibit stellar halos that are older and more spherically distributed than the main body of the galaxy. In some cases, there...
Kaufmann, Tobias, Bullock, James S., Maller, Ariyeh H., Fang, Taotao, Wadsley, James
We present a pair of high-resolution smoothed particle hydrodynamics (SPH) simulations that explore the evolution and cooling behavior of hot gas around Milky-Way size galaxies. The simulations...
Pairing of Supermassive Black Holes in unequal-mass galaxy mergers (2008)
Callegari, Simone, Mayer, Lucio, Kazantzidis, Stelios, Colpi, Monica, Governato, Fabio, Quinn, Thomas, ...
We examine the pairing process of supermassive black holes (SMBHs) down to scales of 20-100 pc using a set of N-body/SPH simulations of binary mergers of disk galaxies with mass ratios of 1:4 and...
Roškar, Rok, Debattista, Victor P., Quinn, Thomas R., Stinson, Gregory S., Wadsley, James
Stars in disks of spiral galaxies are usually assumed to remain roughly at their birth radii. This assumption is built into decades of modelling of the evolution of stellar populations in our own...
Clues to Radial Migration from the Properties of Outer Disks (2008)
Roškar, Rok, Debattista, Victor P., Quinn, Thomas R., Stinson, Gregory S., Wadsley, James, Kaufmann, Tobias
The outer disks of galaxies present a unique laboratory for studying the process of disk formation. A considerable fraction of observed disks exhibit a break in their surface brightness profiles. The...
Damped Lyman Alpha Systems in Galaxy Formation Simulations (2008)
Pontzen, Andrew, Governato, Fabio, Pettini, Max, Booth, C. M., Stinson, Greg, Wadsley, James, ...
We investigate the population of z=3 damped Lyman alpha absorbers (DLAs) in a recent series of high resolution galaxy formation simulations. The simulations are of interest because they form at z=0...
The Formation of Polar Disk Galaxies (2008)
Brook, Chris B., Governato, Fabio, Quinn, Thomas, Wadsley, James, Brooks, Alyson M., Willman, Beth, ...
Polar Ring Galaxies, such as NGC4650A, are a class of galaxy which have two kinematically distinct components that are inclined by almost 90 degrees to each other. These striking galaxies challenge...
Stellar Feedback in Dwarf Galaxy Formation (2007)
Mashchenko, Sergey, Wadsley, James, Couchman, H. M. P.
Dwarf galaxies pose significant challenges for cosmological models. In particular, current models predict a dark matter density that is divergent at the center, in sharp contrast with observations...
1 HIGH PERFORMANCE COMPUTATIONAL ASTROPHYSICS WITH PKDGRAV/GASOLINE (2007)
Joachim Stadel, James Wadsley, Derek C. Richardson
We describe the design and implementation of the pkdgrav (gravity) and gasoline (gravity plus hydrodynamics) astrophysical N-body codes. We present a diverse spectrum of applications using these...
Beyond Inside-Out Growth: Formation and Evolution of Disk Outskirts (2007)
Roškar, Rok, Debattista, Victor P., Stinson, Gregory S., Quinn, Thomas R., Kaufmann, Tobias, Wadsley, James
We have performed a high mass and force resolution simulation of an idealized galaxy forming from dissipational collapse of gas embedded in a spherical dark matter halo. The simulation includes star...
Rapid Formation of Supermassive Black Hole Binaries in Galaxy Mergers with Gas (2007)
Mayer, Lucio, Kazantzidis, Stelios, Madau, Piero, Colpi, Monica, Quinn, Thomas, Wadsley, James
Supermassive black holes (SMBHs) are a ubiquitous component of the nuclei of galaxies. It is normally assumed that, following the merger of two massive galaxies, a SMBH binary will form, shrink due...
Early Gas Stripping as the Origin of the Darkest Galaxies in the Universe (2007)
Mayer, Lucio, Kazantzidis, Stelios, Mastropietro, Chiara, Wadsley, James
The known galaxies most dominated by dark matter (Draco, Ursa Minor and Andromeda IX) are satellites of the Milky Way and the Andromeda galaxies. They are members of a class of faint galaxies, devoid...
Fundamental differences between SPH and grid methods (2007)
Agertz, Oscar, Moore, Ben, Stadel, Joachim, Potter, Doug, Miniati, Francesco, Read, Justin, ...
Fundamental differences between SPH and grid methods (2006)
Agertz, Oscar, Moore, Ben, Stadel, Joachim, Potter, Doug, Miniati, Francesco, Read, Justin, ...
We have carried out a hydrodynamical code comparison study of interacting multiphase fluids. The two commonly used techniques of grid and smoothed particle hydrodynamics (SPH) show striking...
Poole, Gregory B., Fardal, Mark A., Babul, Arif, McCarthy, Ian G., Quinn, Thomas, Wadsley, James
We report on the analysis of a suite of SPH simulations (incorporating cooling and star formation) of mergers involving idealised X-ray clusters whose initial conditions resemble relaxed clusters...
Proto-Brown Dwarf Disks as Products of Protostellar Disk Encounters (2006)
The formation of brown dwarfs via encounters between proto-stars has been confirmed with high-resolution numerical simulations with a restricted treatment of the thermal conditions. The new results...
Mayer, Lucio, Lufkin, Graeme, Quinn, Thomas, Wadsley, James
We report on the results of the first 3D SPH simulation of massive, gravitationally unstable protoplanetary disks with radiative transfer. We adopt a flux-limited diffusion scheme justified by the...
Cosmological puzzle resolved by stellar feedback in high redshift galaxies (2006)
Mashchenko, Sergey, Couchman, H. M. P., Wadsley, James
The standard cosmological model, now strongly constrained by direct observation at early epochs, is very successful in describing the structure of the evolved universe on large and intermediate...
Stinson, Greg, Seth, Anil, Katz, Neal, Wadsley, James, Governato, Fabio, Quinn, Tom
We present an analysis of star formation and feedback recipes appropriate for galactic smoothed particle hydrodynamics simulations. Using an isolated Milky Way-like galaxy, we constrain these recipes...
Multi-scale simulations of merging galaxies with supermassive black holes (2006)
Mayer, Lucio, Kazantzidis, Stelios, Madau, Piero, Colpi, Monica, Quinn, Thomas, Wadsley, James
We present the results of the first multi-scale N-Body+SPH simulations of merging galaxies containing central supermassive black holes (SMBHs) and having a spatial resolution of only a few parsecs....
Angular momentum transport and disk morphology in SPH simulations of galaxy formation (2006)
Kaufmann, Tobias, Mayer, Lucio, Wadsley, James, Stadel, Joachim, Moore, Ben
We perform controlled N-Body/SPH simulations of disk galaxy formation by cooling a rotating gaseous mass distribution inside equilibrium cuspy spherical and triaxial dark matter halos. We...
Valenzuela, Octavio, Rhee, George, Klypin, Anatoly, Governato, Fabio, Stinson, Gregory, Quinn, Thomas, ...
Two well studied dwarf galaxies -- NGC 3109 and NGC 6822 -- present some of the strongest observational support for a flat core at the center of galactic dark matter (DM) halos. We use detailed...
The Secular Evolution of Disk Structural Parameters (2005)
Debattista, Victor P., Mayer, Lucio, Carollo, C. Marcella, Moore, Ben, Wadsley, James, Quinn, Thomas
We present a comprehensive series of $N$-body as well as $N$-body + SPH simulations to study the secular evolution of the structure of disk galaxies. Our simulations are organized in a hierarchy of...
Kaufmann, Tobias, Mayer, Lucio, Wadsley, James, Stadel, Joachim, Moore, Ben
We study the formation of disks via the cooling flow of gas within galactic haloes using smoothed particle hydrodynamics simulations. These simulations resolve mass scales of a few thousand solar...
Simultaneous ram pressure and tidal stripping; how dwarf spheroidals lost their gas (2005)
Mayer, Lucio, Mastropietro, Chiara, Wadsley, James, Stadel, Joachim, Moore, Ben
We perform high-resolution N-Body+SPH simulations of gas-rich dwarf galaxy satellites orbiting within a Milky Way-sized halo and study for the first time the combined effects of tides and ram...
High resolution SPH simulations of disk formation in CDM halos; resolution tests (2004)
Kaufmann, Tobias, Mayer, Lucio, Moore, Ben, Stadel, Joachim, Wadsley, James
We perform N-Body/SPH simulations of disk galaxy formation inside equilibrium spherical and triaxial cuspy dark matter halos. We systematically study the disk properties and morphology as we increase...
The gravitational and hydrodynamical interaction between the LMC and the Galaxy (2004)
Mastropietro, Chiara, Moore, Ben, Mayer, Lucio, Wadsley, James, Stadel, Joachim
We use high resolution N-Body/SPH simulations to study the hydrodynamical and gravitational interaction between the Large Magellanic Cloud and the Milky Way. We model the dark and hot extended halo...
Kazantzidis, Stelios, Mayer, Lucio, Colpi, Monica, Madau, Piero, Debattista, Victor P., Wadsley, James, ...
We analyze the effect of dissipation on the orbital evolution of supermassive black holes (SMBHs) using high-resolution self-consistent gasdynamical simulations of binary equal- and unequal-mass...
Mayer, Lucio, Wadsley, James, Quinn, Thomas, Stadel, Joachim
We use high resolution 3D SPH simulations to study the evolution of self-gravitating binary protoplanetary disks. Heating by shocks and cooling are included. We consider different orbital separations...
The Origin and Properties of Intracluster Stars in a Rich Cluster (2004)
Willman, Beth, Governato, Fabio, Wadsley, James, Quinn, Thomas
We use a multi million particle N-body + SPH simulation to follow the formation of a rich galaxy cluster in a Lambda+CDM cosmology, with the goal of understanding the origin and properties of...
Giant planet formation from disk instability; cooling and heating (2003)
Mayer, Lucio, Wadsley, James, Quinn, Thomas, Stadel, Joachim
We present the results of high resolution SPH simulations of the evolution of gravitationally unstable protoplanetary disks. We report on calculations in which the disk is evolved using a locally...
Mayer, Lucio, Quinn, Thomas, Wadsley, James, Stadel, Joachim
We carry out a large set of very high resolution, three dimensional smoothed particle hydrodynamics (SPH) simulations describing the evolution of gravitationally unstable gaseous protoplanetary...
Sweeping and shaking dwarf satellites (2003)
We present the first high-resolution N-Body/SPH simulations that follow the evolution of low surface brightness disk satellites in a primary halo containing both dark matter and a hot gas component....
Simulations of Gaseous Disc-Embedded Planet Interaction (2003)
Lufkin, Graeme, Quinn, Thomas, Wadsley, James, Stadel, Joachim, Governato, Fabio
We present three-dimensional self-gravitating smoothed-particle hydrodynamics (SPH) simulations of an isothermal gaseous disc interacting with an embedded planet. Discs of varying stability are...
Gasoline: An adaptable implementation of TreeSPH (2003)
Wadsley, James, Stadel, Joachim, Quinn, Thomas
The key algorithms and features of the Gasoline code for parallel hydrodynamics with self-gravity are described. Gasoline is an extension of the efficient Pkdgrav parallel N-body code using smoothed...
We perform several high resolution N-Body/SPH simulations of low surface brightness galaxies (LSBs) embedded in cold dark matter halos to study how likely is bar formation in such systems. The...
Simulations of unstable gaseous disks and the origin of giant planets (2003)
Mayer, Lucio, Quinn, Thomas, Wadsley, James, Stadel, Joachim
We study the evolution of cold, gravitationally unstable protoplanetary gaseous disks performing 3D SPH simulations with up to a million particles on large parallel machines. We show that...
Formation of giant planets by fragmentation of protoplanetary disks (2003)
Mayer, Lucio, Quinn, Thomas, Wadsley, James, Stadel, Joachim
The evolution of gravitationally unstable protoplanetary gaseous disks has been studied with the use of three-dimensional smoothed particle hydrodynamics simulations with unprecedented resolution. We...
High Performance Computing in Astrophysics: Parallel Gasdynamics and Gasoline (2003)
this paper we begin by tracing past progress in computational astrophysics with a particular focus on selfgravitating systems (N -body) and the inclusion of hydrodynamics. Historically, many codes...
Fragmentation and Collapse of Turbulent Molecular Clouds (2002)
Tilley, David A., Pudritz, Ralph E., Wadsley, James
We performed simulations of self-gravitating hydrodynamic turbulence to model the formation of filaments, clumps and cores in molecular clouds. We find that when the mass on the initial computational...
The Metamorphosis of Tidally Stirred Dwarf Galaxies (2001)
Mayer, Lucio, Governato, Fabio, Colpi, Monica, Moore, Ben, Quinn, Thomas, Wadsley, James, ...
We present results from high-resolution N-Body/SPH simulations of rotationally supported dwarf irregular galaxies moving on bound orbits in the massive dark matter halo of the Milky Way.The dwarf...
Tidal stirring and the origin of dwarf spheroidals in the Local Group (2000)
Mayer, Lucio, Governato, Fabio, Colpi, Monica, Moore, Ben, Quinn, Tom, Wadsley, James, ...
N-Body/SPH simulations are used to study the evolution of dwarf irregular galaxies (dIrrs) entering the dark matter halo of the Milky Way or M31 on plunging orbits. We propose a new dynamical...