5.1k citations · 6.9k across the 41 of their papers we have counts for
18 papers · 1 filter
Predictions of Quasar Clustering: Redshift, Luminosity and Selection Dependence
Robert J. Thacker, Evan Scannapieco, H. M. P. Couchman +1
We show that current clustering observations of quasars and luminous AGN can be explained by a merger model augmented by feedback from outflows. Using numerical simulations large e…
Subhaloes in Scale-Free Cosmologies
P. J. Elahi, R. J. Thacker, L. M. Widrow +1
We explore the dependence of the subhalo mass function on the spectral index n of the linear matter power spectrum using scale-free Einstein-de Sitter simulations with n=-1 and n=-…
An N-body/SPH Study of Isolated Galaxy Mass Density Profiles
Kelly Foyle, Stephane Courteau, Robert Thacker
We investigate the evolution of mass density profiles in secular disk galaxy models, paying special attention to the development of a two-component profile from a single initial ex…
Measuring AGN Feedback with the Sunyaev-Zel'dovich Effect
Evan Scannapieco, Robert J. Thacker, H. M. P. Couchman
One of the most important and poorly-understood issues in structure formation is the role of outflows driven by active galactic nuclei (AGN). Using large-scale cosmological simulat…
Quasars: What turns them off?
Robert J. Thacker, Evan Scannapieco, H. M. P. Couchman
(Abridged) We explore the idea that the anti-hierarchical turn-off observed in the quasar population arises from self-regulating feedback, via an outflow mechanism. Using a detaile…
A New Fast Parallel Statistical Measurement Technique for Computational Cosmology
R. J. Thacker, H. M. P. Couchman
Higher order cumulants of point processes, such as skew and kurtosis, require significant computational effort to calculate. The traditional counts-in-cells method implicitly requi…
A Parallel Adaptive P3M code with Hierarchical Particle Reordering
R. J. Thacker, H. M. P. Couchman
We discuss the design and implementation of HYDRA_OMP a parallel implementation of the Smoothed Particle Hydrodynamics-Adaptive P3M (SPH-AP3M) code HYDRA. The code is designed prim…
Simulating the joint evolution of quasars, galaxies and their large-scale distribution
Volker Springel, Simon D. M. White, Adrian Jenkins +14
The cold dark matter model has become the leading theoretical paradigm for the formation of structure in the Universe. Together with the theory of cosmic inflation, this model make…
The Sources of Intergalactic Metals
E. Scannapieco, C. Pichon, B. Aracil +5
We study the clustering properties of metals in the intergalactic medium (IGM) as traced by 619 CIV, 81 SiIV, N >= 10^12 cm^-2 and 316 MgII, and 82 FeII N >= 10^11.5 cm^-2 absorpti…
Toward an Improved Analytical Description of Lagrangian Bias
Evan Scannapieco, Robert J. Thacker
We carry out a detailed numerical investigation of the spatial correlation function of the initial positions of cosmological dark matter halos. In this Lagrangian coordinate system…
Temporal Bias in the Clustering of Massive Cosmological Objects
Evan Scannapieco, Robert J. Thacker
It is a well-established fact that massive cosmological objects exhibit a ``geometrical bias'' that boosts their spatial correlations with respect to the underlying mass distributi…
On the Spatial Correlations of Lyman Break Galaxies
Evan Scannapieco, Robert J. Thacker
Motivated by the observed discrepancy between the strong spatial correlations of Lyman break galaxies (LBGs) and their velocity dispersions, we consider a theoretical model in whic…
Violence in the Dark Ages
R. J. Thacker, E. Scannapieco, M. Davis
A wide range of observational and theoretical arguments suggest that the universe experienced a period of heating and metal enrichment, most likely from starbursting dwarf galaxies…
Star Formation, Supernovae Feedback and the Angular Momentum Problem in Numerical CDM Cosmogony: Half Way There?
R. J. Thacker, H. M. P. Couchman
We present a smoothed particle hydrodynamic (SPH) simulation that reproduces a galaxy that is a moderate facsimile of those observed. The primary failing point of previous simulati…
High-Redshift Galaxy Outflows and the Formation of Dwarf Galaxies
Evan Scannapieco, Robert J. Thacker, Marc Davis
We examine the effects of galaxy outflows on the formation of dwarf galaxies in numerical simulations of the high-redshift Universe. Using a Smoothed Particle Hydrodynamic code, we…
Implementing Feedback in Simulations of Galaxy Formation: A Survey of Methods
R. J. Thacker, H. M. P. Couchman
We present a detailed investigation of different approaches to modeling feedback in simulations of galaxy formation. Gas-dynamic forces are evaluated using Smoothed Particle Hydrod…
High Resolution Simulation of Galaxy Formation with Feedback
R. J. Thacker, H. M. P. Couchman
We present results from a Smoothed Particle Hydrodynamic (SPH) simulation of galaxy formation that exceeds the minimum resolution requirement suggested by Steinmetz & Muller (1993)…
Smoothed Particle Hydrodynamics in cosmology: a comparative study of implementations
R. J. Thacker, E. R. Tittley, F. R. Pearce +2
We analyse the performance of twelve different implementations of Smoothed Particle Hydrodynamics (SPH) using seven tests designed to isolate key hydrodynamic elements of cosmologi…