Adaptive Mesh Fluid Simulations on GPU (2009)
Wang, Peng, Abel, Tom, Kaehler, Ralf
We describe an implementation of compressible inviscid fluid solvers with block-structured adaptive mesh refinement on Graphics Processing Units using NVIDIA's CUDA. We show that a class of high...
Computational Eulerian Hydrodynamics and Galilean Invariance (2009)
Robertson, Brant E., Kravtsov, Andrey V., Gnedin, Nickolay Y., Abel, Tom, Rudd, Douglas H.
Eulerian hydrodynamical simulations are a powerful and popular tool for modeling fluids in astrophysical systems. In this work, we critically examine recent claims that these methods violate Galilean...
Outflow Feedback Regulated Massive Star Formation in Parsec-Scale Cluster Forming Clumps (2009)
Wang, Peng, Li, Zhi-Yun, Abel, Tom, Nakamura, Fumitaka
(Abridged) We investigate massive star formation in turbulent, magnetized, parsec-scale clumps of molecular clouds including protostellar outflow feedback using Enzo-based MHD simulations with...
The Formation of Population III Binaries from Cosmological Initial Conditions (2009)
Turk, Matthew J., Abel, Tom, O'Shea, Brian W.
Previous high resolution cosmological simulations predict the first stars to appear in the early universe to be very massive and to form in isolation. Here we discuss a cosmological simulation in...
Galaxy Mergers with Adaptive Mesh Refinement: Star Formation and Hot Gas Outflow (2009)
Kim, Ji-hoon, Wise, John H., Abel, Tom
In hierarchical structure formation, merging of galaxies is frequent and known to dramatically affect their properties. To comprehend these interactions high-resolution simulations are indispensable...
The Impact of Inhomogeneous Reionization on the Satellite Galaxy Population of the Milky Way (2009)
Busha, Michael T., Alvarez, Marcelo A., Wechsler, Risa H., Abel, Tom, Strigari, Louis E.
We use the publicly available subhalo catalogs from the Via Lactea simulation along with a Gpc-scale N-body simulation to understand the impact of inhomogeneous reionization on the satellite galaxy...
Connecting Reionization to the Local Universe (2008)
Alvarez, Marcelo A., Busha, Michael T., Abel, Tom, Wechsler, Risa H.
We present results of combined N-body and three-dimensional reionization calculations to determine the relationship between reionization history and local environment in a volume 1 Gpc/h across and a...
Accretion onto the First Stellar Mass Black Holes (2008)
Alvarez, Marcelo A., Wise, John H., Abel, Tom
The first stars in the universe, forming at redshifts z>15 in minihalos with masses of order 10^6 Msun, may leave behind black holes as their remnants. These objects could conceivably serve as...
Abstract GPU-Assisted Raycasting for Cosmological Adaptive Mesh Refinement Simulations (2008)
T. Möller, R. Machiraju, T. Ertl, M. Chen (editors, Ralf Kaehler, John Wise, ...
In the recent years the advent of powerful graphics hardware with flexible, programmable fragment shaders enabled interactive raycasting implementations which perform the ray-integration on a...
First Stars III Conference Summary (2008)
O'Shea, Brian W., McKee, Christopher F., Heger, Alexander, Abel, Tom
The understanding of the formation, life, and death of Population III stars, as well as the impact that these objects had on later generations of structure formation, is one of the foremost issues in...
Using magnetohydrodynamic (MHD) adaptive mesh refinement simulations, we study the formation and early evolution of disk galaxies with a magnetized interstellar medium. For a $10^{10}$ \msun halo...
The Radiative Feedback Of The First Cosmological Objects (2007)
Zolt' An, Zolt An Haiman, Tom Abel, Martin J. Rees
In hierarchical models of structure formation, an early cosmic UV background (UVB) is produced by the small (T vir ¸ ! 10 4 K) halos that collapse before reionization. The UVB at energies below...
THREE-DIMENSIONAL RADIATIVE TRANSFER (2007)
Los efectos de la transferencia radiativa (RT) juegan un papel crucial en el historial termico del medio intergalactico. Aqu presento los avances recientes en el desarrollo de los metodos numericos...
ABSTRACT Rendering The First Star In The Universe- A Case Study (2007)
Ralf Kähler, Donna Cox, Robert Patterson, Stuart Levy, Hans-christian Hege, Tom Abel
For quantitative examination of phenomena that simultaneously occur on very different spatial and temporal scales, adaptive hierarchical schemes are required. A special numerical multilevel...
RevMexAA (Serie de Conferencias), 9, 300--304 (2000) (2007)
Radiative Transfer (RT) e#ects play a crucial role in the thermal history of the intergalactic medium. Here I discuss recent advances in the development of numerical methods that introduce RT to...
How Very Massive Metal Free Stars Start Cosmological Reionization (2007)
(Abridged) Using ab initio cosmological Eulerian adaptive mesh refinement radiation hydrodynamical calculations, we discuss how very massive stars start the process of cosmological reionization. The...
Resolving the Formation of Protogalaxies. III. Feedback from the First Stars (2007)
The first stars form in dark matter halos of masses ~10^6 M_sun as suggested by an increasing number of numerical simulations. Radiation feedback from these stars expels most of the gas from their...
Resolving the Formation of Protogalaxies. II. Central Gravitational Collapse (2007)
Wise, John H., Turk, Matthew J., Abel, Tom
Numerous cosmological hydrodynamic studies have addressed the formation of galaxies. Here we choose to study the first stages of galaxy formation, including non-equilibrium atomic primordial gas...
Suppression of H_2 Cooling in the Ultraviolet Background (2007)
The first luminous objects in the concordance cosmology form by molecular hydrogen cooling in dark matter dominated halos of masses ~10^6 M_sun. We use Eulerian adaptive mesh refinement simulations...
Metal Cooling in Simulations of Cosmic Structure Formation (2007)
Smith, Britton D., Sigurdsson, Steinn, Abel, Tom
The addition of metals to any gas can significantly alter its evolution by increasing the rate of radiative cooling. In star-forming environments, enhanced cooling can potentially lead to...
Resolving the Formation of Protogalaxies. I. Virialization (2007)
(Abridged) Galaxies form in hierarchically assembling dark matter halos. With cosmological three dimensional adaptive mesh refinement simulations, we explore in detail the virialization of baryons in...
Quasar H II Regions During Cosmic Reionization (2007)
Alvarez, Marcelo A., Abel, Tom
Cosmic reionization progresses as HII regions form around sources of ionizing radiation. Their average size grows continuously until they percolate and complete reionization. We demonstrate how this...
Wang, Peng, Abel, Tom, Zhang, Weiqun
Astrophysical relativistic flow problems require high resolution three-dimensional numerical simulations. In this paper, we describe a new parallel three-dimensional code for simulations of special...
Supermassive Black Hole Growth and Merger Rates from Cosmological N-body Simulations (2007)
Micic, Miroslav, Holley-Bockelmann, Kelly, Sigurdsson, Steinn, Abel, Tom
Understanding how seed black holes grow into intermediate and supermassive black holes (IMBHs and SMBHs, respectively) has important implications for the duty-cycle of active galactic nuclei (AGN),...
Dynamical Treatment of Virialization Heating in Galaxy Formation (2007)
In a hierarchical picture of galaxy formation virialization continually transforms gravitational potential energy into kinetic energies of the baryonic and dark matter. For the gaseous component the...
The Role of Primordial Kicks on Black Hole Merger Rates (2006)
Micic, Miroslav, Abel, Tom, Sigurdsson, Steinn
Primordial stars are likely to be very massive >30 Msun, form in isolation, and will likely leave black holes as remnants in the centers of their host dark matter halos. We expect primordial stars to...
Formation of Primordial Stars in a LCDM Universe (2006)
Yoshida, Naoki, Omukai, Kazuyuki, Hernquist, Lars, Abel, Tom
We study the formation of the first generation of stars in the standard cold dark matter model, using a very high-resolution hydordynamic simulations. Our simulation achieves a dynamic range of...
The HII Region of a Primordial Star (2006)
Abel, Tom, Wise, John H., Bryan, Greg L.
The concordance model of cosmology and structure formation predicts the formation of isolated very massive stars at high redshifts in dark matter dominated halos of 10^5 to 10^6 Msun. These stars...
Mac Low, Mordecai-Mark, Toraskar, Jayashree, Oishi, Jeffrey S., Abel, Tom
The nature of ultracompact H II regions (UCHRs) remains poorly determined. In particular, they are about an order of magnitude more common than would be expected if they formed around young massive...
The Role of Primordial Kicks on Black Hole Merger Rates (2005)
Micic, Miroslav, Abel, Tom, Sigurdsson, Steinn
Primordial stars are likely to be very massive $\geq30\Msun$, form in isolation, and will likely leave black holes as remnants in the centers of their host dark matter halos in the mass range...
An excursion set model of the cosmic web: The abundance of sheets, filaments and halos (2005)
Shen, Jiajian, Abel, Tom, Mo, H. J., Sheth, Ravi
We discuss an analytic approach for modeling structure formation in sheets, filaments and knots. This is accomplished by combining models of triaxial collapse with the excursion set approach: sheets...
The Formation of Primordial Luminous Objects (2005)
Ripamonti, Emanuele, Abel, Tom
In these lecture notes we review the current knowledge about the formation of the first luminous objects. We start from the cosmological context of hierarchical models of structure formation, and...
Forming a Primordial Star in a Relic HII Region (2005)
O'Shea, Brian W., Abel, Tom, Whalen, Dan, Norman, Michael L.
There has been considerable theoretical debate over whether photoionization and supernova feedback from the first Population III stars facilitate or suppress the formation of the next generation of...
The Number of Supernovae from Primordial Stars in the Universe (2004)
Recent simulations of the formation of the first luminous objects in the universe predict isolated very massive stars to form in dark matter halos with virial temperatures large enough to allow...
Initial Ionization of Compressible Turbulence (2004)
Li, Yuexing, Mac Low, Mordecai-Mark, Abel, Tom
We study the effects of the initial conditions of turbulent molecular clouds on the ionization structure in newly formed H_{ii} regions, using three-dimensional, photon-conserving radiative transfer...
Introducing Enzo, an AMR Cosmology Application (2004)
O'Shea, Brian W., Bryan, Greg, Bordner, James, Norman, Michael L., Abel, Tom, Harkness, Robert, ...
In this paper we introduce Enzo, a 3D MPI-parallel Eulerian block-structured adaptive mesh refinement cosmology code. Enzo is designed to simulate cosmological structure formation, but can also be...
Cosmic reionization by stellar sources: population III stars (2004)
Sokasian, Aaron, Yoshida, Naoki, Abel, Tom, Hernquist, Lars, Springel, Volker
Ripamonti, Emanuele, Abel, Tom
The mechanisms which could lead to chemo-thermal instabilities and fragmentation during the formation of primordial protostars are investigated analytically. We introduce approximations for H2...
Radiation Hydrodynamical Evolution of Primordial H II Regions (2003)
Whalen, Daniel, Abel, Tom, Norman, Michael L.
We simulate the ionization environment of z ~ 20 luminous objects formed within the framework of the current CDM cosmology and compute their UV escape fraction. These objects are likely single very...
The Angular Momentum of Gas in Proto-Galaxies: II -- The Impact of Preheating (2003)
We examine the effect of preheating of the intergalactic medium on galaxy formation using cosmological hydrodynamical simulations. By performing simulations both with and without a simple model for...
Cosmic Reionisation by Stellar Sources: Population III Stars (2003)
Sokasian, Aaron, Yoshida, Naoki, Abel, Tom, Hernquist, Lars, Springel, Volker
We combine fast radiative transfer calculations with high resolution hydrodynamical simulations to study an epoch of early hydrogen reionisation by primordial stellar sources at redshifts 15
Cosmic Reionisation by Stellar Sources: Population II Stars (2003)
Sokasian, Aaron, Abel, Tom, Hernquist, Lars, Springel, Volker
We study the reionisation of the Universe by stellar sources using a numerical approach that combines fast 3D radiative transfer calculations with high resolution hydrodynamical simulations. Ionising...
Simulations of Early Structure Formation: Primordial Gas Clouds (2003)
Yoshida, Naoki, Abel, Tom, Hernquist, Lars, Sugiyama, Naoshi
(abridged) We use large cosmological simulations to study the origin of primordial star-forming clouds in a Lambda CDM universe, by following the formation of dark matter halos and the cooling of gas...
first stars Elektronische Daten (2003)
Abel, Tom, Astrophysics Conference
Talk Abstract von Kongress: Star and Structure Formation: From First Light to the Milky Way, Astrophysics Conference, August 18-22, 2003, ETH Zurich, Switzerland
Numerical Simulations of High Redshift Star Formation in Dwarf Galaxies (2002)
Tassis, Konstantinos, Abel, Tom, Bryan, Greg L., Norman, Michael L.
We present first results from three-dimensional hydrodynamic simulations of the high redshift formation of dwarf galaxies. The simulations use an Eulerian adaptive mesh refinement technique to follow...
Effects of a Soft X-ray Background on Structure Formation at High Redshift (2002)
Machacek, Marie M., Bryan, Greg L., Abel, Tom
We use three dimensional hydrodynamic simulations to investigate the effects of a soft X-ray background, that could have been produced by an early generation of mini-quasars, on the subsequent...
Fujita, Akimi, Martin, Crystal, Mac Low, Mordecai-Mark, Abel, Tom
We study the escape of Lyman continuum radiation from the disks of dwarf starburst galaxies, with and without supershells, by solving the radiation transfer problem of stellar radiation through them....
The Nature of the Ionising Background at z=2.5-5 (2002)
Sokasian, Aaron, Abel, Tom, Hernquist, Lars E.
Using radiative transfer calculations and cosmological simulations of structure formation, we study constraints that can be placed on the nature of the cosmic ultraviolet (UV) background in the...
Abel, Tom, Croft, Rupert A. C., Hernquist, Lars, White, Simon D. M.
We use non-radiative N-body/SPH simulations of structure formation in a LCDM cosmology to compare the angular momentum distributions of dark matter and gas in a large sample of halos. We show that...
Evolution and explosion of very massive primordial stars (2002)
Heger, Alexander, Woosley, Stan, Baraffe, Isabelle, Abel, Tom
The Epoch of Helium Reionization (2001)
Sokasian, Aaron, Abel, Tom, Hernquist, Lars. E.
We study the reionization of Helium II by quasars using a numerical approach that combines 3D radiative transfer calculations with cosmological hydrodynamical simulations. Sources producing the...
The Formation of the First Star in the Universe (2001)
Abel, Tom, Bryan, Greg L., Norman, Michael L.
We describe results from a fully self-consistent three dimensional hydrodynamical simulation of the formation of one of the first stars in the Universe. Dark matter dominated pre-galactic objects...
Bryan, Greg L., Abel, Tom, Norman, Michael L.
As an entry for the 2001 Gordon Bell Award in the "special" category, we describe our 3-d, hybrid, adaptive mesh refinement (AMR) code, Enzo, designed for high-resolution, multiphysics, cosmological...
On the "initial" Angular Momentum of Galaxies (2001)
Abel, Tom, Croft, Rupert C., Hernquist, Lars
Spherical density profiles and specific angular momentum profiles of Dark Matter halos found in cosmological N-body simulations have been measured extensively. The distribution of the total angular...
Adaptive Ray Tracing for Radiative Transfer around Point Sources (2001)
Abel, Tom, Wandelt, Benjamin D.
We describe a novel adaptive ray tracing scheme to solve the equation of radiative transfer around point sources in hydrodynamical simulations. The angular resolution adapts to the local...
Di Matteo, Tiziana, Perna, Rosalba, Abel, Tom, Rees, Martin J.
Absorption or emission against the cosmic microwave background radiation (CMB) may be observed in the redshifted 21cm line if the spin temperature of the neutral intergalactic medium prior to...
Cosmological Hydrogen Reionization with Three Dimensional Radiative Transfer (2001)
Razoumov, Alexei O., Norman, Michael L., Abel, Tom, Scott, Douglas
We present new calculations of the inhomogeneous process of cosmological reionization by carefully following the radiative transfer in pre-computed hydrodynamical simulations of galaxy formation....
Multi--dimensional Cosmological Radiative Transfer with a Variable Eddington Tensor Formalism (2001)
Gnedin, Nickolay Y., Abel, Tom
We present a new approach to numerically model continuum radiative transfer based on the Optically Thin Variable Eddington Tensor (OTVET) approximation. Our method insures the exact conservation of...
Simulating Reionization in Numerical Cosmology (2001)
Sokasian, Aaron, Abel, Tom, Hernquist, Lars E.
The incorporation of radiative transfer effects into cosmological hydrodynamical simulations is essential for understanding how the intergalactic medium (IGM) makes the transition from a neutral...
Greg L. Bryan, Tom Abel, Michael L. Norman
As an entry for the 2001 Gordon Bell Award in the “special ” category, we describe our 3-d, hybrid, adaptive mesh refinement (AMR) code Enzo designed for high-resolution, multiphysics,...
Photon Consumption in Minihalos during Cosmological Reionization (2000)
Haiman, Zoltan, Abel, Tom, Madau, Piero
At the earliest epochs of structure formation in cold dark matter (CDM) cosmologies, the smallest nonlinear objects are the numerous small halos that condense with virial temperatures below 10,000 K....
Simulations of Pregalactic Structure Formation with Radiative Feedback (2000)
Machacek, Marie E., Bryan, Greg L., Abel, Tom
We present results from three-dimensional hydrodynamic simulations of the high redshift collapse of pregalactic clouds including feedback effects from a soft H2 photodissociating UV radiation field....
First Structure Formation and the First Stars (2000)
Norman, Michael L., Abel, Tom, Bryan, Greg
We discuss the results of recent 3D simulations of first structure formation in relationship to the formation of the first stars. On the basis of a new, high-resolution AMR simulation (spatial...
Three Dimensional Radiative Transfer (2000)
Radiative Transfer (RT) effects play a crucial role in the thermal history of the intergalactic medium. Here I discuss recent advances in the development of numerical methods that introduce RT to...
The Formation and Fragmentation of Primordial Molecular Clouds (2000)
Abel, Tom, Bryan, Greg L., Norman, Michael L.
Many questions in physical cosmology regarding the thermal history of the intergalactic medium, chemical enrichment, reionization, etc. are thought to be intimately related to the nature and...
The Role of H2 Molecules in Cosmological Structure Formation (2000)
We review the relevance of H2 molecules for structure formation in cosmology. Molecules are important at high redshifts, when the first collapsed structures appear with typical temperatures of a few...
Three-dimensional radiative transfer (2000)
Radiative Transfer (RT) e ects play a crucial role in the thermal history of the intergalactic medium. Here I discuss recent advances in the development of numerical methods that introduce RT to...
The Radiative Feedback of the First Cosmological Objects (1999)
Haiman, Zoltan, Abel, Tom, Rees, Martin J.
In hierarchical models of structure formation, an early cosmic UV background (UVB) is produced by the small (T_vir < 10^4 K) halos that collapse before reionization. The UVB at energies below 13.6eV...
Radiative Transfer Effects during Photoheating of the Intergalactic Medium (1999)
Abel, Tom, Haehnelt, Martin G.
The thermal history of the intergalactic medium (IGM) after reionization is to a large extent determined by photoheating. Here we demonstrate that calculations of the photoheating rate which neglect...
Absorption Line Signatures of Gas in Mini Dark Matter Halos (1999)
Kepner, Jeremy, Tripp, Todd, Abel, Tom, Spergel, David
Recent observations and theoretical calculations suggest that some QSO absorption line systems may be due to gas in small dark matter halos with circular velocities on the order of 30 km/s....
Abel, Tom, Norman, Michael L., Madau, Piero
Many questions in physical cosmology regarding the thermal and ionization history of the intergalactic medium are now successfully studied with the help of cosmological hydrodynamical simulations....
Ciardi, Benedetta, Ferrara, Andrea, Abel, Tom
We study the effects of the ionizing and dissociating photons produced by PopIII objects on the surrounding intergalactic medium. We find that the typical size of a H_2 photodissociated region, R_d ~...
The Formation and Fragmentation of Primordial Molecular Clouds (1998)
Abel, Tom, Bryan, Greg L., Norman, Michael L.
Many questions in physical cosmology regarding the thermal history of the intergalactic medium, chemical enrichment, reionization, etc. are thought to be intimately related to the nature and...
Simulating Inhomogeneous Reionization (1998)
Norman, Michael L., Paschos, Paschalis, Abel, Tom
We describe an approach for incorporating radiative transfer into 3D hydrodynamic cosmological simulations. The method, while approximate, allows for a self-consistent treatment of self-shielding and...
A Minihalo Model for the Lyman Limit Absorption Systems at High Redshift (1997)
We propose that a large fraction of the QSO Lyman limit absorption systems (LLS) observed at high redshift (z > 3) originate from gas trapped in small objects, such as minihalos, that form prior to...
First Structure Formation: II. Cosmic String + Hot Dark Matter Models (1997)
Abel, Tom, Stebbins, Albert, Anninos, Peter, Norman, Michael L.
We examine the structure of baryonic wakes in the cosmological fluid which would form behind GUT-scale cosmic strings at early times (redshifts z > 100) in a neutrino-dominated universe. We show,...
First Structure Formation: I. Primordial Star Forming Regions in hierarchical models (1997)
Abel, Tom, Anninos, Peter, Norman, Michael L., Zhang, Yu
We investigate the possibility of very early formation of primordial star clusters from high-\sigma perturbations in cold dark matter dominated structure formation scenarios. For this we have...
Primordial Star Forming Regions in a CDM Universe (1996)
Zhang, Yu, Norman, Michael L., Anninos, Peter, Abel, Tom
We developed a three-dimensional 2-level hierarchical cosmological code with a realistic and robust treatment of multi-species non-equilibrium ionization and radiative cooling processes, and use it...
Anninos, Peter, Zhang, Yu, Abel, Tom, Norman, Michael L.
We have developed a method of solving for multi-species chemical reaction flows in non--equilibrium and self--consistently with the hydrodynamic equations in an expanding FLRW universe. The method is...
How small were the first cosmological objects? (1996)
Tegmark, Max, Silk, Joseph, Rees, Martin, Blanchard, Alain, Abel, Tom, Palla, Francesco
The minimum mass that a virialized gas cloud must have in order to be able to cool in a Hubble time is computed, using a detailed treatment of the chemistry of molecular hydrogen. With a simple model...