Jelic, Vibor, Zaroubi, Saleem, Aghanim, Nabila, Douspis, Marian, Koopmans, Leon V. E., Langer, Mathieu, ...
The Universe's Epoch of Reionization (EoR) can be studied using a number of observational probes that provide complementary or corroborating information. Each of these probes suffers from its own...
Measuring the History of Cosmic Reionization using the 21-cm PDF from Simulations (2009)
Ichikawa, Kazuhide, Barkana, Rennan, Iliev, Ilian T., Mellema, Garrelt, Shapiro, Paul
The 21-cm PDF (i.e., distribution of pixel brightness temperatures) is expected to be highly non-Gaussian during reionization and to provide important information on the distribution of density and...
A Physical Model of Lyman Alpha Emitters (2009)
Tilvi, Vithal, Malhotra, Sangeeta, Rhoads, James E., Scannapieco, Evan, Thacker, Robert J., Iliev, Ilian T., ...
We present a simple physical model for populating dark matter halos with Lyman Alpha Emiiters(LAEs) and predict the physical properties of LAEs at z~3-7. The central tenet of this model is that the...
Cosmological Radiative Transfer Comparison Project II: The Radiation-Hydrodynamic Tests (2009)
Iliev, Ilian T., Whalen, Daniel, Mellema, Garrelt, Ahn, Kyungjin, Baek, Sunghye, Gnedin, Nickolay Y., ...
The development of radiation hydrodynamical methods that are able to follow gas dynamics and radiative transfer self-consistently is key to the solution of many problems in numerical astrophysics....
Non-parametric foreground subtraction for 21cm epoch of reionization experiments (2009)
Harker, Geraint, Zaroubi, Saleem, Bernardi, Gianni, Brentjens, Michiel A., De Bruyn, A. G., Ciardi, Benedetta, ...
An obstacle to the detection of redshifted 21cm emission from the epoch of reionization (EoR) is the presence of foregrounds which exceed the cosmological signal in intensity by orders of magnitude....
Fast large-scale reionization simulations (2009)
Thomas, Rajat M., Zaroubi, Saleem, Ciardi, Benedetta, Pawlik, Andreas H., Labropoulos, Panagiotis, Jelic, Vibor, ...
Harker, Geraint J. A., Zaroubi, Saleem, Thomas, Rajat M., Jelic, Vibor, Labropoulos, Panagiotis, Mellema, Garrelt, ...
Non-parametric foreground subtraction for 21-cm epoch of reionization experiments (2009)
Harker, Geraint, Zaroubi, Saleem, Bernardi, Gianni, Brentjens, Michiel A., De Bruyn, A. G., Ciardi, Benedetta, ...
Radiation-magnetohydrodynamic simulations of the photoionisation of magnetised globules (2008)
Henney, William J., Arthur, S. Jane, De Colle, Fabio, Mellema, Garrelt
We present the first three-dimensional radiation-magnetohydrodynamic simulations of the photoionisation of a dense, magnetised molecular globule by an external source of ultraviolet radiation. We...
Harker, Geraint J. A., Zaroubi, Saleem, Thomas, Rajat M., Jelic, Vibor, Labropoulos, Panagiotis, Mellema, Garrelt, ...
Detecting redshifted 21cm emission from neutral hydrogen in the early Universe promises to give direct constraints on the epoch of reionization (EoR). It will, though, be very challenging to extract...
Fast Large-Scale Reionization Simulations (2008)
Thomas, Rajat M., Zaroubi, Saleem, Ciardi, Benedetta, Pawlik, Andreas H., Labropoulos, Panagiotis, Jelic, Vibor, ...
We present an efficient method to generate large simulations of the Epoch of Reionization (EoR) without the need for a full 3-dimensional radiative transfer code. Large dark-matter-only simulations...
Ahn, Kyungjin, Shapiro, Paul R., Iliev, Ilian T., Mellema, Garrelt, Pen, Ue-Li
The first, self-consistent calculations are presented of the cosmological, H2-dissociating UV background produced during the epoch of reionization by the sources of reionization. Large-scale...
The Inhomogeneous Background of H2 Dissociating Radiation During Cosmic Reionization (2008)
Ahn, Kyungjin, Shapiro, Paul R., Iliev, Ilian T., Mellema, Garrelt, Pen, Ue-Li
The first, self-consistent calculations of the cosmological H_2 dissociating UV background produced during the epoch of reionization (EOR) by the sources of reionization are presented. Large-scale...
The Theory and Simulation of the 21-cm Background from the Epoch of Reionization (2008)
Shapiro, Paul R., Iliev, Ilian T., Mellema, Garrelt, Pen, Ue-Li, Merz, Hugh
The redshifted 21-cm line of distant neutral H atoms provides a probe of the cosmic ``dark ages'' and the epoch of reionization (``EOR'') which ended them. The radio continuum produced by this...
Simulating Cosmic Reionization (2008)
Iliev, Ilian T., Shapiro, Paul R., Mellema, Garrelt, Merz, Hugh, Pen, Ue-Li
The Cosmic Dark Ages and the Epoch of Reionization constitute a crucial missing link in our understanding of the evolution of the intergalactic medium and the formation and evolution of galaxies. Due...
Current models of the observable consequences of cosmic reionization and their detectability (2008)
Iliev, Ilian T., Mellema, Garrelt, Pen, Ue-Li, Bond, Richard J., Shapiro, Paul R.
A number of large current experiments aim to detect the signatures of the cosmic reionization at redshifts z > 6. Their success depends crucially on understanding the character of the reionization...
Peplinski, Adam, Artymowicz, Pawel, Mellema, Garrelt
We present a numerical study of rapid, so called type III migration for Jupiter-sized planets embedded in a protoplanetary disc. We limit ourselves to the case of outward migration, and study in...
Growing and moving low-mass planets in non-isothermal disks (2008)
Paardekooper, Sijme-Jan, Mellema, Garrelt
Aims.We study the interaction of a low-mass planet with a protoplanetary disk with a realistic treatment of the energy balance by doing radiation-hydrodynamical simulations. We look at accretion and...
Planetesimal and gas dynamics in binaries (2008)
Paardekooper, Sijme-Jan, Thebault, Philippe, Mellema, Garrelt
Observations of extrasolar planets reveal that planets can be found in close binary systems, where the semi-major axis of the binary orbit is less than 20 AU. The existence of these planets...
Iliev, Ilian T., Mellema, Garrelt, Pen, Ue-Li, Shapiro, Paul R.
Direct detection of the Dark Ages and the Epoch of Reionization (EOR) is among the main scientific objectives of all current and future low-frequency radio facilities. In this paper we summarize and...
Cosmological radiative transfer codes comparison project - I. The static density field tests (2007)
Iliev, Ilian T., Ciardi, Benedetta, Alvarez, Marcelo A., Maselli, Antonella, Ferrara, Andrea, Gnedin, Nickolay Y., ...
Radiative transfer simulations are now at the forefront of numerical astrophysics. They are becoming crucial for an increasing number of astrophysical and cosmological problems; at the same time...
Shaping Planetary Nebulae: Is It Different For [wr] Stars? (2007)
. This review discusses the physics of the formation of planetary nebulae around low mass WR stars, or [WR] stars. It especially focuses on the dierences which can be expected due to the dierent...
The kinematics of the planetary nebula BD+30 (2007)
Myfanwy Bryce And, Myfanwy Bryce, Garrelt Mellema
In this paper we describe the results of the first optical kinematic study of the planetary nebula BD+30 ffi 3639. This system has a central star of the Wolf-Rayet type and is believed to be fairly...
Iliev, Ilian T., Shapiro, Paul R., McDonald, Patrick, Mellema, Garrelt, Pen, Ue-Li
Observations of high-redshift Ly-alpha sources are a major tool for studying the high-redshift Universe. We discuss the effect of the reionizing intergalactic medium on the observability of Ly-alpha...
Reionization: Characteristic Scales, Topology and Observability (2007)
Iliev, Ilian T., Shapiro, Paul R., Mellema, Garrelt, Pen, Ue-Li, McDonald, Patrick, Alvarez, Marcelo A.
Recently the numerical simulations of the process of reionization of the universe at z>6 have made a qualitative leap forward, reaching sufficient sizes and dynamic range to determine the...
Simulating Reionization: Character and Observability (2007)
Iliev, Ilian T., Shapiro, Paul R., Mellema, Garrelt, Pen, Ue-Li, McDonald, Patrick, Bond, J. Richard
In recent years there has been considerable progress in our understanding of the nature and properties of the reionization process. In particular, the numerical simulations of this epoch have made a...
Weinmann, Simone M., Maccio', Andrea V., Iliev, Ilian T., Mellema, Garrelt, Moore, Ben
The reionization of the Universe has profound effects on the way galaxies form and on their observed properties at later times. Of particular importance is the relative timing of the reionization...
Current models of the observable consequences of cosmic reionization and their detectability (2007)
Iliev, Ilian T., Mellema, Garrelt, Pen, Ue-Li, Bond, J. Richard, Shapiro, Paul R.
A number of large current experiments aim to detect the signatures of the Cosmic Reionization at redshifts z>6. Their success depends crucially on understanding the character of the reionization...
The Signature of Patchy Reionization in the Polarization Anisotropy of the CMB (2007)
Doré, Olivier, Holder, Gil, Alvarez, Marcelo, Iliev, Ilian T., Mellema, Garrelt, Pen, Ue-Li, ...
The inhomogeneous ionization state of the universe when the first sources of ionizing radiation appeared should lead to anisotropies in the polarization of the cosmic microwave background. We use...
Holder, Gilbert, Iliev, Ilian T., Mellema, Garrelt
Large fluctuations in the electron column density can occur during the reionization process. We investigate the possibility of deriving the electron density fluctuations through detailed mapping of...
Iliev, Ilian T., Pen, Ue-Li, Bond, J. Richard, Mellema, Garrelt, Shapiro, Paul R.
We present the first calculation of the kinetic Sunyaev-Zel'dovich (kSZ) effect due to the inhomogeneous reionization of the universe based on detailed large-scale radiative transfer simulations of...
Self-regulated reionization (2006)
Iliev, Ilian T., Mellema, Garrelt, Shapiro, Paul R., Pen, Ue-Li
Recently, we have presented the first large-scale radiative transfer simulations of reionization. Here we present new simulations which extend the source halo mass range downward to 10^8M_solar, to...
The Kinetic Sunyaev-Zel'dovich Effect from Patchy Reionization: the View from the Simulations (2006)
Iliev, Ilian T., Pen, Ue-Li, Bond, J. Richard, Mellema, Garrelt, Shapiro, Paul R.
We present the first calculation of the kinetic Sunyaev-Zel'dovich (kSZ) effect due to the inhomogeneus reionization of the universe based on detailed large-scale radiative transfer simulations of...
Mellema, Garrelt, Iliev, Ilian T., Pen, Ue-Li, Shapiro, Paul R.
We present detailed predictions for the redshifted 21cm signal from the epoch of reionization. These predictions are obtained from radiative transfer calculations on the results of large scale (100/h...
Cosmological Radiative Transfer Codes Comparison Project I: The Static Density Field Tests (2006)
Iliev, Ilian T., Ciardi, Benedetta, Alvarez, Marcelo A., Maselli, Antonella, Ferrara, Andrea, Gnedin, Nickolay Y., ...
Radiative transfer simulations are now at the forefront of numerical astrophysics. They are becoming crucial for an increasing number of astrophysical and cosmological problems; at the same time...
Cosmological radiative transfer codes comparison project – I. The static density field tests (2006)
Iliev, Ilian T., Ciardi, Benedetta, Alvarez, Marcelo A., Maselli, Antonella, Ferrara, Andrea, Gnedin, Nickolay Y., ...
Dynamical HII Region Evolution in Turbulent Molecular Clouds (2005)
Mellema, Garrelt, Arthur, S. Jane, Henney, William J., Iliev, Ilian T., Shapiro, Paul R.
We present numerical radiation-hydrodynamic simulations of the evolution of HII regions formed in an inhomogeneous medium resulting from turbulence simulations. We find that the filamentary structure...
Simulating Cosmic Reionization at Large Scales I: the Geometry of Reionization (2005)
Iliev, Ilian T., Mellema, Garrelt, Pen, Ue-Li, Merz, Hugh, Shapiro, Paul R., Alvarez, Marcelo A.
We present the first large-scale radiative transfer simulations of cosmic reionization, in a simulation volume of (100/h Mpc)^3, while at the same time capturing the dwarf galaxies which are...
C^2-Ray: A new method for photon-conserving transport of ionizing radiation (2005)
Mellema, Garrelt, Iliev, Ilian T., Alvarez, Marcelo A., Shapiro, Paul R.
We present a new numerical method for calculating the transfer of ionizing radiation, called C^2-Ray=Conservative, Causal Ray-tracing method. The method is explicitly photon-conserving, so the...
Rijkhorst, Erik-Jan, Plewa, Tomasz, Dubey, Anshu, Mellema, Garrelt
We have developed a three-dimensional radiative transfer method designed specifically for use with parallel adaptive mesh refinement hydrodynamics codes. This new algorithm, which we call hybrid...
Iliev, Ilian T., Shapiro, Paul R., Scannapieco, Evan, Mellema, Garrelt, Alvarez, Marcelo A., Raga, Alejandro C., ...
The propagation of cosmological ionization fronts (I-fronts) during reionization is strongly influenced by small-scale structure. Here we summarize our recent attemps to understand the effect of this...
Planets opening dust gaps in gas disks (2004)
Paardekooper, Sijme-Jan, Mellema, Garrelt
We investigate the interaction of gas and dust in a protoplanetary disk in the presence of a massive planet using a new two-fluid hydrodynamics code. In view of future observations of planet-forming...
On expansion parallax distances for planetary nebulae (2003)
The distances to individual wind-driven bubbles such as Planetary Nebulae (PNe) can be determined using expansion parallaxes: the angular expansion velocity in the sky is compared to the radial...
3D AMR Simulations of Point-Symmetric Nebulae (2003)
Rijkhorst, Erik-Jan, Icke, Vincent, Mellema, Garrelt
At the end of their lives low mass stars such as our Sun lose most of their mass. The resulting planetary nebulae show a wide variety of shapes, from spherical to highly bipolar. According to the...
Three-Dimensional Adaptive Mesh Refinement Simulations of Point-Symmetric Nebulae (2003)
Rijkhorst, Erik-Jan, Icke, Vincent, Mellema, Garrelt
Previous analytical and numerical work shows that the generalized interacting stellar winds model can explain the observed bipolar shapes of planetary nebulae very well. However, many circumstellar...
The post-AGB evolution of AGB mass loss variations (2003)
Meijerink, Rowin, Mellema, Garrelt, Simis, Yvonne
We present new numerical hydrodynamical modelling of the evolution of Asymptotic Giant Branch (AGB) mass loss fluctuations during the post-AGB/Planetary Nebula phase. These models show that after...
High-resolution radio structure and optical kinematics of NGC 7027 (2003)
Bains, Indra, Bryce, Myfanwy, Mellema, Garrelt, Redman, Matt P., Thomasson, Peter
Abstract not available.
High-resolution radio structure and optical kinematics of NGC 7027 (2003)
Bains, Indra, Bryce, Myfanwy, Mellema, Garrelt, Redman, Matt P., Thomasson, Peter
Abstract not available.
High-resolution radio structure and optical kinematics of NGC 7027 (2003)
Bains, Indra, Bryce, Myfanwy, Mellema, Garrelt, Redman, Matt P., Thomasson, Peter
Abstract not available.
High-resolution radio structure and optical kinematics of NGC 7027 (2003)
Bains, Indra, Bryce, Myfanwy, Mellema, Garrelt, Redman, Matt P., Thomasson, Peter
Abstract not available.
High-resolution radio structure and optical kinematics of NGC 7027 (2003)
Bains, Indra, Bryce, Myfanwy, Mellema, Garrelt, Redman, Matt P., Thomasson, Peter
Abstract not available.
Stellar wind bubbles around WR and [WR] stars (2002)
Mellema, Garrelt, Lundqvist, Peter
We study the dynamics of stellar wind bubbles around hydrogen-deficient stars using numerical simulations with time- and ion dependent cooling. We consider two types of hydrogen-deficient stars,...
Evolution of clouds in radio galaxy cocoons (2002)
Mellema, Garrelt, Kurk, Jaron, Rottgering, Huub
This letter presents a numerical study of the evolution of an emission line cloud of initial density 10 cm$^{-3}$, temperature $10^4$ K, and size 200 pc, being overtaken by a strong shock wave....
The electron temperature of the inner halo of the Planetary Nebula NGC 6543 (2001)
Hyung, Siek, Mellema, Garrelt, Lee, Seong-Jae, Kim, Hyouk
We investigate the electron temperature of the inner halo and nebular core regions of NGC 6543, using archival Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC2) images taken through...
Shaping Planetary Nebulae: is it different for [WR] stars? (1999)
This review discusses the physics of the formation of planetary nebulae around low mass WR stars, or [WR] stars. It especially focuses on the differences which can be expected due to the different...
The kinematics of the planetary nebula BD+30 3639 (1999)
Bryce, Myfanwy, Mellema, Garrelt
In this paper we describe the results of the first optical kinematic study of the planetary nebula BD+30 3639. This system has a central star of the Wolf-Rayet type and is believed to be fairly...
Radiative Feedback and the Photoevaporation of Intergalactic Clouds (1998)
Shapiro, Paul R., Raga, Alejandro C., Mellema, Garrelt
The first sources of ionizing radiation to condense out of the dark and neutral IGM sent ionization fronts sweeping outward through their surroundings, overtaking other primordial gas-clouds and...
Outflow collimation in young stellar objects (1997)
In this paper we explore the effect of radiative losses on purely hydrodynamic jet collimation models applicable to Young Stellar Objects (YSOs). In our models aspherical bubbles form from the...
Photo-evaporation of clumps in Planetary Nebulae (1997)
Mellema, Garrelt, Raga, Alejandro C., Canto, Jorge, Lundqvist, Peter, Balick, Bruce, Steffen, Wolfgang, ...
We study the evolution of dense neutral clumps located in the outer parts of planetary nebulae. These clumps will be photo-ionized by the ionizing radiation from the central star and change their...
Reionization Feedback and the Photoevaporation of Intergalactic Clouds (1997)
Shapiro, Paul R., Raga, Alejandro C., Mellema, Garrelt
Energy released by a small fraction of the baryons in the universe, which condensed out of while the IGM was cold, dark, and neutral,reheated and reionized it, exposing gas clouds within it to the...
The formation of bipolar planetary nebulae (1997)
Using a radiation-hydrodynamics code I follow the formation of planetary nebulae around stars of different mass. Because a more massive central star evolves much faster than a lower mass one, it is...
Hydrodynamic collimation of YSO jets (1997)
We present the results of numerical hydrodynamic models for the collimation of outflows from young stellar objects. We show that the presence of a toroidal environment can lead to efficient formation...
Hydrodynamical Models of Outflow Collimation in YSOs (1996)
We explore the physics of time-dependent hydrodynamic collimation of jets from Young Stellar Objects (YSOs). Using parameters appropriate to YSOs we have carried out high resolution hydrodynamic...
This paper reports the results of the numerical study of the formation of aspherical Planetary Nebulae through the Generalised Interacting Winds Model, taking into account the effects caused by the...
General Relativistic Hydrodynamics with a Roe solver (1994)
Eulderink, Frits, Mellema, Garrelt
We present a numerical method to solve the equations of general relativistic hydrodynamics in a given external gravitational field. The method is based on a generalization of Roe's approximate...
Hot bubble and slow wind dynamics in PNe (Radiation-gasdynamics of PNe V) (1994)
This paper looks into various aspects brought to light by numerical work on the generalized interacting winds model for planetary nebulae. First, a detailed comparison between radiative and...
Numerical models and our understanding of aspherical Planetary Nebulae (1994)
The status of numerical hydrodynamical models for Planetary Nebulae is reviewed. Since all of the numerical work is based on the interacting winds model, we start with a description of this model and...
The gasdynamic evolution of spherical planetary nebulae: Radiation-gasdynamics of PNe III (1994)
Using a radiation-gasdynamics code the evolution of spherical planetary nebulae is followed, while taking into account the evolution of central star and the fast wind. These models show the...
From the Owl to the Eskimo: the Radiation-Gasdynamics of Planetary Nebulae IV (1994)
We present the results of two-dimensional radiation-gasdynamic simulations of aspherical Planetary Nebulae (PNe) evolution. These simulations were constructed using the Generalized Interacting...
Numerical models for the formation of aspherical planetary nebulae--door Garrelt Mellema. (1993)
Thesis (doctoral)--Rijksuniversiteit te Leiden, 1993.