Strong magnetic fields in normal galaxies at high redshifts (2008)
Bernet, Martin L., Miniati, Francesco, Lilly, Simon J., Kronberg, Philipp P., Dessauges-Zavadsky, Miroslava
The origin and growth of magnetic fields in galaxies is still something of an enigma. It is generally assumed that seed fields are amplified over time through the dynamo effect, but there are few...
COSMIC RAYS AND THEIR RADIATIVE PROCESSES IN NUMERICAL COSMOLOGY (2008)
Dongsu Ryu, Francesco Miniati, Tom W. Jones, Hyesung Kang
para calcular, de manera simplificada, la aceleración y el transporte de los rayos cósmicos. La rutina fue diseñada para seguir de manera explícita la aceleración difusiva en choques y la...
Ultrahigh energy cosmic rays as heavy nuclei from cluster accretion shocks (2007)
Inoue, Susumu, Sigl, Guenter, Miniati, Francesco, Armengaud, Eric
Large-scale accretion shocks around massive clusters of galaxies, generically expected in hierarchical scenarios of cosmological structure formation, are shown to be potential sources of the observed...
Angular Anisotropies in the Cosmic Gamma-ray Background as a Probe of its Origin (2007)
Miniati, Francesco, Koushiappas, Savvas M., Di Matteo, Tiziana
Notwithstanding the advent of the Gamma-ray Large Area Telescope, theoretical models predict that a significant fraction of the cosmic gamma-ray background (CGB), at the level of 20% of the currently...
Ultrahigh energy cosmic rays as heavy nuclei from cluster accretion shocks (2007)
Inoue, Susumu, Sigl, Guenter, Miniati, Francesco, Armengaud, Eric
Large-scale accretion shocks around massive clusters of galaxies, generically expected in the cold dark matter scenario of cosmological structure formation, are shown to be plausible sources of the...
Fundamental differences between SPH and grid methods (2007)
Agertz, Oscar, Moore, Ben, Stadel, Joachim, Potter, Doug, Miniati, Francesco, Read, Justin, ...
Glimm-Godunov's Method for Cosmic-ray-hydrodynamics (2006)
A numerical method for integrating the equations describing a dynamically coupled system made of a fluid and cosmic-rays is developed. In smooth flows the effect of CR pressure is accounted for by...
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...
Block Structured Adaptive Mesh and Time Refinement for Hybrid, Hyperbolic + N-body Systems (2006)
Miniati, Francesco, Colella, Phillip
We present a new numerical algorithm for the solution of coupled collisional and collisionless systems, based on the block structured adaptive mesh and time refinement strategy (AMR). We describe the...
Cosmic rays and their radiative processes in numerical cosmology (2006)
Dongsu Ryu, Francesco Miniati, Tom W. Jones, Hyesung Kang
Cosmic rays and their radiative processes in numerical cosmology
A Modified Higher Order Godunov's Scheme for Stiff Source Conservative Hydrodynamics (2006)
Miniati, Francesco, Colella, Phillip
Hyperbolic conservation laws with stiff source terms appear in the study of a variety of physical systems. Early work showed that the use of formally second-order accurate semi-implicit methods could...
Gamma Ray Astronomy with Magnetized Zevatrons (2005)
Armengaud, Eric, Sigl, Guenter, Miniati, Francesco
Nearby sources of cosmic rays up to a ZeV(=10^21 eV) could be observed with a multi-messenger approach including secondary gamma-rays and neutrinos. If cosmic rays above ~10^18 eV are produced in...
Deeper Chandra Follow-up of Cygnus TeV Source Perpetuates Mystery (2005)
Butt, Yousaf, Drake, Jeremy, Benaglia, Paula, Combi, Jorge, Dame, Thomas, Miniati, Francesco, ...
A 50 ksec Chandra observation of the unidentified TeV source in Cygnus reported by the HEGRA collaboration reveals no obvious diffuse X-ray counterpart. However, 240 Pointlike X-ray sources are...
Fluorescent Ly-alpha emission from the high-redshift intergalactic medium (2005)
Cantalupo, Sebastiano, Porciani, Cristiano, Lilly, Simon J., Miniati, Francesco
We combine a high-resolution hydro-simulation of the LambdaCDM cosmology with two radiative transfer schemes (for continuum and line radiation) to predict the properties, spectra and spatial...
Ultrahigh Energy Nuclei Propagation in a Structured, Magnetized Universe (2004)
Armengaud, Eric, Sigl, Guenter, Miniati, Francesco
We compare the propagation of iron and proton nuclei above 10^19 eV in a structured Universe with source and magnetic field distributions obtained from a large scale structure simulation and source...
Cosmic Magnetic Fields and Their Influence on Ultra-High Energy Cosmic Ray Propagation (2004)
Sigl, Guenter, Miniati, Francesco, Ensslin, Torsten
We discuss the influence of large scale cosmic magnetic fields on the propagation of hadronic cosmic rays above 10^19 eV based on large scale structure simulations. Our simulations suggest that...
The 21 centimeter emission from the reionization epoch: extended and point source foregrounds (2004)
Di Matteo, Tiziana, Ciardi, Benedetta, Miniati, Francesco
Fluctuations in the redshifted 21 centimeter emission from neutral hydrogen probe the epoch of reionization. We examine the observability of this signal and the impact of extragalactic foreground...
Ultra-High Energy Cosmic Ray Probes of Large Scale Structure and Magnetic Fields (2004)
Sigl, Guenter, Miniati, Francesco, Ensslin, Torsten
We study signatures of a structured universe in the multi-pole moments, auto-correlation function, and cluster statistics of ultra-high energy cosmic rays above 10^19 eV. We compare scenarios where...
Signatures of Magnetized Large Scale Structure in Ultra-High Energy Cosmic Rays (2003)
Sigl, Guenter, Miniati, Francesco, Ensslin, Torsten
We investigate the impact of a structured universe in the multi-pole moments, auto-correlation function, and cluster statistics of cosmic rays above 10^19 eV. We compare structured and uniform source...
Ultraviolet Background Radiation from Cosmic Structure Formation (2003)
Miniati, Francesco, Ferrara, Andrea, White, Simon D. M., Bianchi, Simone
We calculate the contribution to the ultraviolet background (UVB) from thermal emission from gas shock heated by cosmic structure formation. Our main calculation is based on an updated version of...
Cosmic Ray Acceleration by Stellar Associations? The Case of Cygnus OB2 (2003)
Butt, Yousaf, Benaglia, Paula, Combi, Jorge, Corcoran, Michael, Dame, Thomas, Drake, Jeremy, ...
The origins of all extra-solar cosmic rays -- both the ultra high-energy and lower energy Galactic variety -- remain unclear. It has been argued that the large scale shocks and turbulence induced by...
Numerical Modeling of Gamma Radiation from Galaxy Clusters (2003)
We investigate the spatial and spectral properties of non-thermal emission from clusters of galaxies at gamma-ray energies between 10 keV and 10 TeV due to inverse-Compton (IC) emission, pion-decay...
Ultra-High Energy Cosmic Rays in a Structured and Magnetized Universe (2003)
Sigl, Guenter, Miniati, Francesco, Ensslin, Torsten
We simulate propagation of cosmic ray nucleons above 10^{19} eV in scenarios where both the source distribution and magnetic fields within about 50 Mpc from us are obtained from an unconstrained...
CHANDRA/VLA Follow-up of TeV J2032+4131, the Only Unidentified TeV Gamma-ray Source (2003)
Butt, Yousaf, Benaglia, Paula, Combi, Jorge, Corcoran, Michael, Dame, Thomas, Drake, Jeremy, ...
The HEGRA Cherenkov telescope array group recently reported a steady and extended unidentified TeV gamma-ray source lying at the outskirts of Cygnus OB2. This is the most massive stellar association...
Structure shocks as a source of cosmic rays in clusters (2003)
Jones, T. W., Miniati, Francesco, Ryu, Dongsu, Kang, Hyesung, Hallmann, Eric J.
Investigating Galaxy Clusters through Gamma-ray Emission (2002)
We address the role of gamma-ray astronomy in the investigation of nonthermal processes in the large scale structure of the universe. Based on EGRET upper limits on nearby galaxy clusters (GCs) we...
Structure Shocks as a Source of Cosmic Rays in Clusters (2002)
Jones, T. W., Miniati, Francesco, Ryu, Dongsu, Kang, Hyesung, Hallman, Eric J.
Shocks are a ubiquitous consequence of cosmic structure formation, and they play an essential role in heating galaxy cluster media. Virtually all of the gas in clusters has been processed by one or...
Gamma-rays from the Large Scale Structure of the Universe (2002)
Gamma-ray astronomy will play a crucial role in the investigation of nonthermal processes in the large scale structure of the universe. Particularly, galaxy clusters (GC) observations at this photon...
Bagchi, Joydeep, Ensslin, Torsten A., Miniati, Francesco, Stalin, C. S., Singh, M., Raychaudhury, Somak, ...
We report the discovery of large-scale diffuse radio emission from what appears to be a large-scale filamentary network of galaxies in the region of cluster ZwCl 2341.1+0000, and stretching over an...
Inter-galactic Shock Acceleration and the Cosmic Gamma-ray Background (2002)
We investigate numerically the contribution to the cosmic gamma-ray background from cosmic-rays ions and electrons accelerated at intergalactic shocks associated with cosmological structure...
Miniati, Francesco, Jones, T. W., Kang, Hyesung, Ryu, Dongsu
We study the generation and distribution of high energy electrons in cosmic environment and their observational consequences by carrying out the first cosmological simulation that includes directly...
Miniati, Francesco, Ryu, Dongsu, Kang, Hyesung, Jones, T. W.
We investigate the production of cosmic ray (CR) protons at cosmological shocks by performing, for the first time, numerical simulations of large scale structure formation that include directly the...
COSMOCR: A Numerical Code for Cosmic Ray Studies in Computational Cosmology (2001)
We present COSMOCR, a numerical code for the investigation of cosmic ray related studies in computational cosmology. The code follows the diffusive shock acceleration, the mechanical and radiative...
Winds and Shocks in Galaxy Clusters: Shock Acceleration on an Intergalactic Scale (2000)
Jones, T. W., Miniati, Francesco, Ryu, Dongsu, Kang, Hyesung
We review the possible roles of large scale shocks as particle accelerators in clusters of galaxies. Recent observational and theoretical work has suggested that high energy charged particles may...
3-D MHD Numerical Simulations of Cloud-Wind Interactions (2000)
Gregori, G., Miniati, Francesco, Ryu, Dongsu, Jones, T. W.
We present results from three-dimensional (3-D) numerical simulations investigating the magnetohydrodynamics of cloud-wind interactions. The initial cloud is spherical while the magnetic field is...
Properties of Cosmic Shock Waves in Large Scale Structure Formation (2000)
Miniati, Francesco, Ryu, Dongsu, Kang, Hyesung, Jones, T. W., Cen, Renyue, Ostriker, Jeremiah P.
We have examined the properties of shock waves in simulations of large scale structure formation for two cosmological scenarios (a SCDM and a LCDM with Omega =1). Large-scale shocks result from...
Miniati, Francesco, Ryu, Dongsu, Jones, T. W., Kang, Hyesung
We investigate the dynamical importance of a newly recognized possible source of significant feedback generated during structure formation; namely cosmic ray (CR) pressure. We present evidence for...
Cosmic rays and their radiative processes in numerical cosmology (2000)
Jones , Tom W., Kang , Hyesung, Miniati , Francesco, Ryu , Dongsu
A cosmological hydrodynamic code is described, which includes a routine to compute cosmic ray acceleration and transport in a simpli ed way. The routine was designed to follow explicitly di usive...
Thesis (Ph. D.)--University of Minnesota, 2000.
Cosmic Rays and Their Radiative Processes in Numerical Cosmology (1999)
Ryu, Dongsu, Miniati, Francesco, Jones, Tom W., Kang, Hyesung
A cosmological hydrodynamic code is described, which includes a routine to compute cosmic ray acceleration and transport in a simplified way. The routine was designed to follow explicitly diffusive...
Enhanced Cloud Disruption by Magnetic Field Interaction (1999)
Gregori, G., Miniati, Francesco, Ryu, Dongsu, Jones, T. W.
We present results from the first three-dimensional numerical simulations of moderately supersonic cloud motion through a tenuous, magnetized medium. We show that the interaction of the cloud with a...
Large Cosmic Shock Waves as Sites for Particle Acceleration (1999)
Miniati, Francesco, Ryu, Dongsu, Kang, Hyesung, Jones, T. W.
The properties of cosmic shock waves are studied through numerical simulations in two cosmological scenarios (SCDM and LCDM). The scaling relations for the average radius and velocity associated with...
On the Exchange of Kinetic and Magnetic Energy Between Clouds and the Interstellar Medium (1999)
Miniati, Francesco, Jones, T. W., Ryu, Dongsu
We investigate, through 2D MHD numerical simulations, the interaction of a uniform magnetic field oblique to a moving interstellar cloud. In particular we explore the transformation of cloud kinetic...
Magnetohydrodynamics of Cloud Collisions in a Multi-phase Interstellar Medium (1998)
Miniati, Francesco, Ryu, Dongsu, Ferrara, Andrea, Jones, T. W.
We extend previous studies of the physics of interstellar cloud collisions by beginning investigation of the role of magnetic fields through 2D magnetohydrodynamic (MHD) numerical simulations. We...
A Divergence-Free Upwind Code for Multidimensional Magnetohydrodynamic Flows (1998)
Ryu, Dongsu, Miniati, Francesco, Jones, T. W., Frank, Adam
A description is given for preserving ${\bmsy\nabla}\cdot{\vec B}=0$ in a magnetohydrodynamic (MHD) code that employs the upwind, Total Variation Diminishing (TVD) scheme and the Strang-type operator...
Hydrodynamics of Cloud Collisions in 2D: The Fate of Clouds in a Multi-phase Medium (1997)
Miniati, Francesco, Jones, T. W., Ferrara, Andrea, Ryu, Dongsu
We have studied head-on collisions between equal-mass, mildly supersonic (Mach number 1.5) HI clouds, in a standard Two-phase ISM (T_cl = 74 K, n_cl = 22 cm^-3, \chi = 100). We explore the role of...
Energy Dissipation in Interstellar Cloud Collisions (1997)
Ricotti, Massimo, Ferrara, Andrea, Miniati, Francesco
We present a study of the kinetic energy dissipation in interstellar cloud collisions. The main aim is to understand the dependence of the elasticity (defined as the ratio of the final to the initial...
The survival of interstellar clouds against Kelvin-Helmholtz instabilities (1997)
Vietri, Mario, Ferrara, Andrea, Miniati, Francesco
We consider the stability of clouds surrounded by a hotter confining medium with respect to which they are in motion, against Kelvin-Helmholtz instabilities (KHI). In the presence of cooling, sound...