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200 papers

We present a new model of the heliospheric interface - the region of the solar wind interaction with the local interstellar medium. This new model performs a multi-component treatment of charged particles in the heliosphere. All charged…

Astrophysics · Physics 2009-11-11 Yury G. Malama , Vlad V. Izmodenov , Sergey V. Chalov

A model of the density distribution in the intergalactic medium, motivated by that found in numerical simulations, is used to demonstrate the effect of a clumpy IGM and discrete sources on the reionization of the universe. In an…

Astrophysics · Physics 2009-10-31 Jordi Miralda-Escude , Martin Haehnelt , Martin J. Rees

Extensions have been made recently to the coronal approximation for the purpose of modelling line emission from carbon and oxygen in the lower solar atmosphere. The same modelling is used here for other elements routinely observed in the…

Solar and Stellar Astrophysics · Physics 2021-06-30 R. P. Dufresne , G. Del Zanna , P. J. Storey

The transformation of cold neutral intergalactic hydrogen into a highly ionized warm plasma marks the end of the cosmic dark ages and the beginning of the age of galaxies. The details of this process reflect the nature of the early sources…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-07 Nickolay Y. Gnedin , Piero Madau

We present a semi-analytic model for the thermal and ionization history of the universe at 1000 >~ z >~ 3. This model incorporates much of the essential physics included in full-scale hydrodynamical simulations, such as (1) gravitational…

Astrophysics · Physics 2009-10-31 Weihsueh A. Chiu , Jeremiah P. Ostriker

Polarization properties of the photons emitted in the two-photon decay of hydrogen-like ions are studied within the framework of the density matrix and second-order perturbation theory. In particular, we derive the polarization correlation…

Atomic Physics · Physics 2011-08-23 Filippo Fratini , Andrey Surzhykov

We present simulations of cosmic reionization and reheating from $z=18$ to $z=5$, investigating the role of stars (emitting soft UV-photons), nuclear black holes (BHs, with power-law spectra), X-ray binaries (XRBs, with hard X-ray dominated…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-16 Marius B. Eide , Benedetta Ciardi , Luca Graziani , Philipp Busch , Yu Feng , Tiziana Di Matteo

We propose a model kinetic system of the hydrogen atom (two levels plus continuum) under the conditions typical for atmospheres of Type IIP supernovae in the plateau stage. Despite the simplicity of this system, it describes realistically…

Solar and Stellar Astrophysics · Physics 2019-12-16 M. Sh. Potashov , A. V. Yudin

The radiative recombination of a free electron into an excited state of a bare, high-Z ion is studied, together with its subsequent decay, within the framework of the density matrix theory and Dirac's relativistic equation. Special…

Atomic Physics · Physics 2010-11-29 A. V. Maiorova , A. Surzhykov , S. Tashenov , V. M. Shabaev , S. Fritzsche , G. Plunien , Th. Stoehlker

We use (3+1) dimensional ideal hydrodynamics to describe the space-time evolution of strongly interacting matter created in Au+Au and Pb+Pb collisions. The model is applied for the domain of bombarding energies 1-160 AGeV which includes…

High Energy Physics - Phenomenology · Physics 2015-03-19 A. V. Merdeev , L. M. Satarov , I. N. Mishustin

We have developed a modular semi-numerical code that computes the time and spatially dependent ionization of neutral hydrogen (HI), neutral (HeI) and singly ionized helium (HeII) in the intergalactic medium (IGM). The model accounts for…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-02 Anne Hutter

A theoretical study of the K-shell ionization of hydrogen-like ions, colliding with bare nuclei, is performed within the framework of the time-dependent Dirac equation. Special emphasis is placed on the ionization probability that is…

Atomic Physics · Physics 2023-04-20 O. Novak , R. Kholodov , A. Surzhykov , A. N. Artemyev , Th. Stöhlker

We implement a treatment of Helium {\sc ii} absorption and re-emission into the \TD cosmological simulations to study its impact on the metagalactic ultraviolet background (UVB) in three dimensions. By comparing simulations with and without…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-02 Ezra Huscher , Kristian Finlator , Samir Kušmić , Maya Steen

Full radiative transfer in 3D space has been solved to pursue the reionization history in an inhomogeneous universe. It has been shown that the reionization of an inhomogeneous universe is not a prompt event, but a fairly slow process.…

Astrophysics · Physics 2007-05-23 M. Umemura , T. Nakamoto , H. Susa

We report on laboratory measurements of molecular hydrogen formation and recombination on an olivine slab as a function of surface temperature under conditions relevant to those encountered in the interstellar medium. On the basis of our…

Astrophysics · Physics 2009-10-30 V. Pirronello , O. Biham , C. Liu , L. Shen , G. Vidali

The history of the transition from a neutral intergalactic medium (IGM) to one that is almost fully ionized can reveal the character of cosmological ionizing sources. We study the evolution of the volume filling factor of HII and HeIII…

Astrophysics · Physics 2009-10-30 Piero Madau , Francesco Haardt , Martin J. Rees

A multi-fluid model for an atomic hydrogen-proton mixture in the upper atmosphere of extrosolar planet is presented when the continuity and momentum equations of each component have been already solved with an energy equation. The particle…

Earth and Planetary Astrophysics · Physics 2011-05-13 J. H. Guo

The two-photon decay in hydrogen-like ions is investigated within the framework of second order perturbation theory and Dirac's relativistic equation. Special attention is paid to the angular correlation of the emitted photons as well as to…

Atomic Physics · Physics 2014-10-23 P. Amaro , F. Fratini , S. Fritzsche , P. Indelicato , J. P. Santos , A. Surzhykov

Radiative association and photodissociation rates are calculated for quadrupole transitions of H2. A complete set of bound and unbound states are included in a self-consistent master equation to obtain steady-state concentrations for a…

Astrophysics of Galaxies · Physics 2016-10-12 Robert C. Forrey

A 1+1 dimensional hydrodynamical model in the light-cone coordinates is used to describe central heavy-ion collisions at ultrarelativistic bombarding energies. Deviations from Bjorken's scaling are taken into account by choosing finite-size…

High Energy Physics - Phenomenology · Physics 2008-11-26 L. M. Satarov , I. N. Mishustin , A. V. Merdeev , H. Stoecker