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Theoretical studies and current observations of the high-redshift intergalactic medium (IGM) indicate that at least two cosmic transitions occur by the time the universe reaches gas metallicities of about $10^{-3}$ of solar values. These…

Astrophysics · Physics 2009-11-11 Aparna Venkatesan

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

We explore the impact of cosmic reionization on nearby isolated dwarf galaxies using a compilation of SFHs estimated from deep HST data and a cosmological hydrodynamical simulation of the Local Group. The nearby dwarfs show a wide diversity…

We explore to what extent simple algebraic models can be used to describe H II regions when winds, radiation pressure, gravity and photon breakout are included. We a) develop algebraic models to describe the expansion of photoionised H II…

Astrophysics of Galaxies · Physics 2020-01-08 Sam Geen , Eric Pellegrini , Rebekka Bieri , Ralf Klessen

Star-forming galaxies are considered to be the leading candidate sources that dominate the cosmic reionization at z>7, and the search for analogs at moderate redshift showing Lyman continuum (LyC) leakage is currently a active line of…

We present the escape fraction of hydrogen ionizing photons (f_esc) from a sample of 34 high-resolution cosmological zoom-in simulations of galaxies at z>5 in the Feedback in Realistic Environments project, post-processed with a Monte Carlo…

Recent observations of high-redshift galaxies and quasars indicate that the hydrogen component of the intergalactic medium (IGM) must have been reionized at some redshift z>6. Prior to complete reionization, sources of ultraviolet radiation…

Astrophysics · Physics 2009-10-31 Piero Madau , Martin J. Rees

We present the first simulations of the formation and feedback of massive stars which account for radiation forces as well as photoionization feedback (along with protostellar outflows). In two different accretion scenarios modeled, we…

Astrophysics of Galaxies · Physics 2018-08-29 Rolf Kuiper , Takashi Hosokawa

Galactic cosmic rays (CRs) play a crucial role in ionisation, dissociation, and excitation processes within dense cloud regions where UV radiation is absorbed by dust grains and gas species. CRs regulate the abundance of ions and radicals,…

(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 models include non-equilibrium primordial…

Astrophysics · Physics 2009-11-13 John H. Wise , Tom Abel

We use new studies of the cosmic evolution of star-forming galaxies to estimate the production rate of ionizing photons from hot, massive stars at low and intermediate redshifts. The luminosity function of blue galaxies in the Canada-France…

Astrophysics · Physics 2015-06-24 E. Giallongo , A. Fontana , P. Madau

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 massive stars that are copious UV…

Astrophysics · Physics 2009-11-10 Daniel Whalen , Tom Abel , Michael L. Norman

We present a suite of cosmological radiation-hydrodynamical simulations of the assembly of galaxies driving the reionization of the intergalactic medium (IGM) at z >~ 6. The simulations account for the hydrodynamical feedback from…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-11 Andreas H. Pawlik , Joop Schaye , Claudio Dalla Vecchia

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<z<30. With relatively conservative assumptions,…

Astrophysics · Physics 2009-11-10 Aaron Sokasian , Naoki Yoshida , Tom Abel , Lars Hernquist , Volker Springel

Using a reionization model simultaneously accounting for a number of experimental data sets, we investigate the nature and properties of reionization sources. Such model predicts that hydrogen reionization starts at z \approx 15, is…

Astrophysics · Physics 2009-11-13 T. Roy Choudhury , A. Ferrara

Processing by interstellar photons affects the composition of the icy mantles on interstellar grains. The rate of photodissociation in solids differs from that of molecules in the gas phase. The aim of this work was to determine an average,…

Astrophysics of Galaxies · Physics 2018-05-16 Juris Kalvans

The formation of the first galaxies during cosmic dawn and reionization (at redshifts $z=5-30$), triggered the last major phase transition of our universe, as hydrogen evolved from cold and neutral to hot and ionized. The 21-cm line of…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-14 Julian B. Muñoz , Yuxiang Qin , Andrei Mesinger , Steven G. Murray , Bradley Greig , Charlotte Mason

The evolution of radiation emitted during the dynamical collapse of metal-free protostellar clouds is investigated within a spherically symmetric hydrodynamical scheme that includes the transfer of radiation and the chemistry of the…

Astrophysics · Physics 2009-11-06 Emanuele Ripamonti , Francesco Haardt , Andrea Ferrara , Monica Colpi

In this paper, we address which sources contributed most of the reionizing photons. Our argument assumes that the reionization ended around z ~ 6 and that it was a relatively quick process, i.e., that there was a non-negligible fraction of…

Astrophysics · Physics 2009-11-10 Haojing Yan , Rogier A. Windhorst

The identification of sources driving cosmic reionization, a major phase transition from neutral Hydrogen to ionized plasma around 600-800 Myr after the Big Bang (Dayal et al. 2018, Mason et al. 2019, Robertson et al. 2022), has been a…

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