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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. These new computations represent an…

Astrophysics · Physics 2009-11-07 Alexei O. Razoumov , Michael L. Norman , Tom Abel , Douglas Scott

In this Letter we discuss what happens to hydrogen recombination energy that is released during regular common envelope (CE) events, as opposed to self-regulated CE events. We show that the amount of recombination energy that can be…

Solar and Stellar Astrophysics · Physics 2018-05-23 Natalia Ivanova

Energy release in the early Universe (z<~ 2x10^6) should lead to some broad spectral distortion of the cosmic microwave background (CMB) radiation field, which can be characterized as y-type distortion when the injection process started at…

Astrophysics · Physics 2015-05-13 J. Chluba , R. A. Sunyaev

The subject of cosmological hydrogen recombination has received much attention recently because of its importance to predictions for and cosmological constraints from CMB observations. While the central role of the two-photon decay 2s->1s…

Astrophysics · Physics 2008-11-26 Christopher M. Hirata

We present an extension of the recombination formalism to analyze the effects from the variation of the hadron wavefunctions. The hadron spectra are sensitive to the shape of the wavefunctions. However, when we fit the wavefunction…

High Energy Physics - Phenomenology · Physics 2009-09-29 Byungsik Hong , Chueng-Ryong Ji , Dong-Pil Min

Charmonium production at heavy-ion colliders is considered within the comovers interaction model. The formalism is extended by including possible secondary J/psi production through recombination and an estimate of recombination effects is…

High Energy Physics - Phenomenology · Physics 2008-12-18 A. Capella , L. Bravina , E. G. Ferreiro , A. B. Kaidalov , K. Tywoniuk , E. Zabrodin

We calculate the recombination spectra of the He-like ions He~I, C~V, N~VI, O~VII, Ne~IX, Mg~XI, Si~XIII, S~XV, Ar~XVII, Ca~XIX, and Fe~XXV. We include the following physical processes: radiative recombination, dielectronic recombination,…

Astrophysics · Physics 2009-10-31 M. A. Bautista , T. R. Kallman

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

We give a formulation of the radiative transfer equation for Lyman alpha photons which allows us to include the two-photon corrections for the 3s-1s and 3d-1s decay channels during cosmological hydrogen recombination. We use this equation…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 J. Chluba , R. A. Sunyaev

We present an extension to the short-characteristic ray-tracing and non-equilibrium photon-ionization code C2Ray. The new version includes the effects of helium and improved multi-frequency heating. The motivation for this work is to be…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Martina M. Friedrich , Garrelt Mellema , Ilian T. Iliev , Paul R. Shapiro

We present the results of several collisional-radiative models describing optically-thin emissivities of the main lines in neutral helium formed by recombination, for a grid of electron temperatures and densities, typical of H II regions…

Astrophysics of Galaxies · Physics 2022-04-13 G. Del Zanna , P. J. Storey

A reanalysis is made for the helium abundance determination for the Izotov-Thuan (2004) spectroscopic sample of extragalactic H II regions. We find that the effect of underlying stellar absorption of the He I lines, which is more important…

Astrophysics · Physics 2008-11-26 Masataka Fukugita , Masahiro Kawasaki

Primordial magnetic fields (PMFs) may explain observations of magnetic fields on extragalactic scales. They are most cleanly constrained by measurements of cosmic microwave background radiation (CMB) anisotropies. Their effects on cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-18 Karsten Jedamzik , Tom Abel , Yacine Ali-Haimoud

Recombination is a hadronization process that converts partons to hadrons at late time, but the description has no quantitative significance without some meaningful input on the parton distributions at earlier time. Thus observations of…

Nuclear Theory · Physics 2011-04-08 Rudolph C. Hwa

In prerecombination resolutions of the Hubble tension, such as early dark energy, new physics before recombination shifts the values of relevant cosmological parameters so that the models can fit with cosmic microwave background and baryon…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-15 Gen Ye , Bin Hu , Yun-Song Piao

This paper describes a new determination of the primordial helium abundance (Y_P), based on the abundance analysis of five metal-poor extragalactic HII regions. For three regions of the sample (SBS 0335-052, I Zw 18, and H29) we present…

Astrophysics · Physics 2009-11-07 V. Luridiana , A. Peimbert , M. Peimbert , M. Cervino

Observational measures of the primordial helium mass fraction, $Y_{\rm P}$, are of interest for cosmology and fundamental particle physics. Current measures obtained from H II regions agree with the Standard Model prediction to…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-08 Calvin Sykes , Michele Fumagalli , Ryan Cooke , Tom Theuns

In this study, we perform detailed spectroscopic modeling to analyze the interaction of circumstellar material (CSM) with ejecta in both hydrogen-rich and hydrogen-poor superluminous supernovae (SLSNe), systematically varying properties…

High Energy Astrophysical Phenomena · Physics 2025-01-07 Gururaj A. Wagle , Emmanouil Chatzopoulos , Michael J. Baer

We calculate the He I case B recombination cascade spectrum using improved radiative and collisional data. We present new emissivities over a range of electron temperatures and densities. The differences between our results and the current…

Astrophysics · Physics 2009-11-10 R. L. Porter , R. P. Bauman , G. J. Ferland , K. B. MacAdam

Physicochemical properties of solid methane exposed to ionizing radiation have attracted significant interest in recent years. Here we present new trends in the study of radiation effects in solid methane. We particularly focus on…