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Related papers: Self-Consistent Modeling of Reionization in Cosmol…

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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

The intergalactic helium became fully ionized by the end of cosmic noon ($z\sim2$). Similarly to the reionization of hydrogen, helium reionization is expected to be patchy, driven by luminous quasars that ionize the intergalactic gas in…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-14 Mesut Çalışkan , Neha Anil Kumar , Selim C. Hotinli , Marc Kamionkowski

We incorporate quasars into an analytic model to describe the reheating and reionization of the universe. In combination with a previous study of galaxies and Lyman-$\alpha$ clouds, we are able to provide a unified description of structure…

Astrophysics · Physics 2007-05-23 P. Valageas , J. Silk

Recent observations have successfully detected UV or infrared flux from galaxies at the epoch of reionization. However, the origin of their radiative properties has not been fully understood yet. Combining cosmological hydrodynamic…

Astrophysics of Galaxies · Physics 2020-06-10 Shohei Arata , Hidenobu Yajima , Kentaro Nagamine , Yuexing Li , Sadegh Khochfar

We use $N$-body simulations to show that high-redshift galaxy counts provide an interesting constraint on the nature of dark matter, specifically Warm Dark Matter (WDM), owing to the lack of early structure formation these models. Our…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-09 Christian Schultz , Jose Oñorbe , Kevork N. Abazajian , James S. Bullock

Understanding how galaxies and active galactic nuclei (AGN) jointly drive the reionization of the intergalactic medium (IGM) across cosmic time remains a major challenge in cosmology. We present Lumina, a large-volume radiation-hydrodynamic…

We have developed an accurate, one-dimensional, spherically symmetric, Lagrangian hydrodynamics/gravity code, designed to study the effects of radiative cooling and photo-ionization on the formation of protogalaxies. We examine the ability…

Astrophysics · Physics 2009-10-22 A. A. Thoul

The thermal history and structure of the intergalactic medium (IGM) at $z \geq 4$ is an important boundary condition for reionization, and a key input for studies using the Ly$\alpha$ forest to constrain the masses of alternative dark…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-19 Christopher Cain , Evan Scannapieco , Matthew McQuinn , Anson D'Aloisio , Hy Trac

Reionization is an inhomogeneous process, thought to begin in small ionized bubbles of the intergalactic medium (IGM) around overdense regions of galaxies. Recent Lyman-alpha (Ly$\alpha$) studies during the epoch of reionization show…

The characterisation of the atomic and molecular hydrogen content of high-redshift galaxies is a major observational challenge that will be addressed over the coming years with a new generation of radio telescopes. We investigate this…

Cosmology and Nongalactic Astrophysics · Physics 2012-04-13 Alan R. Duffy , Scott T. Kay , Richard A. Battye , C. M. Booth , Claudio Dalla Vecchia , Joop Schaye

Cosmic reionization is driven by the formation of sources of ultraviolet photons, and hence it is an intrinsically asymmetric process, where its earlier stages occur at a slower pace relative to its later stages. Yet most modern cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-16 Paulo Montero-Camacho , Yin Li , Marco Barquero-Hernández , Pablo Renard , Yang Wang , Xiao-Dong Li

The observed scatter in intergalactic Lyman-$\alpha$ opacity at $z \lesssim 6$ requires large-scale fluctuations in the neutral fraction of the intergalactic medium (IGM) after the expected end of reionization. Post-reionization models that…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-22 George D. Becker , Frederick B. Davies , Steven R. Furlanetto , Matthew A. Malkan , Elisa Boera , Craig Douglass

Models and simulations of the epoch of reionization predict that spectra of the 21-cm transition of atomic hydrogen will show a clear fluctuation peak, at a redshift and scale, respectively, that mark the central stage of reionization and…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Anastasia Fialkov , Rennan Barkana , Eli Visbal

We present a new set of analytic models for the expansion of HII regions powered by UV photoionisation from massive stars and compare them to a new suite of radiative magnetohydrodynamic simulations of turbulent, self-gravitating molecular…

Astrophysics of Galaxies · Physics 2016-06-08 Sam Geen , Patrick Hennebelle , Pascal Tremblin , Joakim Rosdahl

The Universe is opaque to extragalactic very high-energy gamma rays (VHEGRs, E>100 GeV) because they annihilate and pair produce on the extragalactic background light. The resulting ultra-relativistic pairs are assumed to lose energy…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Philip Chang , Avery E. Broderick , Christoph Pfrommer

Early JWST observations have revealed substantial numbers of galaxies out to redshifts as high as $z \simeq 14$, reflecting a slow evolution of the galaxy UV luminosity function (LF) not anticipated by many models of galaxy evolution. The…

Astrophysics of Galaxies · Physics 2025-04-16 C. T. Donnan , J. S. Dunlop , R. J. McLure , D. J. McLeod , F. Cullen

The distribution of diffuse gas in the intergalactic medium (IGM) imprints a series of hydrogen absorption lines on the spectra of distant background quasars known as the Lyman-$\alpha$ forest. Cosmological hydrodynamical simulations…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-31 Alberto Rorai , Joseph F. Hennawi , Jose Oñorbe , Martin White , J. Xavier Prochaska , Girish Kulkarni , Michael Walther , Zarija Lukić , Khee-Gan Lee

We study the topology of reionization using accurate three-dimensional radiative transfer calculations post-processed on outputs from cosmological hydrodynamic simulations. In our simulations, reionization begins in overdense regions and…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 K. Finlator , F. Ozel , R. Dave , B. D. Oppenheimer

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 primarily responsible for reionization. We…

The estimate of the ionizing UV background through the proximity effect analysis is discussed. Taking into account the correct bending of the column density distribution which appears in high resolution high s/n data, a value of the UV…

Astrophysics · Physics 2007-05-23 E. Giallongo , S. Cristiani , S. D'Odorico , A. Fontana , S. Savaglio
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