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We present the largest-volume (425 Mpc/h=607 Mpc on a side) full radiative transfer simulation of cosmic reionization to date. We show that there is significant additional power in density fluctuations at very large scales. We…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-05 Ilian T. Iliev , Garrelt Mellema , Kyungjin Ahn , Paul R. Shapiro , Yi Mao , Ue-Li Pen

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 present a detailed analysis of the chemical abundances, ionization state, and origin of a partial Lyman limit system (N(HI) ~ 10^{16} cm^{-2}) at low redshift (z=0.167 towards PKS0405-1219). We also present the first estimate of the…

Astrophysics · Physics 2007-05-23 Hsiao-Wen Chen , Jason X. Prochaska , Kenneth M. Lanzetta

During the epoch of reionization (EoR), the 21-cm signal allows direct observation of the neutral hydrogen (HI) in the intergalactic medium (IGM). In the post-reionization era, this signal instead probes HI in galaxies, which traces the…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-20 Sambit K. Giri , Michele Bianco , Timothée Schaeffer , Ilian T. Iliev , Garrelt Mellema , Aurel Schneider

During the epoch of reionization (EoR), the first generation of luminous sources in our Universe emitted ionizing photons that almost completely ionized the gas in the intergalactic medium (IGM). The growth of ionized bubbles and the…

Astrophysics of Galaxies · Physics 2025-11-26 Sambit K. Giri , Koki Kakiichi , Michele Bianco , P. Daniel Meerburg

We study constraints on allowed reionization histories by comparing predictions of a physical semi-numerical model with secondary temperature and polarization anisotropies of the cosmic microwave background (CMB). Our model has four free…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-02 Tirthankar Roy Choudhury , Suvodip Mukherjee , Sourabh Paul

Quasar absorption lines provide a unique window to the relationship between galaxies and the intergalactic medium during the Epoch of Reionization. In particular, high redshift quasars enable measurements of the neutral hydrogen content of…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-17 Ella Werre , David Robinson , Camille Avestruz , Nickolay Y. Gnedin

X-ray computed tomographic infrastructures are medical imaging modalities that rely on the acquisition of rays crossing examined objects while measuring their intensity decrease. Physical measurements are post-processed by mathematical…

Image and Video Processing · Electrical Eng. & Systems 2022-01-25 Attila Juhos

We explore the impact of reionization topology on 21-cm statistics. Four reionization models are presented which emulate large ionized bubbles around over-dense regions (21CMFAST/ global-inside- out), small ionized bubbles in over-dense…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-15 Catherine A. Watkinson , Jonathan R. Pritchard

We present constraints on the reionization optical depth, $\tau$, obtained using several independent methods. First, we perform a non-parametric reconstruction of the reionization history, using Lyman-$\alpha$ constraints on the evolution…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-29 Willem Elbers

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

If dark matter decay or annihilate, a large amount of energy and particles would be released into the cosmic plasma. Therefore, they could modify the thermal and ionization history of our universe, then leave footprints on the cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-22 Lu Chen , Ke Wang

We present predictions drawn from cosmological hydrodynamic simulations for the physical, photometric and emission line properties of galaxies present during the latter stages of reionization from z=9-6. We find significant numbers of…

Astrophysics · Physics 2009-11-11 Romeel Davé , Kristian Finlator , Benjamin D. Oppenheimer

The role of higher order Lyman series photons on the 21cm absorption or emission signature of the IGM against the background CMB during the Epoch of Reionisation is examined. It is shown that, taking into account the diminishing resonance…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-28 Avery Meiksin

We explore the ability of observations of the global brightness temperature of the 21-cm signal to constrain the reionization history and the properties of the ionizing sources. In order to describe the reionization signal, we employ either…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Andrea Morandi , Rennan Barkana

The mean free path of ionizing photons ($\lambda_\mathrm{mfp}^{912}$) in the intergalactic medium (IGM) is a crucial quantity in modelling the ionization state of IGM and the extragalactic ultraviolet background (EUVB), and is widely used…

Galaxy formation depends critically on the physical state of gas in the circumgalactic medium (CGM) and its interface with the intergalactic medium (IGM), determined by the complex interplay between inflows from the IGM and outflows from…

Astrophysics of Galaxies · Physics 2021-11-16 Daniele Sorini , José Oñorbe , Joseph F. Hennawi , Zarija Lukić

Preparing for the first detection of the cosmic 21-cm signal from large-scale interferometer experiments requires rigorous testing of the data analysis and reduction pipelines. To validate that these pipelines do not erroneously remove or…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-14 Bradley Greig , J. Stuart B. Wyithe , Steven G. Murray , Simon J. Mutch , Cathryn M. Trott

X-ray ptychography utilizes overlapping illuminations to reconstruct the object's phase and absorption signal with spatial resolutions much smaller than the focus size. Usually, the illumination overlap is chosen to be between 50% and 60%…

Materials Science · Physics 2022-07-29 Felix Wittwer , Peter Modregger

During the EoR, the first stars and galaxies appear while creating ionized bubbles that will eventually percolate near z=6. These ionized bubbles and percolation process are nowadays under a lot of scrutiny since observations of the HI gas…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-14 Emilie Thélie , Dominique Aubert , Nicolas Gillet , Pierre Ocvirk