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We present the first application of the isosceles bispectrum to MCMC parameter inference from the cosmic 21-cm signal. We extend the MCMC sampler 21cmMC to use the fast bispectrum code, BiFFT, when computing the likelihood. We create mock…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-19 Catherine A. Watkinson , Bradley Greig , Andrei Mesinger

Fabrication process variations are a major source of yield degradation in the nano-scale design of integrated circuits (IC), microelectromechanical systems (MEMS) and photonic circuits. Stochastic spectral methods are a promising technique…

Computational Engineering, Finance, and Science · Computer Science 2016-11-08 Zheng Zhang , Tsui-Wei Weng , Luca Daniel

Small-scale density fluctuations can significantly affect reionization but are typically modelled quite crudely. Unresolved fluctuations in numerical simulations and analytical calculations are included using a gas clumping factor,…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-06 Michele Bianco , Ilian T. Iliev , Kyungjin Ahn , Sambit K. Giri , Yi Mao , Hyunbae Park , Paul R. Shapiro

We present a new hybrid code for large volume, high resolution simulations of cosmic reionization, which utilizes a N-body algorithm for dark matter, physically motivated prescriptions for baryons and star formation, and an adaptive ray…

Astrophysics · Physics 2009-11-11 Hy Trac , Renyue Cen

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 a new method for modeling inhomogeneous cosmic reionization on large scales. Utilizing high-resolution radiation-hydrodynamic simulations with 2048^3 dark matter particles, 2048^3 gas cells, and 17 billion adaptive rays in a L =…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Nick Battaglia , Hy Trac , Renyue Cen , Abraham Loeb

We use cosmological simulations to explore the large-scale effects of reionization. Since reionization is a process that involves a large dynamic range - from galaxies to rare bright quasars - we need to be able to cover a significant…

Astrophysics · Physics 2008-11-26 Katharina Kohler , Nickolay Y. Gnedin , Andrew J. S. Hamilton

The Epoch of Reionization (EoR) neutral Hydrogen (HI) 21-cm signal evolves significantly along the line-of-sight (LoS) due to the light-cone (LC) effect. It is important to accurately incorporate this in simulations in order to correctly…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-13 Suman Pramanick , Rajesh Mondal , Somnath Bharadwaj

Interferometric experiments designed to detect the highly redshifted 21-cm signal from neutral hydrogen are producing increasingly stringent constraints on the 21-cm power spectrum, but some k-modes remain systematics-dominated. Mutual…

We present simulations of the 21-cm signal during the epoch of reionization. We focus on properly modeling the absorption regime in the presence of inhomogeneous Wouthuysen-Field effect and X-ray heating. We ran radiative transfer…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 S. Baek , B. Semelin , P. Di Matteo , Y. Revaz , F. Combes

We compare the predictions of four different algorithms for the distribution of ionized gas during the Epoch of Reionization. These algorithms are all used to run a 100 Mpc/h simulation of reionization with the same initial conditions. Two…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Oliver Zahn , Andrei Mesinger , Matthew McQuinn , Hy Trac , Renyue Cen , Lars E. Hernquist

The upcoming SKA1-Low radio interferometer will be sensitive enough to produce tomographic imaging data of the redshifted 21-cm signal from the Epoch of Reionization. Due to the non-Gaussian distribution of the signal, a power spectrum…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-10 Sambit K. Giri , Garrelt Mellema , Keri L. Dixon , Ilian T. Iliev

Three-dimensional radiative transfer simulations of the epoch of reionization can produce realistic results, but are computationally expensive. On the other hand, simulations relying on one-dimensional radiative transfer solutions are…

Cosmology and Nongalactic Astrophysics · Physics 2018-02-21 Raghunath Ghara , Garrelt Mellema , Sambit K. Giri , T. Roy Choudhury , Kanan K. Datta , Suman Majumdar

Observations of the end stages of reionization indicate that at $z\approx 5-6$, the ionizing background is not uniform and the mean free path (MFP) changes drastically. As MFP is closely related to the distribution of Lyman Limit Systems…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-02 Jiawen Fan , Huanqing Chen , Camille Avestruz , Affan Khadir

Observation of redshifted 21-cm signals from neutral hydrogen holds the key to understanding the structure formation and its evolution during the reionization and post-reionization era. Apart from the presence of orders of magnitude larger…

Instrumentation and Methods for Astrophysics · Physics 2022-03-02 Jais Kumar , Prasun Dutta , Samir Choudhuri , Nirupam Roy

The 21 cm signal contains a wealth of information about the formation of the first stars and the reionization of the intergalactic medium during the Cosmic Dawn (CD) and Epoch of Reionization (EoR). The timing of these important milestones…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-15 Nadia Cooper , Carina Norregaard , Romain Meriot , Jonathan R. Pritchard

We present detailed predictions for the redshifted 21cm signal from the epoch of reionization. These predictions are obtained from radiative transfer calculations on the results of large scale (100/h Mpc), high dynamic range, cosmological…

Astrophysics · Physics 2009-11-11 Garrelt Mellema , Ilian T. Iliev , Ue-Li Pen , Paul R. Shapiro

We develop two algorithms, based on maximum likelihood (ML) inference, for estimating the parameters of polarized radio sources which emit at a single rotation measure (RM), e.g., pulsars. These algorithms incorporate the flux density…

Instrumentation and Methods for Astrophysics · Physics 2017-10-25 D. H. F. M. Schnitzeler , K. J. Lee

We present here 21 cm predictions from high dynamic range simulations for a range of reionization histories that have been tested against available Lyman-alpha and CMB data. We assess the observability of the predicted spatial 21 cm…

Astrophysics of Galaxies · Physics 2016-09-13 Girish Kulkarni , Tirthankar Roy Choudhury , Ewald Puchwein , Martin G. Haehnelt

We study the effects of sample variance in N--body simulations, as a function of the size of the simulation box, namely in connection with predictions on tomographic shear spectra. We make use of a set of 8 $\Lambda$CDM simulations in boxes…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-20 Luciano Casarini , Oliver Piattella , Silvio Bonometto , Marino Mezzetti