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Modern machine learning will allow for simulation-based inference from reionization-era 21cm observations at the Square Kilometre Array. Our framework combines a convolutional summary network and a conditional invertible network through a…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-16 Benedikt Schosser , Caroline Heneka , Tilman Plehn

Predicting the 21cm signal from the epoch of reionization and cosmic dawn is a complex and challenging task. Various simplifying assumptions have been applied over the last decades to make the modeling more affordable. In this paper, we…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-25 Timothée Schaeffer , Sambit K. Giri , Aurel Schneider

In this paper, we explore the constraints on the reionization history that are provided by current observations of the Lyman-alpha forest and the CMB. Rather than using a particular semi-analytic model, we take the novel approach of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Jonathan R. Pritchard , Abraham Loeb , J. Stuart B. Wyithe

The recent discovery of a Gunn--Peterson (GP) trough in the spectrum of the redshift 6.28 SDSS quasar has raised the tantalizing possibility that we have detected the reionization of the universe. However, a neutral fraction (of hydrogen)…

Astrophysics · Physics 2009-11-07 M. Kaplinghat , M. Chu , Z. Haiman , G. Holder , L. Knox , C. Skordis

We investigate the effect of primordial non-Gaussianity on the cross-correlation between the CMB anisotropies and the 21 cm fluctuations from the epoch of reionization. We assume an analytic reionization model and an ionization fraction…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Hiroyuki Tashiro , Shirley Ho

We simulate a variety of optical systematics for Taurus, a balloon-borne cosmic microwave background (CMB) polarisation experiment, to assess their impact on large-scale E-mode polarisation measurements and constraints of the optical depth…

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

The James Webb Space Telescope (JWST) has observed massive galaxies at high redshifts, which implies an earlier epoch of reionization (EoR) compared with the cosmic microwave background (CMB) results. In this paper, based on \texttt{Planck…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-22 Hao-Hao Li , Xin-zhe Zhang , Taotao Qiu , Jun-Qing Xia

It has been several years since the first detection of Gunn-Peterson troughs in the z > 6 Ly-alpha forest and since the first measurement of the Thomson scattering optical depth through reionization from the cosmic microwave background…

Cosmology and Nongalactic Astrophysics · Physics 2010-09-27 Matthew McQuinn

The Cosmic Dawn Intensity Mapper (CDIM) will transform our understanding of the era of reionization when the Universe formed the first stars and galaxies, and UV photons ionized the neutral medium. CDIM goes beyond the capabilities of…

Recent observations have set the first constraints on the epoch of reionization (EoR), corresponding to the formation epoch of the first luminous objects. Studies of Gunn-Peterson (GP) absorption, and related phenomena, suggest a…

Astrophysics · Physics 2008-11-26 Xiaohui Fan , C. L. Carilli , B. Keating

We have modelled the process of reionization of the IGM by photoionization by galaxies, in order to predict the epoch of reionization. We use a sophisticated semi-analytic model to track the formation of galaxies. Our study represents a…

Astrophysics · Physics 2009-11-11 A. J. Benson , Naoshi Sugiyama , Adi Nusser , C. G. Lacey

Cross-correlations between 21cm observations and galaxy surveys provide a powerful probe of reionization by reducing foreground sensitivity while linking ionization morphology to galaxies. We quantify the constraining power of 21cm-Galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-27 Yannic Pietschke , Anne Hutter , Caroline Heneka

Foreground subtraction is the biggest challenge for future redshifted 21 cm observations to probe reionization. We use a short GMRT observation at 153 MHz to characterize the statistical properties of the background radiation across ~ one…

Astrophysics · Physics 2009-11-13 SK. Saiyad Ali , Somnath Bharadwaj , Jayaram N. Chengalur

The microlensing probability (optical depth $\tau$) toward the Galactic center carries information about the mass distribution of the Galactic bulge/bar, so can be used to constrain the very uncertain shape parameters of the bar. We find…

Astrophysics · Physics 2015-06-24 HongSheng Zhao , Shude Mao

(ABRIDGED)The rise of cosmic structure depends upon the statistical distribution of initial density fluctuations generated by inflation. While the simplest models predict an almost perfectly Gaussian distribution, more-general models…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Anson D'Aloisio , Jun Zhang , Paul R. Shapiro , Yi Mao

We show how the morphological analysis of the maps of the secondary CMB anisotropies can detect an extended period of ``smoldering'' reionization, during which the universe remains partially ionized. Neither radio observations of the…

Astrophysics · Physics 2008-11-26 Nickolay Y. Gnedin , Sergei F. Shandarin

The paper is devoted to the methods of determination of the cosmological parameters from recent CMB observations. We show that the more complex models of kinetics of recombination with a few "missing" parameters describing the recombination…

Astrophysics · Physics 2009-11-07 A. G. Doroshkevich , I. P. Naselsky , P. D. Naselsky , I. D. Novikov

Thomson optical depth tau measurements from Planck provide new insights into the reionization of the universe. In pursuit of model-independent constraints on the properties of the ionising sources, we determine the empirical evolution of…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-07 R. J. Bouwens , G. D. Illingworth , P. A. Oesch , J. Caruana , B. Holwerda , R. Smit , S. Wilkins