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Related papers: Probing Reionization with the 21 cm-Galaxy Cross P…

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We consider the cross-correlation between free electrons and neutral hydrogen during the epoch of reionization. The free electrons are traced by the optical depth to reionization tau, while the neutral hydrogen can be observed through 21 cm…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Pieter Daniel Meerburg , Cora Dvorkin , David N. Spergel

Our understanding of the intergalactic medium at redshifts $z=5$-$6$ has improved considerably in the last few years due to the discovery of quasars with $z>6$ that enable Lyman-$\alpha$ forest studies at these redshifts. A realisation from…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-08 Janakee Raste , Girish Kulkarni , Laura C. Keating , Martin G. Haehnelt , Jonathan Chardin , Dominique Aubert

Separating the cosmological redshifted 21-cm signal from foregrounds is a major challenge. We present the cross-correlation of the redshifted 21-cm emission from neutral hydrogen (HI) in the post-reionization era with the Ly-alpha forest as…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Tapomoy Guha Sarkar , Somnath Bharadwaj , Tirthankar Roy Choudhury , Kanan Datta

Measurement of the 21cm hyperfine transition of neutral hydrogen provides a unique probe of the epoch of reionization and the Dark Ages. Three major mechanisms are believed to dominate the radiation process: emission from neutral hydrogen…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Qian Zheng

Observations of the high-redshift Universe with the 21 cm hyperfine line of neutral hydrogen promise to open an entirely new window onto the early phases of cosmic structure formation. Here we review the physics of the 21 cm transition,…

Astrophysics · Physics 2009-11-11 Steven Furlanetto , S. Peng Oh , Frank Briggs

The redshifted 21-cm signal from neutral hydrogen (HI) in the intergalactic medium (IGM) is a powerful probe of the Epoch of Reionization (EoR). Owing to the complex growth and morphology of ionized regions, the 21-cm brightness-temperature…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-19 Vishrut Pandya , Leon Noble , Suman Majumdar , Debanjan Sarkar , Mohd Kamran , Abhirup Datta

We present the first limits on the Epoch of Reionization (EoR) 21-cm HI power spectra, in the redshift range $z=7.9-10.6$, using the Low-Frequency Array (LOFAR) High-Band Antenna (HBA). In total 13\,h of data were used from observations…

A number of radio interferometers are currently being planned or constructed to observe 21 cm emission from reionization. Not only will such measurements provide a detailed view of that epoch, but, since the 21 cm emission also traces the…

Direct detection of regions of ionized hydrogen (HII) has been suggested as a promising probe of cosmic reionization. Observing the redshifted 21-cm signal of hydrogen from the epoch of reionization (EoR) is a key scientific driver behind…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-20 Paul M. Geil , Simon J. Mutch , Gregory B. Poole , Alan R. Duffy , Andrei Mesinger , J. Stuart B. Wyithe

The reionization process is driven by ionizing photons from dwarf galaxies in halos with virial temperature $T_{\rm vir} \gtrsim 10^4$ K, while minihalos whose $T_{\rm vir}\lesssim 10^4$ K consume ionizing photons and have negative…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-07 Hourui Zhu , Bin Yue , Yidong Xu , Xuelei Chen , Zhiqi Huang

The introduction of low-frequency radio arrays is expected to revolutionize the study of the reionization epoch. Observation of the contrast in redshifted 21cm emission between a large HII region and the surrounding neutral inter-galactic…

Astrophysics · Physics 2009-11-13 Stuart Wyithe

The recent low value of Planck (2016) integrated optical depth to Thomson scattering suggests that the reionization occurred fairly suddenly, disfavoring extended reionization scenarios. This will have a significant impact on the 21cm power…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-27 Sultan Hassan , Romeel Dave , Kristian Finlator , Mario G. Santos

The morphology of the 21-cm signal emitted by the neutral hydrogen present in the intergalactic medium (IGM) during the Epoch of Reionization (EoR) depends both on the properties of the sources of ionizing radiation and on the underlying…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-04 Leon Noble , Mohd Kamran , Suman Majumdar , Chandra Shekhar Murmu , Raghunath Ghara , Garrelt Mellema , Ilian T. Iliev , Jonathan R. Pritchard

We study the signatures of reionization and ionizing properties of the early galaxies in the cross-correlations between the 21cm emission from the spin-flip transition of neutral hydrogen (HI) and the underlying galaxy population, in…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-22 Anne Hutter , Pratika Dayal , Volker Müller , Cathryn Trott

Spatial dependence in the statistics of redshifted 21cm fluctuations promises to provide the most powerful probe of the reionisation epoch. In this paper we consider the second and third moments of the redshifted 21cm intensity distribution…

Astrophysics · Physics 2015-06-24 Stuart Wyithe , Miguel Morales

The process of reionization is now believed to have proceeded in an orchestrated manner beginning with UV photons emitted by high redshift galaxies containing a large fraction of Population III stars carving out ionised regions around them.…

Astrophysics · Physics 2008-11-26 Anze Slosar , Asantha Cooray , Joseph Silk

The fluctuations in the emission of redshifted 21cm photons from neutral inter-galactic hydrogen will provide an unprecedented probe of the reionization era. Conventional wisdom assumes that this 21cm signal disappears as soon as…

Astrophysics · Physics 2015-05-13 Stuart Wyithe , Abraham Loeb

Constraining when and how reionisation began is pivotal for understanding when the first galaxies formed. Lyman-alpha (Ly$\alpha$) emission from galaxies is currently our most promising probe of these early stages. At z>7 the majority of…

Astrophysics of Galaxies · Physics 2023-04-25 Ting-Yi Lu , Charlotte Mason , Anne Hutter , Andrei Mesinger , Yuxiang Qin , Daniel P. Stark , Ryan Endsley

Observations of the epoch of reionization give us clues about the nature and evolution of the sources of ionizing photons, or early stars and galaxies. We present a new suite of structure formation and radiative transfer simulations from…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-27 Keri L. Dixon , Ilian T. Iliev , Garrelt Mellema , Kyungjin Ahn , Paul R. Shapiro

A detection of the 21-cm signal power spectrum from the Epoch of Reionization is imminent, thanks to consistent advancements from telescopes such as LOFAR, MWA, and HERA, along with the development of SKA. In light of this progress, it is…