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We present new upper limits on the 21-cm signal power spectrum from the Epoch of Reionization (EoR), at redshifts $z \approx 10.1, 9.1, \text{ and } 8.3$, based on reprocessed observations from the Low-Frequency Array (LOFAR). The analysis…

The light-cone (LC) effect causes the mean as well as the statistical properties of the redshifted 21-cm signal $T_{\rm b}(\hat{\bf n},\nu)$ to change with frequency $\nu$ (or cosmic time). Consequently, the statistical homogeneity…

Using a Bayesian framework, we quantify what current observations imply about the history of the epoch of reionisation (EoR). We use a popular, three-parameter EoR model, flexible enough to accommodate a wide range of physically-plausible…

宇宙学与河外天体物理 · 物理学 2018-03-01 Bradley Greig , Andrei Mesinger

The high-redshift 21 cm signal from the Epoch of Reionization (EoR) is a promising observational probe of the early universe. Current- and next-generation radio interferometers such as the Hydrogen Epoch of Reionization Array (HERA) and…

宇宙学与河外天体物理 · 物理学 2020-08-13 Paul La Plante , Adam Lidz , James Aguirre , Saul Kohn

Observations of the HI 21cm transition line promises to be an important probe into the cosmic dark ages and epoch of reionization. One of the challenges for the detection of this signal is the accuracy of the foreground source removal. This…

宇宙学与河外天体物理 · 物理学 2015-05-13 A. Datta , S. Bhatnagar , C. L. Carilli

Measuring one-point statistics in redshifted 21 cm intensity maps offers an opportunity to explore non-Gaussian features of the early universe. We assess the impact of instrumental effects on measurements made with the Hydrogen Epoch of…

Statistical observations of the epoch of reionization (EOR) power spectrum provide a rich data set for understanding the transition from the cosmic "dark ages" to the ionized universe we see today. EOR observations have become an active…

天体物理学 · 物理学 2009-11-13 Judd D. Bowman , Miguel F. Morales , Jacqueline N. Hewitt

Measurements of the one-point probability distribution function and higher-order moments (variance, skewness, and kurtosis) of the high-redshift 21 cm fluctuations are among the most direct statistical probes of the non-Gaussian nature of…

宇宙学与河外天体物理 · 物理学 2022-10-12 Piyanat Kittiwisit , Judd D. Bowman , Steven G. Murray , Bharat K. Gehlot , Daniel C. Jacobs , Adam P. Beardsley

The Epoch of Reionization (EoR) remains a poorly understood cosmic era for the most part. Yet, efforts are still going on to probe and understand this epoch. We present a review of the latest developments in the techniques (especially…

宇宙学与河外天体物理 · 物理学 2024-08-26 Chandra Shekhar Murmu , Raghunath Ghara , Suman Majumdar , Kanan K. Datta

A proposed method for dealing with foreground emission in upcoming 21-cm observations from the epoch of reionization is to limit observations to an uncontaminated window in Fourier space. Foreground emission can be avoided in this way,…

宇宙学与河外天体物理 · 物理学 2015-12-23 Hannes Jensen , Suman Majumdar , Garrelt Mellema , Adam Lidz , Ilian T. Iliev , Keri L. Dixon

Cosmic Dawn (CD) and Epoch of Reionization (EoR) are epochs of the Universe which host invaluable information about the cosmology and astrophysics of X-ray heating and hydrogen reionization. Radio interferometric observations of the 21-cm…

宇宙学与河外天体物理 · 物理学 2023-10-10 Anchal Saxena , Alex Cole , Simon Gazagnes , P. Daniel Meerburg , Christoph Weniger , Samuel J. Witte

One of the main challenges in probing the reionization epoch using the redshifted 21 cm line is that the magnitude of the signal is several orders smaller than the astrophysical foregrounds. One of the methods to deal with the problem is to…

宇宙学与河外天体物理 · 物理学 2018-06-25 Dinesh Raut , Tirthankar Roy Choudhury , Raghunath Ghara

In order to study the "Cosmic Dawn" and the Epoch of Reionization with 21 cm tomography, we need to statistically separate the cosmological signal from foregrounds known to be orders of magnitude brighter. Over the last few years, we have…

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…

宇宙学与河外天体物理 · 物理学 2026-01-27 Yannic Pietschke , Anne Hutter , Caroline Heneka

The redshifted 21-cm line of distant neutral H atoms provides a probe of the cosmic ``dark ages'' and the epoch of reionization (``EOR'') which ended them. The radio continuum produced by this redshifted line can be seen in absorption or…

天体物理学 · 物理学 2009-11-13 Paul R. Shapiro , Ilian T. Iliev , Garrelt Mellema , Ue-Li Pen , Hugh Merz

Direct detection of the Epoch of Reionization (EoR) via the red-shifted 21-cm line will have unprecedented implications on the study of structure formation in the infant Universe. To fulfill this promise, current and future 21-cm…

宇宙学与河外天体物理 · 物理学 2017-12-27 Abhik Ghosh , Florent Mertens , Leon V. E. Koopmans

Understanding the low-frequency radio sky in depth is necessary to subtract foregrounds in order to detect the redshifted 21 cm signal of neutral hydrogen from the Cosmic Dawn, Epoch of Reionization (EoR) and post-reionization era. In this…

We have used semi-numerical simulations of reionization to study the behaviour of the power spectrum of the EoR 21-cm signal in redshift space. We have considered two models of reionization, one which has homogeneous recombination (HR) and…

宇宙学与河外天体物理 · 物理学 2013-09-05 Suman Majumdar , Somnath Bharadwaj , T. Roy Choudhury

Measurement of the spatial distribution of neutral hydrogen via the redshifted 21 cm line promises to revolutionize our knowledge of the epoch of reionization and the first galaxies, and may provide a powerful new tool for observational…

宇宙学与河外天体物理 · 物理学 2015-05-14 Miguel F. Morales , J. Stuart B. Wyithe