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In a previous paper we presented the results of applying machine learning to classify whether an HI 21-cm absorption spectrum arises in a source intervening the sight-line to a more distant radio source or within the host of the radio…

Instrumentation and Methods for Astrophysics · Physics 2021-07-14 S. J. Curran

We investigate the 21-cm signature that may arise from the intergalactic medium (IGM) prior to the epoch of full reionization (z>5). In scenarios in which the IGM is reionized by discrete sources of photoionizing radiation, the neutral gas…

Astrophysics · Physics 2009-10-28 Piero Madau , Avery Meiksin , Martin J. Rees

Subtraction of astrophysical foreground contamination from "dirty" sky maps produced by simulated measurements of the Murchison Widefield Array (MWA) has been performed by fitting a 3rd-order polynomial along the spectral dimension of each…

Astrophysics · Physics 2011-02-11 Judd D. Bowman , Miguel F. Morales , Jacqueline N. Hewitt

The Minkowski Functionals (MFs), a set of topological summary statistics, have emerged as a powerful tool for extracting non-Gaussian information. We investigate the prospect of constraining the reionization parameters using the MFs of the…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-10 Kangning Diao , Zhaoting Chen , Xuelei Chen , Yi Mao

The 21 cm bispectrum (BS) offers a powerful probe of the Epoch of Reionization (EoR), but its observational access is severely hindered by dominant astrophysical foregrounds. Considering Murchison Widefield Array (MWA) observations at…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-20 Sukhdeep Singh Gill , Khandakar Md Asif Elahi , Somnath Bharadwaj , Shiv K. Sethi , Akash Kumar Patwa

The redshifted 21 cm line signal is a powerful probe of the cosmic dawn and the epoch of reionization. The global spectrum can potentially be detected with a single antenna and spectrometer. However, this measurement requires an extremely…

Instrumentation and Methods for Astrophysics · Physics 2024-12-10 Shijie Sun , Eloy de Lera Acedo , Fengquan Wu , Bin Yue , Jiacong Zhu , Xuelei Chen

We present early results from a project to measure the sky-averaged (global), redshifted $21\,$cm signal from the Epoch of Reionisation (EoR), using the Murchison Widefield Array (MWA) telescope. Because interferometers are not sensitive to…

We develop and assess the potential of several powerful techniques, designed to investigate the details of reionization. First, we present a procedure to probe the neutral fraction, x_HI, using the Lyman alpha transmission statistics of…

Astrophysics · Physics 2016-08-30 Andrei Mesinger

We compute the bispectra of the 21cm signal during the Epoch of Reionization for three different reionization scenarios that are based on a dark matter N-body simulation combined with a self-consistent, semi-numerical model of galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-08 Anne Hutter , Catherine A. Watkinson , Jacob Seiler , Pratika Dayal , Manodeep Sinha , Darren J. Croton

We explore the possibility of constraining model parameters of the Epoch of Reionization (EoR) from 21cm brightness temperature maps, using a combination of morphological descriptors constructed from the eigenvalues of the Contour Minkowski…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-19 Akanksha Kapahtia , Pravabati Chingangbam , Raghunath Ghara , Stephen Appleby , Tirthankar Roy Choudhury

Searches for Lyman-alpha emission lines are among the most effective ways to identify high-redshift galaxies. They are particularly interesting because they probe not only the galaxies themselves but also the ionization state of the…

Astrophysics · Physics 2009-11-13 Steven R. Furlanetto , Matias Zaldarriaga , Lars Hernquist

Extracting the multiphase structure of the neutral interstellar medium (ISM) is key to understand the star formation in galaxies. The radiative condensation of the diffuse warm neutral medium producing a thermally unstable lukewarm medium…

5G radio at millimeter wave (mmWave) and beyond 5G concepts at 0.1-1 THz can exploit angle and delay measurements for localization, by the virtue of increased bandwidth and large antenna arrays but are limited in terms of blockage caused by…

Signal Processing · Electrical Eng. & Systems 2020-06-12 Henk Wymeersch , Jiguang He , Benoît Denis , Antonio Clemente , Markku Juntti

We present the results of a systematic Giant Metrewave Radio Telescope (GMRT) survey of 21-cm absorption in a representative and unbiased sample of 35 strong MgII systems in the redshift range: zabs~1.10-1.45, 33 of which have W_r>1 \AA.…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 N. Gupta , R. Srianand , P. Petitjean , P. Noterdaeme , D. J. Saikia

Upcoming 21-cm intensity surveys will use the hyperfine transition in emission to map out neutral hydrogen in large volumes of the universe. Unfortunately, large spatial scales are completely contaminated with spectrally smooth…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-27 Chirag Modi , Martin White , Anze Slosar , Emanuele Castorina

One of the most promising ways to study the epoch of reionization (EoR) is through radio observations of the redshifted 21-cm line emission from neutral hydrogen. These observations are complicated by the fact that the mapping of redshifts…

21 cm intensity mapping has emerged as a promising technique to map the large-scale structure of the Universe, at redshifts $z$ from 1 to 10. Unfortunately, many of the key cross-correlations with the cosmic microwave background and…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-20 Hong-Ming Zhu , Ue-Li Pen , Yu Yu , Xuelei Chen

We present and evaluate several strategies to search for prompt, low-frequency radio emission associated with gravitational wave transients using the Murchison Widefield Array (MWA). As we are able to repoint the MWA on timescales of tens…

Instrumentation and Methods for Astrophysics · Physics 2016-10-12 D. L. Kaplan , T. Murphy , A. Rowlinson , S. D. Croft , R. B. Wayth , C. M. Trott

The late-time integrated Sachs-Wolfe (ISW) signal in the CMB temperature anisotropies is an important probe of dark energy when it can be detected by cross-correlation with large-scale structure surveys. Because of their huge sky area,…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-12 Mario Ballardini , Roy Maartens