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Global 21cm cosmology aims to investigate the cosmic dawn and epoch of reionisation by measuring the sky averaged HI absorption signal, which requires, accurate modelling of, or correction for, the bright radio foregrounds and distortions…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-18 Dominic Anstey , Eloy de Lera Acedo , Will Handley

Foreground removal presents a significant obstacle in both current and forthcoming intensity mapping surveys. While numerous techniques have been developed that show promise in simulated datasets, their efficacy often diminishes when…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-14 Jiacheng Ding , Xin Wang , Ue-Li Pen , Xiao-Dong Li

Fluctuations in the redshifted 21 centimeter emission from neutral hydrogen probe the epoch of reionization. We examine the observability of this signal and the impact of extragalactic foreground radio sources. We use cosmological…

Astrophysics · Physics 2009-11-10 Tiziana Di Matteo , Benedetta Ciardi , Francesco Miniati

Absorption or emission against the cosmic microwave background radiation (CMB) may be observed in the redshifted 21cm line if the spin temperature of the neutral intergalactic medium prior to reionization differs from the CMB temperature.…

Astrophysics · Physics 2009-12-10 Tiziana Di Matteo , Rosalba Perna , Tom Abel , Martin J. Rees

The fluid forces associated with primordial magnetic fields (PMFs) generate small-scale fluctuations in the primordial density field, which add to the $\mathrm{\Lambda CDM}$ linear matter power spectrum on small scales. These enhanced…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-01 Hector Afonso G. Cruz , Tal Adi , Jordan Flitter , Marc Kamionkowski , Ely D. Kovetz

We propose a continuous wavelet transform based non-parametric foreground subtraction method for the detection of redshifted 21 cm signal from the epoch of reionization. This method works based on the assumption that the foreground spectra…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Junhua Gu , Haiguang Xu , Jingying Wang , Tao An , Wen Chen

Detecting a deviation from a featureless primordial power spectrum of fluctuations would give profound insight into the physics of the primordial Universe. Depending on their nature, primordial features can either provide direct evidence…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-28 Xingang Chen , P. Daniel Meerburg , Moritz Münchmeyer

We explore the information content of 21cm intensity maps in redshift space using the 1-loop Effective Field Theory power spectrum model and the bispectrum at tree level. The 21cm signal contains signatures of dark matter, dark energy and…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-11 Liantsoa F. Randrianjanahary , Dionysios Karagiannis , Roy Maartens

Foreground subtraction in global redshifted 21 cm measurements is limited by frequency-dependent (chromatic) structure in antenna beam patterns. Chromatic beams couple angular structures in Galactic foreground emission to spectral…

Instrumentation and Methods for Astrophysics · Physics 2015-12-09 Thomas J. Mozdzen , Judd D. Bowman , Raul A. Monsalve , Alan E. E. Rogers

The relatively large Thomson optical depth, tau_e, inferred recently from the WMAP observations suggests that the Universe was reionized in a more complex manner than previously believed. However, the value of tau_e provides only an…

Astrophysics · Physics 2009-11-10 Matias Zaldarriaga , Steven Furlanetto , Lars Hernquist

Observations of the 21cm Epoch of Reionization (EoR) signal are dominated by Galactic and extragalactic foregrounds. The need for foreground removal has led to the development of two main techniques, often referred to as "foreground…

Observations of the redshifted 21-cm signal emitted by neutral hydrogen represent a promising probe of large-scale structure in the universe. However, cosmological 21-cm signal is challenging to observe due to astrophysical foregrounds…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-07 Haochen Wang , Juan Mena-Parra , Tianyue Chen , Kiyoshi Masui

After reionization, emission in the 21 cm hyperfine transition provides a direct probe of neutral hydrogen distributed in galaxies. Different from galaxy redshift surveys, observation of baryon acoustic oscillations in the cumulative 21 cm…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-14 Xiao-Chun Mao

Initial density distribution provides a basis for understanding the complete evolution of cosmological density fluctuations. While reconstruction in our local Universe exploits the observations of galaxy surveys with large volumes,…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-28 Meng Zhou , Yi Mao

The success of HI intensity mapping is largely dependent on how well 21cm foreground contamination can be controlled. In order to progress our understanding further, we present a range of simulated foreground data from four different…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-25 Steven Cunnington , Melis O. Irfan , Isabella P. Carucci , Alkistis Pourtsidou , Jérôme Bobin

Observations of 21cm line from neutral hydrogen promise to be an exciting new probe of astrophysics and cosmology during the Cosmic Dawn and through the Epoch of Reionization (EoR) to when dark energy accelerates the expansion of the…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-24 Tyler A. Cox , Aaron R. Parsons , Joshua S. Dillon , Aaron Ewall-Wice , Robert Pascua

Contamination from instrumental effects interacting with bright astrophysical sources is the primary impediment to measuring Epoch of Reionization and BAO 21 cm power spectra---an effect called mode-mixing. In this paper we identify four…

Instrumentation and Methods for Astrophysics · Physics 2015-06-04 Miguel F. Morales , Bryna Hazelton , Ian Sullivan , Adam Beardsley

It is seen that foregrounds of 21cm Epoch of Reionization experiments, which are expected to have smooth spectral dependence, are dominant in a wedge shaped region of the Fourier space called as Foreground Wedge. A possible way forward to…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-13 Dinesh V. Raut

The redshifted 21 cm line of cosmic atomic hydrogen is one of the most auspicious tools in deciphering the early Universe. Recovering this signal remains an ongoing problem for cosmologists in the field, with the signal being hidden behind…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-18 Joe H. N. Pattison , Jean Cavillot , Harry T. J. Bevins , Dominic J. Anstey , Eloy de Lera Acedo

Simultaneous imaging of fluorescence-labeled and label-free phase objects in the same sample provides distinct and complementary information. Most multimodal fluorescence-phase imaging operates in transmission mode, capturing fluorescence…

Optics · Physics 2024-08-20 Renzhi He , Yucheng Li , Junjie Chen , Yi Xue