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The ambitious scientific goals of the SKA require a matching capability for calibration of atmospheric propagation errors, which contaminate the observed signals. We demonstrate a scheme for correcting the direction-dependent ionospheric…

Instrumentation and Methods for Astrophysics · Physics 2018-07-18 Maria Rioja , Richard Dodson , Thomas Franzen

Neutral hydrogen (HI) 21-cm intensity mapping is an effective method to track the distribution of baryonic matter, and extract astrophysical and cosmological information. The 21-cm intensity field has a nonvanishing cross-correlation with…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-07 Zi-Yan Yuwen , Yu-Er Jiang , Yin-Zhe Ma , Paul La Plante , Adam Lidz , Yan Gong

Future 21 cm intensity mapping surveys such as SKA can provide precise information on the spatial distribution of the neutral hydrogen (HI) in the post-reionization epoch. This information will allow to test the standard LCDM paradigm and…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-26 Matteo Leo , Christian Arnold , Baojiu Li

We present updated constraints on cosmological parameters in a 12-parameter model, extending the standard six-parameter $\Lambda$CDM by including dynamical dark energy (DE: $w_0$, $w_a$), the sum of neutrino masses ($\sum m_{\nu}$), the…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-19 Shouvik Roy Choudhury , Teppei Okumura

We study synergies between three promising methods to measure $2<z<5$ large-scale structure in the next decade. Optical spectroscopic surveys are the most mature, but become increasingly difficult at $z>2$ and suffer from interloper…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-24 Shi-Fan Chen , Emanuele Castorina , Martin White , Anže Slosar

We address the amount of information in the non-Gaussian regime of weak lensing surveys by modelling all relevant covariances of the power spectra and bispectra, using 1000 ray-tracing simulation realizations for a Lambda-CDM model and an…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-09 Issha Kayo , Masahiro Takada , Bhuvnesh Jain

The 21 cm intensity mapping experiments promise to obtain the large-scale distribution of HI gas at the post-reionization epoch. In order to reveal the underlying matter density fluctuations from the HI mapping, it is important to…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-05 Zhenyuan Wang , Yangyao Chen , Yi Mao , Houjun Mo , Huiyuan Wang , Hong Guo , Cheng Li , Jian Fu , Yipeng Jing , Jing Wang , Xiaohu Yang , Zheng Zheng

Neutral hydrogen ($\rm{HI}$) $21$-cm intensity mapping (IM) offers an efficient technique for mapping the large-scale structures in the universe. We introduce the 'Cross' Tapered Gridded Estimator (Cross TGE), which cross-correlates two…

The basic cosmological parameters and the primordial power spectrum together completely specify predictions for the cosmic microwave background radiation anisotropy and large scale structure. Here we show how we can strongly constrain both…

Astrophysics · Physics 2010-11-30 Yun Wang , David N. Spergel , Michael A. Strauss

Observations of the neutral Hydrogen (\HI ) 21-cm signal hold the potential of allowing us to map out the cosmological large scale structures (LSS) across the entire post-reionization era ($z \leq 6$). Several experiments are planned to map…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-11 Debanjan Sarkar , Somnath Bharadwaj , Anathpindika S.

The ambitious scientific goals of SKA require a matching capability for calibration of instrumental and atmospheric propagation contributions as functions of time, frequency and position. The development of novel calibration algorithms to…

Instrumentation and Methods for Astrophysics · Physics 2022-02-01 María J. Rioja , Richard Dodson

Intensity mapping is now becoming a useful tool to study the large-scale structure of the universe through spatial variations in the integrated emission from galaxies and the intergalactic medium. We study intensity mapping of the H-alpha…

Astrophysics of Galaxies · Physics 2017-02-15 Yan Gong , Asantha Cooray , Marta B. Silva , Michael Zemcov , Chang Feng , Mario G. Santos , Olivier Dore , Xuelei Chen

Intensity mapping -- the large-scale mapping of selected spectral lines without resolving individual sources -- is quickly emerging as an efficient way to conduct large cosmological surveys. Multiple surveys covering a variety of lines…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-22 Hannah Fronenberg , Adrian Liu

Removing contaminants is a delicate, yet crucial step in neutral hydrogen (HI) intensity mapping and often considered the technique's greatest challenge. Here, we address this challenge by analysing HI intensity maps of about $100$ deg$^2$…

Foreground removal is the most important step in detecting the large-scale redshifted HI 21-cm signal. Modelling foreground spectra is challenging and is further complicated by the chromatic response of the telescope. We present a…

Instrumentation and Methods for Astrophysics · Physics 2017-07-19 Visweshwar Ram Marthi , Suman Chatterjee , Jayaram Chengalur , Somnath Bharadwaj

Measurement of the power spectrum of high redshift 21 cm emission from neutral hydrogen probes the formation of the first luminous objects and the ionization of intergalactic medium by the first stars. However, the 21 cm signal at these…

Instrumentation and Methods for Astrophysics · Physics 2025-08-13 Katherine Elder , Daniel C. Jacobs , Maria Kovaleva

The post-reionization ${\rm HI}$ 21-cm signal is an excellent candidate for precision cosmology, this however requires accurate modelling of the expected signal. Sarkar et al. (2016) have simulated the real space ${\rm HI}$ 21-cm signal,…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-25 Debanjan Sarkar , Somnath Bharadwaj

We report cosmological results from the Dark Energy Spectroscopic Instrument (DESI) measurements of baryon acoustic oscillations (BAO) when combined with recent data from the Atacama Cosmology Telescope (ACT). By jointly analyzing ACT and…

21 cm intensity mapping (IM) has the potential to be a strong and unique probe of cosmology from redshift of order unity to redshift potentially as high as 30. For post-reionization 21 cm observations, the signal is modulated by the thermal…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-03 Heyang Long , Catalina Morales-Gutiérrez , Paulo Montero-Camacho , Christopher M. Hirata

We consider a search for the anisotropic stochastic gravitational-wave background (SGWB) that decomposes the sky map into its spherical harmonics components in order to obtain estimators of the angular power spectrum. Such a search often…

General Relativity and Quantum Cosmology · Physics 2026-04-21 Erik Floden , Alex Granados , Vuk Mandic
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