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The first direct measurements of the HI intensity mapping power spectrum were recently made using the MeerKAT telescope. These measurements are on nonlinear scales, at redshifts 0.32 and 0.44. We develop a formalism for modelling…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-17 Hamsa Padmanabhan , Roy Maartens , Obinna Umeh , Stefano Camera

We conduct the first case study towards developing optimal foreground mitigation strategies for neutral hydrogen (HI) intensity mapping using radio interferometers at low redshifts. A pipeline for simulation, foreground mitigation and power…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-08 Zhaoting Chen , Laura Wolz , Richard Battye

Intensity mapping (IM) with neutral hydrogen is a promising avenue to probe the large scale structure of the Universe. In this paper, we demonstrate that using the 64-dish MeerKAT radio telescope as a connected interferometer, it is…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-28 Sourabh Paul , Mario G. Santos , Junaid Townsend , Matt J. Jarvis , Natasha Maddox , Jordan D. Collier , Bradley S. Frank , Russ Taylor

Line intensity mapping provides a statistical approach to tracing the large-scale distribution of matter in the Universe. We apply the HI intensity mapping technique to interferometric data from the MeerKAT International GHz-Tiered…

Neutral hydrogen (HI) intensity mapping (IM) surveys are considered a promising tool for investigating the expansion history of the Universe. In this work, we explore the potential of MeerKAT HI IM observations in interferometer mode to…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-25 Ming Zhang , Yichao Li , Jing-Fei Zhang , Xin Zhang

We report the first direct detection of the cosmological power spectrum using the intensity signal from 21-cm emission of neutral hydrogen (HI), derived from interferometric observations with the L-band receivers of the new MeerKAT radio…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-31 Sourabh Paul , Mario G. Santos , Zhaoting Chen , Laura Wolz

We present the first results of the HI intensity mapping power spectrum analysis with the MeerKAT International GigaHertz Tiered Extragalactic Exploration (MIGHTEE) survey. We use data covering $\sim$4 square degrees in the COSMOS field…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-13 Aishrila Mazumder , Laura Wolz , Zhaoting Chen , Sourabh Paul , Mario Santos , Matt Jarvis , Junaid Townsend , Srikrishna Sekhar , Russ Taylor

We perform an extensive suite of N-body simulations of the matter power spectrum, incorporating massive neutrinos in the range M = 0.15-0.6 eV, probing the non-linear regime at scales k < 10 hMpc-1 at z < 3. We extend the widely used…

Cosmology and Nongalactic Astrophysics · Physics 2014-04-29 Simeon Bird , Matteo Viel , Martin G. Haehnelt

A goal for pathfinder intensity mapping (IM) surveys will be detecting features in the neutral hydrogen (HI) power spectrum, which serve as conclusive evidence of cosmological signals. Observing such features at the expected scales in HI IM…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-25 Steven Cunnington

We present a detection of correlated clustering between MeerKAT radio intensity maps and galaxies from the WiggleZ Dark Energy Survey. We find a $7.7\sigma$ detection of the cross-correlation power spectrum, the amplitude of which is…

Cross-correlating neutral hydrogen (HI) 21cm intensity mapping with galaxy surveys provides an effective probe of astrophysical and cosmological information. This work presents a cross-correlation analysis between MeerKAT single-dish HI…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-12 Yu-Er Jiang , Yan Gong , Qi Xiong , Wenxiang Pei , Yun Liu , Furen Deng , Zi-yan Yuwen , Meng Zhang , Xingchen Zhou , Xuelei Chen , Yin-Zhe Ma , Qi Guo , Bin Yue

The neutral hydrogen (HI) power spectrum, measured from intensity fluctuations in the 21-cm background, offers insights into the large-scale structures (LSS) of our Universe in the post-reionization era (redshift $z<6$). A significant…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-10 Mohd Kamran , Martin Sahlén , Debanjan Sarkar , Suman Majumdar

Observations with the Canadian Hydrogen Intensity Mapping Experiment (CHIME) have been used to measure the 21 cm intensity mapping auto power spectrum, at $z\sim 1$, over a frequency range from 608.2 MHz to 707.8 MHz at wavenumbers…

HI intensity mapping is a promising technique to probe large-scale structure, traditionally analyzed via two-point statistics such as the angular power spectrum. This technique has proven very powerful but may miss key non-Gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-12 Pauline Gorbatchev , Jean-Luc Starck , Stefano Camera , Marta Spinelli

We present a new halo model of neutral hydrogen (HI) calibrated to galaxy formation simulations at redshifts $z\sim0.1$ and $z\sim1.0$ that we employ to investigate the constraining power of interferometric HI intensity mapping on HI…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-23 Zhaoting Chen , Laura Wolz , Marta Spinelli , Steven G. Murray

Intensity mapping of neutral hydrogen (HI) is a promising observational probe of cosmology and large-scale structure. We present wide field simulations of HI intensity maps based on N-body simulations of a $2.6\, {\rm Gpc / h}$ box with…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-02 Sebastian Seehars , Aseem Paranjape , Amadeus Witzemann , Alexandre Refregier , Adam Amara , Joel Akeret

Observations of redshifted 21cm radiation from HI at high redshifts is an important future probe of reionization. We consider the Multi-frequency Angular Power Spectrum (MAPS) to quantify the statistics of the HI signal as a joint function…

Astrophysics · Physics 2008-11-26 Kanan K. Datta , T. Roy Choudhury , Somnath Bharadwaj

Mapping of the neutral hydrogen (HI) 21-cm intensity fluctuations across redshifts promises a novel and powerful probe of cosmology. The neutral hydrogen gas mass density, $\Omega_{\rm HI}$ and bias parameter, $b_{\rm HI}$ are key…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-10 Hamsa Padmanabhan , T. Roy Choudhury , Alexandre Refregier

We present and compare several methods to mitigate time-correlated (1/f) noise within the HI intensity mapping component of the MeerKAT Large Area Synoptic Survey (MeerKLASS). By simulating scan strategies, the HI signal, foreground…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-10 Melis O. Irfan , Yichao Li , Mario G. Santos , Philip Bull , Junhua Gu , Steven Cunnington , Keith Grainge , Jingying Wang

Cross-correlating the data of neutral hydrogen (HI) 21cm intensity mapping with galaxy surveys is an effective method to extract astrophysical and cosmological information. In this work, we investigate the cross-correlation of MeerKAT…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-28 Yuer Jiang , Yan Gong , Meng Zhang , Qi Xiong , Xingchen Zhou , Furen Deng , Xuelei Chen , Yin-Zhe Ma , Bin Yue
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