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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

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$^2$…

Photometric surveys have provided incredible amounts of astronomical information in the form of images. However, astronomical images often contain artifacts that can critically hinder scientific analysis by misrepresenting intensities or…

Instrumentation and Methods for Astrophysics · Physics 2020-06-03 Suchetha Cooray , Tsutomu T. Takeuchi , Moe Yoda , Kazuo Sorai

The Siberian Solar Radio Telescope (SSRT) is a solar-dedicated directly-imaging interferometer observing the Sun at 5.7 GHz. The SSRT operates in the two-dimensional mode since 1996. The imaging principle of the SSRT restricts its…

Solar and Stellar Astrophysics · Physics 2014-10-20 Alexey Kochanov , Sergey Anfinogentov , Dmitry Prosovetsky , George Rudenko , Victor Grechnev

The 21-cm intensity mapping (IM) of neutral hydrogen (HI) is a promising tool to probe the large-scale structures. Sky maps of 21-cm intensities can be highly contaminated by different foregrounds, such as Galactic synchrotron radiation,…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-01 Elimboto Yohana , Yin-Zhe Ma , Di Li , Xuelei Chen , Wei-Ming Dai

A new generation of wide-field radio interferometers designed for 21-cm surveys is being built as drift scan instruments allowing them to observe large fractions of the sky. With large numbers of antennas and frequency channels the enormous…

Instrumentation and Methods for Astrophysics · Physics 2017-10-10 Philippe Berger , Niels Oppermann , Ue-Li Pen , J. Richard Shaw

HI intensity mapping is a new observational technique to map fluctuations in the large-scale structure of matter using the 21 cm emission line of atomic hydrogen (HI). Sensitive radio surveys have the potential to detect Baryon Acoustic…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-22 L. C. Olivari , M. Remazeilles , C. Dickinson

The distribution of cosmological neutral hydrogen will provide a new window into the large-scale structure of the Universe with the next generation of radio telescopes and surveys. The observation of this material, through 21cm line…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-28 Jacobo Asorey , David Parkinson , Feng Shi , Yong-Seon Song , Kyungjin Ahn , Juhan Kim , Jian Yao , Le Zhang , Shifan Zuo

Radio-astronomical observations are increasingly contaminated by interference, and suppression techniques become essential. A powerful candidate for interference mitigation is adaptive spatial filtering. We study the effect of spatial…

Astrophysics · Physics 2014-10-13 Amir Leshem , Alle-Jan van der Veen

Radio astronomical observation below 30 MHz is hampered by the refraction and absorption of the ionosphere, and the radio frequency interference (RFI), so far high angular resolution sky intensity map is not available. An interferometer…

Instrumentation and Methods for Astrophysics · Physics 2018-07-09 Qizhi Huang , Shijie Sun , Shifan Zuo , Fengquan Wu , Yidong Xu , Bin Yue , Reza Ansari , Xuelei Chen

We explore the cosmological multitracer synergies between an emission line galaxy distribution from the Dark Energy Spectroscopic Instrument and a Tianlai Project 21-cm intensity map. We use simulated maps generated from a particle…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-17 Feng Shi , Yong-Seon Song , Jacobo Asorey , David Parkinson , Kyungjin Ahn , Jian Yao , Le Zhang , Shifan Zuo

Intensity mapping surveys will provide access to a coarse view of the cosmic large-scale structure in unprecedented large volumes at high redshifts. Given the large fractions of the sky that can be efficiently scanned using emission from…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-09 Oliver Leicht , Cora Uhlemann , Francisco Villaescusa-Navarro , Sandrine Codis , Lars Hernquist , Shy Genel

The Tianlai Pathfinder is designed to demonstrate the feasibility of using a wide field of view radio interferometers to map the density of neutral hydrogen in the Universe after the Epoch of Reionizaton. This approach, called 21~cm…

Next generation radio observatories such as the MWA, LWA, LOFAR, CARMA and SKA provide a number of challenges for interferometric data analysis. These challenges include heterogeneous arrays, direction-dependent instrumental gain, and…

Astrophysics · Physics 2015-05-13 Miguel F. Morales , Michael Matejek

We characterize the problem of artificial polarization for the Submillimeter High Angular Resolution Polarimeter (SHARP) through the use of simulated data and observations made at the Caltech Submillimeter Observatory (CSO). These…

Astrophysics · Physics 2009-11-13 Michael Attard , Martin Houde , Giles Novak , John E. Vaillancourt

Time-series photometry at mid-infrared wavelengths is becoming a common technique to search for atmospheres around rocky exoplanets. This method constrains the brightness temperature of the planet to determine whether heat redistribution is…

3D mapping of matter distribution in the universe through the 21 cm radio emission of atomic hydrogen is a complementary approach to optical surveys for the study of the Large Scale Structures, in particular for measuring the BAO (Baryon…

Instrumentation and Methods for Astrophysics · Physics 2011-09-09 R. Ansari , J. E. Campagne , P. Colom , C. Magneville , J. M. Martin , M. Moniez , J. Rich , C. Yèche

An important application of next-generation wide-field radio interferometers is making high dynamic range maps of radio emission. Traditional deconvolution methods like CLEAN can give poor recovery of diffuse structure, prompting the…

Instrumentation and Methods for Astrophysics · Physics 2024-10-23 Katrine A. Glasscock , Philip Bull , Jacob Burba , Hugh Garsden , Michael J. Wilensky

An algorithm is described for removing extended interferences, for instance from a radar, which are shorter than the time of passage of a radio source across the beam of the radio telescope. The algorithm is developed on the basis of robust…

Astrophysics · Physics 2007-05-23 O. V. Verkhodanov , D. A. Pavlov

Radio frequency data in astronomy enable scientists to analyze astrophysical phenomena. However, these data can be corrupted by radio frequency interference (RFI) that limits the observation of underlying natural processes. In this study,…

Instrumentation and Methods for Astrophysics · Physics 2025-09-08 Allen Chang , Mary Knapp , James LaBelle , John Swoboda , Ryan Volz , Philip J. Erickson
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