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Context. Building on the transformative success of optical redshift surveys, the emerging technique of neutral hydrogen (HI) intensity mapping (IM) offers a novel probe of large-scale structure (LSS) growth and the late-time accelerated…

We present a partial-sky survey of the radio continuum at 2.3 GHz within the scope of the Galactic Emission Mapping (GEM) project, an observational program conceived and developed to reveal the large-scale properties of Galactic synchrotron…

Large inhomogeneities in neutral hydrogen in the universe can be detected at redshifts $z \leq 10$ using the redshifted 21 cm line emission. We use cosmological N-Body simulations for dark matter and a simple model for baryonic collapse to…

Astrophysics · Physics 2015-06-24 J. S. Bagla , Biman Nath , T. Padmanabhan

The Baryon acoustic oscillations from Integrated Neutral Gas Observations (BINGO) telescope is a 40-m~class radio telescope under construction that has been designed to measure the large-angular-scale intensity of HI emission at 980--1260…

Instrumentation and Methods for Astrophysics · Physics 2020-07-08 C. A. Wuensche , L. Reitano , M. W. Peel , I. W. A. Browne , B. Maffei , E. Abdalla , C. Radcliffe , F. Abdalla , L. Barosi , V. Liccardo , E. Mericia , G. Pisano , C. Strauss , F. Vieira , T. Villela , B. Wang

Line intensity mapping (LIM) is a technique for producing 3D maps of the Universe by scanning the sky with a spectrometer sensitive to a range of wavelengths corresponding to the redshifted spectral lines of atoms or molecules, such as…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-16 Samuel H. Kramer , Patrick C. Breysse , Anthony R. Pullen , Faizah K. Siddique , Eric R. Switzer , Peter T. Timbie , Dongwoo Chung

Understanding dark energy requires precision measurements of the expansion history of the universe and the growth of large-scale structure. The 21 cm intensity mapping (21 cm IM) technique enables rapid large-area surveys that can deliver…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-25 Jun-Da Pan , Yichao Li , Guo-Hong Du , Tian-Nuo Li , Xin Zhang

I review the potential for observing cosmic reionization using the HI 21cm line of neutral hydrogren. Studies include observations of the evolution of large scale structure of the IGM (density, excitation temperature, and neutral fraction),…

Astrophysics · Physics 2009-11-13 C. L. Carilli

We present a simulation experiment of a pipeline based on machine learning algorithms for neutral hydrogen (HI) intensity mapping (IM) surveys with different telescopes. The simulation is conducted on HI signals, foreground emission,…

Instrumentation and Methods for Astrophysics · Physics 2022-09-14 Lin-Cheng Li , Yuan-Gen Wang

Neutral hydrogen (HI) will soon be the dark matter tracer observed over the largest volumes of Universe thanks to the 21 cm intensity mapping technique. To unveil cosmological information it is indispensable to understand the HI…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-06 Aurélie Pénin , Obinna Umeh , Mario Santos

We present near-field radio holography measurements of the Simons Observatory Large Aperture Telescope Receiver optics. These measurements demonstrate that radio holography of complex millimeter-wave optical systems comprising cryogenic…

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

At present neutral atomic hydrogen (HI) gas in galaxies at redshifts above $z \sim 0.3$ (the extent of 21-cm emission surveys in individual galaxies) and below $z \sim 1.7$ (where the Lyman-$\alpha$ line is not observable with ground-based…

We investigate a number of potential foregrounds for an ambitious goal of future radio telescopes such as the Square Kilometer Array (SKA) and Low Frequency Array (LOFAR): spatial tomography of neutral gas at high redshift in 21cm emission.…

Astrophysics · Physics 2009-11-07 S. Peng Oh , Katherine J. Mack

Distribution of cold gas in the post-reionization era provides an important link between distribution of galaxies and the process of star formation. Redshifted 21 cm radiation from the Hyperfine transition of neutral Hydrogen allows us to…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-22 Bharat Kumar Gehlot , Jasjeet Singh Bagla

Submillimeter cameras now have up to $10^4$ pixels (SCUBA 2). The proposed CCAT 25-meter submillimeter telescope will feature a 1 degree field-of-view. Populating the focal plane at 350 microns would require more than $10^6$ photon-noise…

A large fraction of baryons predicted from the standard cosmology has been missing observationally. Although previous numerical simulations have indicated that most of the missing baryons reside in large-scale filaments in the form of Warm…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-20 Toshihiro Horii , Shinsuke Asaba , Kenji Hasegawa , Hiroyuki Tashiro

Among the tools available for the study of the dark energy driving the expansion of the Universe, Baryon Acoustic Oscillations (BAO) and their effects on the matter power spectrum are particularly attractive. It was recently proposed to…