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We use the results of previous work building a halo model formalism for the distribution of neutral hydrogen, along with experimental parameters of future radio facilities, to place forecasts on astrophysical and cosmological parameters…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-20 Hamsa Padmanabhan , Alexandre Refregier , Adam Amara

Upcoming 21cm surveys with the SKA1-LOW telescope will enable imaging of the neutral hydrogen distribution on cosmological scales in the early Universe. These surveys are expected to generate huge imaging datasets that will encode more…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-22 Tumelo Mangena , Sultan Hassan , Mario G. Santos

Neutral hydrogen (HI) intensity mapping is a promising technique to probe the large-scale structure of the Universe, improving our understanding on the late-time accelerated expansion. In this work, we first scrutinize how an alternative…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-12 Linfeng Xiao , Andre A. Costa , Bin Wang

Cosmological inference with large galaxy surveys requires theoretical models that combine precise predictions for large-scale structure with robust and flexible galaxy formation modelling throughout a sufficiently large cosmic volume. Here,…

Following on from the second release of calibrated photometry from IPHAS, the INT/WFC Photometric H-alpha Survey of the Northern Galactic Plane, we present incompleteness-corrected stellar density maps in the r and i photometric bands.…

Astrophysics of Galaxies · Physics 2016-01-27 H. J. Farnhill , J. E. Drew , G. Barentsen , E. A. González-Solares

We present a code to generate mock observations of 21 cm intensity mapping experiments. The emphasis of the code is on reducing the computational cost of running a full-blown simulation, trading computational time for accuracy. The code can…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 David Alonso , Pedro G. Ferreira , Mario G. Santos

With new atomic-hydrogen (HI) observations of FAST Extended Atlas of Selected Targets Survey (FEASTS), we present the first statistical comparison of HI morphology between observations and cosmological simulations, focusing on low-column…

Astrophysics of Galaxies · Physics 2026-02-04 Xuchen Lin , Jing Wang , Guinevere Kauffmann , Volker Springel , Rüdiger Pakmor

We present rotation curves of 19 galaxies from THINGS, The HI Nearby Galaxy Survey. The high spatial and velocity resolution of THINGS make these the highest quality HI rotation curves available to date for a large sample of nearby…

Astrophysics · Physics 2009-11-13 W. J. G. de Blok , F. Walter , E. Brinks , C. Trachternach , S-H. Oh , R. C. Kennicutt

Intensity mapping of 21cm emission from neutral hydrogen promises to be a powerful probe of large-scale structure in the post-reionisation epoch. However, HI intensity mapping (IM) experiments will suffer the loss of long-wavelength…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-30 Kavilan Moodley , Warren Naidoo , Heather Prince , Aurelie Penin

We use an analytical forward model based on perturbation theory to predict the neutral hydrogen (HI) overdensity maps at low redshifts. We investigate its performance by comparing it directly at the field level to the simulated HI from the…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-01 Andrej Obuljen , Marko Simonović , Aurel Schneider , Robert Feldmann

We present a detailed study of the hydrogen density distribution in the local interstellar medium (ISM) using the X-ray absorption technique. Hydrogen column densities were precisely measured by fitting X-ray spectra from coronal sources…

High Energy Astrophysical Phenomena · Physics 2024-08-28 E. Gatuzz , J. Wilms , A. Zainab , S. Freund , P. C. Schneider , J. Robrade , S. Czesla , J. A. García , T. R. Kallmanınst

CMB lensing maps probe the mass distribution in projection out to high redshifts, but significant sensitivity to low-redshift structure remains. In this paper we discuss a method to remove the low-redshift contributions from CMB lensing…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-20 Frank J. Qu , Blake D. Sherwin , Omar Darwish , Toshiya Namikawa , Mathew S. Madhavacheril

Large Scale Structures (LSS) in the universe can be traced using the neutral atomic hydrogen HI through its 21cm emission. Such a 3D matter distribution map can be used to test the Cosmological model and to constrain the Dark Energy…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 R. Ansari , J. E. Campagne , P. Colom , J. M. Le Goff , C. Magneville , J. M. Martin , M. Moniez , J. Rich , C. Yèche

A new dataset of atomic oxygen and molecular nitrogen number density profiles, along with thermospheric temperature profiles between 180 and 500 km, has been developed. These profiles are derived from solar occultation measurements made by…

We present a statistical method based on a maximum likelihood approach to constrain the number counts of extragalactic sources below the nominal flux-density limit of continuum imaging surveys. We extract flux densities from a radio map…

Instrumentation and Methods for Astrophysics · Physics 2015-06-16 Ketron Mitchell-Wynne , Mario G. Santos , Jose Afonso , Matt J. Jarvis

The measurement of the large scale distribution of neutral hydrogen in the late Universe, obtained with radio telescopes through the hydrogen 21cm line emission, has the potential to become a key cosmological probe in the upcoming years. We…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-15 Maria Berti , Marta Spinelli , Matteo Viel

We have recently developed a post-processing framework to estimate the abundance of atomic and molecular hydrogen (HI and H2, respectively) in galaxies in large-volume cosmological simulations. Here we compare the HI and H2 content of…

The cosmological power spectrum of the coherent matter flow is measured exploiting an improved prescription for the apparent anisotropic clustering pattern in redshift space. New statistical analysis is presented to provide an optimal…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-22 Yong-Seon Song , Takahiro Nishimichi , Atsushi Taruya , Issha Kayo

The Earth occultation technique has broad applications in both astronomy and atmospheric density measurements. We construct the background model during the occultation of the Crab Nebula observed by the Insight-Hard X-ray Modulation…

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