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Related papers: The atomic Hydrogen content of the post-reionizati…

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We present a semi-empirical model to infer the atomic and molecular hydrogen content of galaxies as a function of halo mass and time. Our model combines the SFR-halo mass-redshift relation (constrained by galaxy abundances) with inverted…

Astrophysics of Galaxies · Physics 2015-06-22 G. Popping , P. S. Behroozi , M. S. Peeples

We describe a combined halo model to constrain the distribution of neutral hydrogen (HI) in the post-reionization universe. We combine constraints from the various probes of HI at different redshifts: the low-redshift 21-cm emission line…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-23 Hamsa Padmanabhan , Alexandre Refregier

Atomic hydrogen (H I) gas, mostly residing in dark matter halos after cosmic reionization, is the fuel for star formation. Its relation with properties of host halo is the key to understand the cosmic H I distribution. In this work, we…

Astrophysics of Galaxies · Physics 2022-07-22 Zhixing Li , Hong Guo , Yi Mao

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 (HI) 21-cm Intensity Mapping (IM) holds the potential to map the large-scale structures in the Universe over a wide redshift range $(z \lesssim 5.5)$, measure cosmological parameters, and shed light on the nature of dark…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-27 Minal Chhabra , Somnath Bharadwaj

The next generation of galaxy surveys will provide more precise measurements of galaxy clustering than have previously been possible. The 21-cm radio signals that are emitted from neutral atomic hydrogen (HI) gas will be detected by…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-12 Fei Qin , Cullan Howlett , Adam R. H. Stevens , David Parkinson

The emission from neutral hydrogen (HI) clouds in the post-reionization era (z < 6), too faint to be individually detected, is present as a diffuse background in all low frequency radio observations below 1420 MHz. The angular and frequency…

Astrophysics · Physics 2009-10-29 Somnath Bharadwaj , Shiv K. Sethi , Tarun Deep Saini

We model the distribution of neutral hydrogen (HI) in the post-reionization era and investigate its detectability in 21 cm intensity mapping with the future SKA radio telescope. We rely on high resolution hydrodynamical N-body simulations.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Francisco Villaescusa-Navarro , Matteo Viel , Kanan K. Datta , T. Roy Choudhury

We present recalibrations of the GALFORM semi-analytical model of galaxy formation in a new N-body simulation with the Planck cosmology. The Planck Millennium simulation uses more than 128 billion particles to resolve the matter…

We measure the scale dependence and redshift dependence of 21 cm line emitted from the neutral hydrogen gas at redshift 1<z<5 using full cosmological hydrodynamic simulations by taking the ratios between the power spectra of HI-dark matter…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-27 Rika Ando , Atsushi J. Nishizawa , Kenji Hasegawa , Ikko Shimizu , Kentaro Nagamine

We measure the neutral atomic hydrogen (HI) gas content of field galaxies at intermediate redshifts of z ~ 0.1 and z ~ 0.2 using hydrogen 21-cm emission lines observed with the Westerbork Synthesis Radio Telescope (WSRT). In order to make…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Jonghwan Rhee , Martin A. Zwaan , Frank H. Briggs , Jayaram N. Chengalur , Philip Lah , Tom Oosterloo , Thijs van der Hulst

The 21cm emission line from neutral hydrogen (HI) contained within galaxies provides a way to make accurate spectroscopic redshift determinations in the radio part of the spectrum. Large radio arrays such as SKA-MID are coming online that…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-30 Ainulnabilah Nasirudin , Philip Bull , Isabelle Ye

While massive quiescent galaxies are known to be poor in atomic hydrogen (HI), their true HI content remains poorly constrained due to the limited sensitivity and morphological biases of existing surveys. We present deep HI observations…

Astrophysics of Galaxies · Physics 2025-10-20 Xiao Li , Cheng Li , Cheng Cheng , Houjun Mo , Jing Wang , Amélie Saintonge

(Abridged) Accurately predicting how the cosmic abundance of neutral hydrogen evolves with redshift is a challenging problem facing modellers of galaxy formation. We investigate the predictions of four currently favoured semi-analytical…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 C. Power , C. M. Baugh , C. G. Lacey

The neutral atomic hydrogen (HI) mass function (HIMF) describes the distribution of the HI content of galaxies at any epoch; its evolution provides an important probe of models of galaxy formation and evolution. Here, we report Giant…

Astrophysics of Galaxies · Physics 2022-11-30 Apurba Bera , Nissim Kanekar , Jayaram N. Chengalur , Jasjeet S. Bagla

We present new analytical estimates of the large scale bias of neutral hydrogen (HI). We use a simple, non-parametric model which monotonically relates the total mass of a halo M_tot with its HI mass M_HI at zero redshift; for earlier times…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Felipe Marin , Nickolay Y. Gnedin , Hee-Jong Seo , Alberto Vallinotto

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

We model the distribution of neutral Hydrogen (HI hereafter) in the post-reionization universe. This model uses gravity only N-Body simulations and an ansatz to assign HI to dark matter haloes that is consistent with observational…

Cosmology and Nongalactic Astrophysics · Physics 2010-09-02 J. S. Bagla , Nishikanta Khandai , Kanan K. Datta

We investigate the impact of neutral hydrogen (HI) in galaxies on the statistics of 21-cm fluctuations using analytic and semi-numerical modelling. Following the reionisation of hydrogen the HI content of the Universe is dominated by damped…

Astrophysics · Physics 2015-05-13 Stuart Wyithe , Lila Warszawski , Paul M. Geil , S. Peng Oh

Observations of intergalactic neutral hydrogen can provide a wealth of information about structure and galaxy formation, potentially tracing accretion and feedback processes on Mpc scales. Below a column density of NHI ~ 10^19 cm-2, the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Attila Popping , Romeel Dave , Robert Braun , Benjamin D. Oppenheimer