Pith. sign in

REVIEW 10 cited by

Ingredients for 21cm intensity mapping

Not yet reviewed by Pith; the record is open.

This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.

SPECIMEN: schema-true, not a live event

T0 review · schema-true

One-sentence machine reading of the paper's core claim.

pith:XXXXXXXX · record.json · timestamp

arxiv 1804.09180 v1 pith:HV7SOXUA submitted 2018-04-24 astro-ph.CO astro-ph.GA

Ingredients for 21cm intensity mapping

classification astro-ph.CO astro-ph.GA
keywords halosfindmassclusteringbiashalolargematter
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved
0 comments
read the original abstract

[Abridged] We study the abundance and clustering properties of HI at redshifts $z\leqslant5$ using TNG100, a large state-of-the-art magneto-hydrodynamic simulation of a 75 Mpc/h box size. We show that most of the HI lies within dark matter halos and quantify the average HI mass hosted by halos of mass M at redshift z. We find that only halos with circular velocities larger than $\simeq$ 30 km/s contain HI. While the density profiles of HI exhibit a large halo-to-halo scatter, the mean profiles are universal across mass and redshift. The HI in low-mass halos is mostly located in the central galaxy, while in massive halos is concentrated in the satellites. We show that the HI and matter density probability distribution functions differ significantly. Our results point out that for small halos the HI bulk velocity goes in the same direction and has the same magnitude as the halo peculiar velocity, while in large halos differences show up. We find that halo HI velocity dispersion follows a power-law with halo mass. We find a complicated HI bias, with HI becoming non-linear already at $k=0.3$ h/Mpc at $z\gtrsim3$. Our simulation reproduces the DLAs bias value from observations. We find that the clustering of HI can be accurately reproduced by perturbative methods. We identify a new secondary bias, by showing that the clustering of halos depends not only on mass but also on HI content. We compute the amplitude of the HI shot-noise and find that it is small at all redshifts. We study the clustering of HI in redshift-space, and show that linear theory can explain the ratio between the monopoles in redshift- and real-space down to small scales at high redshift. We find that the amplitude of the Fingers-of-God effect is larger for HI than for matter. We point out that accurate 21 cm maps can be created from N-body or approximate simulations rather than full hydrodynamic simulations.

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Forward citations

Cited by 10 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. Realistic simulations of galaxy formation in f(R) modified gravity

    astro-ph.CO 2019-07 unverdicted novelty 7.0

    Hydrodynamical simulations in f(R) gravity using Illustris-TNG find observable 20% effects on high-z HI and stellar power spectra exceeding SKA errors, plus changes in disc galaxy formation.

  2. Fast(er)PM and Moving Mesh: JAX-native Geometric Multigrid Methods

    astro-ph.IM 2026-07 conditional novelty 6.0

    Warm-started Chebyshev geometric multigrid is competitive with distributed FFTs for FastPM and enables a differentiable moving-mesh particle–mesh gravity solver in JAX.

  3. Intensity fluctuations of radio halo in galaxy cluster: Insights from power spectrum estimation

    astro-ph.CO 2026-07 conditional novelty 6.0

    Angular power spectra of 610 MHz radio halos show excess power-law fluctuations only in Abell 2744, requiring multiplicative C_ℓ ∝ ℓ^{-3} structure atop an exponential profile and consistent with ICM turbulence.

  4. Weak Evolution of Cosmic Atomic Hydrogen over the Past 4.5 Billion Years

    astro-ph.GA 2026-07 accept novelty 6.0

    Combining FAST and DESI data for 2.5 million galaxies shows cosmic atomic hydrogen density declined by only a factor of 1.35 over 4.5 Gyr, far less than the 2.46-fold decline in star formation.

  5. Cosmology with HI Intensity Mapping

    astro-ph.CO 2026-07 accept novelty 4.0

    SKAO HI intensity mapping forecasts yield competitive LambdaCDM constraints (e.g. H0 to ~0.3 km/s/Mpc optimistic) via power spectrum, BAO, bispectrum and stacking, complementary to CMB and optical surveys.

  6. Using SKAO to Understand the Clustering of Gravitational Wave Sources

    astro-ph.CO 2026-06 unverdicted novelty 3.0

    Forecasts show SKA-Mid cross-correlations with ET/CE gravitational wave events can constrain GW source bias and time-delay distributions.

  7. Cosmology with Multi-Wavelength Line Intensity Mapping Synergies in the SKAO Era

    astro-ph.CO 2026-06 unverdicted novelty 2.0

    Reviews how cross-correlating SKAO 21-cm LIM with other lines like [CII], CO, and Ly-alpha can mitigate systematics, enhance sensitivity, and disentangle cosmological from astrophysical parameters.

  8. HI Simulations for Cosmology with the SKA Observatory

    astro-ph.CO 2026-06 unverdicted novelty 2.0

    Overview of HI modeling methods finds consistency in cosmic HI density but systematic differences in HI-halo mass relation shape and redshift evolution.

  9. Cosmology Intertwined: A Review of the Particle Physics, Astrophysics, and Cosmology Associated with the Cosmological Tensions and Anomalies

    astro-ph.CO 2022-03 accept novelty 2.0

    The paper reviews cosmological tensions including the H0 and S8 discrepancies and explores new physics models that could explain them.

  10. Cosmological Galaxy Formation Modelling in the Era of the Square Kilometre Array

    astro-ph.GA 2026-06 unverdicted novelty 1.0

    Review of state-of-the-art cosmological galaxy formation models for HI, molecular gas and radio continuum in preparation for SKA, advocating coordinated multi-scale simulations, forward modelling and AI emulators.