Looking at the Distant Universe with the MeerKAT Array: The H i Mass Function in the Local Universe
Journal article, 2025
We present measurements of the neutral atomic hydrogen (H i) mass function (HiMF) and cosmic H i density (Omega H I) at 0 <= z <= 0.088 from the Looking at the Distant Universe with MeerKAT Array (LADUMA) survey. Using LADUMA Data Release 1 (DR1), we analyze the HiMF via a new "recovery matrix" method that we benchmark against a more traditional modified maximum likelihood (MML) method. Our analysis, which implements a forward modeling approach, corrects for survey incompleteness and uses extensive synthetic source injections to ensure robust estimates of the HiMF parameters and their associated uncertainties. This new method tracks the recovery of sources in mass bins different from those in which they were injected and incorporates a Poisson likelihood in the forward modeling process, allowing it to correctly handle uncertainties in bins with few or no detections. The application of our analysis to a high-purity subsample of the LADUMA DR1 spectral line catalog in turn mitigates any possible biases that could result from the inconsistent treatment of synthetic and real sources. For the surveyed redshift range, the recovered Schechter function normalization, low-mass slope, and "knee" mass are phi*=3.56-1.92+0.97x10-3 Mpc-3 dex-1, alpha=-1.18-0.19+0.08 , and log(M*/M circle dot)=10.01-0.12+0.31 , respectively, which together imply a comoving cosmic H i density of Omega HI=3.09-0.47+0.65x10-4 . Our results show consistency between recovery matrix and MML methods and with previous low-redshift studies, giving confidence that the cosmic volume probed by LADUMA, even at low redshifts, is not an outlier in terms of its H i content.
i mass
emission
evolution
galaxies
hydrogen
environment
hipass catalog
morphology
deep survey
fast alpha survey
Author
Amir Kazemi-Moridani
Rutgers University
Andrew J. Baker
University of the Western Cape
Rutgers University
Marc Verheijen
University of Groningen
Eric Gawiser
Rutgers University
Sarah-Louise Blyth
University of Cape Town
Danail Obreschkow
University of Western Australia
Laurent Chemin
Universidad Andrés Bello
Jordan D. Collier
Western Sydney University
Commonwealth Scientific and Industrial Research Organisation (CSIRO)
University of Zululand
Kyle W. Cook
University of Louisville
Jacinta Delhaize
University of Cape Town
Ed Elson
University of the Western Cape
Bradley S. Frank
Royal Observatory
Marcin Glowacki
Curtin University
University of Zululand
University of Edinburgh
Kelley Michelle Hess
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Benne W. Holwerda
University of Louisville
Zackary L. Hutchens
The University of North Carolina System
Matt J. Jarvis
University of the Western Cape
University of Oxford
Melanie Kaasinen
European Southern Observatory Santiago
Sphesihle Makhathini
University of Witwatersrand
Abhisek Mohapatra
University of Cape Town
Hengxing Pan
University of Oxford
Anja C. Schroeder
Max Planck Society
Leyya Stockenstroom
University of Cape Town
Mattia Vaccari
Istituto nazionale di astrofisica (INAF)
University of the Western Cape
University of Cape Town
Tobias Westmeier
University of Western Australia
John F. Wu
Space Telescope Science Institute (STScI)
Johns Hopkins University
Martin Zwaan
European Southern Observatory Santiago
Astrophysical Journal
0004-637X (ISSN) 1538-4357 (eISSN)
Vol. 981 2 208Subject Categories (SSIF 2025)
Astronomy, Astrophysics, and Cosmology
DOI
10.3847/1538-4357/ad9f3f