FRB dispersion is an approximately unbiased tracer of matter on linear scales, enabling direct constraints on the baryonic parameter B8 independently of feedback and with statistical power comparable to weak lensing using far fewer objects.
The ALFALFA HI mass function: A dichotomy in the low-mass slope and a locally suppressed 'knee' mass
6 Pith papers cite this work. Polarity classification is still indexing.
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abstract
We present the most precise measurement of the $z = 0$ HI mass function (HIMF) to date based on the final catalogue of the ALFALFA (Arecibo Legacy Fast ALFA) blind HI survey of the nearby Universe. The Schechter function fit has a `knee' mass $\log (M_{*}\,h^{2}_{70}/\mathrm{M_{\odot}}) = 9.94 \pm 0.01 \pm 0.05$, a low-mass slope parameter $\alpha = -1.25 \pm 0.02 \pm 0.1$, and a normalisation $\phi_{*} = (4.5 \pm 0.2 \pm 0.8) \times 10^{-3} \; h^{3}_{70}\,\mathrm{Mpc^{-3}\,dex^{-1}}$, with both random and systematic uncertainties as quoted. Together these give an estimate of the HI content of the $z = 0$ Universe as $\Omega_{\mathrm{HI}} = (3.9 \pm 0.1 \pm 0.6) \times 10^{-4} \, h^{-1}_{70}$ (corrected for HI self-absorption). Our analysis of the uncertainties indicates that the `knee' mass is a cosmologically fair measurement of the $z = 0$ value, with its largest uncertainty originating from the absolute flux calibration, but that the low-mass slope is only representative of the local Universe. We also explore large scale trends in $\alpha$ and $M_{*}$ across the ALFALFA volume. Unlike with the 40 per cent sample, there is now sufficient coverage in both of the survey fields to make an independent determination of the HIMF in each. We find a large discrepancy in the low-mass slope ($\Delta \alpha = 0.14 \pm 0.03$) between the two regions, and argue that this is likely caused by the presence of a deep void in one field and the Virgo cluster in the other. Furthermore, we find that the value of the `knee' mass within the Local Volume appears to be suppressed by $0.18 \pm 0.04$ dex compared to the global ALFALFA value, which explains the lower value measured by the shallower HIPASS. We discuss possible explanations and interpretations of these results and how they can be expanded on with future surveys.
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Review chapter on SKA observations of RELHICs and dim galaxies to constrain LambdaCDM and baryonic physics via HIMF, HIVF, and bTFR down to 10^6 solar masses.
Optical spectroscopy is required to unlock the full potential of SKAO extragalactic surveys through precise redshifts, activity diagnostics, HI stacking, and large-scale structure mapping.
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.
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The FAST Hundred-Deg$^2$ HI Deep (HD$^2$) Survey: Early Results from the Pilot Survey
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Unlocking the Full Potential of SKAO Extra-galactic Science with High-multiplex Optical Spectroscopy
Optical spectroscopy is required to unlock the full potential of SKAO extragalactic surveys through precise redshifts, activity diagnostics, HI stacking, and large-scale structure mapping.
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Cosmological Galaxy Formation Modelling in the Era of the Square Kilometre Array
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.