Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Theoretical and observational constraints on the HI intensity power
  spectrum   Mapping of the neutral hydrogen (HI) 21-cm intensity fluctuations across
redshifts promises a novel and powerful probe of cosmology. The neutral
hydrogen gas mass density, $\Omega_{\rm HI}$ and bias parameter, $b_{\rm HI}$
are key astrophysical inputs to the HI intensity fluctuation power spectrum. We
compile the latest theoretical and observational constraints on $\Omega_{\rm
HI}$ and $b_{\rm HI}$ at various redshifts in the post-reionization universe.
Constraints are incorporated from galaxy surveys, HI intensity mapping
experiments, damped Lyman-$\alpha$ system observations, theoretical
prescriptions for assigning HI to dark matter halos, and the results of
numerical simulations. Using a minimum variance interpolation scheme, we obtain
the predicted uncertainties on the HI intensity fluctuation power spectrum
across redshifts 0-3.5 for three different confidence scenarios. We provide a
convenient tabular form for the interpolated values of $\Omega_{\rm HI}$,
$b_{\rm HI}$ and the HI power spectrum amplitude and their uncertainties. We
discuss the consequences for the measurement of the power spectrum by current
and future intensity mapping experiments.

19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
11
The categories of this paper are: hep-lat
9
The categories of this paper are: nlin
4
The categories of this paper are: cond-mat
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
1
The categories of this paper are: cs