Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Extracting bias using the cross-bispectrum: An EoR and 21 cm-[CII]-[CII]
  case study   The amplitude of redshifted 21 cm fluctuations during the Epoch of
Reionization (EoR) is expected to show a distinctive "rise and fall" behavior
with decreasing redshift as reionization proceeds. On large scales (k <~ 0.1
Mpc^{-1}) this can mostly be characterized by evolution in the product of the
mean 21 cm brightness temperature and a bias factor, b_21(z). This quantity
evolves in a distinctive way that can help in determining the average
ionization history of the intergalactic medium (IGM) from upcoming 21 cm
fluctuation data sets. Here we consider extracting <T_21> b_21(z) using a
combination of future redshifted 21 cm and [CII] line-intensity mapping data
sets. Our method exploits the dependence of the 21 cm-[CII]-[CII]
cross-bispectrum on the shape of triangle configurations in Fourier space. This
allows one to determine <T_21> b_21(z) yet, importantly, is less sensitive to
foreground contamination than the 21 cm auto-spectrum, and so can provide a
valuable cross-check. We compare the results of simulated bispectra with
second-order perturbation theory: on large scales the perturbative estimate of
<T_21> b_21(z) matches the true value to within 10% for <x_i> <~ 0.8. We
consider the 21 cm auto-bispectrum and show that this statistic may also be
used to extract the 21 cm bias factor. Finally, we discuss the survey
requirements for measuring the cross-bispectrum. Although we focus on the 21
cm-[CII]-[CII] bispectrum during reionization, our method may be of broader
interest and can be applied to any two fields throughout cosmic history.

8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an