Constraining dark energy using the cross correlations of weak lensing with post-reionization probes of neutral hydrogen. (arXiv:2010.05816v2 [astro-ph.CO] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Dash_C/0/1/0/all/0/1">Chandrachud B. V. Dash</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sarkar_T/0/1/0/all/0/1">Tapomoy Guha Sarkar</a>
We investigate the prospects of detecting the cross correlation of CMBR
weak-lensing convergence field with the large scale tracers of the underlying
dark matter distribution in the post-reionization epoch. The cross-correlation
is then used to make error projections for dark energy equation of state
(EoS)for models with a time evolving dark energy. We study the
cross-correlation angular power spectrum of the weak-lensing field with the
Lyman-$alpha$ forest and the redshifted HI 21 cm signal from the post
reionization epoch. The angular power spectra is expressed as a line of sight
average over the tomographic slices. We find that on using multiple $400$ hrs
observation with an extended uGMRT like instrument or with a BOSS like survey
with quasar (QSO) density of $16 {rm deg}^{-2}$ the cross-correlation with
weak-lensing convergence field covering half the sky can be detected at a very
high SNR ($>20$). The cross-correlation of weak-lensing with Lyman-$alpha$
forest allows the $1-sigma$ errors on the dark energy EoS parameters for
different parametrizations to be constrained at a level of precision comparable
to combined Planck+SNIa+BAO+HST projections. The 21-cm weak-lensing
cross-correlation is found to provide strong constraints on the present value
of the dark energy EoS parameter at $4%$ for the 7CPL model. The constraints
on $w_a$ is comparable ($sim 12%$) for models other than the 7CPL model. We
also find that the CPL parametrization may not be the best constrained
parametrization for dark energy evolution. The cross-correlation of CMBR
weak-lensing with the post-reionization probes of neutral hydrogen thus holds
the potential to give us valuable understanding about the nature of evolving
dark energy.
We investigate the prospects of detecting the cross correlation of CMBR
weak-lensing convergence field with the large scale tracers of the underlying
dark matter distribution in the post-reionization epoch. The cross-correlation
is then used to make error projections for dark energy equation of state
(EoS)for models with a time evolving dark energy. We study the
cross-correlation angular power spectrum of the weak-lensing field with the
Lyman-$alpha$ forest and the redshifted HI 21 cm signal from the post
reionization epoch. The angular power spectra is expressed as a line of sight
average over the tomographic slices. We find that on using multiple $400$ hrs
observation with an extended uGMRT like instrument or with a BOSS like survey
with quasar (QSO) density of $16 {rm deg}^{-2}$ the cross-correlation with
weak-lensing convergence field covering half the sky can be detected at a very
high SNR ($>20$). The cross-correlation of weak-lensing with Lyman-$alpha$
forest allows the $1-sigma$ errors on the dark energy EoS parameters for
different parametrizations to be constrained at a level of precision comparable
to combined Planck+SNIa+BAO+HST projections. The 21-cm weak-lensing
cross-correlation is found to provide strong constraints on the present value
of the dark energy EoS parameter at $4%$ for the 7CPL model. The constraints
on $w_a$ is comparable ($sim 12%$) for models other than the 7CPL model. We
also find that the CPL parametrization may not be the best constrained
parametrization for dark energy evolution. The cross-correlation of CMBR
weak-lensing with the post-reionization probes of neutral hydrogen thus holds
the potential to give us valuable understanding about the nature of evolving
dark energy.
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