Cross-correlation between the 21-cm signal and [Oiii] emitters during early cosmic reionisation. (arXiv:1906.10863v1 [astro-ph.GA])

Cross-correlation between the 21-cm signal and [Oiii] emitters during early cosmic reionisation. (arXiv:1906.10863v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Moriwaki_K/0/1/0/all/0/1">K. Moriwaki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yoshida_N/0/1/0/all/0/1">N. Yoshida</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Eide_M/0/1/0/all/0/1">M. B. Eide</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ciardi_B/0/1/0/all/0/1">B. Ciardi</a>

We study statistics of the 21-cm signal from the epoch of reionisation. We
propose to use [OIII] line emitting galaxies to cross-correlate with the 21-cm
signal from $z = 7 – 10$. To this aim, we employ simulations of reionisation
obtained post-processing the high-resolution cosmological hydrodynamics
simulation Massive Black-II with the 3D radiative transfer code CRASH to follow
the propagation of ionising photons from a variety of sources. We show that,
during the early phases of reionisation, the 21-cm signal is positively
correlated with the spatial distribution of the [OIII] emitters on large scales
$(k < 1h~rm cMpc^{-1})$. This positive correlation is generated by the temperature - galaxy correlation and it is a few times larger than when we assume that the heating is saturated. As the reionised regions expand, the correlation changes its sign to negative from $z = 10$ to 8. The signals at this epoch can be detected by combining the Square Kilometre Array (SKA) and a wide-field [OIII] emitter survey. We also calculate the cross-power spectrum with a three-dimensional [OIII] intensity field, aiming at exploiting future intensity mapping observations. We conclude that high-redshift [OIII] line emitters provide a promising and unique method to probe the reionisation process when the inter-galactic medium is largely neutral.

We study statistics of the 21-cm signal from the epoch of reionisation. We
propose to use [OIII] line emitting galaxies to cross-correlate with the 21-cm
signal from $z = 7 – 10$. To this aim, we employ simulations of reionisation
obtained post-processing the high-resolution cosmological hydrodynamics
simulation Massive Black-II with the 3D radiative transfer code CRASH to follow
the propagation of ionising photons from a variety of sources. We show that,
during the early phases of reionisation, the 21-cm signal is positively
correlated with the spatial distribution of the [OIII] emitters on large scales
$(k < 1h~rm cMpc^{-1})$. This positive correlation is generated by the
temperature – galaxy correlation and it is a few times larger than when we
assume that the heating is saturated. As the reionised regions expand, the
correlation changes its sign to negative from $z = 10$ to 8. The signals at
this epoch can be detected by combining the Square Kilometre Array (SKA) and a
wide-field [OIII] emitter survey. We also calculate the cross-power spectrum
with a three-dimensional [OIII] intensity field, aiming at exploiting future
intensity mapping observations. We conclude that high-redshift [OIII] line
emitters provide a promising and unique method to probe the reionisation
process when the inter-galactic medium is largely neutral.

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