On the possibility of Baryon Acoustic Oscillation measurements at redshift $z>7.6$ with WFIRST. (arXiv:2001.05183v1 [astro-ph.CO])

On the possibility of Baryon Acoustic Oscillation measurements at redshift $z>7.6$ with WFIRST. (arXiv:2001.05183v1 [astro-ph.CO])
<a href="http://arxiv.org/find/astro-ph/1/au:+Satpathy_S/0/1/0/all/0/1">Siddharth Satpathy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+An_Z/0/1/0/all/0/1">Zhaozhou An</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Croft_R/0/1/0/all/0/1">Rupert A. C. Croft</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Matteo_T/0/1/0/all/0/1">Tiziana Di Matteo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tenneti_A/0/1/0/all/0/1">Ananth Tenneti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Feng_Y/0/1/0/all/0/1">Yu Feng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Heitmann_K/0/1/0/all/0/1">Katrin Heitmann</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rossi_G/0/1/0/all/0/1">Graziano Rossi</a>

The Wide Field Infrared Survey Telescope (WFIRST), with its field of view and
high sensitivity will make surveys of cosmological large-scale structure
possible at high redshifts. We investigate the possibility of detecting Baryon
Acoustic Oscillations (BAO) at redshifts $z>7.6$ for use as a standard ruler.
We use data from the hydrodynamic simulation textsc{BlueTides} in conjunction
with the gigaparsec-scale Outer Rim simulation and a model for patchy
reionization to create mock WFIRST High Latitude Survey grism data for lya
emission line selected galaxies at redshifts $z=7.4$ to $z=10$, covering 2280
square degrees. We measure the monopoles of galaxies in the mock catalogues and
fit the BAO features. We find that for a line flux of $L = 7times 10^{-17}
{rm erg/s/cm}^{2}$, the $5 sigma$ detection limit for the current design, the
BAO feature is partially detectable (measured in three out of four survey
quadrants analysed independently). The resulting root mean square error on the
angular diameter distance to $z=7.7$ is 7.9$%$. If we improve the detection
sensitivity by a factor of two (i.e. $L = 3.5times 10^{-17} {rm
erg/s/cm}^{2}$), the distance error reduces to $1.4%$. We caution that many
more factors are yet to be modelled, including dust obscuration, the damping
wing due to the intergalactic medium, and low redshift interlopers. If these
issues do not strongly affect the results, or different observational
techniques (such as use of multiple lines) can mitigate them, WFIRST or similar
instruments may be able to constrain the angular diameter distance to the high
redshift Universe.

The Wide Field Infrared Survey Telescope (WFIRST), with its field of view and
high sensitivity will make surveys of cosmological large-scale structure
possible at high redshifts. We investigate the possibility of detecting Baryon
Acoustic Oscillations (BAO) at redshifts $z>7.6$ for use as a standard ruler.
We use data from the hydrodynamic simulation textsc{BlueTides} in conjunction
with the gigaparsec-scale Outer Rim simulation and a model for patchy
reionization to create mock WFIRST High Latitude Survey grism data for lya
emission line selected galaxies at redshifts $z=7.4$ to $z=10$, covering 2280
square degrees. We measure the monopoles of galaxies in the mock catalogues and
fit the BAO features. We find that for a line flux of $L = 7times 10^{-17}
{rm erg/s/cm}^{2}$, the $5 sigma$ detection limit for the current design, the
BAO feature is partially detectable (measured in three out of four survey
quadrants analysed independently). The resulting root mean square error on the
angular diameter distance to $z=7.7$ is 7.9$%$. If we improve the detection
sensitivity by a factor of two (i.e. $L = 3.5times 10^{-17} {rm
erg/s/cm}^{2}$), the distance error reduces to $1.4%$. We caution that many
more factors are yet to be modelled, including dust obscuration, the damping
wing due to the intergalactic medium, and low redshift interlopers. If these
issues do not strongly affect the results, or different observational
techniques (such as use of multiple lines) can mitigate them, WFIRST or similar
instruments may be able to constrain the angular diameter distance to the high
redshift Universe.

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