Mapping the cosmic expansion history from LIGO-Virgo-KAGRA in synergy with DESI and SPHEREx. (arXiv:2107.12787v1 [astro-ph.CO])

Mapping the cosmic expansion history from LIGO-Virgo-KAGRA in synergy with DESI and SPHEREx. (arXiv:2107.12787v1 [astro-ph.CO])
<a href="http://arxiv.org/find/astro-ph/1/au:+Diaz_C/0/1/0/all/0/1">Cristina Cigarran Diaz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mukherjee_S/0/1/0/all/0/1">Suvodip Mukherjee</a>

The measurement of the expansion history of the Universe from the redshift
unknown gravitational wave (GW) sources (dark GW sources) detectable from the
network of LIGO-Virgo-KAGRA (LVK) detectors depends on the synergy with the
galaxy surveys having accurate redshift measurements over a broad redshift
range, large sky coverage, and detectability of fainter galaxies. In this work,
we explore the possible synergy of the LVK with the spectroscopic galaxy
surveys such as DESI and SPHEREx to measure the cosmological parameters which
are related to the cosmic expansion history and the GW bias parameters. We show
that by using the three-dimensional spatial cross-correlation between the dark
GW sources and the spectroscopic galaxy samples, we can measure the value of
Hubble constant with about $2%$ and $1.5%$ precision from LVK+DESI and
LVK+SPHEREx respectively from the five years of observation with $50%$
duty-cycle for the GW merger rates driven by the star formation history.
Similarly, the dark energy equation of state can be measured with about $10%$
and $8%$ precision from LVK+DESI and LVK+SPHEREx respectively. We find that
due to the larger sky coverage of SPHEREx than DESI, the performance in
constraining the cosmological parameters is better from the former than the
latter. By combining Euclid along with DESI, and SPHEREx a marginal gain in the
measurability of the cosmological parameters is possible from the sources at
high redshift ($zgeq 0.9$).

The measurement of the expansion history of the Universe from the redshift
unknown gravitational wave (GW) sources (dark GW sources) detectable from the
network of LIGO-Virgo-KAGRA (LVK) detectors depends on the synergy with the
galaxy surveys having accurate redshift measurements over a broad redshift
range, large sky coverage, and detectability of fainter galaxies. In this work,
we explore the possible synergy of the LVK with the spectroscopic galaxy
surveys such as DESI and SPHEREx to measure the cosmological parameters which
are related to the cosmic expansion history and the GW bias parameters. We show
that by using the three-dimensional spatial cross-correlation between the dark
GW sources and the spectroscopic galaxy samples, we can measure the value of
Hubble constant with about $2%$ and $1.5%$ precision from LVK+DESI and
LVK+SPHEREx respectively from the five years of observation with $50%$
duty-cycle for the GW merger rates driven by the star formation history.
Similarly, the dark energy equation of state can be measured with about $10%$
and $8%$ precision from LVK+DESI and LVK+SPHEREx respectively. We find that
due to the larger sky coverage of SPHEREx than DESI, the performance in
constraining the cosmological parameters is better from the former than the
latter. By combining Euclid along with DESI, and SPHEREx a marginal gain in the
measurability of the cosmological parameters is possible from the sources at
high redshift ($zgeq 0.9$).

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