Constraining the neutrino mass using a multi-tracer combination of two galaxy surveys and CMB lensing. (arXiv:2109.03763v1 [astro-ph.CO])
<a href="http://arxiv.org/find/astro-ph/1/au:+Ballardini_M/0/1/0/all/0/1">Mario Ballardini</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Maartens_R/0/1/0/all/0/1">Roy Maartens</a>

Measuring the total neutrino mass is one of the most exciting opportunities
available with next-generation cosmological data sets. We study the possibility
of detecting the total neutrino mass using large-scale clustering in 21cm
intensity mapping and photometric galaxy surveys, together with CMB
information. We include the scale-dependent halo bias contribution due to the
presence of massive neutrinos, and use a multi-tracer analysis in order to
reduce cosmic variance. The multi-tracer combination of an SKAO-MID 21cm
intensity map with Stage~4 CMB lensing dramatically shrinks the uncertainty on
total neutrino mass to $sigma(M_nu) simeq 45,$meV, using only linear
clustering information ($k_{rm max} = 0.1, h/$Mpc) and without a prior on
optical depth. When we add to the multi-tracer the clustering information
expected from LSST, the forecast is $sigma(M_nu) simeq 12,$meV.

Measuring the total neutrino mass is one of the most exciting opportunities
available with next-generation cosmological data sets. We study the possibility
of detecting the total neutrino mass using large-scale clustering in 21cm
intensity mapping and photometric galaxy surveys, together with CMB
information. We include the scale-dependent halo bias contribution due to the
presence of massive neutrinos, and use a multi-tracer analysis in order to
reduce cosmic variance. The multi-tracer combination of an SKAO-MID 21cm
intensity map with Stage~4 CMB lensing dramatically shrinks the uncertainty on
total neutrino mass to $sigma(M_nu) simeq 45,$meV, using only linear
clustering information ($k_{rm max} = 0.1, h/$Mpc) and without a prior on
optical depth. When we add to the multi-tracer the clustering information
expected from LSST, the forecast is $sigma(M_nu) simeq 12,$meV.

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