Cosmological constraints from unWISE and Planck CMB lensing tomography. (arXiv:2105.03421v1 [astro-ph.CO])
<a href="http://arxiv.org/find/astro-ph/1/au:+Krolewski_A/0/1/0/all/0/1">Alex Krolewski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ferraro_S/0/1/0/all/0/1">Simone Ferraro</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+White_M/0/1/0/all/0/1">Martin White</a>
A number of recent, low-redshift, lensing measurements hint at a universe in
which the amplitude of lensing is lower than that predicted from the
$Lambda$CDM model fit to the data of the Planck CMB mission. Here we use the
auto- and cross-correlation signal of unWISE galaxies and Planck CMB lensing
maps to infer cosmological parameters at low redshift. In particular, we
consider three unWISE samples (denoted as “blue,” “green” and “red”) at median
redshifts z~0.6, 1.1, and 1.5, which fully cover the Dark Energy dominated era.
Our cross-correlation measurements, with combined significance S/N ~ 80, are
used to infer the amplitude of low-redshift fluctuations, $sigma_8$, the
fraction of matter in the Universe, $Omega_m$,and the combination $S_8 =
sigma_8 (Omega_m/0.3)^{0.5}$ to which these low-redshift lensing measurements
are most sensitive. The combination of blue and green samples gives a value
$S_8 =0.776pm0.017$, that is fully consistent with other low-redshift lensing
measurements and in $2.6sigma$ tension with the CMB predictions from Planck.
This is noteworthy, because CMB lensing probes the same physics as previous
galaxy lensing measurements, but with very different systematics, thus
providing an excellent complement to previous measurements.
A number of recent, low-redshift, lensing measurements hint at a universe in
which the amplitude of lensing is lower than that predicted from the
$Lambda$CDM model fit to the data of the Planck CMB mission. Here we use the
auto- and cross-correlation signal of unWISE galaxies and Planck CMB lensing
maps to infer cosmological parameters at low redshift. In particular, we
consider three unWISE samples (denoted as “blue,” “green” and “red”) at median
redshifts z~0.6, 1.1, and 1.5, which fully cover the Dark Energy dominated era.
Our cross-correlation measurements, with combined significance S/N ~ 80, are
used to infer the amplitude of low-redshift fluctuations, $sigma_8$, the
fraction of matter in the Universe, $Omega_m$,and the combination $S_8 =
sigma_8 (Omega_m/0.3)^{0.5}$ to which these low-redshift lensing measurements
are most sensitive. The combination of blue and green samples gives a value
$S_8 =0.776pm0.017$, that is fully consistent with other low-redshift lensing
measurements and in $2.6sigma$ tension with the CMB predictions from Planck.
This is noteworthy, because CMB lensing probes the same physics as previous
galaxy lensing measurements, but with very different systematics, thus
providing an excellent complement to previous measurements.
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