Galaxy clustering in the DESI Legacy Survey and its imprint on the CMB. (arXiv:2010.00466v2 [astro-ph.CO] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Hang_Q/0/1/0/all/0/1">Qianjun Hang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Alam_S/0/1/0/all/0/1">Shadab Alam</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Peacock_J/0/1/0/all/0/1">John A. Peacock</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cai_Y/0/1/0/all/0/1">Yan-Chuan Cai</a>
We use data from the DESI Legacy Survey imaging to probe the galaxy density
field in tomographic slices covering the redshift range $0<z<0.8$. After
careful consideration of completeness corrections and galactic cuts, we obtain
a sample of $4.9times 10^7$ galaxies covering 17 739 deg$^2$. We derive
photometric redshifts with precision $sigma_z/(1+z)=0.012 – 0.015$, and
compare with alternative estimates. Cross-correlation of the tomographic galaxy
maps with Planck maps of CMB temperature and lensing convergence probe the
growth of structure since $z=0.8$. The signals are compared with a fiducial
Planck $Lambda$CDM model, and require an overall scaling in amplitude of
$A_kappa=0.901pm 0.026$ for the lensing cross-correlation and $A_{rm ISW} =
0.984 pm 0.349$ for the temperature cross-correlation, interpreted as the
Integrated Sachs-Wolfe effect. The ISW amplitude is consistent with the
fiducial $Lambda$CDM prediction, but lies significantly below the prediction
of the AvERA model of R’acz et al. (2017), which has been proposed as an
alternative explanation for cosmic acceleration. Within $Lambda$CDM, our low
amplitude for the lensing cross-correlation requires a reduction either in
fluctuation normalization or in matter density compared to the Planck results,
so that $Omega_m^{0.78}sigma_8=0.297pm 0.009$. In combination with the total
amplitude of CMB lensing, this favours a shift mainly in density:
$Omega_m=0.274pm0.024$. We discuss the consistency of this figure with
alternative evidence. A conservative compromise between lensing and primary CMB
constraints would require $Omega_m=0.296pm0.006$, where the 95% confidence
regions of both probes overlap.
We use data from the DESI Legacy Survey imaging to probe the galaxy density
field in tomographic slices covering the redshift range $0<z<0.8$. After
careful consideration of completeness corrections and galactic cuts, we obtain
a sample of $4.9times 10^7$ galaxies covering 17 739 deg$^2$. We derive
photometric redshifts with precision $sigma_z/(1+z)=0.012 – 0.015$, and
compare with alternative estimates. Cross-correlation of the tomographic galaxy
maps with Planck maps of CMB temperature and lensing convergence probe the
growth of structure since $z=0.8$. The signals are compared with a fiducial
Planck $Lambda$CDM model, and require an overall scaling in amplitude of
$A_kappa=0.901pm 0.026$ for the lensing cross-correlation and $A_{rm ISW} =
0.984 pm 0.349$ for the temperature cross-correlation, interpreted as the
Integrated Sachs-Wolfe effect. The ISW amplitude is consistent with the
fiducial $Lambda$CDM prediction, but lies significantly below the prediction
of the AvERA model of R’acz et al. (2017), which has been proposed as an
alternative explanation for cosmic acceleration. Within $Lambda$CDM, our low
amplitude for the lensing cross-correlation requires a reduction either in
fluctuation normalization or in matter density compared to the Planck results,
so that $Omega_m^{0.78}sigma_8=0.297pm 0.009$. In combination with the total
amplitude of CMB lensing, this favours a shift mainly in density:
$Omega_m=0.274pm0.024$. We discuss the consistency of this figure with
alternative evidence. A conservative compromise between lensing and primary CMB
constraints would require $Omega_m=0.296pm0.006$, where the 95% confidence
regions of both probes overlap.
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