Cross-correlation between $Planck$ CMB lensing potential and galaxy catalogues from HELP

Understand

We present the study of cross-correlation between Cosmic Microwave Background (CMB) gravitational lensing potential map released by the \textit{Planck} collaboration and photometric redshift galaxy catalogues from the \textit{Herschel} Extragalactic Legacy Project (HELP), divided into four sky patches: NGP, \textit{Herschel} Stripe-82, and two halves of SGP field, covering in total $\sim 660$ deg$^{2}$ of the sky.

• We estimate the galaxy linear bias parameter, $b_{0}$, from joint analysis of cross-power spectrum and galaxy auto-power spectrum using Maximum Likelihood Estimation technique to obtain values ranging from $0.70 \pm 0.01$ for SGP Part-2 to $1.02 \pm 0.02$ for SGP Part-1 field.
• We also estimate the amplitude of cross-correlation and find the values spanning from $0.67 \pm 0.18$ for SGP Part-2 to $0.80 \pm 0.23$ for SGP Part-1 field, respectively.
• For NGP and SGP Part-1 fields the amplitude is consistent with the expected value for the standard cosmological model within $\sim 1\,\sigma$, while for \textit{Herschel} Stripe-82 and SGP Part-2 we find the amplitude to be smaller than expected with $\sim 1.5\,\sigma$ and $\sim 2\,\sigma$ deviation, respectively.