# All-sky angular power spectra from cleaned WISE$\times$SuperCOSMOS galaxy number counts

## TL;DR

This paper develops a method to correct systematic effects in galaxy count data from WISE and SuperCOSMOS, improving angular power spectrum measurements and cosmological parameter estimation on large scales.

## Contribution

It introduces a new integrated model for stellar contamination and obscuration effects, and demonstrates its effectiveness on mock and real data for cosmological analysis.

## Key findings

- Improved angular power spectrum measurements at large scales.
- Consistent cosmological parameters with Planck $
m{ extLambda CDM}$ model.
- Identification of residual systematics in southern hemisphere data.

## Abstract

Aiming to extract cosmological information from linear scales of the WISE$\times$SuperCOSMOS photometric redshift catalog, we perform a characterization of the systematic effects associated with stellar content, evidencing the presence of contamination and obscuration. We create an integrated model for these effects (which together we call `usurper contamination'), devise a method to remove both of them simultaneously and show its functionality by applying it to a set of mock catalogs. When administered to WISE$\times$SuperCOSMOS data, our method shows to improve the measurements of angular power spectra on scales $\ell\lesssim15$ and the extraction of cosmological parameters therefrom, even though a significant excess of power remains at these scales. When ignoring scales $\ell<15$, we still find strong indications of systematics, albeit these can be localized in the southern equatorial hemisphere. An independent analysis of the northern hemisphere at $\ell\geq 15$ agrees with a $\Lambda$CDM model with parameters from the Planck satellite and gives $\Omega_{\mathrm{c}}=0.254\pm0.020$ and $\Omega_{\mathrm{b}}<0.065$ at 95% confidence limit when combined with priors on $H_0$, $A_s$ and $n_s$.