A map-based method for eliminating systematic modes from galaxy clustering power spectra with application to BOSS

Abstract

We develop a practical methodology to remove modes from a galaxy survey power spectrum that are associated with systematic errors. We apply this to the BOSS CMASS sample, to see if it removes the excess power previously observed beyond the best-fit $\Lambda$CDM model on very large scales. We consider several possible sources of data contamination, and check whether they affect the number of targets that can be observed and the power spectrum measurements. We describe a general framework for how such knowledge can be transformed into template fields. Mode subtraction can then be used to remove these systematic contaminants at least as well as applying corrective weighting to the observed galaxies, but benefits from giving an unbiased power. Even after applying templates for all known systematics, we find a large-scale power excess, but this is reduced compared with that observed using the weights provided by the BOSS team. This excess is at much larger scales than the BAO scale and does not affect the main results of BOSS. However, it will be important for the measurement of a scale-dependent bias due to primordial non-Gaussianity. The excess is beyond that allowed by any simple model of non-Gaussianity matching Planck data, and is not matched in other surveys. We show that this power excess can further be reduced but is still present using "phenomenological" templates, designed to consider further potentially unknown sources of systematic contamination. As all discrepant angular modes can be removed using "phenomenological" templates, the potentially remaining contaminant acts radially.

19 pages, accepted by MNRAS

References in corpus (13)

• The 2.5 m Telescope of the Sloan Digital Sky Survey
• Correlation of CMB with large-scale structure: I. ISW Tomography and Cosmological Implications
• The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: mock galaxy catalogues for the BOSS Final Data Release
• The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Observational systematics and baryon acoustic oscillations in the correlation function
• The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: RSD measurement from the LOS-dependent power spectrum of DR12 BOSS galaxies
• The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Modeling the clustering and halo occupation distribution of BOSS-CMASS galaxies in the Final Data Release
• Constraints on primordial non-Gaussianity from 800,000 photometric quasars
• Constraining the halo bispectrum in real and redshift space from perturbation theory and non-linear stochastic bias
• Exploiting the full potential of photometric quasar surveys: Optimal power spectra through blind mitigation of systematics
• Non-detection of a statistically anisotropic power spectrum in large-scale structure
• Unbiased methods for removing systematics from galaxy clustering measurements
• Unbiased pseudo-Cl power spectrum estimation with mode projection
• Unbiased contaminant removal for 3D galaxy power spectrum measurements

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