The completed SDSS-IV extended baryon oscillation spectroscopic survey: pairwise-inverse probability and angular correction for fibre collisions in clustering measurements. Issue 1 (11th August 2020)

• Record Type: Journal Article
• Authors: Mohammad, Faizan G; Percival, Will J; Seo, Hee-Jong; Chapman, Michael J; Bianchi, D; Ross, Ashley J; Zhao, Cheng; Lang, Dustin; Bautista, Julian; Brinkmann, Jonathan; Brownstein, Joel R; Burtin, Etienne; Chuang, Chia-Hsun; Dawson, Kyle S; de la Torre, Sylvain; de Mattia, Arnaud; Eftekharzadeh, Sarah; Fromenteau, Sebastien; Gil-Marín, Héctor; Hou, Jiamin; Mueller, Eva-Maria; Neveux, Richard; Paviot, Romain; Raichoor, Anand; Rossi, Graziano; Schneider, Donald P; Tamone, Amélie; Tinker, Jeremy L; Tojeiro, Rita; Vargas Magaña, Mariana; Zhao, Gong-Bo;
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 498:Issue 1(2020)
• Page Start: 128
• Page End: 143
• Publication Date: 2020-08-11
• Subjects: galaxies: distances and redshifts -- large-scale structure of Universe -- cosmology: observations; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/staa2344
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: The completed extended Baryon Oscillation Spectroscopic Survey (eBOSS) catalogues contain redshifts of 344 080 quasars at 0.8 < z < 2.2, 174 816 luminous red galaxies between 0.6 < z < 1.0, and 173 736 emission-line galaxies over 0.6 < z < 1.1 in order to constrain the expansion history of the Universe and the growth rate of structure through clustering measurements. Mechanical limitations of the fibre-fed spectrograph on the Sloan telescope prevent two fibres being placed closer than 62 arcsec in a single pass of the instrument. These 'fibre collisions' strongly correlate with the intrinsic clustering of targets and can bias measurements of the two-point correlation function resulting in a systematic error on the inferred values of the cosmological parameters. We combine the new techniques of pairwise-inverse probability and the angular upweighting (PIP+ANG) to correct the clustering measurements for the effect of fibre collisions. Using mock catalogues, we show that our corrections provide unbiased measurements, within data precision, of both the projected $\rm {\mathit{ w}_p}\left(\mathit{ r}_p\right)$ and the redshift-space multipole ξ (ℓ = 0, 2, 4) ( s ) correlation functions down to $0.1\, h^{-1}{\rm Mpc}$, regardless of the tracer type. We apply the corrections to the eBOSS DR16 catalogues. We find that, on scales $s\gtrsim 20\, h^{-1}{\rm Mpc}$ for ξ ℓ, as used to make baryon acoustic oscillation and large-scale redshift-space distortion measurements, approximate methods such as nearest-neighbour upweighting are sufficiently accurate given the statistical errors of the data. Using the PIP method, for the first time for a spectroscopic program of the Sloan Digital Sky Survey, we are able to successfully access the one-halo term in the clustering measurements down to $\sim 0.1\, h^{-1}{\rm Mpc}$ scales. Our results will therefore allow studies that use the small-scale clustering to strengthen the constraints on both cosmological parameters and the halo occupation distribution models.