The effect of fibre collisions on the galaxy power spectrum multipoles

Chang Hoon Hahn, Roman Scoccimarro, Michael R. Blanton, Jeremy L. Tinker, Sergio A. Rodríguez-Torres

    Research output: Contribution to journalArticle

    Abstract

    Fibre-fed multi-object spectroscopic surveys, with their ability to collect an unprecedented number of redshifts, currently dominate large-scale structure studies. However, physical constraints limit these surveys from successfully collecting redshifts from galaxies too close to each other on the focal plane. This ultimately leads to significant systematic effects on galaxy clustering measurements. Using simulated mock catalogues, we demonstrate that fibre collisions have a significant impact on the power spectrum, P(k), monopole and quadrupole that exceeds sample variance at scales smaller than k ~ 0.1 h Mpc-1. We present two methods to account for fibre collisions in the power spectrum. The first, statistically reconstructs the clustering of fibre-collided galaxy pairs by modelling the distribution of the line-of-sight displacements between them. It also properly accounts for fibre collisions in the shot-noise correction term of the P(k) estimator. Using this method, we recover the true P(k) monopole of the mock catalogues with residuals of < 0.5 per cent at k = 0.3 h Mpc-1 and < 4 per cent at k = 0.83 h Mpc-1 - a significant improvement over existing correction methods. The quadrupole, however, does not improve significantly. The second method models the effect of fibre collisions on the power spectrum as a convolution with a configuration space top-hat function that depends on the physical scale of fibre collisions. It directly computes theoretical predictions of the fibre-collided P(k) multipoles and reduces the influence of smaller scales to a set of nuisance parameters. Using this method, we reliably model the effect of fibre collisions on the monopole and quadrupole down to the scale limits of theoretical predictions. The methods we present in this paper will allow us to robustly analyse galaxy power spectrum multipole measurements to much smaller scales than previously possible.

    Original languageEnglish (US)
    Pages (from-to)1940-1956
    Number of pages17
    JournalMonthly Notices of the Royal Astronomical Society
    Volume467
    Issue number2
    DOIs
    StatePublished - 2017

    Fingerprint

    multipoles
    power spectra
    collision
    galaxies
    collisions
    fibers
    monopoles
    quadrupoles
    catalogs
    fibre
    effect
    shot noise
    prediction
    predictions
    convolution integrals
    estimators
    line of sight
    method
    configurations
    modeling

    Keywords

    • Cosmology: observations
    • Galaxies: haloes
    • Galaxies: statistics
    • Large-scale structure of Universe
    • Methods: data analysis

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

    Cite this

    Hahn, C. H., Scoccimarro, R., Blanton, M. R., Tinker, J. L., & Rodríguez-Torres, S. A. (2017). The effect of fibre collisions on the galaxy power spectrum multipoles. Monthly Notices of the Royal Astronomical Society, 467(2), 1940-1956. https://doi.org/10.1093/mnras/stx185

    The effect of fibre collisions on the galaxy power spectrum multipoles. / Hahn, Chang Hoon; Scoccimarro, Roman; Blanton, Michael R.; Tinker, Jeremy L.; Rodríguez-Torres, Sergio A.

    In: Monthly Notices of the Royal Astronomical Society, Vol. 467, No. 2, 2017, p. 1940-1956.

    Research output: Contribution to journalArticle

    Hahn, CH, Scoccimarro, R, Blanton, MR, Tinker, JL & Rodríguez-Torres, SA 2017, 'The effect of fibre collisions on the galaxy power spectrum multipoles', Monthly Notices of the Royal Astronomical Society, vol. 467, no. 2, pp. 1940-1956. https://doi.org/10.1093/mnras/stx185
    Hahn, Chang Hoon ; Scoccimarro, Roman ; Blanton, Michael R. ; Tinker, Jeremy L. ; Rodríguez-Torres, Sergio A. / The effect of fibre collisions on the galaxy power spectrum multipoles. In: Monthly Notices of the Royal Astronomical Society. 2017 ; Vol. 467, No. 2. pp. 1940-1956.
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