Browsing by Author "Kirkpatrick, C. C."

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    Clustering of CODEX clusters
    (2021) Lindholm, V.; Finoguenov, A.; Comparat, J.; Kirkpatrick, C. C.; Rykoff, E.; Clerc, N.; Collins, C.; Damsted, S.; Chitham, J. Ider; Padilla, N.
    Context. The clustering of galaxy clusters links the spatial nonuniformity of dark matter halos to the growth of the primordial spectrum of perturbations. The amplitude of the clustering signal is widely used to estimate the halo mass of astrophysical objects. The advent of cluster mass calibrations enables using clustering in cosmological studies. Aims. We analyze the autocorrelation function of a large contiguous sample of galaxy clusters, the Constrain Dark Energy with X-ray (CODEX) sample, in which we take particular care of cluster definition. These clusters were X-ray selected using the ROentgen SATellite (ROSAT) All-Sky Survey (RASS) and then identified as galaxy clusters using the code redMaPPer run on the photometry of the Sloan Digital Sky Survey (SDSS). We develop methods for precisely accounting for the sample selection e ects on the clustering and demonstrate their robustness using numerical simulations. Methods. Using the clean CODEX sample, which was obtained by applying a redshift-dependent richness selection, we computed the two-point autocorrelation function of galaxy clusters in the 01 < z < 03 and 03 < z < 05 redshift bins. We compared the bias in the measured correlation function with values obtained in numerical simulations using a similar cluster mass range. Results. By fitting a power law, we measured a correlation length r0 = 187 11 and slope = 198 014 for the correlation function in the full redshift range. By fixing the other cosmological parameters to their nine-year Wilkinson Microwave Anisotropy Probe (WMAP) values, we reproduced the observed shape of the correlation function under the following cosmological conditions: m0 = 022+004 003 and S8 = 8( m0 03)05 = 085+010 008 with estimated additional systematic errors of m0 = 002 and S8 = 020.We illustrate the complementarity of clustering constraints by combining them with CODEX cosmological constraints based on the X-ray luminosity function, deriving m0 = 025 001 and 8 = 081+001 002 with an estimated additional systematic error of 8 = 004. The mass calibration and statistical quality of the mass tracers are the dominant source of uncertainty.
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    SPIDERS : overview of the X-ray galaxy cluster follow-up and the final spectroscopic data release
    (2020) Clerc, N.; Kirkpatrick, C. C.; Finoguenov, A.; Capasso, R.; Comparat, J.; Damsted, S.; Furnell, K.; Kukkola, A. E.; Chitham, J. I.; Padilla, Nelson; Merloni, A.; Salvato, M.; Gueguen, A.; Dwelly, T.; Collins, C.; Saro, A.; Erfanianfar, G.; Schneider, D. P.; Brownstein, J.; Mamon, G. A.; Jullo, E.; Bizyaev, D.
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    SPIDERS: an overview of the largest catalogue of spectroscopically confirmed x-ray galaxy clusters
    (2021) Kirkpatrick, C. C.; Clerc, N.; Finoguenov, A.; Damsted, S.; Chitham, J. Ider; Kukkola, A. E.; Gueguen, A.; Furnell, K.; Rykoff, E.; Comparat, J.; Saro, A.; Capasso, R.; Padilla, N.; Erfanianfar, G.; Mamon, G. A.; Collins, C.; Merloni, A.; Brownstein, J. R.; Schneider, D. P.
    SPIDERS is the spectroscopic follow-up effort of the Sloan Digital Sky Survey IV (SDSS-IV) project for the identification of X-ray selected galaxy clusters. We present our catalogue of 2740 visually inspected galaxy clusters as part of the SDSS Data Release 16 (DR16). Here we detail the target selection, our methods for validation of the candidate clusters, performance of the survey, the construction of the final sample, and a full description of what is found in the catalogue. Of the sample, the median number of members per cluster is approximately 10, with 818 having 15 or greater. We find that we are capable of validating over 99 per cent of clusters when five redshifts are obtained below z < 0.3 and when nine redshifts are obtained above z > 0.3. We discuss the improvements in this catalogue's identification of cluster using 33 340 redshifts, with Delta Z(phot)/Delta Z(spec) similar to 100, over other photometric and spectroscopic surveys, as well as presenting an update to previous (sigma-L-X) and (sigma-lambda) relations. Finally, we present our cosmological constraints derived using the velocity dispersion function.