Mass calibration and cosmological analysis of the SPT-SZ galaxy cluster sample using velocity dispersion σ v and x-ray Y X measurements

• Published in: The Astrophysical Journal
• Main Authors: Bocquet, S., Saro, A., Mohr, J. J., Aird, K. A., Ashby, M. L. N., Bautz, M., Bayliss, M., Bazin, G., Benson, B. A., Bleem, L. E., Brodwin, M., Carlstrom, J. E., Chang, C. L., Chiu, I., Cho, H. M., Clocchiatti, A., Crawford, T. M., Crites, A. T., Desai, S., de Haan, T., Dietrich, J. P., Dobbs, M. A., Foley, R. J., Forman, W. R., Gangkofner, D., George, E. M., Gladders, M. D., Gonzalez, A. H., Halverson, N. W., Hennig, C., Hlavacek-Larrondo, J., Holder, G. P., Holzapfel, W. L., Hrubes, J. D., Jones, C., Keisler, R., Knox, L., Lee, A. T., Leitch, E. M., Liu, J., Lueker, M., Luong-Van, D., Marrone, D. P., McDonald, M., McMahon, J. J., Meyer, S. S., Mocanu, L., Murray, S. S., Padin, S., Pryke, C., Reichardt, C. L., Rest, A., Ruel, J., Ruhl, J. E., Saliwanchik, B. R., Sayre, J. T., Schaffer, K. K., Shirokoff, E., Spieler, H. G., Stalder, B., Stanford, S. A., Staniszewski, Z., Stark, A. A., Story, K., Stubbs, C. W., Vanderlinde, K., Vieira, J. D., Vikhlinin, A., Williamson, R., Zahn, O., Zenteno, A.
• Language: unknown
• Published: 2022
• Subjects: 79 ASTRONOMY AND ASTROPHYSICS; South Pole; The ''Y''; South pole
• Online Access: http://www.osti.gov/servlets/purl/1296743; https://www.osti.gov/biblio/1296743; https://doi.org/10.1088/0004-637X/799/2/214

Here, we present a velocity-dispersion-based mass calibration of the South Pole Telescope Sunyaev-Zel'dovich effect survey (SPT-SZ) galaxy cluster sample. Using a homogeneously selected sample of 100 cluster candidates from 720 deg 2 of the survey along with 63 velocity dispersion (σ v ) and 16 X-ray Y X measurements of sample clusters, we simultaneously calibrate the mass-observable relation and constrain cosmological parameters. Our method accounts for cluster selection, cosmological sensitivity, and uncertainties in the mass calibrators. The calibrations using σ v and Y X are consistent at the 0.6σ level, with the σ v calibration preferring ~16% higher masses. We use the full SPTCL data set (SZ clusters+σ v +Y X ) to measure σ 8 (Ωm/0.27) 0.3 = 0.809 ± 0.036 within a flat ΛCDM model. The SPT cluster abundance is lower than preferred by either the WMAP9 or Planck +WMAP9 polarization (WP) data, but assuming that the sum of the neutrino masses is m ν = 0.06 eV, we find the data sets to be consistent at the 1.0σ level for WMAP9 and 1.5σ for Planck+WP. Allowing for larger Σm ν further reconciles the results. When we combine the SPTCL and Planck+WP data sets with information from baryon acoustic oscillations and Type Ia supernovae, the preferred cluster masses are 1.9σ higher than the Y X calibration and 0.8σ higher than the σ v calibration. Given the scale of these shifts (~44% and ~23% in mass, respectively), we execute a goodness-of-fit test; it reveals no tension, indicating that the best-fit model provides an adequate description of the data. Using the multi-probe data set, we measure Ω m = 0.299 ± 0.009 and σ8 = 0.829 ± 0.011. Within a νCDM model we find Σm ν = 0.148 ± 0.081 eV. We present a consistency test of the cosmic growth rate using SPT clusters. Allowing both the growth index γ and the dark energy equation-of-state parameter w to vary, we find γ = 0.73 ± 0.28 and w = –1.007 ± 0.065, demonstrating that the eΣxpansion and the growth histories are consistent with a ΛCDM universe (γ = 0.55; w = –1).