Galaxy Cluster Scaling Relations between Bolocam Sunyaev-Zel'dovich Effect and Chandra X-ray Measurements

N. G. Czakon; J. Sayers; A. Mantz; S. R. Golwala; T. P. Downes; P. M. Koch; K. -Y. Lin; S. M. Molnar; L. A. Moustakas; T. Mroczkowski; E. Pierpaoli; J. A. Shitanishi; S. Siegel; K. Umetsu

doi:10.1088/0004-637X/806/1/18

paper

Galaxy Cluster Scaling Relations between Bolocam Sunyaev-Zel'dovich Effect and Chandra X-ray Measurements

arXiv:1406.2800 · doi:10.1088/0004-637X/806/1/18

Abstract

We present scaling relations between the integrated Sunyaev-Zel'dovich Effect (SZE) signal, $Y_{SZ}$ , its X-ray analogue, $Y_{X} \equiv M_{gas} T_{X}$ , and total mass, $M_{tot}$ , for the 45 galaxy clusters in the Bolocam X-ray-SZ (BOXSZ) sample. All parameters are integrated within $r_{2500}$ . $Y_{2500}$ values are measured using SZE data collected with Bolocam, operating at 140 GHz at the Caltech Submillimeter Observatory (CSO). The temperature, $T_{X}$ , and mass, $M_{gas, 2500}$ , of the intracluster medium are determined using X-ray data collected with Chandra, and $M_{tot}$ is derived from $M_{gas}$ assuming a constant gas mass fraction. Our analysis accounts for several potential sources of bias, including: selection effects, contamination from radio point sources, and the loss of SZE signal due to noise filtering and beam-smoothing effects. We measure the $Y_{2500}$ -- $Y_{X}$ scaling to have a power-law index of $0.84 \pm 0.07$ , and a fractional intrinsic scatter in $Y_{2500}$ of $(21 \pm 7) %$ at fixed $Y_{X}$ , both of which are consistent with previous analyses. We also measure the scaling between $Y_{2500}$ and $M_{2500}$ , finding a power-law index of $1.06 \pm 0.12$ and a fractional intrinsic scatter in $Y_{2500}$ at fixed mass of $(25 \pm 9) %$ . While recent SZE scaling relations using X-ray mass proxies have found power-law indices consistent with the self-similar prediction of 5/3, our measurement stands apart by differing from the self-similar prediction by approximately 5 $σ$ . Given the good agreement between the measured $Y_{2500}$ -- $Y_{X}$ scalings, much of this discrepancy appears to be caused by differences in the calibration of the X-ray mass proxies adopted for each particular analysis.

arXiv comment31 pages, 15 figures, accepted by ApJ 04/11/2015. This version is appreciably different from the original submission: it includes an entirely new appendix, extended discussion, and much of the material has been reorganized

Galaxy Cluster Scaling Relations between Bolocam Sunyaev-Zel'dovich Effect and Chandra X-ray Measurements

Abstract

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