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

We present scaling relations between the integrated Sunyaev-Zel’dovich Effect (SZE) signal, $Y_{\mathrm{S}\mathrm{Z}}$, its X-ray analogue, $Y_{\rm X}\equiv M_{\rm gas}T_{\rm X}$,andtotalmass,$M_{\rm tot}$, 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, $T_{\mathrm{X}}$, and mass, $M_{\mathrm{g}\mathrm{a}\mathrm{s},2500}$, of the intracluster medium are determined using X-ray data collected with Chandra, and $M_{\rm tot}$isderivedfrom$M_{\rm gas}$ 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 $Y_{2500}$–$Y_{\mathrm{X}}$ scaling to have a power-law index of $0.84\pm 0.07$, and a fractional intrinsic scatter in $Y_{2500}$ of $(21\pm 7)\mathrm{\%}$ at fixed $Y_{\rm X}$, 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 $(25\pm 9)\mathrm{\%}$. 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$\sigma$. Given the good agreement between the measured $Y_{2500}$–$Y_{\mathrm{X}}$ 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.