The RichnesstoMass Relation of CAMIRA Galaxy Clusters from Weaklensing Magnification in the Subaru Hyper SuprimeCam Survey
Abstract
We present a statistical weaklensing magnification analysis on an optically selected sample of 3029 \texttt{CAMIRA} galaxy clusters with richness $N>15$ in the Subaru Hyper SuprimeCam (HSC) survey. The CAMIRA sample spans a wide redshift range of $0.2\leq z <1.1$. We use two distinct populations of colorselected, fluxlimited background galaxies, namely the low$z$ and high$z$ samples at mean redshifts of $\approx1.1$ and $\approx1.4$, respectively, from which to measure the weaklensing magnification signal by accounting for cluster contamination as well as masking effects. Our magnification bias measurements are found to be uncontaminated according to validation tests against the "nulltest" samples for which the net magnification bias is expected to vanish. The magnification bias for the full \texttt{CAMIRA} sample is detected at a significance level of $8.29\sigma$, which is dominated by the high$z$ background. We forwardmodel the observed magnification data to constrain the richnesstomass ($NM$) relation for the \texttt{CAMIRA} sample. In this work, we can only constrain the normalization of the $NM$ relation by employing informative priors on the mass and redshift trends, and on the intrinsic scatter at fixed mass. The resulting scaling relation is $N\propto {M_{500}}^{0.91\pm0.14} (1 + z)^{0.45\pm0.75}$, with a characteristic richness of $N=\left(19.63\pm3.16\right)$ and intrinsic lognormal scatter of $0.14\pm0.07$ at $M_{500} = 10^{14}h^{1}M_{\odot}$. With the derived $NM$ relation, we provide magnificationcalibrated mass estimates of individual \texttt{CAMIRA} clusters, with the typical uncertainty of $\approx38\percent$ and $\approx30\percent$ at richness$\approx20$ and $\approx40$, respectively. We further compare our magnificationinferred $NM$ relation with those from the shearbased results in the literature, finding good agreement.
 Publication:

arXiv eprints
 Pub Date:
 September 2019
 arXiv:
 arXiv:1909.02042
 Bibcode:
 2019arXiv190902042C
 Keywords:

 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 22 pages, 16 figures. Submitted to the MNRAS. Comments are welcome