Mass accretion rates of the HectoMAP clusters of galaxies (2111.05150v2)

Abstract: We estimate the mass accretion rate (MAR) of the 346 clusters of galaxies in the HectoMAP Cluster Survey. The clusters span the redshift range $0.17-0.42$ and the $M_{200}$ mass range $\approx (0.5 - 3.5)\cdot 10^{14} M_\odot$. The MAR estimate is based on the caustic technique along with a spherical infall model. Our analysis extends the measurement of MARs for 129 clusters at $z<0.3$ from the Cluster Infall Regions in the Sloan Digital Sky Survey (CIRS) and the Hectospec Cluster Survey (HeCS) to redshift $z \sim 0.42$. Averaging over redshift, low-mass clusters with $M_{200}\sim 0.7\cdot 10^{14} M_\odot$ accrete $\sim 3\cdot 10^4 M_\odot$yr$^{-1}$; more massive clusters with $M_{200}\sim 2.8\cdot 10^{14} M_\odot$ accrete $\sim 1\cdot 10^5 M_\odot$yr$^{-1}$. Low- and high-mass clusters increase their MAR by $\sim 46\%$ and $\sim 84\%$, respectively, as the redshift increases from $z\sim 0.17-0.29$ to $z\sim 0.34-0.42$. The MARs at fixed redshift increase with mass and MARs at fixed mass increase with redshift in agreement with $\Lambda$CDM cosmological model for hierarchical structure formation. We consider the extension of MAR measurements to $z \sim 1$.