We present measurements of the radial profile of mass and galaxy number density around X-ray selected ROSAT All Sky Survey-Multi-Component Matched Filter galaxy clusters using Year 3 data from the Dark Energy Survey. We measure the projected cross-correlation signal of the RedMaGiC "high density" galaxies around an approximately volume-limited sample of 255 galaxy clusters at a median redshift of $z=0.4$ and an X-ray luminosity $L_X > 10^{ 44} \,\text{ ergs} \, \text{ s}^{ -1} \, \text{ h}^{ -2}$. This cross-correlation signal measured with a signal-to-noise ratio of 16.41 allows us to infer a 3D number density profile which shows a significant steepening at the edges of these galaxy clusters, namely the splashback radius of $r_{ sp}$ /$h^{ -1} \mathrm{ M_{ \odot}} = 2.19^{ +0.50}_{ -0.43}$. We present the dependence of the splashback radius value over a range of absolute galaxy magnitude cuts to look for any evidence of dynamical friction affecting these results. The weak lensing signal around our galaxy clusters measured with a signal-to-noise ratio of 32.19 allows us to infer a halo mass $\text{ log} (M_{ \rm 200m} / h^{ -1} \text{ Mpc}) = 14.68_{ -0.04}^{ +0.04}$. Comparison of the location of the splashback radius with the spherical overdensity boundary $r_{ \rm 200m}$ shows consistency with the $\mathrm{ \Lambda CDM}$ predictions. We present the first inference of the average mass accretion rate of galaxy clusters using our measurements of the splashback radius.
Categories: astro-ph.CO astro-ph.GA