The Splashback Feature around DES Galaxy Clusters: Galaxy Density and Weak Lensing Profiles

Chang, C. and Baxter, E. and Jain, B. and S_s14anchez, C. and Adhikari, S. and Varga, T.~N. and Fang, Y. and Rozo, E. and Rykoff, E.~S. and Kravtsov, A. and Gruen, D. and Huff, E.~M. and Jarvis, M. and Kim, A.~G. and Prat, J. and MacCrann, N. and McClintock, T. and Palmese, A. and Rapetti, D. and Rollins, R.~P. and Samuroff, S. and Sheldon, E. and Troxel, M.~A. and Wechsler, R.~H. and Zhang, Y. and Zuntz, J. and Abbott, T.~M.~C. and Abdalla, F.~B. and Allam, S. and Annis, J. and Bechtol, K. and Benoit-L_s14evy, A. and Bernstein, G.~M. and Brooks, D. and Buckley-Geer, E. and Carnero Rosell, A. and Carrasco Kind, M. and Carretero, J. and D_s14Andrea, C.~B. and da, L.~N. and Davis, C. and Desai, S. and Diehl, H.~T. and Dietrich, J.~P. and Drlica-Wagner, A. and Eifler, T.~F. and Flaugher, B. and Fosalba, P. and Frieman, J. and Garc_s14ia-Bellido, J. and Gaztanaga, E. and Gerdes, D.~W. and Gruendl, R.~A. and Gschwend, J. and Gutierrez, G. and Honscheid, K. and James, D.~J. and Jeltema, T. and Krause, E. and Kuehn, K. and Lahav, O. and Lima, M. and March, M. and Marshall, J.~L. and Martini, P. and Melchior, P. and Menanteau, F. and Miquel, R. and Mohr, J.~J. and Nord, B. and Ogando, R.~L.~C. and Plazas, A.~A. and Sanchez, E. and Scarpine, V. and Schindler, R. and Schubnell, M. and Sevilla-Noarbe, I. and Smith, R.~C. and Smith, M. and Soares-Santos, M. and Sobreira, F. and Suchyta, E. and Swanson, M.~E.~C. and Tarle, G. and Weller, J.

Keywords

Astrophysics - Cosmology and Nongalactic Astrophysics

Abstract

Splashback refers to the process of matter that is accreting onto a dark matter halo reaching its first orbital apocenter and turning around in its orbit. The cluster-centric radius at which this process occurs, r_sp, defines a halo boundary that is connected to the dynamics of the cluster, in contrast with other common halo boundary definitions such as R_200. A rapid decline in the matter density profile of the halo is expected near r_sp. We measure the galaxy number density and weak lensing mass profiles around RedMapper galaxy clusters in the first year Dark Energy Survey (DES) data. For a cluster sample with mean mass ~2.5 x 10^14 solar masses, we find strong evidence of a splashback-like steepening of the galaxy density profile and measure r_sp=1.16 _s16/- 0.08 Mpc/h, consistent with earlier SDSS measurements of More et al. (2016) and Baxter et al. (2017). Moreover, our weak lensing measurement demonstrates for the first time the existence of a splashback-like steepening of the matter profile of galaxy clusters. We measure r_sp=1.28 _s16/- 0.18 Mpc/h from the weak lensing data, in good agreement with our galaxy density measurements. Applying our analysis to different cluster and galaxy samples, we find that consistent with LambdaCDM simulations, r_sp scales with R_200m and does not evolve with redshift over the redshift range of 0.3--0.6. We also find that potential systematic effects associated with the RedMapper algorithm may impact the location of r_sp, in particular the choice of scale used to estimate cluster richness. We discuss progress needed to understand the systematic uncertainties and fully exploit forthcoming data from DES and future surveys, emphasizing the importance of more realistic mock catalogs and independent cluster samples.

The Splashback Feature around DES Galaxy Clusters: Galaxy Density and Weak Lensing Profiles

Keywords

Abstract

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