The splashback boundary of haloes in hydrodynamic simulations

  title={The splashback boundary of haloes in hydrodynamic simulations},
  author={Stephanie O'Neil and David J Barnes and Mark Vogelsberger and Benedikt Diemer},
  journal={arXiv: Astrophysics of Galaxies},
The splashback radius, $R_{\rm sp}$, is a physically motivated halo boundary that separates infalling and collapsed matter of haloes. We study $R_{\rm sp}$ in the hydrodynamic and dark matter only IllustrisTNG simulations. The most commonly adopted signature of $R_{\rm sp}$ is the radius at which the radial density profiles are steepest. Therefore, we explicitly optimise our density profile fit to the profile slope and find that this leads to a $\sim5\%$ larger radius compared to other… Expand
3 Citations
The mass–size relation of galaxy clusters
The outskirts of accreting dark matter haloes exhibit a sudden drop in density delimiting their multi-stream region. Due to the dynamics of accretion, the location of this physically motivated edgeExpand
The mass and galaxy distribution around SZ-selected clusters
  • T. Shin, B. Jain, +136 authors Y. Zhang
  • Physics
  • Monthly Notices of the Royal Astronomical Society
  • 2021
We present measurements of the radial profiles of the mass and galaxy number density around Sunyaev–Zel’dovich (SZ)-selected clusters using both weak lensing and galaxy counts. The clusters areExpand
An Optimal Estimator of Intrinsic Alignments for Star-forming Galaxies in IllustrisTNG Simulation
Emission line galaxies (ELGs), more generally star-forming galaxies, are valuable tracers of large-scale structure and therefore main targets of upcoming wide-area spectroscopic galaxy surveys. WeExpand


The splashback radius as a physical halo boundary and the growth of halo mass
The boundaries of cold dark matter halos are commonly defined to enclose a density contrast $\Delta$ relative to a reference (mean or critical) density. We argue that a more physical boundary ofExpand
The splashback radius of halos from particle dynamics. II. Dependence on mass, accretion rate, redshift, and cosmology
The splashback radius $R_{\rm sp}$, the apocentric radius of particles on their first orbit after falling into a dark matter halo, has recently been suggested as a physically motivated halo boundaryExpand
Splashback Shells of Cold Dark Matter Halos
The density field in the outskirts of dark matter halos is discontinuous due to a caustic formed by matter at its first apocenter after infall. In this paper, we present an algorithm to identify theExpand
The Splashback Radius of Planck SZ Clusters
We present evidence for the existence of the splashback radius in galaxy clusters selected using the Sunyaev-Zel'dovich effect. We show that the deprojected cross-correlation of galaxy clusters foundExpand
Introducing the Illustris Project: simulating the coevolution of dark and visible matter in the Universe
We introduce the Illustris Project, a series of large-scale hydrodynamical simulations of galaxy formation. The highest resolution simulation, Illustris-1, covers a volume of $(106.5\,{\rm Mpc})^3$,Expand
The splashback radius of halos from particle dynamics. I. The SPARTA algorithm
Motivated by the recent proposal of the splashback radius as a physical boundary of dark-matter halos, we present a parallel computer code for Subhalo and PARticle Trajectory Analysis (Sparta). TheExpand
The splashback radius of optically selected clusters with Subaru HSC Second Public Data Release
Recent constraints on the splashback radius around optically selected galaxy clusters from the redMaPPer cluster-finding algorithm in the literature have shown that the observed splashback radiusExpand
Splashback radius in symmetron gravity
The splashback radius rsp has been identified in cosmological N-body simulations as an important scale associated with gravitational collapse and the phase-space distribution of recently accretedExpand
Probing galaxy evolution in massive clusters using ACT and DES: splashback as a cosmic clock
We measure the projected number density profiles of galaxies and the splashback feature in clusters selected by the Sunyaev--Zeldovich (SZ) effect from the Advanced Atacama Cosmology TelescopeExpand
The Splashback Feature around DES Galaxy Clusters: Galaxy Density and Weak Lensing Profiles
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 clustercentric radius at which thisExpand