1806.07893
UniverseMachine: the correlation between galaxy growth and dark matter halo assembly from z=0-10
Behroozi, Wechsler, Hearin, Conroy
Present a method to flexibly and self-consistently determine individual galaxies' SFRs from their host haloes' potential well depths, assembly histories, and redshifts. The method is constraint by galaxies' observed stellar mass functions, SFRs (specific and cosmic), quenched fractions, UV luminosity functions, UV-stellar mass relations, autocorrelation functions (including quenched and SF subsamples), and quenching dependence on environment; each observable is reproduced over the full z range available, up to 0<z<10. Key findings include: galaxy assembly correlates strongly with halo assembly; quenching at z>1 correlates strongly with halo mass; quenched fractions at fixed halo mass decrease with increasing redshift; massive quenched galaxies reside in higher-mass haloes than star-forming galaxies at fixed galaxy mass; SF and quenched galaxies' SFHs at fixed mass differ most at z<0.5; satellites have large scatter in quenching timescales after infall, and have modestly higher quenched fractions than central galaxies; Planck cosmologies result in up to 0.3 dex lower stellar mass-halo mass ratios at early times; and nonetheless, stellar mass-halo mass ratios rise at z>5. Also presented are revised stellar mass-halo mass relations for all, quenched, SFing, central and satellite galaxies; the dependence of SFHs on halo mass, stellar mass, and galaxy sSFR; quenched fractions and WL surface densities. The public data release includes the massively parallel (>1e5 cores) implementation (the UniverseMachine), the newly complied and remeasured observational data, derived galaxy formation constrains, and mock catalogs including light cones.
1806.08120
Galaxy-galaxy lensing in the outskirts of CLASH clusters: constraints on local shear and testing mass-luminosity scaling relation
Desprez, et al
Present a selection of 24 candidate GGL identified from Hubble images in the outskirts of the massive galaxy clusters from the CLASH survey. These GGLs provide insights into the mass distributions at larger scales than the strong lensing region in the cluster cores. Built parametric mass models for three of these GGLs showing simple lensing configurations, in order to assess the properties of their lens and its environment. Show that the local shear estimated from the GGLs traces the gravitational potential of the clusters at 1-2 arcmin radial distance, allowing us to derive their velocity dispersion. Also find a good agreement between the strength of the shear measured at the GGL positions through strong-lensing modeling and the value derived independently from a WL analysis of the background sources. Overall, show the advantages of using single GGL events in the outskirts of clusters to robustly constrain the local shear, even when only photometric z estimates are known for the source. Argue that the mass-luminosity scaling relation of cluster members can be tested by moving the GGLs found around them, and show that the mass parameters can vary up to ~30% between the cluster and GGL models assuming this scaling relation.
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