Day 1061

Tuesday.


1603.01614
The missing satellite problem in 3d
Nierenberg, Treu, Menci, Lu, Torrey, Vogelsberger

A stringent test of models: ability to simultaneously match the satellite luminosity functions at a range of host halo masses and redshifts.  Measure the LF of faint (sub-SMC luminosity) satellites around hosts with stellar masses 10.5< logM*/Msun < 11.5 to an unprecedented z of 1.5.  This new measurement of the satellite LF provides powerful new constraining power; compare these results with predictions from 4 different simulations and show that although the models perform similarly overall, no one model reproduces the satellite LF reliably at all z and host stellar masses.  Highlights the continued need for improvement in understanding the fundamental physics that governs satellite galaxy evolution.


1603.01742
The outer profile of dark matter haloes: an analytical approach
Shi

A steepening feature in the outer density profiles of dm haloes - the splash back radius - has drawn much attention recently.  A possible observational detection has even been made for galaxy clusters.  Theoretically, Adhikari+ have estimated the location of the splash back radius by computing the secondary infall trajectory of a DM shell through a growing DM halo with an NFW profile.  However, since they imposed a shape of the halo profile rather than computing it consistently from the trajectories of the DM shells, they could not provide the full shape of the DM profile around the splashback radius.  Improve on this by extending the self-similar spherical collapse model of Filmore+Goldreich to a LCDM universe.  This allows us to compute the DM halo profile and the trajectories simultaneously from the mass accretion history.  Results on the splash back location agree qualitatively with Adhikari+, but with small quantitative differences at large mass accretion rates.  Present new fitting formulae for the splashback radius R_sp in various forms, including the rations of R_sp/R_200c and R_sp/R_200m.  Numerical simulations have made the puzzling discovery that the splash back radius scales well with R_200m but not with R_200c.  Trace the origin of this to be the correlated increase of Omega_m and the average halo mass accretion rate with an increasing redshift.