Day 910

Tuesday.


1506.06135
Evidence of halo assembly bias in massive clusters
Miyatake, More, Takada, Spergel, Mandelbaum, Rykoff, Rozo

Present significant evidence of halo assembly bias for redMaPPer galaxy clusters in 0.1<z<0.33.  By dividing the 8,648 clusters into two subsamples based on the average member galaxy separation from the cluster center, first show that the two subsamples have very similar halo mass of M_200m~1.9e14 Msun/h based on the WL signals at small radii R<~10 Mpc/h.  However, their halo bias inferred from both the large-scale WL and the projected auto-correlation functions differs by a factor of ~1.5, which is a signature of assembly bias.  The same bias hypothesis for the two subsamples is excluded at 2.5 sigma in the WL and 4.6 sigma in the auto-correlation data, respectively.


1506.06313
Testing modified gravity with cosmic shear
Harnois-Déraps, Munshi, Valageas, van Waerbeke, Brax, Coles, Rizzo

Use cosmic shear data from CFHTLenS to place constraints on f(R) and Generalized Dilaton models of modified gravity.  This is highly complimentary to other probes since the constraints mainly come from the NL scales: maximal deviations with respect to GR+LCDM scenario occurs at k~1 h/Mpc.  At these scales, it becomes necessary to account for known degeneracies with baryon feedback and massive neutrinos, hence place constraints jointly on these three physical effects.  To achieve this, formulate these modified gravity theories within a common tomographic parameterization, compute their impact on the clustering properties relative to a GR universe, and propagate the observed modifications into the WL xi_± quantity. Confronted against the cosmic shear data, reject the f(R) {|f_R0|=1e-4, n=1} model with more than 99.9% CI when assuming a LCDM DM only model.  In the presence of baryonic feedback processes and massive neutrinos with total mass up to 0.2 eV, the model is disfavored with at least 94% CI in all different combinations studied.  Constraints on the {|f_R0|=1e-4, n=2} model are weaker, but nevertheless disfavored with at least 89% CI.  Identify several specific combinations of neutrino mass, baryon feedback and f(R) or Dilaton gravity models that are excluded by the current cosmic shear data.  Notably, universes with 3 massless neutrinos and no baryon feedback are strongly disfavored in all modified gravity scenarios studied.  These results indicate that competitive constraints may be achieved with future cosmic shear data.