期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 484, 期 1, 页码 989-1006出版社
OXFORD UNIV PRESS
DOI: 10.1093/mnras/sty2258
关键词
gravitational lensing: weak; cosmological parameters; arge-scale structure of Universe
资金
- National Science Foundation Graduate Research Fellowship Program [DGE-1343012]
- Department of Energy Computational Science Graduate Fellowship Program of the Office of Science
- National Nuclear Security Administration in the Department of Energy [DE-FG02-97ER25308]
- National Science Foundation [AST-1516997, AST-1313285, 1228509]
- Department of Energy Office of Science grant [DOE-SC0013718]
- Simons Foundation Investigator
- Center for Cosmology and AstroParticle Physics at the Ohio State University
- Faculty of Arts and Sciences Division of Science, Research Computing Group at Harvard University
The combination of galaxy-galaxy lensing (GGL) with galaxy clustering is one of the most promising routes to determining the amplitude of matter clustering at low redshifts. We show that extending clustering+GGL analyses from the linear regime down to similar to 0.5 h(-1) Mpc scales increases their constraining power considerably, even after marginalizing over a flexible model of non-linear galaxy bias. Using a grid of cosmological N-body simulations, we construct a Taylor-expansion emulator that predicts the galaxy autocorrelation xi(gg)(r) and galaxy-matter cross-correlation xi(gm) (r) as a function of sigma(8), Omega(m), and halo occupation distribution (HOD) parameters, which are allowed to vary with large-scale environment to represent possible effects of galaxy assembly bias. We present forecasts for a fiducial case that corresponds to BOSS LOWZ galaxy clustering and SDSS-depth weak lensing (effective source density similar to 0.3 arcmin(-2)). Using tangential shear and projected correlation function measurements over 0.5 <= r(p) <= 30h(-1) Mpc yields a 2 per cent constraint on the parameter combination sigma(8)Omega(0.6)(m), a factor of two better than a constraint that excludes non-linear scales (r(p) > 2 h(-1) Mpc, 4 h(-1) Mpc for gamma(t) , omega(p)). Much of this improvement comes from the non-linear clustering information, which breaks degeneracies among HOD parameters. Increasing the effective source density to 3 arcmin(-2) sharpens the constraint on sigma(8)Omega(0.6 )(m)by a further factor of two. With robust modelling into the non-linear regime, low-redshift measurements of matter clustering at the 1-per cent level with clustering+GGL alone are well within reach of current data sets such as those provided by the Dark Energy Survey.
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