Modeling and Measuring Redshift Space Distortions and the Alcock-Paczynski Effect in the Baryon Oscillation Spectroscopic Survey Beth Reid Hubble Fellow Lawrence Berkeley National Lab in collaboration with Martin White, Lado Samushia, Will Percival, BOSS galaxy clustering working group Image Courtesy Chris Blake and Sam Moorfield Tuesday, January 31, 2012
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Modeling and Measuring Redshift Space Distortions and the Alcock-Paczynski
Effect in the Baryon Oscillation Spectroscopic Survey
Beth ReidHubble Fellow
Lawrence Berkeley National Labin collaboration with Martin White, Lado Samushia, Will Percival, BOSS galaxy clustering working group
Image Courtesy Chris Blake and Sam Moorfield
Tuesday, January 31, 2012
Outline• Motivation
• Basic redshift space distortions (RSD) in configuration space
• Reid and White 2011 configuration space RSD model(+ connections to other recent RSD work)
• From halos to galaxies...
• BOSS DR9 first results: BAO, RSD and AP constraints
• Future prospects
Beth Reid Nagoya Feb 12
Tuesday, January 31, 2012
RSD motivation: Testing General Relativity
• Once we know the expansion history H(a), we know how perturbations grow in GR: δ(k, a) = aG(H(a))δi(k)
• We want to test both scale (k) and time (a) dependence
Beth Reid Nagoya Feb 13
Tuesday, January 31, 2012
RSD in 3d Galaxy Maps
depends on the geometry of the universe
θ, φ, redshift
comoving coordinates: x, y, z
χ(z) = χtrue + vp/aH(a)
Beth Reid
χ(z) =0∫z c dz’/H(z’)
Nagoya Feb 14
Tuesday, January 31, 2012
RSD in configuration space
Beth Reid 5
x x
real to redshift space separations
|vp| ~ d σ8/d ln a = σ8 * f
isotropic squashed along line of sight
z∇ ⋅ vp = -aHf δm
Nagoya Feb 1
f = d ln σ8 /d ln a
Tuesday, January 31, 2012
RSD: Anisotropy in ξ(rσ, rπ)
Beth Reid 6
White et al. 2011 mock catalogs
Nagoya Feb 1
BOSS DR9: Reid et al., Samushia et al. (in prep)
Tuesday, January 31, 2012
Linear RSD (Kaiser 1987)
Beth Reid Nagoya Feb 17
Tuesday, January 31, 2012
Linear RSD: Legendre Polynomial moments
Beth Reid
General Expansion
Linear theory prediction
Nagoya Feb 18
Tuesday, January 31, 2012
Legendre Polynomial moments
Beth Reid 9
General Expansion
Relation to Pℓ(k)
Nagoya Feb 1
Tuesday, January 31, 2012
Linear theory Legendre polynomial moments: scale dependence
Beth Reid 10 Nagoya Feb 1
Tuesday, January 31, 2012
RSD in configuration space: new quantities of interest
Beth Reid 11
rσ
rπr vz
v̅r, σ2r
v̅t=0, σ2ty rπ
Nagoya Feb 1
Tuesday, January 31, 2012
Linear theory pairwise velocities (δg = bδm)
Beth Reid 12 Nagoya Feb 1
Tuesday, January 31, 2012
Fisher 1995: the Kaiser formula in configuration space
Beth Reid 13
• δ(x), v(x’) correlated Gaussian fields
• Expand around y = rπ
• Equivalent to Kaiser formula
Nagoya Feb 1
Tuesday, January 31, 2012
Pairwise velocity statistics in linear theory
Beth Reid 14 Nagoya Feb 1
Tuesday, January 31, 2012
Outline• Motivation
• Basic redshift space distortions (RSD) in configuration space
• Reid and White 2011 configuration space RSD model(+ connections to other recent RSD work)
• From halos to galaxies...
• BOSS DR9 first results: BAO, RSD and AP constraints
• Future prospects
Beth Reid Nagoya Feb 115
Tuesday, January 31, 2012
Recent work: Matter Density Field
Beth Reid 16
Blake et al., arXiv:1105.2862; see also Scoccimarro 2004
Nagoya Feb 1
Tuesday, January 31, 2012
Why halos?
• Galaxies live there!
• Halos occupy “special” places in the density field; θ is a volume-averaged statistic
• Dependence on halo bias is complex; studies of matter correlations not easily generalized