TITLE:
Correlating the CMB with luminous red galaxies: the integrated Sachs-Wolfe effect
AUTHOR(S):
Nikhil Padmanabhan, Christopher M. Hirata, Uros Seljak, and David Schlegel (Princeton Univ.); Jonathan Brinkmann (Apache Point Obs.);
and Donald P. Schneider (Penn State).
DATE:
2004 Oct 15 (arXiv, v1, posted); 2004 Oct 15 (Phys. Rev. D, submitted); 2005 Jun 06 (revised); 2005 Jul 06 (Phys. Rev. D, accepted);
2005 Aug 24 (Phys. Rev. D, published).
AVAILABILITY:
arXiv astro-ph/0410360 (free); PROLA (requires subscription).
PUBLICATION INFORMATION: Physical Review D, 72, 043525 (2005), 16 pages.
ABSTRACT:
We present a 2.5s detection of the Integrated Sachs-Wolfe (ISW) effect
and discuss the constraints it places on cosmological parameters.
We cross-correlate microwave temperature maps from the WMAP satellite
with a 4000 deg2 luminous red galaxy (LRG) overdensity map
measured by the Sloan Digital Sky Survey.
These galaxies have accurate photometric redshifts (Dz~0.03) and
an approximately volume limited redshift distribution from
z~0.2 to z~0.6 well suited to detecting the ISW effect.
Accurate photometric redshifts allow us to perform a reliable
auto-correlation analysis of the LRGs, eliminating the uncertainty in the
galaxy bias, and combined with cross correlation signal, constrains cosmological parameters --
in particular, the matter density.
We use a minimum variance power spectrum estimator that optimally weights the
data according to expected theoretical templates.
We find a 2.5s signal in the Ka, Q, V, and W WMAP bands,
after combining the information from multipoles 2<=l<400.
This is consistent with the expected amplitude of the ISW effect, but
requires a lower matter density than is usually assumed: the
amplitude, parametrized by the
galaxy bias assuming WM=0.3,
WL=0.7 and s8=0.9, is
bg=4.05+/-1.54 for V band, with similar results for the other
bands. This should be compared to bg=1.82+/-0.02 from the auto-correlation analysis.
These data provide only a weak confirmation (2.5s) of dark energy,
but provide a significant upper limit:
WL=0.80-0.06+0.03(1s)-0.19+0.05(2s),
assuming a cosmology with
WM+WL=1,
Wb=0.05, and s8=0.9, and
w=-1. The weak cross-correlation signal
rules out low matter density/high dark energy density
universes and, in combination with other data,
strongly constrains models with w<-1.3.
We provide a simple prescription to incorporate these constraints
into cosmological parameter estimation methods for (WM, s8,w).
We find no evidence for a systematic contamination of ISW signal, either
from Galactic or extragalactic sources, but we do detect some large
statistical fluctuations on smaller scales that
could affect analyses without the template weighting.
ADS BIBLIOGRAPHIC CODE: 2005PhRvD..72d3525P
COMMENTS:
SDSS Publication #431. This is one of several papers describing the ISW effect in cross-correlation using WMAP first-year data
combined with various tracers of large scale structure (see the references for others). This is the same sample of LRGs used for the
lensing analysis.