Nondetection of a statistically anisotropic power spectrum in largescale structure
Abstract
We search a sample of photometric luminous red galaxies (LRGs) measured by the Sloan Digital Sky Survey (SDSS) for a quadrupolar anisotropy in the primordial power spectrum, in which P(vec k) is an isotropic power spectrum bar P(k) multiplied by a quadrupolar modulation pattern. We first place limits on the 5 coefficients of a general quadrupole anisotropy. We also consider axisymmetric quadrupoles of the form P(vec k) = bar P(k){1+g_{*}[(hat kċhat n)^{2}(1/3)]} where hat n is the axis of the anisotropy. When we force the symmetry axis hat n to be in the direction (l,b) = (94°,26°) identified in the recent Groeneboom et al. analysis of the cosmic microwave background, we find g_{*} = 0.006±0.036 (1σ). With uniform priors on hat n and g_{*} we find that 0.41 < g_{*} < +0.38 with 95% probability, with the wide range due mainly to the large uncertainty of asymmetries aligned with the Galactic Plane. In none of these three analyses do we detect evidence for quadrupolar power anisotropy in large scale structure.
 Publication:

Journal of Cosmology and Astroparticle Physics
 Pub Date:
 May 2010
 DOI:
 10.1088/14757516/2010/05/027
 arXiv:
 arXiv:1003.0673
 Bibcode:
 2010JCAP...05..027P
 Keywords:

 Astrophysics  Cosmology and Extragalactic Astrophysics
 EPrint:
 23 pages