CMB anisotropies: Total angular momentum method
Abstract
A total angular momentum representation simplifies the radiation transport problem for temperature and polarization anisotropy in the cosmic microwave background (CMB). Scattering terms couple only the quadrupole moments of the distributions and each moment corresponds directly to the observable angular pattern on the sky. We develop and employ these techniques to study the general properties of anisotropy generation from scalar, vector, and tensor perturbations to the metric and the matter, both in the cosmological fluids and from any seed perturbations (e.g., defects) that may be present. The simpler, more transparent form and derivation of the Boltzmann equations brings out the geometric and modelindependent aspects of temperature and polarization anisotropy formation. Large angle scalar polarization provides a robust means to distinguish between isocurvature and adiabatic models for structure formation in principle. Vector modes have the unique property that the CMB polarization is dominated by magnetictype parity at small angles (a factor of 6 in power compared with 0 for the scalars and 8/13 for the tensors) and hence potentially distinguishable independent of the model for the seed. The tensor modes produce a different sign from the scalars and vectors for the temperaturepolarization correlations at large angles. We explore conditions under which one perturbation type may dominate over the others including a detailed treatment of the photonbaryon fluid before recombination.
 Publication:

Physical Review D
 Pub Date:
 July 1997
 DOI:
 10.1103/PhysRevD.56.596
 arXiv:
 arXiv:astroph/9702170
 Bibcode:
 1997PhRvD..56..596H
 Keywords:

 98.70.Vc;
 98.80.Es;
 Background radiations;
 Observational cosmology;
 Astrophysics
 EPrint:
 32 pg., 10 figs., RevTeX, minor changes reflect published version, minor typos corrected, also available at http://www.sns.ias.edu/~whu