Distinguishing standard reionization from dark matter models

Journal Article · Tue Jun 15 04:00:00 EDT 2010 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.81.123510· OSTI ID:21413215

Natarajan, Aravind; Schwarz, Dominik J ^[1]

---

1. McWilliams Center for Cosmology, Carnegie Mellon University, Department of Physics, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States)

The Wilkinson Microwave Anisotropy Probe (WMAP) experiment has detected reionization at the 5.5{sigma} level and has reported a mean optical depth of 0.088{+-}0.015. A powerful probe of reionization is the large-angle EE polarization power spectrum, which is now (since the first five years of data from WMAP) cosmic variance limited for 2{<=}l{<=}6. Here we consider partial reionization caused by weakly interacting massive particle dark matter annihilation, and calculate the expected polarization power spectrum. We compare the dark matter models with a standard two-step reionization theory, and examine whether the models may be distinguished using current, and future cosmic microwave background (CMB) observations. We consider dark matter annihilation at intermediate redshifts (z<60) due to halos, as well as annihilation at higher redshifts due to free particles. In order to study the effect of high redshift dark matter annihilation on CMB power spectra, it is essential to include the contribution of residual electrons (left over from recombination) to the ionization history. Dark matter halos at redshifts z<60 influence the low multipoles l<20 in the EE power spectrum, while the annihilation of free particle dark matter at high redshifts z>100 mainly affects multipoles l>10.

• OSTI ID: 21413215
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 12 Vol. 81; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ANISOTROPY
ANNIHILATION
BASIC INTERACTIONS
COMPARATIVE EVALUATIONS
DATA ANALYSIS
ELECTROMAGNETIC RADIATION
ELECTRONS
ELEMENTARY PARTICLES
EVALUATION
FERMIONS
INTERACTIONS
IONIZATION
LEPTONS
MATTER
MICROWAVE RADIATION
MULTIPOLES
NONLUMINOUS MATTER
PARTICLE INTERACTIONS
PARTICLES
POLARIZATION
RADIATIONS
RECOMBINATION
RED SHIFT
RELICT RADIATION
SPECTRA
WEAK INTERACTIONS