Search results for "CMBR theory"

showing 2 items of 2 documents

Constraints on dark matter annihilation from CMB observations before Planck

2013

We compute the bounds on the dark matter (DM) annihilation cross section using the most recent Cosmic Microwave Background measurements from WMAP9, SPT'11 and ACT'10. We consider DM with mass in the MeV-TeV range annihilating 100% into either an e(+)e(-) or a mu(+)mu(-) pair. We consider a realistic energy deposition model, which includes the dependence on the redshift, DM mass and annihilation channel. We exclude the canonical thermal relic abundance cross section ( = 3 x 10(-26) cm(3)s(-1)) for DM masses below 30 GeV and 15 GeV for the e(+)e(-) and mu(+)mu(-) channels, respectively. A priori, DM annihilating in halos could also modify the reionization history of the Universe at late times…

AstrofísicaCosmology and Nongalactic Astrophysics (astro-ph.CO)Cosmic microwave backgroundDark matterFOS: Physical sciencesAstrophysicsAstrophysics::Cosmology and Extragalactic Astrophysics01 natural sciences7. Clean energyPartícules (Física nuclear)symbols.namesakeHigh Energy Physics - Phenomenology (hep-ph)0103 physical sciencesPlanck010303 astronomy & astrophysicsReionizationPhysicsdark matter theoryCosmologiaAnnihilation010308 nuclear & particles physicsAstronomy and AstrophysicsCMBR theoryRedshiftStarsHigh Energy Physics - PhenomenologysymbolsHalophysicsAstrophysics - Cosmology and Nongalactic Astrophysics
researchProduct

Sachs-Wolfe at second order: the CMB bispectrum on large angular scales

2009

We calculate the Cosmic Microwave Background anisotropy bispectrum on large angular scales in the absence of primordial non-Gaussianities, assuming exact matter dominance and extending at second order the classic Sachs-Wolfe result delta T/T = Phi/3. The calculation is done in Poisson gauge. Besides intrinsic contributions calculated at last scattering, one must consider integrated effects. These are associated to lensing, and to the time dependence of the potentials (Rees-Sciama) and of the vector and tensor components of the metric generated at second order. The bispectrum is explicitly computed in the flat-sky approximation. It scales as l(-4) in the scale invariant limit and the shape d…

PhysicsNew horizonsCosmology and Nongalactic Astrophysics (astro-ph.CO)Cosmic microwave backgroundFOS: Physical sciencesAstronomy and AstrophysicsAstrophysics::Cosmology and Extragalactic AstrophysicsCMBR theoryCosmologyMarie curiesymbols.namesakecosmological perturbation theoryGalileo (satellite navigation)symbolsnon-gaussianityBispectrumHumanitiesOrder (virtue)Astrophysics - Cosmology and Nongalactic Astrophysics
researchProduct