Cosmic microwave background bispectrum of vector modes induced from primordial magnetic fields

Abstract

We calculate the cosmic microwave background bispectrum of vector modes induced from primordial magnetic fields. We take into account the full angular dependence of the bispectrum and discuss the amplitude and also the shape of the bispectrum in $\ell$ space. In the squeezed limit as ${\ell }_1={\ell }_2\gg {\ell }_3$, we estimate a typical values of the normalized reduced bispectrum as ${\ell }_1({\ell }_1+1){\ell }_3({\ell }_3+1)|b_{{\ell }_1{\ell }_2{\ell }_3}|\sim 2\times 10^{-19}$, for the strength of the primordial magnetic field smoothed on $1\mathrm{Mpc}$ scale $B_{1\mathrm{Mpc}}=4.7\mathrm{nG}$ assuming a nearly scale-invariant spectrum of magnetic fields. We find that a constraint on the magnetic field strength will be roughly estimated as $B_{1\mathrm{Mpc}}<10\mathrm{nG}$ if PLANCK places a limit on the nonlinearity parameter of local-type configuration as $|f_{\mathrm{NL}}^{\mathrm{local}}|<5$.

5 pages, 2 figures. Accepted for publication in PRD Rapid Communications

References in corpus (5)

• Inflationary Cosmology
• CMB anisotropies from primordial inhomogeneous magnetic fields
• CMB bispectrum from primordial magnetic fields on large angular scales
• The cosmic microwave background temperature bispectrum from scalar perturbations induced by primordial magnetic fields
• Analytic formulae of the CMB bispectra generated from non-Gaussianity in the tensor and vector perturbations

Cited by in corpus (1)

• Cosmic microwave background bispectrum of tensor passive modes induced from primordial magnetic fields