Optimal limits on primordial magnetic fields from CMB temperature bispectrum of passive modes

Journal Article · Thu Mar 01 04:00:00 EST 2012 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2012/03/041· OSTI ID:22280104

Shiraishi, Maresuke; Yokoyama, Shuichiro; Ichiki, Kiyotomo ^[1]; Nitta, Daisuke ^[2]

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1. Department of Physics and Astrophysics, Nagoya University, Nagoya 464-8602 (Japan)
2. Astronomical Institute, Tohoku University, Aoba Aramaki Aoba, Sendai 980-8578 (Japan)

We investigate bounds on the strength of the primordial magnetic field (PMF) from the cosmic microwave background (CMB) bispectra of the intensity (temperature) modes induced from the auto- and cross-correlated bispectra of the scalar and tensor components of the PMF anisotropic stress. At first, we construct a general formula for the CMB intensity and polarization bispectra from PMFs composed of any type of perturbation. Then we derive an approximate expression which traces the exact shape of the CMB bispectrum in order to reduce the computation time with respect to a large number of the multipole configurations, and also show that the non-Gaussian structure coming from PMFs is classified as the local-type configuration. Computing the signal-to-noise ratio on the basis of the approximate formula with the information of the instrumental noises and resolutions, we find expected upper bounds on the magnetic field strength, when the magnetic spectrum is nearly scale invariant (n{sub B} = −2.9), smoothed on 1Mpc scale at 95% confidence level from the WMAP and PLANCK experiments as B{sub 1Mpc} < 4.0−6.7nG and 3.8−6.5nG, respectively, depending on the energy scale of the magnetic field production from 10{sup 14}GeV to 10{sup 3}GeV. Our new consequences imply slight overestimations by the previous rough discussions.

• OSTI ID: 22280104
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 03 Vol. 2012; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ANISOTROPY
APPROXIMATIONS
ASTROPHYSICS
COSMOLOGICAL MODELS
COSMOLOGY
DISTURBANCES
MAGNETIC FIELDS
POLARIZATION
RELICT RADIATION
RESOLUTION
SCALARS
SIGNAL-TO-NOISE RATIO
STRESSES
TENSORS