Keitaro Takahashi

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Origin of magnetic fields in the universe
NGC6946
Keitaro Takahashi Yukawa Institute for
Theoretical Physics
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ubiquitous magnetic fields
neutron star
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10 G
9
10 G
white dwarf
active galactic nuclei
6
10 G
3
10 G
Sun
1 G
Earth
1mG
cluster of galaxies
SNR
1mG
cosmological
galaxy
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1km 10 km 1pc
1kpc 1Mpc size
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Origin of magnetic fields of the earth is one of
the most important problems in modern physics.
galactic magnetic fields 1µG ? galactic
dynamo ? tiny seed magnetic fields
earth ? astronomical objects cosmological fields?
magnetogenesis in the early universe
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brief history of the universe
recombination 400,000 years p e ? H
inflation accelerated expansion quantum
fluctuations
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cosmic microwave background
fluctuations ? anisotropy in CMB average
temperature 3K anisotropy 10
-5
WMAP
CMB observation ? cosmological parameters (age,
matter density, spatial curvature)
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dark matter density
multipole expansion
?full moon
parameter estimation
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components of the universe
Thomson scattering
photons ? CMB
baryons (protons electrons)
gravity
cold dark matter
neutrinos
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magnetogenesis
baryon
Thomson scattering
protons
photons ? CMB
electrons
Coulomb interaction
Thomson scattering ? deviation in motion due to
mass difference ? generation of net electric
charge density and current ? generation of
magnetic fields
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magnetogenesis
deviation between protons and electrons due to
Thomson scattering (separate treatment) fluid
vorticity (nonlinear effect) ? magnetogensis
from density fluctuations (correlation with
CMB) 10 Gauss ? cosmological fields
seed fields
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KT et al., Science 311 (2006)827