constraints on magnetic fields july 6 2015 ppt
DESCRIPTION
documentTRANSCRIPT
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Constraints on Magnetic FieldsConstraints on Magnetic Fieldsfrom Large Scale Structurefrom Large Scale Structure
Tina KahniashviliTina KahniashviliAbastumani Astrophysical Observatory, Abastumani Astrophysical Observatory,
Ilia State University, GeorgiaIlia State University, Georgia&&
McWilliams Center for Cosmology, McWilliams Center for Cosmology, Carnegie Mellon University, USACarnegie Mellon University, USA
NORDITA July 6 2015NORDITA July 6 2015
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Outline
Observable Effects on LSS Observable Effects on LSS Lyman-alpha forestLyman-alpha forest Other cosmological testsOther cosmological tests
LimitsLimits
Based on: Kahniashvili, Maravin, Natarajan, Battaglia, Tevzadze, ApJ 2013Kahniashvili, Tevzadze, Sethi, Pandey, RatraPRD 2010
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Magnetic Field in the UniverseMagnetic Field in the Universe Must be small Must be small
enough to preserve enough to preserve the isotropy of the the isotropy of the UniverseUniverse
BBN bound: BBN bound: Additional 10% to Additional 10% to the radiation the radiation energy density energy density Limits order of Limits order of
microGaussmicroGauss
Frozen-in conditionFrozen-in condition magnetic flux magnetic flux
conservation conservation
Coupling with Coupling with plasmaplasma MHD in the MHD in the
expanding Universe expanding Universe
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Magnetic Field StatisticsMagnetic Field Statistics Spectral shapeSpectral shape
P(k) ~ k at large P(k) ~ k at large scales for causally scales for causally generated fieldsgenerated fields
P(k) ~ k at large P(k) ~ k at large scales for inflation scales for inflation generated fieldsgenerated fields
P(k) ~ k or P(k) P(k) ~ k or P(k) ~ k at small ~ k at small scalesscales
Correlation length Correlation length Limitation for Limitation for
causal fieldscausal fields Evolution (free Evolution (free
decay) during the decay) during the expansion expansion Faster growth for Faster growth for
helical fieldshelical fields
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-3
-11/3-2
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Magnetized Cosmological Magnetized Cosmological Perturbations Perturbations
Density perturbations - scalar mode Density perturbations - scalar mode Fast and slow magnetosound wavesFast and slow magnetosound waves
Vorticity perturbations - vector mode Vorticity perturbations - vector mode Alfven wavesAlfven waves
Gravitational waves - tensor ModeGravitational waves - tensor Mode
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Scalar Magnetized Mode Scalar Magnetized Mode
Adams, et al.1996
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Linear Magnetized Density Linear Magnetized Density Perturbations Perturbations
Ordinary adiabatic Ordinary adiabatic perturbations perturbations Harrison-ZelHarrison-Zeldovich dovich spectrum spectrum P(k) ~ k P(k) ~ k
Magnetized density Magnetized density perturbations (linear) perturbations (linear) P(k) ~ k P(k) ~ k white noise white noise
Kim, Olinto, Rosner 1996 Kim, Olinto, Rosner 1996
P(k) ~ k P(k) ~ k scale-scale-invariant (inflation)invariant (inflation)
Gopal & Sethi 2003Gopal & Sethi 2003 Gopal & Sethi 2003Gopal & Sethi 2003
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Non-linear EffectsNon-linear Effects
Magnetized Jeans Magnetized Jeans effect effect Additional magnetic Additional magnetic
pressurepressure Fast-magneto-sound Fast-magneto-sound
waves waves Sound speed Sound speed
rescalling rescalling
Adams et al. 1996Adams et al. 1996
Damping Damping Diffusion (Alfven Diffusion (Alfven
waves) waves) MHD MHD Shaw and Lewis 2012Shaw and Lewis 2012
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Kahniashvili, Tevzadze, Sethi, Pandey, Ratra 2010
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Magnetized Matter Power SpectrumMagnetized Matter Power Spectrum
Kahniashvili et al. ApJ 2013Kahniashvili et al. ApJ 2013
CAMBCAMB modification by modification by
Shaw & Lewis Shaw & Lewis 20102010
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Density Perturbations Amplitude Density Perturbations Amplitude
Jenkins et al. 2001Jenkins et al. 2001
Kahniashvili et al. ApJ 2013Kahniashvili et al. ApJ 2013
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Halos AbundanceHalos Abundance Press-SchechterPress-Schechter
Modification by Sheth & Modification by Sheth & Tolmen 1999Tolmen 1999
Kahniashvili et al. ApJ 2013
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Lyman-alpha DataLyman-alpha Data P(k) sensitive at P(k) sensitive at
k~0.1-100Mpck~0.1-100Mpc -1
Kahniashvili et al. ApJ 2013
Data: Data: Croft et al. 2002 Croft et al. 2002
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LimitsLimits
Strongest limits from Strongest limits from Lyman-alpha dataLyman-alpha data
Planck 2015 Results Planck 2015 Results (XVI cosmological (XVI cosmological parameters)parameters)BBLL at 1Mpc < nG for at 1Mpc < nG for nnBB ~ -3 ~ -3
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CMB Faraday RotationCMB Faraday Rotation Homogeneous Homogeneous
magnetic field magnetic field Kosowsky & Loeb 1996Kosowsky & Loeb 1996
Stochastic Magnetic Stochastic Magnetic Field Field
Kahniashvili et al. 2010Kahniashvili et al. 2010
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Thermal SZ EffectThermal SZ Effect
Kahniashvili et al. ApJ 2013
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THANKS!THANKS!
Constraints on Magnetic Fields from Large Scale StructureOutlineMagnetic Field in the UniverseMagnetic Field StatisticsMagnetized Cosmological PerturbationsScalar Magnetized ModeLinear Magnetized Density PerturbationsNon-linear EffectsPowerPoint PresentationSlide 10Magnetized Matter Power SpectrumDensity Perturbations AmplitudeHalos AbundanceLyman-alpha DataLimitsCMB Faraday RotationSlide 17Thermal SZ EffectTHANKS!