Conveners
10 - Cosmic magnetic fields: Probes
- Tina Kahniashvili
10 - Cosmic magnetic fields: Probes
- Tina Kahniashvili
10 - Cosmic magnetic fields: Origin, evolution and signatures
- Tina Kahniashvili
10 - Cosmic magnetic fields: origin, evolution and signatures
- Tina Kahniashvili
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Prof. Philipp Kronberg (University of Toronto)15/12/2015, 14:00TalkA non-negligible fraction of a Supermassive Black Hole's (SMBH) rest mass energy gets transported into extragalactic space - by remarkable processes in jets which are not completely understood. The bulk of the energy flow from the SMBH (e.g. $10^7$ M$_\odot$) appears to be electromagnetic, rather than via a particle beam flux. Also, remarkably, these jets contain current flows that remain...Go to contribution page
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Andrew Fletcher15/12/2015, 14:25TalkThis talk will provide an overview of our current knowledge about galactic magnetic fields. The typical properties of magnetic fields in galactic discs and halos will be described as well as magnetic field characteristics at different length scales between 10 pc and 10 kpc. The talk will concentrate on reviewing what is known from observations, but will also point out the areas where...Go to contribution page
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PAOLO DA VELA (INFN - National Institute for Nuclear Physics)15/12/2015, 14:45TalkThe origin of cosmic magnetic fields permeating galaxies and clusters is still unknown.To undertstand the origin and the evolution of the primordial cosmic magnetic fields we need to probe the existence and to characterize magnitude and correlation length of magnetic field in voids (Intergalactic magnetic field, IGMF), where pollution from magnetic fields associated to structures is expected...Go to contribution page
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Prof. Reinhard Schlickeiser (Ruhr University Bochum, Germany)15/12/2015, 15:05TalkTwo recent estimates of lower limits for the stochastic primordial magnetic fields are reviewed. The first estimate pioneered by Neronov and Vovk (2010) is based on GeV-TeV $\gamma $-ray observations of distant blazars by air-Cherenkov telecopes and the FERMI satellite. The generated $e^{\pm }$ pair beams from double photon collisions with the extragalactic background light have been expected...Go to contribution page
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Philip Chang15/12/2015, 15:25TalkConstraints on the primordial intergalactic magnetic field from the non-observation of inverse Compton cascades around extragalactic very high energy sources, i.e., the TeV blazars, assume that inverse Compton scattering is the dominant physical mechanism by which dilute ultrarelativistic pair beams lose their energy. Over the last few years, we have considered the effect of plasma...Go to contribution page
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Daniela Paoletti (INAF and INFN)15/12/2015, 16:15TalkPrimordial magnetic fields (PMF) may represent the "progenitors" of the fields we observe in large scale structures and their study could open a new observational window on the early universe. The Cosmic Microwave Background, thanks to its different probes, represents one of the best laboratory to investigate and constrain the nature of PMF. I will present the Planck 2015 constraints on...Go to contribution page
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Dr Kerstin Kunze (University of Salamanca)15/12/2015, 16:35TalkThe presence of large scale magnetic fields at different epochs can be probed by their impact on different observables such as the CMB spectrum, primary and secondary CMB anisotropies, matter power spectrum and 21cm line emission. I will give an overview of these effects together with constraints from current and future experiments.Go to contribution page
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Dr Levon Pogosian (Simon Fraser University)15/12/2015, 16:55TalkI will discuss CMB signatures of primordial magnetic fields, some of the existing constraints, and what can be expected from future CMB experiments.Go to contribution page
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Hector Javier Hortua (Universidad Nacional)15/12/2015, 17:15PosterIn this work we compute the temperature-polarization correlations (C_l^(TB) and C_l^(EB)) in the cosmic microwave background (CMB) generated by the presence of causal primordial magnetic fields with a helical contribution. We analize the effect of an infrared cutoff in the power spectrum of causal fields on the cross-correlation and we compare our result with previous work.Go to contribution page
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Christos Tsagas (Aristotle University of Thessaloniki)16/12/2015, 14:00TalkInflation has long been thought as the best way of producing large-scale primordial magnetic fields. To achieve fields strong enough to seed the galactic dynamo, most of the generation mechanisms operate outside conventional electromagnetic theory, which is typically restored after the end of the de Sitter phase. Breaking away from standard electromagnetism can lead to substantially stronger...Go to contribution page
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Dr Alexey Boyarsky (Leiden University (NL)), Oleg Ruchayskiy (Ecole Polytechnique Federale de Lausanne (CH))16/12/2015, 14:21TalkIf chiral (left-right) asymmetry is present in the plasma, the electric current, parallel to the magnetic field, appears. This is known as "*chiral magnetic effect*". We demonstrate that this effect changes the dynamics of the magnetized relativistic plasma and present the proper equations of chiral relativistic magnetohydrodynamics, containing a new, axion-like, degree of freedom. There...Go to contribution page
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Jennifer Schober16/12/2015, 14:42TalkUnder extreme conditions, e.g. at high temperatures like in the early Universe, the usual magnetohydrodynamical (MHD) equations need to be extended. The origin of the modification is the asymmetry of the chemical potential of right- and left-handed fermions. To describe the evolution of a plasma, additional terms as well as new equations for the chiral chemical potential have to be included....Go to contribution page
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Axel Brandenburg (Nordita)16/12/2015, 15:03TalkThere was a time when primordial magnetic fields posed a serious contender to explaining the origin of magnetic fields in galaxies and on larger scales. This has changed drastically during the past three decades, and now the dynamo origin of galactic magnetic fields is unchallenged. Nevertheless, primordial magnetic fields might still be an attractive possibility to explaining magnetic...Go to contribution page
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Andrey Beresnyak (Naval Research Laboratory)16/12/2015, 15:24TalkMHD Turbulence is a strongly nonlinear dynamics of conductive fluids, e.g. plasma. Recent progress in theory regarding almost all basic regimes of this dynamics -- from how the magnetic field is generated (dynamo problem), to how turbulence is decaying, to what are the asymptotic scaling laws, allowed us to proceed with more observationally motivated questions. One of them is why almost all...Go to contribution page
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Dr Andrey Saveliev (University of Hamburg/Keldysh Institute)16/12/2015, 16:15TalkIn order to give a consistent picture of cosmic, i.e. galactic and extragalactic, magnetic fields, different approaches are possible and often even necessary. Here we present three of them: First, a semianalytic analysis of the time evolution of primordial magnetic fields from which their properties and, subsequently, the nature of present-day intergalactic magnetic fields may be deduced....Go to contribution page
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Dr Francesco Miniati (ETHZ - ETH Zurich)16/12/2015, 16:35TalkMassive galaxy clusters (GC) are filled with a hot, turbulent and magnetised intra-cluster medium (ICM). They are still forming under the action of gravitational instability driving supersonic accretion flows, which partially dissipate into heat through a complex network of large scale shocks, while partly excite giant turbulent eddies and cascade. Amongst others turbulence amplifies...Go to contribution page
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Guenter Sigl (II. Institut für theoretische Physik, Universität Hamburg)16/12/2015, 16:55TalkWe will present work on the chiral magnetic instability in the context of hot neutron stars and its possible role for magneto genesis in the early Universe. Whether a chiral asymmetry in the electron sector, induced for example by the electroweak interaction, leads to growing helical magnetic fields depends on many factors that will be discussed in this talk.Go to contribution page
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Dario Grasso (INFN)16/12/2015, 17:15TalkFermi-LAT, PAMELA, AMS-02, Planck and IceCube are providing us with impressive multimessenger pictures of our Galaxy. The diffuse components of those emissions are commonly modeled assuming uniform cosmic ray (CR) transport properties. Such an approach, however, is not motivated neither by theoretical nor observational arguments. I will show that relaxing the uniform CR propagation assumption...Go to contribution page