Séminaire / Seminar GReCO |
| « Magnetic turbulence from synchrotron intensity and polarization fluctuations » |
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D. Pogosian |
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We will discuss a statistical description of synchrotron fluctuations arising
from magnetized turbulence. We demonstrate that the synchrotron intensity fluctuations are anisotropic with enhanced correlations present along the direction of the magnetic field. This anisotropy is dominated by the quadrupole component with the ratio between quadrupole and monopole parts being sensitive to the compressibility of underlying turbulence. We show how the structure of correlations reflects what turbulent modes are present. We shall also discuss synchrotron polarization fluctuations in the presence of Faraday rotation. Several measures that can be used to obtain the spectral slopes and correlation scales of both the underlying magnetic turbulent gas responsible for the emission and the spectrum of the Faraday rotation fluctuations are introduced. Our results are relevant for quantitative studies of magnetic turbulence in our galaxy and beyond using synchrotron emission as well as separation of synchrotron foreground emission from cosmological signals, namely CMB or highly redshifted HI emission. We expect applications of our techniques both with existing synchrotron data sets as well as with big forthcoming data sets from LOFAR and SKA. |
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lundi 27 juin 2016 - 11:00 Salle des séminaires Évry Schatzman Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |