Spatial variations of the SrI 4607\AA scattering polarization signals at subgranular scale observed with ZIMPOL at GREGOR telescope.

2019
Sr I 4607\AA spectral line shows one of the strongest scattering polarization signals in the visible solar spectrum. The amplitudes of these signals are expected to vary at granularspatial scales. This variation can be due to changes in the magnetic field intensity and orientation ( Hanle effect) as well as due to spatial and temporal variations in the plasma properties. Measuring the spatial variation of such polarization signal would allow us to study the properties of the magnetic fields at subgranular region. But, the observations are challenging since both high spatial resolution and high spectropolarimetric sensitivity are required at the same time. To the aim of measuring these spatial variations at granularscale, we carried out a spectro-polarimetric measurement with the Zurich IMaging POLarimeter(ZIMPOL), at the GREGOR solar telescopeat different limb distances on solar disk. Our results show a spatial variation of scattering linear polarization signals in Sr I 4607\AA line at the granularscale at every $\mu$, starting from 0.2 to 0.8. The correlation between the polarization signal amplitude and the continuum intensity imply statistically that the scattering polarization is higher at the granularregions than in the intergranular lanes.
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