Abstract
Aims. For the detection and the study of small-scale magnetic fields on the Sun, it is important to obtain observations with both high spatial resolution and high polarimetric sensitivity. Methods. A second narrow-band etalon and a full Stokes polarimeter, based on ferroelectric liquid crystals, were implemented in the two-dimensional Gottingen Fabry-Perot spectrometer/polarimeter at the Vacuum Tower Telescope, Observatorio del Teide/Tenerife. First observations with the Fe 6173 A line and their data analysis with speckle methods are described. Results. The new polarimeter yields magnetograms of a field of view of 31 x 52 with minimised seeing induced signals and without spurious signals as from the use of beam-splitting calcites. The achieved spatial and temporal resolution are 0.30-035 and 36s, respectively. With a detection limit for the field strength of 16G (=3σ), a polarimetric sensitivity of 7-8 x 10 15 Mx is obtained. Examples of intensity maps, Dopplergrams, and magnetograms from quiet and active regions on the Sun are discussed. Some of the results on solar magnetism are on 1) a pore with small-scale structure where we find a region with very low temperature gradient, 2) polar faculae with strong magnetic field signals and weaker signals in other areas surrounding them, and 3) small-scale inter-network magnetic fields with area fillings in the resolution elements of the order of 0.15.
Highlights
Small-scale magnetic fields represent important ingredients for the structure and the dynamics of the atmosphere of the Sun
Some of the results on solar magnetism are on 1) a pore with small-scale structure where we find a region with very low temperature gradient, 2) polar faculae with strong magnetic field signals and weaker signals in other areas surrounding them, and 3) small-scale inter-network magnetic fields with area fillings in the resolution elements of the order of 0.15
While in many parts of the pore the V amplitudes amounted to 20% of the local continuum intensity, they were small in this special area before and after scattered light correction, smaller than 2%
Summary
The new polarimeter yields magnetograms of a field of view of 31 × 52 with minimised seeing induced signals and without spurious signals as from the use of beam-splitting calcites. With a detection limit for the field strength of 16 G (=3σ), a polarimetric sensitivity of 7−8 × 1015 Mx is obtained. Dopplergrams, and magnetograms from quiet and active regions on the Sun are discussed. Some of the results on solar magnetism are on 1) a pore with small-scale structure where we find a region with very low temperature gradient, 2) polar faculae with strong magnetic field signals and weaker signals in other areas surrounding them, and 3) small-scale inter-network magnetic fields with area fillings in the resolution elements of the order of 0.15. Sun: magnetic fields – techniques: high angular resolution – techniques: polarimetric
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