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Simultaneous visible and infrared spectro-polarimetry of a solar internetwork region

J. Sanchez Almeida·I. Dominguez Cerdena·F. Kneer
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Abstract

We present the first simultaneous infrared (IR) and visible spectro-polarimetric observations of a solar internetwork region. The Fe I lines at 6301.6 A, 6302.5 A, 15648 A, and 15652 A were observed, with a lag of only 1 min, using highly sensitive spectro-polarimeters operated in two different telescopes (VTT and THEMIS at the Observatorio del Teide). Some 30% of the observed region shows IR and visible Stokes V signals above noise. These polarization signals indicate the presence of kG magnetic field strengths (traced by the visible lines) co-existing with sub-kG fields (traced by the infrared lines). In addition, one quarter of the pixels with signal have visible and IR Stokes V profiles with opposite polarity. We estimate the probability density function of finding each longitudinal magnetic field strength in the region. It has a tail of kG field strengths that accounts for most of the (unsigned) magnetic flux of the region.

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J. Sanchez Almeida, I. Dominguez Cerdena, F. Kneer. 2003-09-26. Simultaneous visible and infrared spectro-polarimetry of a solar internetwork region. https://doi.org/10.1086/379969

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