Spectropolarimetric investigation of an Ellerman bomb: 1. Observations

Abstract

Spectra of an Ellerman bomb in the NOAA 11024 active region were obtained in spectropolarimetric observations with the French–Italian THEMIS telescope (Tenerife, Spain). The variations of profiles of the Stokes parameters I, Q, U, and V of photospheric lines were analyzed. The chosen lines had different intensities and magnetic-field sensitivities. It was found that the photospheric line profiles in the Ellerman bomb spectra differed greatly from the profiles for the quiet photosphere outside the active region. The Stokes I profiles of photospheric lines in the Ellerman bomb spectra were much weaker. The largest values of the Stokes parameters Q, U, and V were derived for the Fe I λ 630.25 nm magnetosensitive line. The Stokes parameter V was the highest in the central region of the Ellerman bomb, while the maximum Q and U parameters were observed at one of the edges of the Ellerman bomb. It follows from the comparison of the Stokes parameters for the Ellerman bomb and microflares that the Q, U, and V parameters for the bomb are much higher than those for flares.