Modeling line-of-sight magnetograms of active regions

M. POISSON; M. LÓPEZ FUENTES; C. H. MANDRINI; F. GRINGS; P. DÉMOULIN

Yerevan

Simposio; IAU Symposium 365: Dynamics of Solar and Stellar Convection Zones and Atmospheres; 2023

International Astronomical Union

Active regions (ARs) appear in the solar atmosphere as a consequence of the emergence ofmagnetic flux ropes (FRs). Due to the presence of twist, the photospheric line-of-sight (LOS)magnetograms of emerging ARs show an elongation of the polarities known as magnetic tongues.These tongues can affect the estimation of tilt angles during their emergence phase. In this work,we propose a Bayesian method to model LOS magnetograms of emerging ARs using a half-torustwisted FR model. We apply this model to 21 emerging ARs observed during Solar Cycle 23.We find that the Bayesian method corrects the tilt when compared to other methods, removingthe spurious rotation of the polarities produced by the retraction of the tongues during theemergence. We find a variation in Joy’s law with the stage of the AR emergence and the methodused for its estimation