Stellar longitudinal magnetic field determination through multi-Zeeman signatures

¹ Instituto de Astronomia – Universidad Nacional Autonoma de Mexico, Apdo. Postal 70-264, 04510 D.F. México, Mexico
e-mail: jramirez@astro.unam.mx
² Armagh Observatory, College Hill, Armagh BT61 9DG, UK
³ Universidad de Guadalajara, Av. Vallarta 2602, Arcos Vallarta, 44100 Guadalajara, Jalisco, Mexico
⁴ Instituto de Astronomia – Universidad Nacional Autonoma de Mexico, Apdo. Postal 877, 22860 Ensenada, B. C., Mexico

Received: 10 March 2016
Accepted: 7 October 2016

Abstract

Context. A lot of effort has been put into the detection and determination of stellar magnetic fields using the spectral signal obtained from the combination of hundreds or thousands of individual lines, an approach known as a multi-line analysis. So far, however, most of the developed multi-line techniques that retrieve mean stellar longitudinal magnetic fields can sometimes entail substantial simplifications concerning line shapes and Zeeman splittings.

Aims. In this paper we determine stellar longitudinal magnetic fields by means of the Principal Components Analysis and Zeeman Doppler Imaging (PCA-ZDI) multi-line technique, based on accurate polarised spectral line synthesis.

Methods. In this paper we present the methodology for performing inversions of profiles obtained using PCA-ZDI.

Results. Inversions with various magnetic geometries, field strengths and rotational velocities show that we can correctly determine the effective longitudinal magnetic field in stars using the PCA-ZDI method.