Linear spectropolarimetric analysis of fairall 9 with VLT/FORS2
Mazzei, Paola; D'Onofrio, Mauro; Czerny, Bożena; Panda, Swayamtrupta; Marziani, Paola; Wang, Jian-Min; Jiang, Bo-Wei; Popović, Luka Č.; Afanasiev, Victor L.; Shablovinskaya, Elena; Śniegowska, Marzena; Savić, Đorđe; del Olmo, Ascensión
China, Italy, Belgium, Serbia, Russia, Poland, Spain
Abstract
The quasar main sequence appears to be an incredibly powerful tool to organize the diversity in large samples of type-1 quasars but the most important physical parameters governing it are still unclear. Here, we investigate the origin of the broadening and of a defining feature of Population B sources: a strong redward asymmetry of the Balmer emission lines. We focus on a prototypical source, Fairall 9. Spectropolarimetric data of the Fairall 9 broad H β and H α profiles allowed for a view of the geometric and dynamical complexity of the line emitting regions. Measurements (1) provided evidence of rotational motion; (2) were helpful to test the presence of polar and equatorial scatterers, and their association with non-virial motions. However, we suggest that the polarization properties appear to be more consistent with a warped disc geometry induced by Lense-Thirring precession.