The Relationship between Mg ii Broad Emission and Quasar Inclination Angle

Frontiers in Astronomy and Space Sciences

Wildy, Conor¹  Czerny, Bozena¹ 

[1] Center for Theoretical Physics, Polish Academy of Sciences, Poland

关键词: active galaxies;    accretion;    Broad line region;    spectroscopy;    Mg II;   

DOI  :  10.3389/fspas.2017.00043

学科分类：空间科学

来源: Frontiers

【 摘 要 】

Several observed spectral properties of quasars are believed to be influenced by quasar orientation. In this investigation we examine the effect of orientation on the Mg II line located at 2798 A in a sample of 36 radio-loud quasars, with orientation angles having been obtained in a previous study using radio observations. We find no significant relationship between orientation angle and either Mg II line full-width at half-maximum or equivalent width. The lack of correlation with inclination angle contradicts previous studies which also use radio data as a proxy for inclination angle and suggests the Mg II emission region does not occupy a disk-like geometry. The lack of correlation with Mg II equivalent width, however, is reported in at least one previous study. Although the significance is not very strong (86 percent), there is a possible negative relationship between inclination angle and Fe II strength which, if true, could explain the Fe II anti-correlation with [O III] strength associated with Eigenvector 1. Interestingly, there are objects having almost edge-on inclinations while still exhibiting broad lines. This could be explained by a torus which is either clumpy (allowing sight lines to the central engine) or mis-aligned with the accretion disk.

【 授权许可】

CC BY