Kavli Affiliate: Claude Canizares | Summary:Weak spectral features in BL Lacertae objects (BL Lac) often provide a unique opportunity to probe the inner region of this rare type of active galactic nucleus. We present a Hubble Space Telescope/Cosmic Origins Spectrograph observation of the BL Lac H 2356-309. A weak Ly$α$ emission line was detected. This […]
Continue.. An HST/COS Observation of Broad Ly$α$ Emission and Associated Absorption Lines of the BL Lacertae Object H 2356-309