Measurement of black hole mass for low-z (z≤ 0.8) Active Galactic Nuclei (AGNs) is difficult due to the strong contribution from host galaxy stellar light necessitating detailed spectral decomposition to estimate the AGN ...

Soon after the discovery of the first quasars, a small decrement in the spectrum of a quasar shortward of its Lyα emission line was measured. Recognizing the decrement was due to the Lyα resonance absorption of radiation ...