Abstract Details
| Name: Vedavathi P Affiliation: Bangalore University, Bengaluru Conference ID: ASI2019_244 Title : Emission line and continuum variability study of active galaxies for redshift 0 < z ≤1.0 Authors and Co-Authors : Vedavathi P and Vijayakumar H Doddamani Abstract Type : Oral Abstract Category : Thesis Abstract : IUE satellite launched in 1978 has made very successful spectroscopic observations of active galaxies till 1997 for the redshift 0.001 to 3.2. We have undertaken spectroscopic analysis of nearly 110 objects for their continuum and emission line variability characteristics in this thesis. We have found only a small fraction of the NGC catalogued AGNs to be satisfying the generally accepted characteristics of active galaxies. The emission lines Lyα, Si IV, C IV, He II, C III], and Mg II have been observed as the strong and broad emission lines in most of the active galaxies. We have standardised the UV continuum and line flux variability by Rmax and Fvar parameters as many of these active galaxies (~ 30 %) were observed repeatedly. We have found the highest Fvar to be 0.311 at 1325 Å continuum in the case of MRK 478 from long term monitoring observations and small amplitude variability of 9% at 1325 Å in the case of NGC 4151 from the most constraining shortest time scale (1 hour) observations. We have found the line flux ratio C IV/C IIII] ranging between 3 - 7 and is consistent with the prediction of Kwan and Krolik (1981) model for Seyfert 1 galaxies. We have found no appreciable delay among continuum-continuum flux correlations. However a small zero-lag delay of 0.02 days has been found in the case of line-line flux correlations in NGC 4151 implying smaller geometry of BLR region compared to the 4 ±3 days size by Clavel et al (1990). The implications of these results on the UV variability characteristics of Seyfert galaxies and Quasars are discussed in greater detail in my talk. Key Words: Active galaxies, Seyfert1 galaxies, Quasars, UV variability. . |