Name: Aratrika Dey
Affiliation: Indian Institute of Astrophysics
Conference ID : ASI2022_357
Title : A comparative study of the long term optical and IR variability of high redshift narrow line and broad line Seyfert 1 galaxie
Authors : Aratrika Dey (PhD student, IIA) Dr. CS Stalin (Professor, IIA) Dr. Suvendu Rakshit (Scientist, ARIES)
Abstract Type: Oral
Abstract Category : Extragalactic Astronomy
Abstract : Narrow Line Seyfert 1 (NLSy1) galaxies are a special class of active galactic nuclei (AGN) identified by Osterbrock and Pogge about four decades ago. They are classified based on the presence of narrow H_beta emission line with the full width at half maximum < 2000 km/sec, strong FeII emission and weak OIII emission line. The study on NLSy1 galaxies is now restricted to low redshift (z < 0.8), because, definition requires the presence of H_beta emission line which is redshifted outside the spectral coverage of major ground based spectroscopic surveys available today. In the year 2021, Rakshit et al. have arrived at a sample of z > 0.8 NLSy1 candidates treating the MgII line at 2800 Angstroms as a proxy for the H_beta emission line. We have carried out a comparative analysis of the long term optical and infrared variability characteristics of the high redshift sample of NLSy1 galaxies vis-a-vis broad line Seyfert 1 (BLSy1) galaxies. The control sample of BLSy1 galaxies were selected such that they match in the optical g-band brightness, redshift and black hole mass to the sample of NLSy1 galaxies. In the optical band, BLSy1 galaxies are found to display a marginal increase in variability compared to NLSy1 galaxies. We also investigated the correlation of optical variability with radio-loudness, relativistic jet power and accretion rate of the sample. Details of the results will be discussed.