A comparative study of the intra-night optical variability of powerful AGNs

Abstract

In order to address a currently much debated issue, we are carrying out a systematic search for intra-night optical micro-variability in major classes of powerful (Mᵥ ≥ -23.0 mag)active galactic nuclei (AGNs). Our sample include 7 sets of AGNs, covering marrow redshift bins across the range 0.18 ² z ² 2.2. Each set consist of a radio-quiet quasar, a radio lobe-dominated quasar, a BL Lac object and/or a radio core-dominated quasar (blazar), all having mᵥ ~16 mag. The observations were made primarily using the 104-cm telescope of State Observatory, Nainital. The monitoring completed so far (~90 nights) clearly indicates that, compared to the other AGN type, BL Lacs are distinctly more prone to exhibit intra-night optical variations.