Abstract:
Although well established for BL Lac objects and radio-loud
quasars, the occurrence of intra-night optical variability (INOV) in radio-quiet
quasars is still debated, primarily since only a handful of INOV events with good
statistical significance, albeit small amplitude, have been reported so far. This
has motivated us to continue intra-night optical monitoring of bona-fide radio-
quiet quasars (RQQs). Here we present the results for a sample of 11 RQQs
monitored by us on 19 nights. On 5 of these nights a given RQQ was monitored
simultaneously from two well separated observatories. In all, two clear cases
and two probable cases of INOV events were detected. From these data, we
estimate an INOV duty cycle of ∼8% for RQQs which would increase to 19% if
the ‘probable variable’ cases are also included. Such comparatively small INOV
duty cycles for RQQs, together with the small INOV amplitudes (∼1%), are in
accord with the previously deduced characteristics of this phenomenon.
