Optical variability of radio-intermediate quasars
  We report the results of our intensive intranight optical monitoring of 8
`radio-intermediate quasars' (RIQs) having flat or inverted radio spectra. The
monitoring was carried out in {\it R-} band on 25 nights during 2005-09. An
intranight optical variability (INOV) detection threshold of $\sim$ 1--2% was
achieved for the densely sampled differential light curves (DLCs). These
observations amount to a large increase over those reported hitherto for this
rare and sparsely studied class of quasars which can, however, play an
important role in understanding the link between the dominant varieties of
powerful AGN, namely the radio-quiet quasars (RQQs), radio-loud quasars (RLQs)
and blazars. Despite the probable presence of relativistically boosted nuclear
jets, clear evidence for INOV in our extensive observations was detected only
on one night. These results demonstrate that as a class, RIQs are much less
extreme in nuclear activity compared to blazars. The availability in the
literature of INOV data for another 2 RIQs conforming to our selection criteria
allowed us to enlarge the sample to 10 RIQs (monitored on a total of 42 nights
for a minimum duration of $\sim 4$ hours per night). The absence of large
amplitude INOV $(\psi > 3%)$ persists in this enlarged sample. This extensive
database has enabled us to arrive at the first estimate for the INOV Duty Cycle
(DC) of RIQs. The DC is found to be small ($\sim$ 9%). The corresponding value
is known to be $\sim 60%$ for BL Lacs and $\approx 15%$ for RLQs and RQQs. On
longer-term, the RIQs are found to be fairly variable with typical amplitudes
of $\approx$ 0.1-mag. The light curves of these RIQs are briefly discussed in
the context of a theoretical framework proposed earlier for linking this rare
kind of quasars to the much better studied dominant classes of quasars.
