Exploring the Connection between UV/Optical Variations and Radio
  Emission in Radio-Quiet Quasars: Clues on Radio Emission Origin
  The radio emission in radio-quiet quasars (RQQs) has been a long mystery and
its physical origin remains unclear. In a previous work we find UV/optical more
variable quasars have stronger X-ray emission, indicating a link between disc
turbulence and X-ray corona heating. In this work, for the first time, we
investigate the relation between UV/optical variability and the radio emission
in RQQs selected from SDSS stripe 82 and FIRST radio survey. We median stack
the FIRST images and detect clear signals from RQQs in the co-added images of
individually radio non-detected sources. Controlling the effects of other
parameters, including redshift, black hole mass, bolometric luminosity and
Eddington ratio, we find more variable RQQs, which are known to be X-ray
relatively brighter, show tentatively weaker radio emission, contrary to the
linear X-ray/radio correlation if the radio emission is from or driven by the
corona. The discovery also suggests that if the radio emission in RQQs is
driven by AGN activity (such as weak jet), the underlying driving process is
independent to the disc turbulence which drives UV/optical variability and
probably also corona heating. Alternatively, the radio emission could be due to
star formation in the host galaxies.
