Very Large Array imaging rules out precessing radio jets in three
  DES$-$SDSS-selected candidate periodic quasars
  Periodic quasars have been suggested as candidates for hosting binary
supermassive black holes (SMBHs), although alternative scenarios remain
possible to explain the optical light curve periodicity. To test the
alternative hypothesis of precessing radio jet, we present deep 6 GHz radio
imaging conducted with NSF's Karl G. Jansky Very Large Array (VLA) in its C
configuration for the three candidate periodic quasars, DES
J024703.24$-$010032.0, DES J024944.66$-$000036.8, and DES
J025214.67$-$002813.7. Our targets were selected based on their optical
variability using 20-yr long multi-color light curves from the Dark Energy
Survey (DES) and the Sloan Digital Sky Survey (SDSS). The new VLA observations
show that all three periodic quasars are radio-quiet with the radio loudness
parameters measured to be $R\equiv f_{6\,{\rm cm}}/f_{{\rm 2500}}$ of
$\lesssim$1.0$-$1.5 and the $k$-corrected luminosities $\nu L_\nu$[6 GHz] of
$\lesssim$5$-$21 $\times$ 10$^{39}$ erg s$^{-1}$. They are in stark contrast to
previously known periodic quasars proposed as binary SMBH candidates such as
the blazar OJ 287 and PG1302$-$102. Our results rule out optical emission
contributed from precessing radio jets as the origin of the optical periodicity
in the three DES$-$SDSS-selected candidate periodic quasars. Future continued
optical monitoring and complementary multi-wavelength observations are still
needed to further test the binary SMBH hypothesis as well as other competing
scenarios to explain the optical periodicity.
