Discovery of the optically bright, wide separation double quasar SDSS
  J1442+4055
  Optically bright, wide separation double (gravitationally lensed) quasars can
be easily monitored, leading to light curves of great importance in determining
the Hubble constant and other cosmological parameters, as well as the structure
of active nuclei and halos of galaxies. Searching for new double quasars in the
SDSS-III database, we discovered SDSS J1442+4055. This consists of two bright
images (18-19 magnitudes in the r band) of the same distant quasar at redshift
z = 2.575. The two quasar images are separated by about 2.1 arcsec, show
significant parallel flux variations and can be monitored from late 2015. We
also found other two double quasar candidates, SDSS J1617+3827 (z = 2.079) and
SDSS J1642+3200 (z = 2.264), displaying evidence for the presence of a lensing
object and parallel flux variations, but requiring further spectroscopic
observations to be confirmed as lensed quasars.
