Highly Variable Objects in the Palomar-QUEST Survey: A Blazar Search
  using Optical Variability
  We identify 3,113 highly variable objects in 7,200 square degrees of the
Palomar-QUEST Survey, which each varied by more than 0.4 magnitudes
simultaneously in two broadband optical filters on timescales from hours to
roughly 3.5 years. The primary goal of the selection is to find blazars by
their well-known violent optical variability. Because most known blazars have
been found in radio and/or X-ray wavelengths, a sample discovered through
optical variability may have very different selection effects, elucidating the
range of behavior possible in these systems. A set of blazars selected in this
unusual manner will improve our understanding of the physics behind this
extremely variable and diverse class of AGN. The object positions, variability
statistics, and color information are available using the Palomar-QUEST CasJobs
server. The time domain is just beginning to be explored over large sky areas;
we do not know exactly what a violently variable sample will hold. About 20% of
the sample has been classified in the literature; over 70% of those objects are
known or likely AGN. The remainder largely consists of a variety of variable
stars, including a number of RR Lyrae and cataclysmic variables.
