Highly variable objects in the palomar-quest survey: A blazar search using optical variability

Anne Bauer, Charles Baltay, Paolo Coppi, Ciro Donalek, Andrew Drake, S. G. Djorgovski, Nancy Ellman, Eilat Glikman, Matthew Graham, Jonathan Jerke, Ashish Mahabal, David Rabinowitz, Richard Scalzo, Roy Williams

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


We identify 3113 highly variable objects in 7200 deg2 of the Palomar-QUEST (PQ) Survey, which each varied by more than 0.4 mag 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 active galactic nucleus (AGN). The object positions, variability statistics, and color information are available using the PQ 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 AGNs. The remainder largely consists of a variety of variable stars, including a number of RR Lyrae and cataclysmic variables.

Original languageEnglish
Pages (from-to)46-53
Number of pages8
JournalAstrophysical Journal
Issue number1
StatePublished - 2009


  • BL Lacertae objects: general
  • Catalogs
  • Galaxies: active
  • Quasars: general


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