TEMPORAL CORRELATIONS BETWEEN OPTICAL AND GAMMA-RAY ACTIVITY IN BLAZARS

• Published in: The Astrophysical journal Vol. 797; no. 2; pp. 137 - 11
• Main Authors: Cohen, Daniel P., Romani, Roger W., Filippenko, Alexei V., Cenko, S. Bradley, Lott, Benoit, Zheng, WeiKang, Li, Weidong
• Format: Journal Article
• Language: English
• Published: United States American Astronomical Society 08.12.2014; Institute of Physics (IOP)
• Subjects: active galactic nuclei: blazars; Astrophysics; Automation; Blazars; Correlation; Emission; galaxies: jets; Gamma rays; High Energy Physics - Phenomenology; Physics; quasars: general; Searching; Telescopes; Temporal logic; galaxies jets; quasars general; active galactic nuclei blazars
• ISSN: 1538-4357; 0004-637X; 1538-4357
• DOI: 10.1088/0004-637X/797/2/137

We have been using the 0.76 m Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory to optically monitor a sample of 157 blazars that are bright in gamma-rays being detected with high significance (10[sigma]) in one year by the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope. We attempt to observe each source on a three-day cadence with KAIT, subject to weather and seasonal visibility. Using the discrete correlation function (DCF), here we search for temporal relationships between optical and gamma-ray light curves in the 40 brightest sources in hopes of placing constraints on blazar acceleration and emission zones. A stacked average DCF of the 40 sources verifies this correlation trend, with a peak above 99% significance indicating a characteristic time delay consistent with 0 days. The findings strongly support the widely accepted leptonic models of blazar emission. It is clear that long-term monitoring at high cadence is necessary to reveal the underlying physical correlation.