Optical Monitoring of Gamma-Ray Blazars
In concert with the Fermi Large Area Telescope (LAT) monitoring of the entire sky at gamma-rays, E > 100 MeV, we perform photometric (BVRI) and polarimetric R-band observations of a sample of gamma-ray blazars with the 1.8-meter Perkins telescope at Lowell observatory using the PRISM camera developed by Prof. K. Janes et al. at BU and Lowell Observatory, with funding from the NSF, BU, and Lowell Observatory. The R-band light curves and curves of polarization parameters are presented at our website along with VLBA images of blazars and radio galaxies. We combine our optical photometric and polarimetric observations with measurements of our colleagues carried out at 1) the 70 cm AZT-8 telescope of the Crimean Astrophysical Observatory (Nauchnij) and 40 cm LX200 telelescope of St. Petersburg State U. (Petergof, Russia); 2) the 2.2 m telescope of Calar Alto Observatory (Almeria, Spain) within the MAPCAT program; and 3) the 1.54 m Kuiper and 2.3 m Bok telescopes of Steward Observatory (Mt. Bigelow and Kitt Peak, AZ) within Paul Smith's program of optical observational support of Fermi LAT observations. Analysis of combined optical light curves of a sample of gamma-ray blazars, along with gamma-ray and X-ray light curves, are presented in Willamson et al. 2014. A comprehensive study of polarization behavior of the sources in our sample is in preparation, although the optical polarization behavior of individual sources is discussed in a number of papers based on our observations, e.g., Marscher et al. 2010, Agudo et al. 2011, Jorstad et al. 2013, Larionov et al. 2013, Morozova et al. 2014, and others (see our list of publication devoted to multifrequency observations of a sample of gamma-ray blazars).
In the past, we have monitored the quasars PKS 1510-089, 3C 273, and 3C 279, as well as the quasar-like object BL Lacertae and the radio galaxies 3C120 and 3C111 at the 1.8-meter Perkins telescope at Lowell observatory as part of a long-term multi-wavelength program to understand the physics of relativistic jets in regions close to the "central engines." Collaborators observing in the optical band include Tom Balonek (Foggy Bottom Observatory, Colgate U.), Valeri Larionov and Vladimir Hagen-Thorn (St. Petersburg State U., Russia), Martin Gaskell (University of Nebraska), Gino Tosti (Perugia U. Observatory, Italy), and Massimo Villata and Claudia Raiteri (Torino U. Observatory, Italy), H. Richard Miller and John McFarland (Georgia State U.), Mark Turler (Geneva Obs.), and Omar Kurtanidze (Abastumani Obs.). Ian McHardy (U. Southampton, UK) of our RXTE team was the lead investigator for observations with the robotic Liverpool Telescope on La Palma, Canary Islands.