Long-term multiwavelength studies of high-redshift blazar 0836+710^⋆

¹ University of CukurovaDepartment of Physics, 01330 Adana, Turkey
e-mail: aakyuz@cu.edu.tr
² NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
e-mail: David.J.Thompson@nasa.gov
³ CRESST, Department of Astronomy, University of Maryland, College Park, MD 20742, USA
⁴ CRESST, CSST, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
⁵ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
⁶ Department of Physics, Stockholm University, AlbaNova, 106 91 Stockholm, Sweden
⁷ The Oskar Klein Centre for Cosmoparticle Physics, AlbaNova, 106 91 Stockholm, Sweden
⁸ Department of Astronomy, Stockholm University, 106 91 Stockholm, Sweden
⁹ Astro Space Center of Lebedev Physical Institute, Profsoyuznaya Str. 84/32, 117997 Moscow, Russia
¹⁰ Sternberg Astronomical Institute, Moscow State University, Universitetskii pr. 13, 119992 Moscow, Russia
¹¹ Abastumani Observatory, 383762 Abastumani, Republic of Georgia
¹² Landessternwarte, Zentrum für Astronomie der Universität Heidelberg, Königstuhl 12, 69117 Heidelberg, Germany
¹³ Engelhardt Astronomical Observatory, Kazan Federal University, Tatarstan, Russia

Received: 17 April 2013
Accepted: 12 June 2013

Abstract

Aims. The observation of γ-ray flares from blazar 0836+710 in 2011, following a period of quiescence, offered an opportunity to study correlated activity at different wavelengths for a high-redshift (z = 2.218) active galactic nucleus.

Methods. Optical and radio monitoring, plus Fermi-LAT γ-ray monitoring provided 2008−2012 coverage, while Swift offered auxiliary optical, ultraviolet, and X-ray information. Other contemporaneous observations were used to construct a broad-band spectral energy distribution.

Results. There is evidence of correlation but not a measurable lag between the optical and γ-ray flaring emission. In contrast, there is no clear correlation between radio and γ-ray activity, indicating radio emission regions that are unrelated to the parts of the jet that produce the γ rays. The γ-ray energy spectrum is unusual in showing a change of shape from a power law to a curved spectrum when going from the quiescent state to the active state.