Long-term multiwavelength studies of high-redshift blazar 0836+710⋆
University of CukurovaDepartment of Physics,
2 NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
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
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.
Key words: galaxies: active / gamma rays: galaxies / quasars: individual: 0836+710
Data for all figures appearing in this paper are available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (188.8.131.52) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/556/A71 and at the Fermi-LAT publications Web site, http://www-glast.stanford.edu/cgi-bin/pubpub
© ESO, 2013