1. Multiwavelength behaviour of the blazar OJ 248 from radio to gamma-rays
- Author
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M. I. Carnerero, Sofia O. Kurtanidze, J. A. Acosta-Pulido, E. N. Kopatskaya, Paolo Leto, C. S. Lin, A. B. Grinon-Marin, Sol N. Molina, D. A. Morozova, H. C. Lin, R. Bachev, Neelam Panwar, A. I. Manilla-Robles, M. Orienti, Valeri M. Larionov, Marcello Giroletti, J. L. Gomez, P. A. González-Morales, Antoniya Valcheva, Carolina Casadio, Anne Lähteenmäki, Helmut Wiesemeyer, Uwe Bach, Goran Damljanović, Corrado Trigilio, Y. T. Metodieva, D. O. Mirzaqulov, Sunay Ibryamov, Elena G. Larionova, A. Bueno Bueno, T. S. Grishina, H. Y. Hsiao, V. Ramakrishnan, G. Umana, D. Carosati, Wen Ping Chen, Arkady A. Arkharov, V. Bozhilov, Ivan Agudo, Mark Gurwell, A. Pastor Yabar, I. M. McHardy, David Hiriart, Carla Buemi, Manasvita Joshi, A. Strigachev, Alan P. Marscher, S. G. Jorstad, A. Di Paola, Lorand A. Sigua, L. V. Larionova, M. J. Arévalo, N. V. Efimova, D. Blinov, Erika Benítez, C. M. Raiteri, Brian W. Taylor, Omar M. Kurtanidze, I. Puerto Giménez, Evgeni Ovcharov, Yu. V. Troitskaya, M. G. Nikolashvili, Sergio Velasco, Ann E. Wehrle, A. A. Mokrushina, Paul S. Smith, M. Villata, Ivan S. Troitsky, Sh. A. Ehgamberdiev, Merja Tornikoski, M. Rossini, G. M. Richter, Filippo D'Ammando, C. Lázaro, O. Vince, Carnerero MI, Raiteri CM, Villata M, Acosta-Pulido JA, DAmmando F, Smith PS, Larionov VM, Agudo I, Arevalo MJ, Arkharov AA, Bach U, Bachev R, Benitez E, Blinov DA, Bozhilov V, Buemi CS, Bueno AB, Carosati D, Casadio C, Chen WP, Damljanovic G, Di Paola A, Efimova NV, Ehgamberdiev SA, Giroletti M, Gomez JL, Gonzalez-Morales PA, Grinon-Marin AB, Grishina TS, Gurwell MA, Hiriart D, Hsiao HY, Ibryamov S, Jorstad SG, Joshi M, Kopatskaya EN, Kurtanidze OM, Kurtanidze SO, Lahteenmaki A, Larionova EG, Larionova LV, Lazaro C, Leto P, Lin CS, Lin HC, Manilla-Robles AI, Marscher AP, McHardy IM, Metodieva Y, Mirzaqulov DO, Mokrushina AA, Molina SN, Morozova DA, Nikolashvili MG, Orienti M, Ovcharov E, Panwar N, Yabar AP, Gimenez IP, Ramakrishnan V, Richter GM, Rossini M, Sigua LA, Strigachev A, Taylor B, Tornikoski M, Trigilio C, Troitskaya YV, Troitsky IS, Umana G, Valcheva A, Velasco S, Vince O, Wehrle AE, Wiesemeyer H, Anne Lähteenmäki Group, Department of Radio Science and Engineering, Aalto-yliopisto, and Aalto University
- Subjects
active [Galaxies] ,Radio galaxy ,Astrophysics::High Energy Astrophysical Phenomena ,ta221 ,galaxies: active ,ta1171 ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,law.invention ,Telescope ,Observatory ,law ,quasars: general ,Emission spectrum ,Blazar ,ta216 ,Physics ,individual: OJ 248 [Quasars] ,ta115 ,ta213 ,ta114 ,Linear polarization ,quasars: individual: OJ 248 ,Astronomy ,Astronomy and Astrophysics ,general [Quasars] ,galaxies: active, galaxies: jets, quasars: general, quasars: individual: OJ 248 ,galaxies: jets ,Light curve ,Astrophysics - Astrophysics of Galaxies ,Space and Planetary Science ,jets [Galaxies] ,Astrophysics - High Energy Astrophysical Phenomena ,Fermi Gamma-ray Space Telescope - Abstract
We present an analysis of the multiwavelength behaviour of the blazar OJ 248 at z = 0.939 in the period 2006-2013. We use low-energy data (optical, near-infrared, and radio) obtained by 21 observatories participating in the GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT), as well as data from the Swift (optical-UV and X-rays) and Fermi (gamma-rays) satellites, to study flux and spectral variability and correlations among emissions in different bands. We take into account the effect of absorption by the Damped Lyman Alpha intervening system at z = 0.525. Two major outbursts were observed in 2006-2007 and in 2012-2013 at optical and near-IR wavelengths, while in the high-frequency radio light curves prominent radio outbursts are visible peaking at the end of 2010 and beginning of 2013, revealing a complex radio-optical correlation. Cross-correlation analysis suggests a delay of the optical variations after the gamma-ray ones of about a month, which is a peculiar behaviour in blazars. We also analyse optical polarimetric and spectroscopic data. The average polarization percentage P is less than 3 per cent, but it reaches about 19 per cent during the early stage of the 2012-2013 outburst. A vague correlation of P with brightness is observed. There is no preferred electric vector polarisation angle and during the outburst the linear polarization vector shows wide rotations in both directions, suggesting a complex behaviour or structure of the jet and possible turbulence. The analysis of 140 optical spectra acquired at the Steward Observatory reveals a strong Mg II broad emission line with an essentially stable flux of 6.2 e-15 erg cm-2 s-1 and a full width at half-maximum of 2053 km s-1., Comment: 16 pages, 20 figures, 2 tables, in press for MNRAS
- Published
- 2015