Multiwavelength behaviour of the blazar OJ 248 from radio to γ-rays

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.

arXiv comment16 pages, 20 figures, 2 tables, in press for MNRAS

References in corpus (49)

• The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission
• The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI: Final data release of the combined LDS and IAR surveys with improved stray-radiation corrections
• The Swift X-ray Telescope
• The Swift Ultra-Violet/Optical Telescope
• Reverberation Measurements for 17 Quasars and the Size-Mass-Luminosity Relations in Active Galactic Nuclei
• The Burst Alert Telescope (BAT) on the Swift MIDEX Mission
• Fermi Large Area Telescope Second Source Catalog
• Photometric Calibration of the Swift Ultraviolet/Optical Telescope
• On Uncertainties in Cross-Correlation Lags and the Reality of Wavelength-Dependent Continuum Lags in Active Galactic Nuclei
• Turbulent, Extreme Multi-Zone Model for Simulating Flux and Polarization Variability in Blazars
• Probing the Inner Jet of the Quasar PKS 1510-089 with Multi-waveband Monitoring during Strong Gamma-ray Activity
• Roma-BZCAT: A multifrequency catalogue of Blazars
• The AGILE Mission
• Discovery of Damped Lyman-Alpha Systems at Redshifts Less Than 1.65 and Results on their Incidence and Cosmological Mass Density
• Optical and radio behaviour of the BL Lacertae object 0716+714
• The Kinematic Connection Between QSO-Absorbing Gas and Galaxies at Intermediate Redshift
• The structure and emission model of the relativistic jet in the quasar 3C 279 inferred from radio to high-energy gamma-ray observations in 2008-2010
• Synchrotron Self-Compton Model for Rapid Nonthermal Flares in Blazars with Frequency-Dependent Time Lags
• Swift X-ray Telescope Monitoring of Fermi-LAT Gamma Ray Sources of Interest
• The On-orbit Calibrations for the Fermi Large Area Telescope
• Variability of Active Galactic Nuclei
• The awakening of BL Lacertae: observations by Fermi, Swift, and the GASP-WEBT
• The Outburst of the Blazar S5 0716+71 in 2011 October: Shock in a Helical Jet
• Low-Redshift Damped Lyman Alpha Galaxies Toward the Quasars B2 0827+243, PKS 0952+179, PKS 1127-145, and PKS 1629+120
• Fermi Large Area Telescope and multi-wavelength observations of the flaring activity of PKS 1510-089 between 2008 September and 2009 June
• Modeling the production of flares in $\gamma$-ray quasars
• Multiwavelength observations of 3C 454.3. III. Eighteen months of AGILE monitoring of the "Crazy Diamond"
• Correlated variability in the blazar 3C 454.3
• Flare-like variability of the Mg IIλ2800Å emission line in the gamma-ray blazar 3C 454.3
• The correlated optical and radio variability of BL Lacertae. WEBT data analysis 1994-2005
• Relativistic Outflow Drives Gamma-Ray Emission in 3C345
• The radio delay of the exceptional 3C 454.3 outburst. Follow-up WEBT observations in 2005-2006
• The GASP-WEBT monitoring of 3C 454.3 during the 2008 optical-to-radio and gamma-ray outburst
• AGILE detection of extreme gamma-ray activity from the blazar PKS 1510-089 during March 2009. Multifrequency analysis
• External Compton Radiation from Rapid Nonthermal Flares in Blazars
• The long-lasting activity of 3C 454.3. GASP-WEBT and satellite observations in 2008-2010
• Geometry and inclination of the broad line region in blazars
• A 3.5mm Polarimetric Survey of Radio-loud Active Galactic Nuclei
• Variability of the blazar 4C 38.41 (B3 1633+382) from GHz frequencies to GeV energies
• Another look at the BL Lacertae flux and spectral variability
• The Highly Relativistic Kiloparsec-Scale Jet of the Gamma-Ray Quasar 0827+243
• The WEBT campaign to observe AO 0235+16 in the 2003-2004 observing season
• Testing the inverse-Compton catastrophe scenario in the intra-day variable blazar S5 0716+71: II. A search for intra-day variability at millimetre wavelengths with the IRAM 30 m telescope
• Multi-frequency monitoring of gamma-ray loud blazars: I. Light curves and spectral energy distributions
• Spectroscopic monitoring of the BL Lac object AO 0235+164
• Infrared properties of blazars: putting the GASP-WEBT sources into context
• On the origin of the gamma-ray/optical lags in luminous blazars
• 7 mm continuum observations of ultra compact HII regions
• Rotation of the optical polarization angle associated with the 2008 γ-ray flare of blazar w comae

Cited by in corpus (30)

• Exceptional outburst of the blazar CTA 102 in 2012: The GASP-WEBT campaign and its extension
• Quasi-periodic behaviour in the optical and γ-ray light curves of blazars 3C 66A and B2 1633+38
• Multiwavelength behaviour of the blazar 3C279: decade-long study from $\gamma$-ray to radio
• Dissecting the long-term emission behaviour of the BL Lac object Mrk 421
• The complex variability of blazars: Time-scales and periodicity analysis in S4 0954+65
• A spine-sheath model for strong-line blazars
• Broadband Spectral Fitting of Blazars using XSPEC
• Temporal correlation between the optical and γ-ray flux variations in the blazar 3C 454.3
• Synchrotron emission from the blazar PG 1553+113. An analysis of its flux and polarization variability
• Investigating the multiwavelength behaviour of the flat spectrum radio quasar CTA 102 during 2013-2017
• Multiwavelength Photometric and Spectropolarimetric Analysis of the FSRQ 3C 279
• H.E.S.S. detection of very-high-energy gamma-ray emission from the quasar PKS 0736+017
• Correlation between optical and $\gamma$-ray flux variations in bright flat spectrum radio quasars
• Peak of spectral energy distribution play an important role in intra-day variability of Blazars?
• The TANAMI Multiwavelength Program: Dynamic SEDs of Southern Blazars
• The optical behaviour of BL Lacertae at its maximum brightness levels: a blend of geometry and energetics
• A blazar in the epoch of reionization
• The gamma-ray and Optical Variability Analysis of the BL Lac Object 3FGL J0449.4-4350
• Correlation between optical flux and polarization variations in Flat Spectrum Radio Quasars on diverse timescales
• An International Survey of Front-End Receivers and Observing Performance of Telescopes for Radio Astronomy
• Variability and evolution of the optical polarization of a sample of gamma-ray blazars
• The variability of blazars throughout the electromagnetic spectrum
• Polarimetric Properties of Blazars Caught by the WEBT
• Mid-infrared Variability of gamma-ray emitting blazars
• The beamed jet and quasar core of the distant blazar 4C 71.07
• Temporal variability and estimation of jet parameters for Ton 599
• Unveiling the monster heart: unbeamed properties of blazar 4C 71.07
• Polarization Studies in Different Blazar Types. Part I: Correlation between Optical Brightness and Polarization Degree
• Twenty years of blazar monitoring with the INAF radio telescopes
• Broadband Spectro-temporal Study on Blazar TXS 1700+685