3C273 variability at 7 mm: Evidences of shocks and precession in the jet

Abstract

We report 4 years of observations of 3C273 at 7 mm obtained with the Itapetinga Radiotelescope, in Brazil, between 2009 and 2013. We detected a flare in 2010 March, when the flux density increased by 50% and reached 35 Jy. After the flare, the flux density started to decrease and reached values lower than 10 Jy. We suggest that the 7 mm flare is the radio counterpart of the $\gamma$-ray flare observed by Fermi/LAT in 2009 September, in which the flux density at high energies reached a factor of fifty of its average value. A delay of 170 days between the radio and $\gamma$-ray flares was revealed using the Discrete Correlation Function (DCF) that can be interpreted in the context of a shock model, in which each flare corresponds to the formation of a compact superluminal component that expands and becomes optically thin at radio frequencies at latter epochs. The difference in flare intensity between frequencies and at a different times, is explained as a consequence of an increase in the Doppler factor $\delta$, as predicted by the 16 year precession model proposed by Abraham & Romero, which has a large effect on boosting at high frequencies while does not affect too much the observed optically thick radio emission. We discuss other observable effects of the variation in $\delta$, as the increase in the formation rate of superluminal components, the variations in the time delay between flares and the periodic behaviour of the radio light curve that we found compatible with changes in the Doppler factor.

9 pages, 8 figures

References in corpus (11)

• MOJAVE: Monitoring of Jets in AGN with VLBA Experiments. V. Multi-epoch VLBA Images
• 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
• Correlated Multi-Waveband Variability in the Blazar 3C~279 from 1996 to 2007
• Similarity of the Optical-IR and Gamma-Ray Time Variability of Fermi Blazars
• The multiwavelength variability of 3C 273
• Radio/gamma-ray time delay in the parsec-scale cores of active galactic nuclei
• Radio variability properties for radio sources
• Fermi-LAT observations of the exceptional gamma-ray outbursts of 3C 273 in September 2009
• Oblique Shocks As The Origin Of Radio To Gamma-ray Variability In AGN
• Relation between Events in the Millimeter-wave Core and Gamma-ray Outbursts in Blazar Jets
• Parsec-Scale Behavior of Blazars during High Gamma-Ray States

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• Optical monitoring of BL Lac object S5 0716+714 and FSRQ 3C273 from 2000 to 2014
• The high energy spectrum of 3C 273
• Diversity of gamma-ray and Radio Variabilities of Bright Blazars and Implications for gamma-ray Emission Location
• Multiwavelength flaring activity of PKS1510-089
• Multiwavelength analysis of brightness variations of 3C~279: Probing the relativistic jet structure and its evolution