"Orphan" $\gamma$-ray Flares and Stationary Sheaths of Blazar Jets

Abstract

Blazars exhibit flares across the entire electromagnetic spectrum. Many $\gamma$-ray flares are highly correlated with flares detected at longer wavelengths; however, a small subset appears to occur in isolation, with little or no correlated variability at longer wavelengths. These "orphan" $\gamma$-ray flares challenge current models of blazar variability, most of which are unable to reproduce this type of behavior. Macdonald et al. have developed the Ring of Fire model to explain the origin of orphan $\gamma$-ray flares from within blazar jets. In this model, electrons contained within a blob of plasma moving relativistically along the spine of the jet inverse-Compton scatter synchrotron photons emanating off of a ring of shocked sheath plasma that enshrouds the jet spine. As the blob propagates through the ring, the scattering of the ring photons by the blob electrons creates an orphan $\gamma$-ray flare. This model was successfully applied to modeling a prominent orphan $\gamma$-ray flare observed in the blazar PKS 1510$-$089. To further support the plausibility of this model, Macdonald et al. presented a stacked radio map of PKS 1510$-$089 containing the polarimetric signature of a sheath of plasma surrounding the spine of the jet. In this paper, we extend our modeling and stacking techniques to a larger sample of blazars: 3C 273, 4C 71$.$01, 3C 279, 1055$+$018, CTA 102, and 3C 345, the majority of which have exhibited orphan $\gamma$-ray flares. We find that the model can successfully reproduce these flares, while our stacked maps reveal the existence of jet sheaths within these blazars.

19 pages, 27 figures, accepted for publication in ApJ. arXiv admin note: text overlap with arXiv:1505.01239

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Cited by in corpus (22)

• Kinematics of Parsec-Scale Jets of Gamma-Ray Bright Blazars at 43 GHz during Ten Years of the VLBA-BU-BLAZAR Program
• Multiwavelength Variability Signatures of Relativistic Shocks in Blazar Jets
• Multiwavelength behaviour of the blazar 3C279: decade-long study from $\gamma$-ray to radio
• A unified model for orphan and multi-wavelength blazar flares
• CTA 102 in exceptionally high state during 2016-17
• RadioAstron Space VLBI Imaging of the jet in M87: I. Detection of high brightness temperature at 22 GHz
• A fully-kinetic model for orphan gamma-ray flares in blazars
• Ejection of Double knots from the radio core of PKS 1510--089 during the strong gamma-ray flares in 2015
• Electron Acceleration In Blazars: Application to the 3C 279 Flare on 2013 December 20
• Repeated pattern of gamma-ray flares in the lightcurve of the blazar 3C 279
• A Method for Locating High Energy Dissipation Region in Blazar
• A wiggling filamentary jet at the origin of the blazar multi-wavelength behaviour
• Probing the innermost regions of AGN jets and their magnetic fields with RadioAstron IV. The quasar 3C 345 at 18 cm: Magnetic field structure and brightness temperature
• Repeated patterns of gamma-ray flares suggest structured jets of blazars as likely neutrino sources
• On the Origin of Gamma-ray Flares from Bright Fermi Blazars
• Up around the bend: a multi-wavelength view of the quasar 3C 345
• Locating the GeV Emission Region in the Jets of Blazars from Months-Timescale Multi-Wavelength Outbursts
• Understanding the Broadband Emission Process of 3C 279 through Longterm Spectral Analysis
• H.E.S.S. detection and multi-wavelength study of the $z\sim$ 1 blazar PKS 0346$-$27
• Probing circular polarization and magnetic field structure in AGN
• Where within the 3C 84 jet are $\gamma$-rays produced?
• Pinpointing the location of the gamma-ray emitting region in the FSRQ 4C+01.28