TY - JOUR

T1 - "Orphan" gamma-Ray Flares and Stationary Sheaths of Blazar Jets

AU - MacDonald, Nicholas R.

AU - Jorstad, Svetlana G.

AU - Marscher, Alan P.

PY - 2017/11/20

Y1 - 2017/11/20

N2 - 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.-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.-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.

AB - 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.-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.-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.

KW - galaxies: active

KW - galaxies: jets

KW - polarization

KW - radiation mechanisms: non-thermal

KW - relativistic processes

KW - techniques: interferometric

KW - HELICAL MAGNETIC-FIELD

KW - INNER JET

KW - POLARIZATION

KW - 3C-273

U2 - 10.3847/1538-4357/aa92c8

DO - 10.3847/1538-4357/aa92c8

M3 - статья

VL - 850

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1

M1 - 87

ER -