A survey of X-ray emission from 100 kpc radio jets

Schwartz, D. A.; Marshall, Herman L.; Worrall, D. M.; Birkinshaw, Mark; Perlman, Eric S.; Lovell, J. E. J.; Jauncey, D. L.; Murphy, D. W.; Gelbord, Jonathan; Godfrey, L.; Bicknell, G. V.

doi:10.1017/s1743921315002215

Cited by 2 publications

(1 citation statement)

References 17 publications

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“…EGRET has observed the source during its different pointed observations. Before the launch of Fermi, several studies were carried out to understand the γ-ray, X-ray, and UV/optical emission and spectral nature of PKS 0208-512 using the EGRET and other broad-band observations [43][44][45][46][47][48][49][50][51][52][53][54][55]. Using the EGRET and initial two years of Fermi-LAT observations, Bhattacharya et al [29] reported that PKS 0208-512 showed more than a factor of ten decrease in the average γ-ray flux from EGRET to Fermi era.…”

Section: Introductionmentioning

confidence: 99%

Long-Term Monitoring of Blazar PKS 0208-512: A Change of γ-Ray Baseline Activity from EGRET to Fermi Era

Bhattacharya

Bhattacharyya

et al. 2022

Universe

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The blazar PKS 0208-512 was in the lowest γ-ray brightness state during the initial 10 years of observations with the Fermi Gamma-ray Space Telescope (Fermi), which was an order of magnitude lower than its flux state during the EGRET era (1991–2000). The weekly averaged maximum γ-ray flux of this source during the first 10 years of Fermi observation is nearly a factor of 3 lower than the highest flux observed by EGRET in a single epoch. During the period 2018–2020, the source showed a large γ-ray flare, with the average brightness similar to the period 1991–2000. We observed the source with AstroSat, during its low and high activity states, respectively. We carried out broad-band spectral energy distribution (SED) modeling of the source using a one-zone leptonic emission model during its various brightness states. From the SED modeling, we found that there was an inefficient conversion from the bulk energy to the particle energy during the long-term low-activity states as compared to the high flux state during the EGRET era and the later part of Fermi observation.

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Section: Introductionmentioning

confidence: 99%

Long-Term Monitoring of Blazar PKS 0208-512: A Change of γ-Ray Baseline Activity from EGRET to Fermi Era

Bhattacharya

Bhattacharyya

et al. 2022

Universe

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Particle acceleration in shearing flows: the case for large-scale jets

Wang

Reville

Liu

et al. 2021

Monthly Notices of the Royal Astronomical Society

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X-ray observations of kilo-parsec scale jets indicate that a synchrotron origin of the sustained non-thermal emission is likely. This requires distributed acceleration of electrons up to near PeV energies along the jet. The underlying acceleration mechanism is still unclear. Shear acceleration is a promising candidate, as velocity-shear stratification is a natural consequence of the collimated flow of a jet. We study the details of shear acceleration by solving the steady-state Fokker-Planck-type equation and provide a simple general solution for trans-relativistic jets for a range of magnetohydrodynamic turbulent power-law spectra. In general, the accelerated particle population is a power-law spectrum with an exponential-like cut-off, where the power-law index is determined by the turbulence spectrum and the balance of escape and acceleration of particles. Adopting a simple linearly decreasing velocity profile in the boundary of large-scale jets, we find that the multi-wavelength spectral energy distribution of X-ray jets, such as Centaurus A and 3C 273, can be reproduced with electrons that are accelerated up to ∼ PeV. In kpc-scale jets, protons may be accelerated up to ∼ EeV, supporting the hypothesis that large-scale jets are strong candidates for ultra-high-energy-cosmic-ray sources within the framework of shear acceleration.

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A survey of X-ray emission from 100 kpc radio jets

Cited by 2 publications

References 17 publications

Long-Term Monitoring of Blazar PKS 0208-512: A Change of γ-Ray Baseline Activity from EGRET to Fermi Era

Long-Term Monitoring of Blazar PKS 0208-512: A Change of γ-Ray Baseline Activity from EGRET to Fermi Era

Particle acceleration in shearing flows: the case for large-scale jets

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