Off-axis emission from relativistic plasma flows

Abstract

We show that there is no universal law describing how the spectra and luminosity of synchrotron and inverse Compton radiation from relativistic jets change with increasing observation angle. Instead, the physics of particle acceleration leaves pronounced imprints in the observed spectra and allows for a freedom in numerous modifications of them. The impact of these effects is the largest for high-energy radiation and depends on the details of particle acceleration mechanism(s), what can be used to discriminate between different models. Generally, the beam patterns of relativistic jets in GeV-TeV spectral domain are much wider than the inverse Lorentz factor. The off-axis emission in this energy range appear to be brighter, have much harder spectra and a much higher cut-off frequency compared to the values derived from Doppler boosting considerations alone. The implications include the possibility to explain high-latitude unidentified EGRET sources as off-axis but otherwise typical relativistic-jet sources, such as blazars, and the prediction of GeV-TeV afterglow from transient jet sources, such as Gamma-Ray Bursts. We also discuss the phenomenon of beam-pattern broadening in application to neutrino emission.

Submitted to the Astrophysical Journal

References in corpus (11)

• Unified Schemes for Radio-Loud Active Galactic Nuclei
• The Physics of Gamma-Ray Bursts
• Sources of Relativistic Jets in the Galaxy
• Gamma-Ray Bursts: Progress, Problems & Prospects
• Particle acceleration by ultra-relativistic shocks: theory and simulations
• Theory of "Jitter" Radiation from Small-Scale Random Magnetic Fields and Prompt Emission from Gamma-Ray Burst Shocks
• Particle Acceleration through Multiple Conversions from Charged into Neutral State and Back
• A Study of Prompt Emission Mechanisms in Gamma-Ray Bursts
• Relativistic Winds from Compact Gamma-ray Sources: I. Radiative Acceleration in the Klein-Nishina Regime
• A Plasma Instability Theory of Gamma-Ray Burst Emission
• Electromagnetic Catastrophe in Ultrarelativistic Shocks and the Prompt Emission of Gamma-Ray Bursts

Cited by in corpus (5)

• The physical conditions of the afterglow implied by MAGIC's sub-TeV observations of GRB 190114C
• Radiation from relativistic jets in blazars and the efficient dissipation of their bulk energy via photon breeding
• Detection of Small Flares from the Crab Nebula with Fermi-LAT
• The beaming pattern of External Compton Emission from relativistic outflows
• Photon breeding mechanism in relativistic jets: astrophysical implications