Kinematics of and emission from helically orbiting blobs in a relativistic magnetized jet

Abstract

We present a general relativistic (GR) model of jet variability in active galactic nuclei due to orbiting blobs in helical motion along a funnel or cone shaped magnetic surface anchored to the accretion disk near the black hole. Considering a radiation pressure driven flow in the inner region, we find that it stabilizes the flow, yielding Lorentz factors ranging between 1.1 and 7 at small radii for reasonable initial conditions. Assuming these as inputs, simulated light curves (LCs) for the funnel model include Doppler and gravitational shifts, aberration, light bending, and time delay. These LCs are studied for quasi-periodic oscillations (QPOs) and the power spectral density (PSD) shape and yield an increased amplitude ($\sim$ 12 %); a beamed portion and a systematic phase shift with respect to that from a previous special relativistic model. The results strongly justify implementing a realistic magnetic surface geometry in Schwarzschild geometry to describe effects on emission from orbital features in the jet close to the horizon radius. A power law shaped PSD with a typical slope of $-2$ and QPOs with timescales in the range of $(1.37-130.7)$ days consistent with optical variability in Blazars, emerges from the simulations for black hole masses $M_{\bullet }=(0.5-5)\times 10^8{M}_{\odot }$ and initial Lorentz factors ${\gamma }_{jet,i}=2-10$. The models presented here can be applied to explain radio, optical, and X-ray variability from a range of jetted sources including active galactic nuclei, X-ray binaries and neutron stars.

41 pages, 13 Figures (19 sub-figures), 2 Tables, 1 Appendix; minor corrections made; Accepted for publication in the Astrophysical Journal

References in corpus (10)

• Jet Launching Structure Resolved Near the Supermassive Black Hole in M87
• Pulse profiles of millisecond pulsars and their Fourier amplitudes
• Optical Intra-day Variability in Blazars
• The Outburst of the Blazar AO 0235+164 in 2006 December: Shock-in-Jet Interpretation
• Violent Intranight Optical Variability of a Radio-Loud Narrow-Line Seyfert 1 Galaxy: SDSS J094857.3+002225
• X-Ray Variability and the Inner Region in Active Galactic Nuclei
• The relativistic shift of narrow spectral features from black-hole accretion discs
• Light Echoes in Kerr Geometry: A Source of High Frequency QPOs from Random X-ray Bursts
• QPOs from Random X-ray Bursts around Rotating Black Holes
• Orbital signatures from observed light curves of blazars

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• Quasi-periodic behaviour in the optical and γ-ray light curves of blazars 3C 66A and B2 1633+38
• Evolving parsec-scale radio structure in the most distant blazar known
• Multi-wavelength temporal and spectral variability of the blazar OJ 287 during and after the December 2015 flare: a major accretion disc contribution
• A peculiar multi-wavelength flare in the Blazar 3C 454.3
• Parsec-scale jet properties of the quasar PG 1302$-$102
• Signature of Inverse Compton emission from blazars
• Characterization of Variability in Blazar Light curves
• Multiple Wavelength Variability and Quasi-Periodic Oscillation of PMN J0948+0022
• Jet-powered Outflows in Supermassive Black Hole Binary Candidate SDSS J1048+0055
• A relativistic orbit model for temporal properties of AGN