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Title: GRB and blazar jets shining through their stripes

Abstract

Black hole-driven relativistic astrophysical jets, such as blazars and gamma-ray bursts (GRBs), are powerful sources of electromagnetic radiation. Their emission is powered by some energy dissipation and particle acceleration mechanism operating in situ at large distances from the black hole. We propose that the formation of the dissipative structures in the jet is controlled by the time variability of the accretion disc. We argue that the open magnetic field lines through the black hole, which drive a strongly magnetized jet, may have their polarity reversing over time-scales related to the growth of the magnetorotational dynamo in the disc. Consequently, the jet is characterized by an alternating toroidal field polarity along its propagation axis, i.e. it is a ‘striped jet’. Magnetic reconnection in the current sheets that form between the stripes dissipates the alternating field energy and thus powers further jet acceleration. Here, we consider a jet with a broad distribution of stripe widths l > l min, above a dominant scale l min. We find that the bulk acceleration of the jet, driven by the annihilation of the stripes, is very gradual. The dissipation rate peaks at a distance $$z_{\rm peak}\sim 10^6 R_\mathrm{ g}\, (\Gamma _\infty /30)^2\, (l_{\rm min}/1000R_\mathrm{ g})$$|,more » where R g is the black hole’s gravitational radius and Γ the jet’s asymptotic Lorentz factor, and exhibits a very broad plateau extending by ~4–5 orders of magnitude in distance. The prolonged energy dissipation accounts for the flat-to-inverted long-wavelength spectra commonly observed in jets. The model can also account for the broad range of flaring time-scales of blazars and the fact that their bulk acceleration appears to continue out to ~100 pc scales. In GRB jets, the model predicts comparable power for the photopsheric and Thomson-thin emission components.« less

Authors:
 [1];  [2]
  1. Purdue Univ., West Lafayette, IN (United States)
  2. Univ. of Colorado, Boulder, CO (United States). Center for Integrated Plasma Studies
Publication Date:
Research Org.:
Univ. of Colorado, Boulder, CO (United States)
Sponsoring Org.:
USDOE Office of Science (SC); National Science Foundation (NSF); National Aeronautics and Space Administration (NASA)
OSTI Identifier:
1611045
Grant/Contract Number:  
SC0008409; NNX16AB32G; NNX17AG21G; NNX16AB28G; NNX17AK57G; AST-1411879
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Monthly Notices of the Royal Astronomical Society
Additional Journal Information:
Journal Volume: 484; Journal Issue: 1; Journal ID: ISSN 0035-8711
Publisher:
Royal Astronomical Society
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; Astronomy & Astrophysics; relativistic processes; BL Lacertae objects: general; galaxies: jets; gamma-ray burst: general

Citation Formats

Giannios, D., and Uzdensky, D. A. GRB and blazar jets shining through their stripes. United States: N. p., 2019. Web. doi:10.1093/mnras/stz082.
Giannios, D., & Uzdensky, D. A. GRB and blazar jets shining through their stripes. United States. https://doi.org/10.1093/mnras/stz082
Giannios, D., and Uzdensky, D. A. Thu . "GRB and blazar jets shining through their stripes". United States. https://doi.org/10.1093/mnras/stz082. https://www.osti.gov/servlets/purl/1611045.
@article{osti_1611045,
title = {GRB and blazar jets shining through their stripes},
author = {Giannios, D. and Uzdensky, D. A.},
abstractNote = {Black hole-driven relativistic astrophysical jets, such as blazars and gamma-ray bursts (GRBs), are powerful sources of electromagnetic radiation. Their emission is powered by some energy dissipation and particle acceleration mechanism operating in situ at large distances from the black hole. We propose that the formation of the dissipative structures in the jet is controlled by the time variability of the accretion disc. We argue that the open magnetic field lines through the black hole, which drive a strongly magnetized jet, may have their polarity reversing over time-scales related to the growth of the magnetorotational dynamo in the disc. Consequently, the jet is characterized by an alternating toroidal field polarity along its propagation axis, i.e. it is a ‘striped jet’. Magnetic reconnection in the current sheets that form between the stripes dissipates the alternating field energy and thus powers further jet acceleration. Here, we consider a jet with a broad distribution of stripe widths l > lmin, above a dominant scale lmin. We find that the bulk acceleration of the jet, driven by the annihilation of the stripes, is very gradual. The dissipation rate peaks at a distance $z_{\rm peak}\sim 10^6 R_\mathrm{ g}\, (\Gamma _\infty /30)^2\, (l_{\rm min}/1000R_\mathrm{ g})$|, where Rg is the black hole’s gravitational radius and Γ∞ the jet’s asymptotic Lorentz factor, and exhibits a very broad plateau extending by ~4–5 orders of magnitude in distance. The prolonged energy dissipation accounts for the flat-to-inverted long-wavelength spectra commonly observed in jets. The model can also account for the broad range of flaring time-scales of blazars and the fact that their bulk acceleration appears to continue out to ~100 pc scales. In GRB jets, the model predicts comparable power for the photopsheric and Thomson-thin emission components.},
doi = {10.1093/mnras/stz082},
url = {https://www.osti.gov/biblio/1611045}, journal = {Monthly Notices of the Royal Astronomical Society},
issn = {0035-8711},
number = 1,
volume = 484,
place = {United States},
year = {2019},
month = {1}
}

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Works referencing / citing this record:

Unraveling the Complex Behavior of Mrk 421 with Simultaneous X-Ray and VHE Observations during an Extreme Flaring Activity in 2013 April
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Non-dissipative photospheres in GRBs: spectral appearance in the Fermi/GBM catalogue
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Inductive Acceleration of Ions in Poynting-flux-dominated Outflows
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