Radio and γ-Ray Activity in the Jet of the Blazar S5 0716+714
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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Date
2022-01-01
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Degree programme
Language
en
Pages
21
1-21
1-21
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Astrophysical Journal, Volume 925, issue 1
Abstract
We explore the connection between the γ-ray and radio emission in the jet of the blazar 0716+714 by using 15, 37, and 230 GHz radio and 0.1-200 GeV γ-ray light curves spanning 10.5 yr (2008-2019). We find significant positive and negative correlations between radio and γ-ray fluxes in different time ranges. The time delays between radio and γ-ray emission suggest that the observed γ-ray flares originated from multiple regions upstream of the radio core, within a few parsecs from the central engine. Using time-resolved 43 GHz Very Long Baseline Array maps we identified 14 jet components moving downstream along the jet. Their apparent speeds range from 6c to 26c, and they show notable variations in their position angles upstream from the stationary component (∼0.53 mas from the core). The brightness temperature declines as a function of distance from the core according to a power law that becomes shallower at the location of the stationary component. We also find that the periods at which significant correlations between radio and γ-ray emission occur overlap with the times when the jet was oriented to the north. Our results indicate that the passage of a propagating disturbance (or shock) through the radio core and the orientation of the jet might be responsible for the observed correlation between the radio and γ-ray variability. We present a scenario that connects the positive correlation and the unusual anticorrelation by combining the production of a flare and a dip at γ-rays by a strong moving shock at different distances from the jet apex.Description
Funding Information: D.-W.K. acknowledges the support from the National Research Foundation of Korea (NRF) through the next generation fellowship 2019R1A6A3A13095962. S.T. and D.-W.K acknowledge the support from the NRF grant 2019R1F1A1059721. The work of E.V.K. is supported in the framework of the state project “Science” by the Ministry of Science and Higher Education of the Russian Federation under the contract 075-15-2020-778. The work of M.B. is supported by the South African Research Chairs Initiative (SARChI) of the Department of Science and Innovation and the National Research Foundation 21 Funding Information: We have analyzed the long-term centimeter and millimeter radio and γ-ray light curves of the blazar 0716+714 to explore the connection between high- and low-energy radiation and to pinpoint the production site of the high-energy emission. By using VLBA observations, we were able to probe the parsec-scale jet activity in detail. Our primary conclusions are the following. of South Africa through SARChI grant UID 64789. J.L.G. acknowledges the support of the Spanish Ministerio de Economía y Competitividad (grants AYA2016-80889-P, PID2019-108995GB-C21), the Consejería de Economía, Conocimiento, Empresas y Universidad of the Junta de Andalucía (grant P18-FR-1769), the Consejo Superior de Investigaciones Científicas (grant 2019AEP112), and the State Agency for Research of the Spanish MCIU through the Center of Excellence Severo Ochoa award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709). V.R. acknowledges the support from the FONDECYT postdoctoral grant 3190878. The Submillimeter Array is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academia Sinica. This publication makes use of facilities and data obtained at the Metsähovi Radio Observatory, operated by Aalto University, Finland. This research has made use of data from the OVRO 40 m monitoring program (Richards et al. ), supported by private funding from the California Institute of Technology and the Max Planck Institute for Radio Astronomy, and by NASA grants NNX08AW31G, NNX11A043G, and NNX14AQ89G and NSF grants AST-0808050 and AST-1109911. This study makes use of 43 GHz VLBA data from the VLBA-BU Blazar Monitoring Program (VLBA-BU-BLAZAR; http://www.bu.edu/blazars/VLBAproject.html ), funded by NASA through the Fermi Guest Investigator Program. The VLBA is an instrument of the National Radio Astronomy Observatory. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated by Associated Universities, Inc. This work makes use of public Fermi data obtained from Fermi Science Support Center (FSSC). Publisher Copyright: © 2022. The Author(s). Published by the American Astronomical Society.
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Kim, D W, Kravchenko, E V, Kutkin, A M, Böttcher, M, Gómez, J L, Gurwell, M, Jorstad, S G, Lähteenmäki, A, Marscher, A P, Ramakrishnan, V, Tornikoski, M, Trippe, S, Weaver, Z & Williamson, K E 2022, ' Radio and γ-Ray Activity in the Jet of the Blazar S5 0716+714 ', The Astrophysical Journal, vol. 925, no. 1, 64, pp. 1-21 . https://doi.org/10.3847/1538-4357/ac31b4