A near magnetic-to-kinetic energy equipartition flare from the relativistic jet in AO 0235 + 164 during 2013–2019

Whee Yeon Cheong; Sang Sung Lee; Sang Hyun Kim; Sincheol Kang; Jae Young Kim; Bindu Rani; Anthony C.S. Readhead; Sebastian Kiehlmann; Anne Lähteenmäki; Merja Tornikoski; Joni Tammi; Venkatessh Ramakrishnan; Iván Agudo; Antonio Fuentes; Efthalia Traianou; Juan Escudero; Clemens Thum; Ioannis Myserlis; Carolina Casadio; Mark Gurwell

doi:10.1093/mnras/stad3250

A near magnetic-to-kinetic energy equipartition flare from the relativistic jet in AO 0235 + 164 during 2013–2019

Whee Yeon Cheong
, Sang Sung Lee
, Sang Hyun Kim
, Sincheol Kang
, Jae Young Kim
, Bindu Rani
, Anthony C.S. Readhead
, Sebastian Kiehlmann
, Anne Lähteenmäki
, Merja Tornikoski
, Joni Tammi
, Venkatessh Ramakrishnan
, Iván Agudo
, Antonio Fuentes
, Efthalia Traianou
, Juan Escudero
, Clemens Thum
, Ioannis Myserlis
, Carolina Casadio
, Mark Gurwell

School of Earth System Sciences

University of Science and Technology UST
Korea Astronomy and Space Science Institute
NASA Goddard Space Flight Center
American University Washington DC
California Institute of Technology
Foundation for Research and Technology-Hellas
University of Crete
Aalto University
University of Turku
CSIC - Institute of Astrophysics of Andalusia
Max Planck Institute for Radio Astronomy
Institut de Radioastronomie Millimétrique
Harvard-Smithsonian Center for Astrophysics

Research output: Contribution to journal › Article › peer-review

6 Scopus citations

Abstract

We present the multiwavelength flaring activity of the blazar AO 0235 + 164 during its recent active period from 2013 to 2019. From a discrete correlation function analysis, we find a significant (> 95 per cent) correlation between radio and gamma-ray light curves with flares at longer wavelengths following flares at shorter wavelengths. We identify a new jet component in 43 GHz Very Long Baseline Array data that was ejected from the radio core on MJD 57246⁺₋₃₀²⁶ (2015 August 12), during the peak of the 2015 radio flare. From the analysis of the jet component, we derived a Doppler factor of δ_var = 28.5 ± 8.4, a bulk Lorentz factor of Γ = 16.8⁺₋₃³^.₁⁶, and an intrinsic viewing angle of θ_v = 1.42⁺₋₀¹^.₅₂⁰⁷ degrees. Investigation of the quasi-simultaneous radio data revealed a partially absorbed spectrum with the turnover frequency varying in the range of 10−70 GHz and the peak flux density varying in the range of 0.7−4 Jy. We find the synchrotron self-absorption magnetic field strength to be B_SSA = 15.3⁺₋₁₄¹²^.₀⁶ mG at the peak of the 2015 radio flare, which is comparable to the equipartition magnetic field strength of B_EQ = 43.6⁺₋₁₀¹⁰^.₄⁶ mG calculated for the same epoch. Additional analysis of the radio emission region in the relativistic jet of AO 0235 + 164 suggests that it did not significantly deviate from equipartition during its recent flaring activity.

Original language	English
Pages (from-to)	882-894
Number of pages	13
Journal	Monthly Notices of the Royal Astronomical Society
Volume	527
Issue number	1
DOIs	https://doi.org/10.1093/mnras/stad3250
State	Published - 1 Jan 2024

Keywords

BL Lacertae objects: individual: AO 0235 + 164
galaxies: active
galaxies: jets
gamma-rays: galaxies
radio continuum: galaxies

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10.1093/mnras/stad3250

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Cheong, W. Y., Lee, S. S., Kim, S. H., Kang, S., Kim, J. Y., Rani, B., Readhead, A. C. S., Kiehlmann, S., Lähteenmäki, A., Tornikoski, M., Tammi, J., Ramakrishnan, V., Agudo, I., Fuentes, A., Traianou, E., Escudero, J., Thum, C., Myserlis, I., Casadio, C., & Gurwell, M. (2024). A near magnetic-to-kinetic energy equipartition flare from the relativistic jet in AO 0235 + 164 during 2013–2019. Monthly Notices of the Royal Astronomical Society, 527(1), 882-894. https://doi.org/10.1093/mnras/stad3250

@article{6eb368d669214d6da9bbe7e10cd256f0,

title = "A near magnetic-to-kinetic energy equipartition flare from the relativistic jet in AO 0235 + 164 during 2013{\textendash}2019",

abstract = "We present the multiwavelength flaring activity of the blazar AO 0235 + 164 during its recent active period from 2013 to 2019. From a discrete correlation function analysis, we find a significant (> 95 per cent) correlation between radio and gamma-ray light curves with flares at longer wavelengths following flares at shorter wavelengths. We identify a new jet component in 43 GHz Very Long Baseline Array data that was ejected from the radio core on MJD 57246+−3026 (2015 August 12), during the peak of the 2015 radio flare. From the analysis of the jet component, we derived a Doppler factor of δvar = 28.5 ± 8.4, a bulk Lorentz factor of Γ = 16.8+−33.16, and an intrinsic viewing angle of θv = 1.42+−01.5207 degrees. Investigation of the quasi-simultaneous radio data revealed a partially absorbed spectrum with the turnover frequency varying in the range of 10−70 GHz and the peak flux density varying in the range of 0.7−4 Jy. We find the synchrotron self-absorption magnetic field strength to be BSSA = 15.3+−1412.06 mG at the peak of the 2015 radio flare, which is comparable to the equipartition magnetic field strength of BEQ = 43.6+−1010.46 mG calculated for the same epoch. Additional analysis of the radio emission region in the relativistic jet of AO 0235 + 164 suggests that it did not significantly deviate from equipartition during its recent flaring activity.",

keywords = "BL Lacertae objects: individual: AO 0235 + 164, galaxies: active, galaxies: jets, gamma-rays: galaxies, radio continuum: galaxies",

author = "Cheong, \{Whee Yeon\} and Lee, \{Sang Sung\} and Kim, \{Sang Hyun\} and Sincheol Kang and Kim, \{Jae Young\} and Bindu Rani and Readhead, \{Anthony C.S.\} and Sebastian Kiehlmann and Anne L{\"a}hteenm{\"a}ki and Merja Tornikoski and Joni Tammi and Venkatessh Ramakrishnan and Iv{\'a}n Agudo and Antonio Fuentes and Efthalia Traianou and Juan Escudero and Clemens Thum and Ioannis Myserlis and Carolina Casadio and Mark Gurwell",

note = "Publisher Copyright: {\textcopyright} 2023 The Author(s).",

year = "2024",

month = jan,

day = "1",

doi = "10.1093/mnras/stad3250",

language = "English",

volume = "527",

pages = "882--894",

journal = "Monthly Notices of the Royal Astronomical Society",

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Cheong, WY, Lee, SS, Kim, SH, Kang, S, Kim, JY, Rani, B, Readhead, ACS, Kiehlmann, S, Lähteenmäki, A, Tornikoski, M, Tammi, J, Ramakrishnan, V, Agudo, I, Fuentes, A, Traianou, E, Escudero, J, Thum, C, Myserlis, I, Casadio, C & Gurwell, M 2024, 'A near magnetic-to-kinetic energy equipartition flare from the relativistic jet in AO 0235 + 164 during 2013–2019', Monthly Notices of the Royal Astronomical Society, vol. 527, no. 1, pp. 882-894. https://doi.org/10.1093/mnras/stad3250

TY - JOUR

T1 - A near magnetic-to-kinetic energy equipartition flare from the relativistic jet in AO 0235 + 164 during 2013–2019

AU - Cheong, Whee Yeon

AU - Lee, Sang Sung

AU - Kim, Sang Hyun

AU - Kang, Sincheol

AU - Kim, Jae Young

AU - Rani, Bindu

AU - Readhead, Anthony C.S.

AU - Kiehlmann, Sebastian

AU - Lähteenmäki, Anne

AU - Tornikoski, Merja

AU - Tammi, Joni

AU - Ramakrishnan, Venkatessh

AU - Agudo, Iván

AU - Fuentes, Antonio

AU - Traianou, Efthalia

AU - Escudero, Juan

AU - Thum, Clemens

AU - Myserlis, Ioannis

AU - Casadio, Carolina

AU - Gurwell, Mark

PY - 2024/1/1

Y1 - 2024/1/1

N2 - We present the multiwavelength flaring activity of the blazar AO 0235 + 164 during its recent active period from 2013 to 2019. From a discrete correlation function analysis, we find a significant (> 95 per cent) correlation between radio and gamma-ray light curves with flares at longer wavelengths following flares at shorter wavelengths. We identify a new jet component in 43 GHz Very Long Baseline Array data that was ejected from the radio core on MJD 57246+−3026 (2015 August 12), during the peak of the 2015 radio flare. From the analysis of the jet component, we derived a Doppler factor of δvar = 28.5 ± 8.4, a bulk Lorentz factor of Γ = 16.8+−33.16, and an intrinsic viewing angle of θv = 1.42+−01.5207 degrees. Investigation of the quasi-simultaneous radio data revealed a partially absorbed spectrum with the turnover frequency varying in the range of 10−70 GHz and the peak flux density varying in the range of 0.7−4 Jy. We find the synchrotron self-absorption magnetic field strength to be BSSA = 15.3+−1412.06 mG at the peak of the 2015 radio flare, which is comparable to the equipartition magnetic field strength of BEQ = 43.6+−1010.46 mG calculated for the same epoch. Additional analysis of the radio emission region in the relativistic jet of AO 0235 + 164 suggests that it did not significantly deviate from equipartition during its recent flaring activity.

AB - We present the multiwavelength flaring activity of the blazar AO 0235 + 164 during its recent active period from 2013 to 2019. From a discrete correlation function analysis, we find a significant (> 95 per cent) correlation between radio and gamma-ray light curves with flares at longer wavelengths following flares at shorter wavelengths. We identify a new jet component in 43 GHz Very Long Baseline Array data that was ejected from the radio core on MJD 57246+−3026 (2015 August 12), during the peak of the 2015 radio flare. From the analysis of the jet component, we derived a Doppler factor of δvar = 28.5 ± 8.4, a bulk Lorentz factor of Γ = 16.8+−33.16, and an intrinsic viewing angle of θv = 1.42+−01.5207 degrees. Investigation of the quasi-simultaneous radio data revealed a partially absorbed spectrum with the turnover frequency varying in the range of 10−70 GHz and the peak flux density varying in the range of 0.7−4 Jy. We find the synchrotron self-absorption magnetic field strength to be BSSA = 15.3+−1412.06 mG at the peak of the 2015 radio flare, which is comparable to the equipartition magnetic field strength of BEQ = 43.6+−1010.46 mG calculated for the same epoch. Additional analysis of the radio emission region in the relativistic jet of AO 0235 + 164 suggests that it did not significantly deviate from equipartition during its recent flaring activity.

KW - BL Lacertae objects: individual: AO 0235 + 164

KW - galaxies: active

KW - galaxies: jets

KW - gamma-rays: galaxies

KW - radio continuum: galaxies

UR - https://www.scopus.com/pages/publications/85177495775

U2 - 10.1093/mnras/stad3250

DO - 10.1093/mnras/stad3250

M3 - Article

AN - SCOPUS:85177495775

SN - 0035-8711

VL - 527

SP - 882

EP - 894

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 1

ER -

A near magnetic-to-kinetic energy equipartition flare from the relativistic jet in AO 0235 + 164 during 2013–2019

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Keywords

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