Multiwavelength variability and correlation studies of Mrk 421 during historically low X-ray and γ-ray activity in 2015–2016

the MAGIC; FACT; Fermi LAT Collaboration

Multiwavelength variability and correlation studies of Mrk 421 during historically low X-ray and γ-ray activity in 2015–2016

the MAGIC
, FACT
, Fermi LAT Collaboration

Gran Sasso Science Institute
RWTH Aachen University
University of Rijeka
Max-Planck-Institut für Physik
Saha Institute of Nuclear Physics
Research Unit; CIBERNED and Universidad de La Laguna
and Physics University of Udine
ICRANet
Istituto di Astrofisica e Planetologia Spaziali (IAPS)
The Barcelona Institute of Science and Technology
University of Tokyo
University of Zagreb, Faculty of Electrical Engineering and Computing
IPARCOS-UCM (Instituto de Física de Partículas y del Cosmos)
Centro Brasileiro de Pesquisas Fisicas
University of Padova
University of Lodz
University of Siena
c/o DESY
Gran Saso Science Institute
Instituto de Astrofísica de Andalucía-CSIC
University of Pisa
University of Barcelona
Yerevan Physics Institute
Centro de Investigaciones Energéticas Medioambientales y Tecnológicas (CIEMAT)
Port d’Informació Científica (PIC)
University of Turin
Politecnico di Bari
University of Turku
University of São Paulo
Hiroshima University
National Academy of Sciences of Armenia
Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, University of Split
Josip Juraj Strossmayer University of Osijek
Kyoto University
Tokai University
University of Trieste
INAF Istituto di Radioastronomia
Institute for Nuclear Research and Nuclear Energy Bulgarian Academy of Sciences
Yamagata University
University of Oulu
Aalto University
University of Bologna
NASA Goddard Space Flight Center
Biochemical and Environmental Engineering
Ruđer Bošković Institute
ESAC campus
INFN Sezione di Perugia
INFN Roma Tor Vergata
Konan University
ETH Zurich
MAGIC
University of Dortmund
University of Geneva
University of Würzburg
Ip Paris
INAF Istituto di Radioastronomia
Space Science Data Center (SSDC)-ASI
Osservatorio Astronomico di Roma
Science and Research Directorate
University of Colorado at Denver
Brigham Young University
Boston University
Saint Petersburg State University
Universidad de Concepción

Research output: Contribution to journal › Conference article › peer-review

Abstract

In this work, we report multi-band flux variability and correlations of the nearby (z=0.031) blazar Markarian 421 (Mrk 421) using multi-wavelength (MWL) data from November 2014 to June 2016. In this period, Mrk 421 exhibited historically low activity in X-rays and very-high-energy gamma rays (VHE; E>0.1 TeV) and an additional spectral component was observed by Swift-BAT. The highest flux variability occurs in X-rays and VHE which, despite the low activity, show a significant positive correlation with no time lag. The hardness ratios in the X-rays and VHE γ-rays show the "harder-when-brighter" trend observed in many blazars. Interestingly, the trend flattens at the highest fluxes, which suggests different processes dominating the brightest states. Enlarging our data set with data from the years 2007 to 2014, we measured a positive correlation between the optical and GeV emission centered at zero time lag, and a positive correlation between the optical/GeV and the radio emission over a range of about 60 days centered at a time lag of 43+9/-6 days. This observation is consistent with the radio-bright zone being located about 0.2 parsec downstream from the optical/GeV emission regions. In most of the energy bands, the flux distribution follows the Lognormal, rather than the Normal function, indicating that the variability may be dominated by a multiplicative process.

Original language	English
Article number	866
Journal	Proceedings of Science
Volume	395
Publication status	Published - 18 Mar 2022
Event	37th International Cosmic Ray Conference, ICRC 2021 - Virtual, Berlin, Germany Duration: 12 Jul 2021 → 23 Jul 2021

Cite this

@article{457d90b71e0248dca15945b88c6c11cd,

title = "Multiwavelength variability and correlation studies of Mrk 421 during historically low X-ray and γ-ray activity in 2015{\textendash}2016",

abstract = "In this work, we report multi-band flux variability and correlations of the nearby (z=0.031) blazar Markarian 421 (Mrk 421) using multi-wavelength (MWL) data from November 2014 to June 2016. In this period, Mrk 421 exhibited historically low activity in X-rays and very-high-energy gamma rays (VHE; E>0.1 TeV) and an additional spectral component was observed by Swift-BAT. The highest flux variability occurs in X-rays and VHE which, despite the low activity, show a significant positive correlation with no time lag. The hardness ratios in the X-rays and VHE γ-rays show the {"}harder-when-brighter{"} trend observed in many blazars. Interestingly, the trend flattens at the highest fluxes, which suggests different processes dominating the brightest states. Enlarging our data set with data from the years 2007 to 2014, we measured a positive correlation between the optical and GeV emission centered at zero time lag, and a positive correlation between the optical/GeV and the radio emission over a range of about 60 days centered at a time lag of 43+9/-6 days. This observation is consistent with the radio-bright zone being located about 0.2 parsec downstream from the optical/GeV emission regions. In most of the energy bands, the flux distribution follows the Lognormal, rather than the Normal function, indicating that the variability may be dominated by a multiplicative process.",

author = "\{the MAGIC\} and FACT and \{Fermi LAT Collaboration\} and B. Banerjee and T. Terzi{\'c} and D. Paneque and P. Majumdar and Acciari, \{V. A.\} and S. Ansoldi and Antonelli, \{L. A.\} and M. Artero and K. Asano and A. Babi{\'c} and B. Banrje and A. Baquero and \{Barres de Almeida\}, U. and Barrio, \{J. A.\} and I. Batkovi{\'c} and \{Becerra Gonz{\'a}lez\}, J. and W. Bednarek and L. Bellizzi and E. Bernardini and M. Bernardos and A. Berti and J. Besenrieder and W. Bhattacharyya and C. Bigongiari and O. Blanch and H. B{\"o}kenkamp and G. Bonnoli and Bo{\v s}njak and G. Busetto and R. Carosi and G. Ceribella and M. Cerruti and Y. Chai and A. Chilingarian and S. Cikota and Colak, \{S. M.\} and E. Colombo and Contreras, \{J. L.\} and J. Cortina and S. Covino and G. D{\textquoteright}Amico and V. D{\textquoteright}Elia and \{Da Vela\}, P. and F. Dazzi and \{De Angelis\}, A. and \{De Lotto\}, B. and M. Delfino and J. Delgado and \{Delgado Mendez\}, C. and D. Horan",

note = "Publisher Copyright: {\textcopyright} Copyright owned by the author(s).; 37th International Cosmic Ray Conference, ICRC 2021 ; Conference date: 12-07-2021 Through 23-07-2021",

year = "2022",

month = mar,

day = "18",

language = "English",

volume = "395",

journal = "Proceedings of Science",

issn = "1824-8039",

publisher = "Sissa Medialab Srl",

}

TY - JOUR

T1 - Multiwavelength variability and correlation studies of Mrk 421 during historically low X-ray and γ-ray activity in 2015–2016

AU - the MAGIC

AU - FACT

AU - Fermi LAT Collaboration

AU - Banerjee, B.

AU - Terzić, T.

AU - Paneque, D.

AU - Majumdar, P.

AU - Acciari, V. A.

AU - Ansoldi, S.

AU - Antonelli, L. A.

AU - Artero, M.

AU - Asano, K.

AU - Babić, A.

AU - Banrje, B.

AU - Baquero, A.

AU - Barres de Almeida, U.

AU - Barrio, J. A.

AU - Batković, I.

AU - Becerra González, J.

AU - Bednarek, W.

AU - Bellizzi, L.

AU - Bernardini, E.

AU - Bernardos, M.

AU - Berti, A.

AU - Besenrieder, J.

AU - Bhattacharyya, W.

AU - Bigongiari, C.

AU - Blanch, O.

AU - Bökenkamp, H.

AU - Bonnoli, G.

AU - Bošnjak,

AU - Busetto, G.

AU - Carosi, R.

AU - Ceribella, G.

AU - Cerruti, M.

AU - Chai, Y.

AU - Chilingarian, A.

AU - Cikota, S.

AU - Colak, S. M.

AU - Colombo, E.

AU - Contreras, J. L.

AU - Cortina, J.

AU - Covino, S.

AU - D’Amico, G.

AU - D’Elia, V.

AU - Da Vela, P.

AU - Dazzi, F.

AU - De Angelis, A.

AU - De Lotto, B.

AU - Delfino, M.

AU - Delgado, J.

AU - Delgado Mendez, C.

AU - Horan, D.

PY - 2022/3/18

Y1 - 2022/3/18

N2 - In this work, we report multi-band flux variability and correlations of the nearby (z=0.031) blazar Markarian 421 (Mrk 421) using multi-wavelength (MWL) data from November 2014 to June 2016. In this period, Mrk 421 exhibited historically low activity in X-rays and very-high-energy gamma rays (VHE; E>0.1 TeV) and an additional spectral component was observed by Swift-BAT. The highest flux variability occurs in X-rays and VHE which, despite the low activity, show a significant positive correlation with no time lag. The hardness ratios in the X-rays and VHE γ-rays show the "harder-when-brighter" trend observed in many blazars. Interestingly, the trend flattens at the highest fluxes, which suggests different processes dominating the brightest states. Enlarging our data set with data from the years 2007 to 2014, we measured a positive correlation between the optical and GeV emission centered at zero time lag, and a positive correlation between the optical/GeV and the radio emission over a range of about 60 days centered at a time lag of 43+9/-6 days. This observation is consistent with the radio-bright zone being located about 0.2 parsec downstream from the optical/GeV emission regions. In most of the energy bands, the flux distribution follows the Lognormal, rather than the Normal function, indicating that the variability may be dominated by a multiplicative process.

AB - In this work, we report multi-band flux variability and correlations of the nearby (z=0.031) blazar Markarian 421 (Mrk 421) using multi-wavelength (MWL) data from November 2014 to June 2016. In this period, Mrk 421 exhibited historically low activity in X-rays and very-high-energy gamma rays (VHE; E>0.1 TeV) and an additional spectral component was observed by Swift-BAT. The highest flux variability occurs in X-rays and VHE which, despite the low activity, show a significant positive correlation with no time lag. The hardness ratios in the X-rays and VHE γ-rays show the "harder-when-brighter" trend observed in many blazars. Interestingly, the trend flattens at the highest fluxes, which suggests different processes dominating the brightest states. Enlarging our data set with data from the years 2007 to 2014, we measured a positive correlation between the optical and GeV emission centered at zero time lag, and a positive correlation between the optical/GeV and the radio emission over a range of about 60 days centered at a time lag of 43+9/-6 days. This observation is consistent with the radio-bright zone being located about 0.2 parsec downstream from the optical/GeV emission regions. In most of the energy bands, the flux distribution follows the Lognormal, rather than the Normal function, indicating that the variability may be dominated by a multiplicative process.

M3 - Conference article

AN - SCOPUS:85145777358

SN - 1824-8039

VL - 395

JO - Proceedings of Science

JF - Proceedings of Science

M1 - 866

T2 - 37th International Cosmic Ray Conference, ICRC 2021

Y2 - 12 July 2021 through 23 July 2021

ER -

Multiwavelength variability and correlation studies of Mrk 421 during historically low X-ray and γ-ray activity in 2015–2016

Abstract

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