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The complex variability of blazars : Time-scales and periodicity analysis in S4 0954+65. / WEBT Collaboration.

In: Monthly Notices of the Royal Astronomical Society, Vol. 504, No. 4, 01.07.2021, p. 5629-5646.

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WEBT Collaboration. / The complex variability of blazars : Time-scales and periodicity analysis in S4 0954+65. In: Monthly Notices of the Royal Astronomical Society. 2021 ; Vol. 504, No. 4. pp. 5629-5646.

BibTeX

@article{6fe415c1aeb247ea97431645487dba1e,

title = "The complex variability of blazars: Time-scales and periodicity analysis in S4 0954+65",

abstract = "Among active galactic nuclei, blazars show extreme variability properties. We here investigate the case of the BL Lac object S4 0954+65 with data acquired in 2019-2020 by the Transiting Exoplanet Survey Satellite (TESS) and by the Whole Earth Blazar Telescope (WEBT) Collaboration. The 2-min cadence optical light curves provided by TESS during three observing sectors of nearly 1 month each allow us to study the fast variability in great detail. We identify several characteristic short-term time-scales, ranging from a few hours to a few days. However, these are not persistent, as they differ in the various TESS sectors. The long-term photometric and polarimetric optical and radio monitoring undertaken by the WEBT brings significant additional information, revealing that (i) in the optical, long-term flux changes are almost achromatic, while the short-term ones are strongly chromatic; (ii) the radio flux variations at 37 GHz follow those in the optical with a delay of about 3 weeks; (iii) the range of variation of the polarization degree and angle is much larger in the optical than in the radio band, but the mean polarization angles are similar; (iv) the optical long-term variability is characterized by a quasi-periodicity of about 1 month. We explain the source behaviour in terms of a rotating inhomogeneous helical jet, whose pitch angle can change in time. ",

keywords = "BL Lacertae objects: general, BL Lacertae objects: individual: S4 0954+65, Galaxies: active, Galaxies: jets",

author = "{WEBT Collaboration} and Raiteri, {C. M.} and M. Villata and Larionov, {V. M.} and Jorstad, {S. G.} and Marscher, {A. P.} and Weaver, {Z. R.} and Acosta-Pulido, {J. A.} and I. Agudo and T. Andreeva and A. Arkharov and R. Bachev and E. Ben{\'i}tez and M. Berton and I. Bj{\"o}rklund and Borman, {G. A.} and V. Bozhilov and Carnerero, {M. I.} and D. Carosati and C. Casadio and Chen, {W. P.} and G. Damljanovic and F. D'Ammando and J. Escudero and A. Fuentes and M. Giroletti and Grishina, {T. S.} and Gupta, {A. C.} and Hagen-Thorn, {V. A.} and M. Hart and D. Hiriart and Hou, {W. J.} and D. Ivanov and Kim, {J. Y.} and Kimeridze, {G. N.} and C. Konstantopoulou and Kopatskaya, {E. N.} and Kurtanidze, {O. M.} and Kurtanidze, {S. O.} and A. L{\"a}hteenm{\"a}ki and Larionova, {E. G.} and Larionova, {L. V.} and N. Marchili and G. Markovic and M. Minev and Morozova, {D. A.} and I. Myserlis and Nikiforova, {A. A.} and Savchenko, {S. S.} and Troitskaya, {Y. V.} and Vasilyev, {A. A.}",

note = "Publisher Copyright: {\textcopyright} 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.",

year = "2021",

month = jul,

day = "1",

doi = "10.1093/mnras/stab1268",

language = "English",

volume = "504",

pages = "5629--5646",

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

issn = "0035-8711",

publisher = "Wiley-Blackwell",

number = "4",

}

RIS

TY - JOUR

T1 - The complex variability of blazars

T2 - Time-scales and periodicity analysis in S4 0954+65

AU - WEBT Collaboration

AU - Raiteri, C. M.

AU - Villata, M.

AU - Larionov, V. M.

AU - Jorstad, S. G.

AU - Marscher, A. P.

AU - Weaver, Z. R.

AU - Acosta-Pulido, J. A.

AU - Agudo, I.

AU - Andreeva, T.

AU - Arkharov, A.

AU - Bachev, R.

AU - Benítez, E.

AU - Berton, M.

AU - Björklund, I.

AU - Borman, G. A.

AU - Bozhilov, V.

AU - Carnerero, M. I.

AU - Carosati, D.

AU - Casadio, C.

AU - Chen, W. P.

AU - Damljanovic, G.

AU - D'Ammando, F.

AU - Escudero, J.

AU - Fuentes, A.

AU - Giroletti, M.

AU - Grishina, T. S.

AU - Gupta, A. C.

AU - Hagen-Thorn, V. A.

AU - Hart, M.

AU - Hiriart, D.

AU - Hou, W. J.

AU - Ivanov, D.

AU - Kim, J. Y.

AU - Kimeridze, G. N.

AU - Konstantopoulou, C.

AU - Kopatskaya, E. N.

AU - Kurtanidze, O. M.

AU - Kurtanidze, S. O.

AU - Lähteenmäki, A.

AU - Larionova, E. G.

AU - Larionova, L. V.

AU - Marchili, N.

AU - Markovic, G.

AU - Minev, M.

AU - Morozova, D. A.

AU - Myserlis, I.

AU - Nikiforova, A. A.

AU - Savchenko, S. S.

AU - Troitskaya, Y. V.

AU - Vasilyev, A. A.

PY - 2021/7/1

Y1 - 2021/7/1

N2 - Among active galactic nuclei, blazars show extreme variability properties. We here investigate the case of the BL Lac object S4 0954+65 with data acquired in 2019-2020 by the Transiting Exoplanet Survey Satellite (TESS) and by the Whole Earth Blazar Telescope (WEBT) Collaboration. The 2-min cadence optical light curves provided by TESS during three observing sectors of nearly 1 month each allow us to study the fast variability in great detail. We identify several characteristic short-term time-scales, ranging from a few hours to a few days. However, these are not persistent, as they differ in the various TESS sectors. The long-term photometric and polarimetric optical and radio monitoring undertaken by the WEBT brings significant additional information, revealing that (i) in the optical, long-term flux changes are almost achromatic, while the short-term ones are strongly chromatic; (ii) the radio flux variations at 37 GHz follow those in the optical with a delay of about 3 weeks; (iii) the range of variation of the polarization degree and angle is much larger in the optical than in the radio band, but the mean polarization angles are similar; (iv) the optical long-term variability is characterized by a quasi-periodicity of about 1 month. We explain the source behaviour in terms of a rotating inhomogeneous helical jet, whose pitch angle can change in time.

AB - Among active galactic nuclei, blazars show extreme variability properties. We here investigate the case of the BL Lac object S4 0954+65 with data acquired in 2019-2020 by the Transiting Exoplanet Survey Satellite (TESS) and by the Whole Earth Blazar Telescope (WEBT) Collaboration. The 2-min cadence optical light curves provided by TESS during three observing sectors of nearly 1 month each allow us to study the fast variability in great detail. We identify several characteristic short-term time-scales, ranging from a few hours to a few days. However, these are not persistent, as they differ in the various TESS sectors. The long-term photometric and polarimetric optical and radio monitoring undertaken by the WEBT brings significant additional information, revealing that (i) in the optical, long-term flux changes are almost achromatic, while the short-term ones are strongly chromatic; (ii) the radio flux variations at 37 GHz follow those in the optical with a delay of about 3 weeks; (iii) the range of variation of the polarization degree and angle is much larger in the optical than in the radio band, but the mean polarization angles are similar; (iv) the optical long-term variability is characterized by a quasi-periodicity of about 1 month. We explain the source behaviour in terms of a rotating inhomogeneous helical jet, whose pitch angle can change in time.

KW - BL Lacertae objects: general

KW - BL Lacertae objects: individual: S4 0954+65

KW - Galaxies: active

KW - Galaxies: jets

UR - http://www.scopus.com/inward/record.url?scp=85108587265&partnerID=8YFLogxK

U2 - 10.1093/mnras/stab1268

DO - 10.1093/mnras/stab1268

M3 - Article

AN - SCOPUS:85108587265

VL - 504

SP - 5629

EP - 5646

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 4

ER -

ID: 84328154

The complex variability of blazars: Time-scales and periodicity analysis in S4 0954+65

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