Periodicity analysis of the radio light curve of the Seyfert galaxy III Zw 2

Li, H.Z.; Xie, Gaogang; Hong, Dunpin; Chen, L.E.; Yi, Ting-Feng; Tang, Yanke; Bao, Y. Y.; Lü, L.Z.; Na, W.W.; Ren, Jiangtao

doi:10.1016/j.newast.2009.08.001

Cited by 14 publications

(14 citation statements)

References 36 publications

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“…This suggests that the source of the reflection completely changed over the course of only 11−years between these observations though the illuminating hard X-ray source has remained relatively constant as evidenced by the comparable flux. Considering only the XMM-Newton and Suzaku data in combination with results from radio light curve analysis we hypothesise the cause of the strange behaviour exhibited by III Zw 2 is due to a precessing radio jet, as first mentioned by Brunthaler et al (2003Brunthaler et al ( , 2005, being described in more detail later by Li et al (2010). Brunthaler et al (2003Brunthaler et al ( , 2005) discuss a periodicity of approximately five years of the radio emission from III Zw 2 and mention a precessing jet as a potential explanation to the observations.…”

Section: Discussionmentioning

confidence: 88%

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The changing source of X-ray reflection in the radio-intermediate Seyfert 1 galaxy III Zw 2

Gonzalez

Waddell

Gallo

2017

Monthly Notices of the Royal Astronomical Society

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We report on X-ray observations of the radio-intermediate, X-ray bright Seyfert 1 galaxy, III Zw 2, obtained with XMM-Newton, Suzaku, and Swift over the past 17years. The source brightness varies significantly over yearly time scales, but more modestly over periods of days. Pointed observations with XMM-Newton in 2000 and Suzaku in 2011 show spectral differences despite comparable X-ray fluxes. The Suzaku spectra are consistent with a power law continuum and a narrow Gaussian emission feature at ∼ 6.4 keV, whereas the earlier XMM-Newton spectrum requires a broader Gaussian profile and soft-excess below ∼ 2 keV. A potential interpretation is that the primary power law emission, perhaps from a jet base, preferentially illuminates the inner accretion disc in 2000, but the distant torus in 2011. The interpretation could be consistent with the hypothesised precessing radio jet in III Zw 2 that may have originated from disc instabilities due to an ongoing merging event.

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Section: Discussionmentioning

confidence: 88%

“…The radio emission from III Zw 2 is extremely variable, by as much as a factor of 20 (Aller et al 1985) exhibiting a quasi-periodic activity cycle with period P = 5.14 ± 0.19 yr (Li et al 2010). Variability is also present in the optical (e.g.…”

Section: Introductionmentioning

confidence: 99%

The changing source of X-ray reflection in the radio-intermediate Seyfert 1 galaxy III Zw 2

Gonzalez

Waddell

Gallo

2017

Monthly Notices of the Royal Astronomical Society

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“…First, the source exhibits highly fluctuating radio flux density at 37 GHz (more than a factor of ten peak-to-through ratio; Chamani et al 2020), which could be due to variable jet power. It undergoes a recurrent activity roughly every five years (Li et al 2010) with a detected variable gamma-ray emission in the short term (Liao et al 2016). Secondly, the radio morphology is point-like most of the time, but occasionally a blob is ejected (Brunthaler et al 2005;Lister et al 2019).…”

Section: Summary and Discussionmentioning

confidence: 99%

Testing the magnetic flux paradigm for AGN radio loudness with a radio-intermediate quasar

Chamani

Savolainen

Hada

et al. 2021

A&A

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For understanding the diversity of jetted active galactic nuclei (AGN) and especially the puzzling wide range in their radio loudness, it is important to understand what role the magnetic fields play in setting the power of relativistic jets in AGN. We have performed VLBA phase-referencing observations of the radio-intermediate quasar IIIZw 2 to estimate jet magnetic flux by measuring the core-shift effect. Multi-frequency observations at 4 GHz, 8 GHz, 15 GHz, and 24 GHz were made using three nearby calibrators as reference sources. By combining the self-referencing core shift of each calibrator with the phase-referencing core shifts, we obtained an upper limit of 0.16 mas for the core shift between 4 and 24 GHz in IIIZw 2. By assuming equipartition between magnetic and particle energy densities and adopting the flux-freezing approximation, we further estimated the upper limit for both the magnetic field strength and poloidal magnetic flux threading the black hole. We find that the upper limit to the measured magnetic flux is smaller by at least a factor of five compared to the value predicted by the magnetically arrested disk (MAD) model. An alternative way to derive the jet magnetic field strength from the turnover of the synchrotron spectrum leads to an even smaller upper limit. Hence, the central engine of IIIZw 2 has not reached the MAD state, which could explain why it has failed to develop a powerful jet even though the source harbours a fast-spinning black hole. However, it generates an intermittent jet, which is possibly triggered by small-scale magnetic field fluctuations, as predicted by the magnetic flux paradigm. We propose here that combining black hole spin measurements with magnetic field measurements from the very-long-baseline-interferometry core-shift observations of AGN over a range of jet powers could provide a strong test for the dominant factor that sets the jet power relative to the available accretion power.

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“…Blazar variabilities have been well studied by many authors (e.g. Chen et al 2014;Li et al 2006Li et al , 2009Li et al , 2010Li et al , 2015Poon et al 2009;Qian et al 2007;Raiteri et al 2003;Sillanpää et al 1988;Xie et al 2008;Zhang et al 2008). …”

Section: Introductionmentioning

confidence: 99%

Multiband Variability Analysis of Mrk 421

Li¹,

Jiang²,

Guo³

et al. 2016

PASP

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We have assembled the historical variability data of Mrk 421 at radio 15 GHz, X-ray and γ-ray bands, spanning about 6.3, 10.3 and 7.5 yr, respectively. We analyzed the variability by using three methods. The results indicated that there is a period of 287.6 ± 4.4 days for 15 GHz, 309.5 ± 5.8 days for X-ray and 283.4 ± 4.7 days for γ-ray, respectively. This period can be reasonably explained by the nonballistic helical motion of the emitting material. The correlation analysis suggested that the variabilities of radio 15 GHz, X-ray and γ-ray are remarkable correlated, and the emission of radio 15 GHz lags behind that of X-ray, and the X-ray flux lags behind the γ-ray. This suggests that the γ-ray derives from inverse Compton (IC) scattering of the synchrotron photons, supporting the synchrotron self-Compton (SSC) model. Moreover, the time delay between different wavebands could be explained by the shock-in-jet models, in which a moving emission region produces the radio to γ-ray activity, implying that the emission region of γ-ray is closer to the center than ones of X-ray and radio emission.

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Periodicity analysis of the radio light curve of the Seyfert galaxy III Zw 2

Cited by 14 publications

References 36 publications

The changing source of X-ray reflection in the radio-intermediate Seyfert 1 galaxy III Zw 2

The changing source of X-ray reflection in the radio-intermediate Seyfert 1 galaxy III Zw 2

Testing the magnetic flux paradigm for AGN radio loudness with a radio-intermediate quasar

Multiband Variability Analysis of Mrk 421

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