Optical variability of Mrk 421

Chen, Xu; Hu, Shijian; Guo, Dadong; Du, Jun

doi:10.1007/s10509-013-1693-x

Cited by 20 publications

(17 citation statements)

References 65 publications

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“…The SMBBH model has been successfully applied to explain a number of observational phenomena of blazar (e.g. Chen et al 2014;Britzen et al 2012;Li et al 2015;Valtonen et al 2011;Sillanpää et al 1988;Tsalmantza et al 2011). We assume that SMBBH exists in the center of Mrk 421 and a helical magnetic field exists in the jet.…”

Section: Discussionmentioning

confidence: 99%

“…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%

“…By using the Jurkevich method, Liu et al (1997) found that there are two possible periods with timescales of 23.1 ±1.1 and 15.3 ±0.7 years in the B band of Mrk 421. Chen et al (2014) investigated the B and V bands historical variability data, and a possible period of about 1.36 years was found. These previous results suggest that various quasi-periodic timescales exist in the variability of Mrk 421 at multiple wavebands.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Multiband Variability Analysis of Mrk 421

Li¹,

Jiang²,

Guo³

et al. 2016

PASP

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“…In view of this, it appears rather strange and unexplainable that an almost 30-years age method, which is already known for its practical deficiency, is still so frequently used in the astronomical practice (e.g. Burt et al 2014;Brothwell et al 2014;Kelly et al 2014;Hartman et al 2014;Nucita et al 2014;Chen et al 2014;Lin et al 2014;Romano et al 2014;Buccino et al 2014;Brucalassi et al 2014, among publications of only the year of this writing).…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Keplerian periodogram for Doppler exoplanet detection: optimized computation and analytic significance thresholds

Baluev

2014

Monthly Notices of the Royal Astronomical Society

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We consider the so-called Keplerian periodogram, in which the putative detectable signal is modelled by a highly non-linear Keplerian radial velocity function, appearing in Doppler exoplanetary surveys. We demonstrate that for planets on high-eccentricity orbits the Keplerian periodogram is far more efficient than the classic Lomb-Scargle periodogram and even the multiharmonic periodograms, in which the periodic signal is approximated by a truncated Fourier series.We provide new numerical algorithm for computation of the Keplerian periodogram. This algorithm adaptively increases the parameteric resolution where necessary, in order to uniformly cover all local optima of the Keplerian fit. Thanks to this improvement, the algorithm provides more smooth and reliable results with minimized computing demands.We also derive a fast analytic approximation to the false alarm probability levels of the Keplerian periodogram. This approximation has the form (P z 3/2 +Qz)W exp(−z), where z is the observed periodogram maximum, W is proportional to the settled frequency range, and the coefficients P and Q depend on the maximum eccentricity to scan.

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“…A $12 yr period was detected in the optical flux variation of OJ 287 (Villata et al, 1998;Fan et al, 2010). Chen et al (2014) analyzed the optical light curves of Mrk 421 and found a possible period of 1.36 yr. In particular, many authors have investigated the light curves of BL Lacertae for possible periods, leading to different results (Villata et al, 2004a).…”

Section: Introductionmentioning

confidence: 99%

Long-term optical and radio variability of BL Lacertae

Guo

et al. 2015

New Astronomy

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Well-sampled optical and radio light curves of BL Lacertae in B, V, R, I bands and 4.8, 8.0, 14.5 GHz from 1968 to 2014 were presented in this paper. A possible $1.26 \pm 0.05$ yr period in optical bands and a $7.50 \pm 0.15$ yr period in radio bands were detected based on discrete correlation function, structure function as well as Jurkevich method. Correlations among different bands were also analyzed and no reliable time delay was found between optical bands. Very weak correlations were detected between V band and radio bands. However, in radio bands the variation at low frequency lagged that at high frequency obviously. The spectrum of BL Lacertae turned mildly bluer when the object turned brighter, and stronger bluer-when-brighter trends were found for short flares. A scenario including a precessing helical jet and periodic shocks was put forward to interpret the variation characteristics of BL Lacertae.Comment: 7 pages, 11 figures, submitte

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Optical variability of Mrk 421

Cited by 20 publications

References 65 publications

Multiband Variability Analysis of Mrk 421

Multiband Variability Analysis of Mrk 421

Keplerian periodogram for Doppler exoplanet detection: optimized computation and analytic significance thresholds

Long-term optical and radio variability of BL Lacertae

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