Microvariability of S5 0716+714, a γ-Ray Blazar

Nesci, R.; Massaro, E.; Maesano, M.; Montagni, F.; D’Alessio, F.; Tosti, G.; Luciani, M.

doi:10.1007/978-94-011-4970-9_164

Cited by 27 publications

(34 citation statements)

References 1 publication

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“…In other words, the spectrum became steeper when the object was bright and flatter when it faded. This behaviour is opposite to the general reports for this class of objects (e.g., Kedziora-Chudczer et al 2001;Racine 1970;Massaro et al 1998;Maesano et al 1997;Papadakis et al 2003), and common models (e.g., Li & Kusunose 2000;Chiang & Böttcher 2002;Wang & Kusunose 2002;Dermer 1998;Spada et al 2001;Sikora et al 2001;Qian et al 1991;Wiita 1996;Dermer & Schlickeiser 2002;Nesci et al 1998;Marscher et al 1980;Trèvese & Vagnetti 2002) which state that blazars become bluer when they brighten. This peculiar behaviour was also noted by Clements et al (2003) in early 2002, just a month after the flare of December 2001.…”

Section: Variability Behaviourcontrasting

confidence: 73%

Optical variability of PKS 0736+017

Ramirez¹,

Diego²,

Dultzin‐Hacyan³

et al. 2004

A&A

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Abstract. We present BVR photometric observations of the blazar PKS 0736+017. These observations were carried out with three telescopes in Mexico and two in Spain between December 1998 and April 2003. PKS 0736+017 shows remarkable variation at different timescales and amplitudes. Maximum brightness was detected on December 19, 2001 (B = 14.90 ± 0.01, V = 14.34 ± 0.01, and R = 13.79 ± 0.01). A peculiar tendency to redden with increased brightness was detected throughout our observations. Moreover, in one season a good correlation between flux level and spectral slope is shown. This anomalous behaviour cannot be described by common flare models of blazars. The flux vs. spectral slope correlation observed in this and other blazars is worth further study.

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Section: Variability Behaviourcontrasting

confidence: 73%

Optical variability of PKS 0736+017

Ramirez¹,

Diego²,

Dultzin‐Hacyan³

et al. 2004

A&A

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“…S5 0716+714 is a prominent blazar in optical bands and has shown variability on diverse timescales from minutes through hours to days (e.g. Heidt & Wagner 1996;Nesci et al 1998;Giommi et al 1999;Raiteri et al 1999;Raiteri et al 2003;Gupta et al 2008;Gupta et al 2012;Agarwal et al 2016) in radio to X ray bands (e.g. Wagner et al 1996;Raiteri et al 2003 and references therein).…”

Section: S5 0716+714mentioning

confidence: 99%

Core shift effect in blazars

Agarwal

Mohan

Gupta

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We studied the pc-scale core shift effect using radio light curves for three blazars, S5 0716+714, 3C 279 and BL Lacertae, which were monitored at five frequencies (ν) between 4.8 GHz and 36.8 GHz using the University of Michigan Radio Astronomical Observatory (UMRAO), the Crimean Astrophysical Observatory (CrAO), and Metsahovi Radio Observatory for over 40 years. Flares were Gaussian fitted to derive time delays between observed frequencies for each flare (∆t), peak amplitude (A), and their half width. Using A ∝ ν α we infer α in the range −16.67 to 2.41 and using ∆t ∝ ν 1/kr , we infer k r ∼ 1, employed in the context of equipartition between magnetic and kinetic energy density for parameter estimation. From the estimated core position offset (Ω rν ) and the core radius (r core ), we infer that opacity model may not be valid in all cases. The mean magnetic field strength at 1 pc (B 1 ) and at the core (B core ), are in agreement with previous estimates. We apply the magnetically arrested disk model to estimate black hole spins in the range 0.15 − 0.9 for these blazars, indicating that the model is consistent with expected accretion mode in such sources. The power law shaped power spectral density has slopes −1.3 to −2.3 and is interpreted in terms of multiple shocks or magnetic instabilities.

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“…Racine 1970;Speziali & Natali 1998;Böttcher et al 2003;Fan et al 2001;Hu et al 2006). Nesci et al (1998) found the source to be variable with the amplitudes of flux variations larger at shorter wavelengths. Papadakis et al (2003) studied the rise and decay time-scales of the source during the course of a single night and found them to increase with decreasing frequency.…”

Section: Introductionmentioning

confidence: 98%

Nature of intranight optical variability of BL Lacertae

Gaur¹,

Gupta²,

Bachev³

et al. 2015

Mon. Not. R. Astron. Soc.

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We present the results of extensive multi-band intra-night optical monitoring of BL Lacertae during 2010-2012. BL Lacertae was very active in this period and showed intense variability in almost all wavelengths. We extensively observed it for a total for 38 nights; on 26 of them observations were done quasi-simultaneously in B, V, R and I bands (totaling 113 light curves), with an average sampling interval of around 8 minutes. BL Lacertae showed significant variations on hour-like timescales in a total of 19 nights in different optical bands. We did not find any evidence for periodicities or characteristic variability time-scales in the light curves. The intranight variability amplitude is generally greater at higher frequencies and decreases as the source flux increases. We found spectral variations in BL Lacertae in the sense that the optical spectrum becomes flatter as the flux increases but in several flaring states deviates from the linear trend suggesting different jet components contributing to the emission at different times.

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Microvariability of S5 0716+714, a γ-Ray Blazar

Cited by 27 publications

References 1 publication

Optical variability of PKS 0736+017

Optical variability of PKS 0736+017

Core shift effect in blazars

Nature of intranight optical variability of BL Lacertae

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