Optical Variability in IBL S5 0716+714 during the 2013–2015 Outbursts

Kaur, Navpreet; Baliyan, K. S.; Chandra, S.; Sameer,; Ganesh, S.

doi:10.3847/1538-3881/aac5e4

Cited by 19 publications

(18 citation statements)

References 92 publications

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“…S5 0716+714 at redshift z = 0.31 ± 0.08 (Nilsson et al 2008) is well known for its intra-day variability (e.g. Wagner et al 1996;Villata et al 2000;Sasada et al 2008;Chandra et al 2011;Kaur et al 2018, and references therein). An intensive 5-d campaign was organized by the WEBT in March 2014.…”

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confidence: 99%

The dual nature of blazar fast variability: Space and ground observations of S5 0716+714

Raiteri

Villata

Carosati

et al. 2020

Monthly Notices of the Royal Astronomical Society

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Blazar S5 0716+714 is well-known for its short-term variability, down to intra-day time-scales. We here present the 2-min cadence optical light curve obtained by the TESS space telescope in 2019 December – 2020 January and analyse the object fast variability with unprecedented sampling. Supporting observations by the Whole Earth Blazar Telescope Collaboration in B, V, R, and I bands allow us to investigate the spectral variability during the TESS pointing. The spectral analysis is further extended in frequency to the UV and X-ray bands with data from the Neil Gehrels Swift Observatory. We develop a new method to unveil the shortest optical variability time-scales. This is based on progressive de-trending of the TESS light curve by means of cubic spline interpolations through the binned fluxes, with decreasing time bins. The de-trended light curves are then analysed with classical tools for time-series analysis (periodogram, auto-correlation and structure functions). The results show that below 3 d there are significant characteristic variability time-scales of about 1.7, 0.5, and 0.2 d. Variability on time-scales $\lesssim 0.2$ d is strongly chromatic and must be ascribed to intrinsic energetic processes involving emitting regions, likely jet sub-structures, with dimension less than about 10−3 pc. In contrast, flux changes on time-scales $\gtrsim 0.5$ d are quasi-achromatic and are probably due to Doppler factor changes of geometric origin.

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confidence: 99%

The dual nature of blazar fast variability: Space and ground observations of S5 0716+714

Raiteri

Villata

Carosati

et al. 2020

Monthly Notices of the Royal Astronomical Society

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“…Our IDV observations, as well as those of Amirkhanyan (2006); Hu et al (2014); Ghisellini et al (1997); Wu et al (2007); Bhatta et al (2016); Dai et al (2013); Wu et al (2005); Stalin et al (2009); Feng et al (2020) show a strong BWB trend. We and Hu et al (2014); Wu et al (2007); Dai et al (2013); Kaur et al (2018); Stalin et al (2009) note the presence of the BWB trend on a long timescale, whereas Ghisellini et al (1997); Raiteri et al (2003) report about the achromatic behavior of long-term variability. Stalin et al (2006); Agarwal et al (2016) report the absence of chromatism in both IDV and long-term variability.…”

Section: Discussionmentioning

confidence: 63%

A geometrical interpretation for the properties of multiband optical variability of the blazar S5 0716+714

Butuzova

2020

Preprint

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We present the results of multiband observations of the blazar S5 0716+714 intra-night variability performed during 23 nights in the period from 04.2014 through 04.2015. The bluer-when-brighter trend is detected in both intra-and inter-night data. We assume that the jet component crossing the region where the medium becomes transparent to the optical radiation forms almost all optical emission of S5 0716+714. Deviations of some parts of the component from the general trajectory of the component can cause the Doppler factor of these parts to increase. Various maximum Doppler factors achieved by these parts of the component and different volumes occupied by them with the concave synchrotron self-absorption spectrum result in both the observed various color index behavior in variability and explain the absence of dependence of the bluer-when-brighter behavior on the object magnitude. We estimated spectral maximum frequencies from intra-and inter-night data. Both the agreement of the obtained values of ν m ≈ (1.0 − 2.5) • 10 14 GHz and the fact that ν m is less than the frequencies of optical observations confirm our assumption about the nature of the blazar S5 0716+714 region radiating in the optical range.

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“…Masses of the central black hole of 3C 454.3, S5 0716+714 and PKS 2155-304 are uncertain and have a wide ranges, which are (0.3 -2)×10 9 M ⊙ (Bonnoli et al 2011), (0.3 -4)×10 9 M ⊙ (Kaur et al 2018) and (0.3 -3)×10 9 M ⊙ (Gupta 2014) respectively. The primary black hole mass of OJ 287 (a binary supermassive black hole system) is ∼1.8 ×10 10 M ⊙ (Rodríguez-Ramírez et al 2020, and references therein).…”

Section: Estimated N E Of the Jet Emission Region And Matter Supplied...mentioning

confidence: 99%

Blazars SED in Conical Plasma Flow : a Monte Carlo study

Kumar,

Kushwaha

2021

Preprint

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Blazars host the most powerful persistent relativistic conical jet-a highly collimated anisotropic flow of material/plasma. Motivated by this, we explore the blazar's broadband spectral energy distribution (SED) in an anisotropic flow of plasma which emits via synchrotron and inverse Compton (IC) mechanism. The flow is conical with two velocity components: a highly relativistic flow component along the jet axis and a random perpendicular component with average random Lorentz factor γ ran << than the average component along the jet axis γ . Assuming a broken power-law electron population, we calculated the broadband SED using synchrotron and IC processes assuming a cylindrical (of radius R and length L) emission region. For the IC process, we used Monte Carlo approach. We found that such anisotropic flow can reproduce blazars broadband emission as well as general short and high amplitude variability, indicating that spectral and temporal variability are not sufficient to distinguish among existing models. We demonstrate this by reproducing SEDs of FSRQ 3C 454.3 and three BL Lacs objects OJ 287, S5 0716+714, PKS 2155-304. Our formalism and set-up also allow us to investigate the effect of the geometry and dimension of emission region on observed broadband spectra. We found that the SEDs of low synchrotron peak (LSP) blazar can be explained by considering only SSC (synchrotron self-Compton) if R/L (< 0.01), broadly mimicking a spine-sheath geometry. In general, the degeneracy between non-thermal particle number density and length of the emission region (L) allow us to reproduce any variability in terms of particle number density.

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Optical Variability in IBL S5 0716+714 during the 2013–2015 Outbursts

Cited by 19 publications

References 92 publications

The dual nature of blazar fast variability: Space and ground observations of S5 0716+714

The dual nature of blazar fast variability: Space and ground observations of S5 0716+714

A geometrical interpretation for the properties of multiband optical variability of the blazar S5 0716+714

Blazars SED in Conical Plasma Flow : a Monte Carlo study

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