MULTI-WAVELENGTH STUDY OF FLARING ACTIVITY IN BL Lac OBJECT S5 0716+714 DURING THE 2015 OUTBURST

Chandra, Sunil; Zhang, Haocheng; Kushwaha, Pankaj; Singh, K. P.; Böttcher, M.; Kaur, Navpreet; Baliyan, K. S.

doi:10.1088/0004-637x/809/2/130

Cited by 46 publications

(55 citation statements)

References 46 publications

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“…Furthermore, this model predicts very noisy PA swings, but observations have often seen rather smooth swings that disfavor a stochastic origin (Kiehlmann et al 2017). The third possibility is a regulated magnetic field alteration due to local energy dissipations, such as shocks or magnetic instabilities (Zhang et al 2015;Nalewajko 2017). Magnetohydrodynamic simulations have shown that shocks and kink instabilities can locally modify the magnetic field and dissipate jet energy, giving rise to correlated flares, low PD, and smoothly rotating PA.…”

Section: Discussionmentioning

confidence: 92%

“…Similar to their 180 • counterparts, these events show one or multiple flares as well as low and fluctuating polarization degree (PD). But here the PA can rotate much more than 180 • , either consistently in one direction (Marscher et al 2010) or in both directions (Chandra et al 2015). Because of the large-amplitude and rather smooth PA rotation, they are unlikely due to stochastic processes in a turbulent magnetic field.…”

Section: Introductionmentioning

confidence: 87%

“…The 3DPol code is a polarized radiation transfer code (Zhang et al 2015). The code evaluates the Stokes parameters from each of emission zones based on the magnetic field and nonthermal particle distribution, then traces the Stokes parameters to the plane of sky.…”

Section: Model Descriptionmentioning

confidence: 99%

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Large-amplitude Blazar Polarization Angle Swing as a Signature of Magnetic Reconnection

Zhang

Guo

et al. 2018

ApJL

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Relativistic magnetic reconnection events can widely exist in magnetized plasmas in astrophysical systems. During this process, oppositely directed magnetic field lines reconnect and release magnetic energy, efficiently accelerating nonthermal particles. However, so far there is little clear observational signatures of relativistic magnetic reconnection events in astrophysical systems. Blazars are relativistic magnetized plasma outflows from supermassive black holes. Their multi-wavelength flares may be powered by relativistic magnetic reconnection. The highly variable radiation and polarization signatures are well covered by multi-wavelength observation campaigns, making them ideal targets to examine the magnetic reconnection model. Recent observations have found that several blazar flares are accompanied by optical polarization angle swings which may be of as large amplitude as > 180 • , challenging existing theoretical models. In this paper, we present integrated particle-in-cell (PIC) and polarized radiation transfer simulations of magnetic reconnection events. We find that plasmoid coalescences in the reconnection layer can give rise to highly variable light curves, low and fluctuating polarization degree, and rotating polarization angle. In particular, large-amplitude polarization angle swings, similar to those observed during blazar flares, can be a unique signature of relativistic magnetic reconnection events.

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Section: Discussionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 87%

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Large-amplitude Blazar Polarization Angle Swing as a Signature of Magnetic Reconnection

Zhang

Guo

et al. 2018

ApJL

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“…However, the sampling of PD is sparse, so that we cannot verify this correspondence from the two light curves directly. A better sampling example, i.e., the intra-day variation study of S5 0715+714, seems to support such correspondence, see Figure 1 in Chandra et al (2015). Based on Equation 8, the linear correlation between log and log νF ν , i.e., 2(1+α θ ) 3+αo , can be derived in the case that variations of PD and flux are due to the variation of δ, see Table 3.…”

Section: Polarization and Optical V Bandmentioning

confidence: 84%

Curvature-induced Polarization and Spectral Index Behavior for PKS 1502+106

Shao

Jiang

Chen

2019

ApJ

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A comprehensive study of multifrequency correlations can shed light on the nature of variation for blazars. In this work, we collect the long-term radio, optical and γ-ray light curves of PKS 1502+106. After performing the localized cross-correlation function analysis, we find that correlations between radio and γ-ray or V band are beyond the 3σ significance level. The lag of the γ-ray relative to 15 GHz is −60 +5 −10 days, translating to a distance 3.18 +0.50 −0.27 parsec (pc) between them. Within uncertainties, the locations of the γ-ray and optical emitting regions are roughly the same, and are away from the jet base within 1.2 pc. The derived magnetic field in optical and γ-ray emitting regions is about 0.36 G. The logarithm of γ-ray flux is significantly linearly correlated with that of V band fluxes, which can be explained by the synchrotron self-Compton (SSC) process, the external Compton (EC) processes, or the combination of them. We find a significant linear correlation in the plot of log (polarization degree) versus log νF ν at V band, and use the empirical relation Π ∼ sin n θ ′ (θ ′ is the observing angle in the comoving frame blob) to explain it. The behaviors of color index (generally redder when brighter at the active state) and γ-ray spectral index (softer when brighter) could be well explained by the twisted jet model. These findings suggest that the curvature effect (mainly due to the change of the viewing angle) is dominant in the variation phenomena of fluxes, spectral indices, and polarization degrees for PKS 1502+106.

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“…The BL Lac S5 0716+714 exhibited an unprecedented optical/NIR flare on January 2015, which triggered multiwavelength observations, and detection up to VHE energies with MAGIC (Chandra et al 2015;MAGIC Collaboration, et al 2018c;Manganaro et al 2016). It is classified as an ISP (Giommi et al 1999).…”

Section: S5 0716+714mentioning

confidence: 99%

High-energy neutrino flux from individual blazar flares

Oikonomou

Murase

Padovani

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Motivated by the recently reported evidence of an association between a high-energy neutrino and a γ-ray flare from the blazar TXS 0506+056, we calculate the expected high-energy neutrino signal from past, individual flares, from twelve blazars, selected in declinations favourable for detection with IceCube. To keep the number of free parameters to a minimum, we mainly focus on BL Lac objects and assume the synchrotron self-Compton mechanism produces the bulk of the high-energy emission. We consider a broad range of the allowed parameter space for the efficiency of proton acceleration, the proton content of BL Lac jets, and the presence of external photon fields. To model the expected neutrino fluence we use simultaneous multi-wavelength observations. We find that in the absence of external photon fields and with jet proton luminosity normalised to match the observed production rate of ultra-high-energy cosmic rays, individual flaring sources produce a modest neutrino flux in IceCube, N IC,10yr ν µ ,>100 TeV 10 −3 muon neutrinos with energy exceeding 100 TeV, stacking ten years of flare periods selected in the > 800 MeV Fermi energy range, from each source. Under optimistic assumptions about the jet proton luminosity and in the presence of external photon fields, we find that the two most powerful sources in our sample, AO 0235+164, and OJ 287, would produce, in total, N IC×10,10yr ν µ ,all flares,>100 TeV ≈ 3 muon neutrinos during Fermi flaring periods, in future neutrino detectors with total instrumented volume ∼ ten times larger than IceCube, or otherwise, constrain the proton luminosity of blazar jets.

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MULTI-WAVELENGTH STUDY OF FLARING ACTIVITY IN BL Lac OBJECT S5 0716+714 DURING THE 2015 OUTBURST

Cited by 46 publications

References 46 publications

Large-amplitude Blazar Polarization Angle Swing as a Signature of Magnetic Reconnection

Large-amplitude Blazar Polarization Angle Swing as a Signature of Magnetic Reconnection

Curvature-induced Polarization and Spectral Index Behavior for PKS 1502+106

High-energy neutrino flux from individual blazar flares

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