Multiwavelength Variations of 3c 454.3 During the 2010 November to 2011 January Outburst

Wehrle, A. E.; Marscher, A. P.; Jorstad, S. G.; Gurwell, M. A.; Joshi, M.; MacDonald, Nicholas R.; Williamson, Karen E.; Agudo, I.; Grupe, D.

doi:10.1088/0004-637x/758/2/72

Cited by 85 publications

(129 citation statements)

References 32 publications

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“…In addition, when knot K11b encountered stationary knot A2, it brightened and became more highly polarized (Figure 19 The higher polarization when superluminal knots K11b and K12b reached stationary knot A2 could have been caused by an increase in the strength and order of the magnetic field from compression by a stationary shock corresponding to A2. This situation bears a striking resemblance to that in 3C 454.3 when new knot K09 encountered stationary knot C (Wehrle et al 2012b;Jorstad et al 2013). Just as in the case of 3C 454.3, the stationary knot's EVPA is always nearly aligned with the jet direction, a signature of a transversely oriented shock with magnetic field compressed along the shock front (Hughes et al 1985(Hughes et al , 1989.…”

Section: Kinematics Of the Parsec-scale Radio Jet And Relationship Tomentioning

confidence: 62%

“…The observations were carried out in consecutive pairs with different scan directions. The SPIRE-Photometer observations were done in "small map" mode with a total on-source time of 37 s, as in our previous observations of 3C454.3 (Wehrle et al 2012b). We obtained a total of 38 PACS-Photometer images at each filter band (70, 160 μm) taken on 19 days between 2012 October 29 and 2013 January 29.…”

Section: Fir Observations With the Herschel Space Observatorymentioning

confidence: 99%

“…We did not apply a color correction (equivalent to assuming that F ν ∝ ν − α , with α = 1, or νF ν = constant in SPIRE and PACS terminologies), since we did not know, a priori, the value of the spectral index over the Herschel bandpasses; we used the same approach in our 3C454.3 analysis (Wehrle et al 2012b). We present the measured flux densities in Table 1, a composite 3-color SPIRE image of BL Lac and its surroundings on 2013 January 21 in Figure 3, and the light curves in Figure 4.…”

Section: Fir Observations With the Herschel Space Observatorymentioning

confidence: 99%

“…To determine the 3σ level of significance of a given correlation, we use the same methodology as in our paper on 3C454.3 (Wehrle et al 2012b); we have not yet implemented a new, more robust method that has been proposed recently by Emmanopoulos et al (2013). For each light curve used in the cross-correlation analysis, we generate 5000 simulated light curves binned in the same manner as the observed data and with the same mean and standard deviation of the flux.…”

Section: Details Of Correlationsmentioning

confidence: 99%

“…The source of seed photons for IC scattering in BL Lac objects is thought to be synchrotron photons from the jet itself, unlike FSRQs where the external photon fields from the broad emission-line region and torus containing hot dust can play a major role. For some BL Lac objects and FSRQs, multiple sites of emission may be required to fit the observed multiwavelength SEDs Wehrle et al 2012b, and references therein). BL Lac has broad H-α and H-β lines (Vermeulen et al 1995) that vary in flux.…”

Section: Introductionmentioning

confidence: 99%

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Erratic Flaring of Bl Lac in 2012–2013: Multiwavelength Observations

Wehrle

Grupe

Jorstad

et al. 2016

ApJ

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BL Lac, the eponymous blazar, flared to historically high levels at millimeter, infrared, X-ray, and gamma-ray wavelengths in 2012. We present observations made with Herschel, Swift, NuSTAR, Fermi, the Submillimeter Array, CARMA, and the VLBA in 2012-2013, including three months with nearly daily sampling at several wavebands. We have also conducted an intensive campaign of 30 hr with every-orbit observations by Swift and NuSTAR, accompanied by Herschel, and Fermi observations. The source was highly variable at all bands. Time lags, correlations between bands, and the changing shapes of the spectral energy distributions can be explained by synchrotron radiation and inverse Compton emission from nonthermal seed photons originating from within the jet. The passage of four new superluminal very long baseline interferometry knots through the core and two stationary knots about 4 pc downstream accompanied the high flaring in 2012-2013. The seed photons for inverse Compton scattering may arise from the stationary knots and from a Mach disk near the core where relatively slowmoving plasma generates intense nonthermal radiation. The 95 spectral energy distributions obtained on consecutive days form the most densely sampled, broad wavelength coverage for any blazar. The observed spectral energy distributions and multi-waveband light curves are similar to simulated spectral energy distributions and light curves generated with a model in which turbulent plasma crosses a conical shock with a Mach disk.

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Section: Kinematics Of the Parsec-scale Radio Jet And Relationship Tomentioning

confidence: 62%

Section: Fir Observations With the Herschel Space Observatorymentioning

confidence: 99%

Section: Fir Observations With the Herschel Space Observatorymentioning

confidence: 99%

Section: Details Of Correlationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Erratic Flaring of Bl Lac in 2012–2013: Multiwavelength Observations

Wehrle

Grupe

Jorstad

et al. 2016

ApJ

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The optical variability properties of flat spectrum radio quasar 3C 454.3

2015

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The transience and persistence of high optical polarisation state in beamed radio quasars

Chand

Gopal-Krishna²,

Omar³

et al. 2023

Publ. Astron. Soc. Aust.

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We examine the long-term stability (on decade-like timescales) of optical ‘high polarisation’ (HP) state with ${p_{opt}}$ ${> 3\%}$ , which commonly occurs in flat-spectrum (i.e., beamed) radio quasars (FSRQs) and is a prominent marker of blazar state. Using this clue, roughly a quarter of the FSRQ population has been reported to undergo HP $\leftrightarrow$ non-HP state transition on year-like timescales. This work examines the extent to which HP (i.e., blazar) state can endure in a FSRQ, despite these ‘frequent’ state transitions. This is the first attempt to verify, using purely opto-polarimetric data for a much enlarged sample of blazars, the recent curious finding that blazar state in individual quasars persists for at least a few decades, despite its changing/swinging observed fairly commonly on year-like timescales. The present analysis is based on a well-defined sample of 83 radio quasars, extracted from the opto-polarimetric survey RoboPol (2013–2017), for which old opto-polarimetric data taken prior to 1990 could be found in the literature. By a source-wise comparison of these two datasets of the same observable ( $p_{opt}$ ), we find that $\sim$ 90% of the 63 quasars found in blazar state in our RoboPol sample, were also observed to be in that state about three decades before. On the other hand, within the RoboPol survey itself, we find that roughly a quarter of the blazars in our sample migrated to the other polarisation state on year-like timescales, by crossing the customary $p_{opt}$ = 3% threshold. Evidently, these relatively frequent transitions (in either direction) do not curtail the propensity of a radio quasar to retain its blazar (i.e., HP) state for at least a few decades. The observed transitions/swings of polarisation state are probably manifestation of transient processes, like ejections of synchrotron plasma blobs (VLBI radio knots) from the active nucleus.

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Multiwavelength Variations of 3c 454.3 During the 2010 November to 2011 January Outburst

Cited by 85 publications

References 32 publications

Erratic Flaring of Bl Lac in 2012–2013: Multiwavelength Observations

Erratic Flaring of Bl Lac in 2012–2013: Multiwavelength Observations

The optical variability properties of flat spectrum radio quasar 3C 454.3

The transience and persistence of high optical polarisation state in beamed radio quasars

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