Application of the spine-layer jet radiation model to outbursts in the broad-line radio galaxy 3C 120

Janiak, M.; Sikora, Marek; Moderski, R.

doi:10.1093/mnras/stw465

Cited by 14 publications

(19 citation statements)

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“…The γ-rays from 3C 120 had been already detected by Fermi LAT during first 15 months' scan of the whole sky (Abdo et al 2010a) which was then confirmed by the data accumulated for two years (Kataoka et al 2011). Also a long-term (several months) variability had been found using the five-year Fermi LAT data (Sahakyan et al 2015) with short periods (days and hours) of brightening (Tanaka et al 2015;Janiak et al 2016). Inverse Compton scattering of synchrotron photons seems to be the mechanism responsible for the γ-ray emission from 3C 120 (Tanaka et al 2015;Sahakyan et al 2015) while the flares and the fast γ-ray variability are explained within more complex structured jet scenarios (Janiak et al 2016).…”

Section: Introductionmentioning

confidence: 72%

“…Also a long-term (several months) variability had been found using the five-year Fermi LAT data (Sahakyan et al 2015) with short periods (days and hours) of brightening (Tanaka et al 2015;Janiak et al 2016). Inverse Compton scattering of synchrotron photons seems to be the mechanism responsible for the γ-ray emission from 3C 120 (Tanaka et al 2015;Sahakyan et al 2015) while the flares and the fast γ-ray variability are explained within more complex structured jet scenarios (Janiak et al 2016). Combining of the data derived at the sub-pc and kilo-parsec regions of the same jet could greatly help to understand the features of powerful extragalactic jets, e.g., shed some light on the evolution and propagation of the jets from the central engine to the outer regions, where the jet is starting to significantly decelerate.…”

Section: Introductionmentioning

confidence: 92%

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Comparing 3C 120 jet emission at small and large scales

Zargaryan

Gasparyan

Baghmanyan

et al. 2017

A&A

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Context. Important information on the evolution of the jet can be obtained by comparing the physical state of the plasma at its propagation through the broad-line region (where the jet is most likely formed) into the intergalactic medium, where it starts to significantly decelerate. Aims. We compare the constraints on the physical parameters in the innermost (≤ pc) and outer (≥ kpc) regions of the 3C 120 jet by means of a detailed multiwavelength analysis and theoretical modeling of their broadband spectra. Methods. The data collected by Fermi LAT (γ-ray band), Swift (X-ray and ultraviolet bands) and Chandra (X-ray band) are analyzed together and the spectral energy distributions are modeled using a leptonic synchrotron and inverse Compton model, taking into account the seed photons originating inside and outside of the jet. The model parameters are estimated using the Markov Chain Monte Carlo method.Results. The γ-ray flux from the inner jet of 3C 120 was characterized by rapid variation from MJD 56900 to MJD 57300. Two strong flares were observed on April 24, 2015 when, within 19.0 minutes and 3.15 hours the flux was as high as (7.46 ± 1.56) × 10 −6 photon cm −2 s −1 and (4.71 ± 0.92) × 10 −6 photon cm −2 s −1 respectively, with ≥ 10σ. During these flares the apparent isotropic γ-ray luminosity was L γ ≃ (1.20 − 1.66) × 10 46 erg s −1 which is not common for radio galaxies. The broadband emission in the quiet and flaring states can be described as synchrotron self-Compton emission while inverse Compton scattering of dusty torus photons cannot be excluded for the flaring states. The X-ray emission from the knots can be well reproduced by inverse Compton scattering of cosmic microwave background photons only if the jet is highly relativistic (since even when δ = 10 still U e /U B ≥ 80). These extreme requirements can be somewhat softened assuming the X-rays are from the synchrotron emission of a second population of very-high-energy electrons. Conclusions. We found that the jet power estimated at two scales is consistent, suggesting that the jet does not suffer severe dissipation, it simply becomes radiatively inefficient.

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Section: Introductionmentioning

confidence: 72%

Section: Introductionmentioning

confidence: 92%

Comparing 3C 120 jet emission at small and large scales

Zargaryan

Gasparyan

Baghmanyan

et al. 2017

A&A

View full text Add to dashboard Cite

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“…This progressive slowdown in the apparent velocity of components could be explained by a change in the velocity and/or a change in the orientation of the components. A precession model for 3C 120 has been already proposed by [12] as well as by [13]. Interestingly, in [13], the authors interpreted the γ-ray event in September 2014 considering the jet as formed by a fast spine and a slower outer layer, where it is only the spine that changes its direction and occasionally points more toward the observer, as during γ-ray flares.…”

Section: Mjdmentioning

confidence: 96%

“…A precession model for 3C 120 has been already proposed by [12] as well as by [13]. Interestingly, in [13], the authors interpreted the γ-ray event in September 2014 considering the jet as formed by a fast spine and a slower outer layer, where it is only the spine that changes its direction and occasionally points more toward the observer, as during γ-ray flares. By using the observed apparent velocities, and minimizing the required reorientation of the jet, we could estimate the Lorentz factor Γ = 6.3, and a change in viewing angle from 9.2 • to 3.6 • , where the latter corresponds to the epoch of the ejection of component d11 and the γ-ray event.…”

Section: Mjdmentioning

confidence: 96%

The Connection between the Radio Jet and the γ-ray Emission in the Radio Galaxy 3C 120 and the Blazar CTA 102

et al. 2016

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We present multi-wavelength studies of the radio galaxy 3C 120 and the blazar CTA 102 during unprecedented γ-ray flares for both sources. In both studies the analysis of γ-ray data has been compared with a series of 43 GHz VLBA images from the VLBA-BU-BLAZAR program, providing the necessary spatial resolution to probe the parsec scale jet evolution during the high Galaxies 2016, 4, 34; doi:10.3390/galaxies4040034www.mdpi.com/journal/galaxies Galaxies 2016, 4, 34 2 of 9 energy events. To extend the radio dataset for 3C 120 we also used 15 GHz VLBA data from the MOJAVE sample. These two objects which represent very different classes of AGN, have similar properties during the γ-ray events. The γ-ray flares are associated with the passage of a new superluminal component through the mm VLBI core, but not all ejections of new components lead to γ-ray events. In both sources γ-ray events occurred only when the new components are moving in a direction closer to our line of sight. We locate the γ-ray dissipation zone a short distance from the radio core but outside of the broad line region, suggesting synchrotron self-Compton scattering as the probable mechanism for the γ-ray production.

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“…Even when the emission is most likely produced in a compact region of the jet (e.g., Cen A core (Abdo et al 2010d), M87 (Abdo et al 2009b) and NGC 1275 (Abdo et al 2009a)), the most popular one-zone synchrotron/synchrotron self Compton (SSC) model clearly fails to explain the observed multiwavelength properties. More complicated models, multi-zone (Lenain et al 2008) or structured jet (Tavecchio & Ghisellini 2008;Janiak et al 2016;Tavecchio & Ghisellini 2014), based on different assumptions should be employed to explain the observed data properly. New and high-quality data are still needed to fully understand the origin of multiwavelength emission from non-blazar AGNs.…”

Section: Introductionmentioning

confidence: 99%

Fermi-LAT observation of nonblazar AGNs

Sahakyan

Baghmanyan

Zargaryan

2018

A&A

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Context. Fermi-LAT has recently detected γ-ray emission from active galactic nuclei which do not show clear evidence for optical blazar characteristics or have jets pointing away from the observer (non-blazar AGNs). These are interesting γ-ray emitters providing an alternative approach to studying high energy emission processes. Aims. Investigation of the spectral and temporal properties of γ-ray emission from non-blazar AGNs using the recent Fermi-LAT observational data. Methods. The data collected by Fermi-LAT during 2008-2015, from the observations of 26 non-blazar AGNs, including eleven FRI and ten FRII radio galaxies/SSRQs and five NLSY1s are analyzed using the new PASS 8 event selection and instrument response function. Possible spectral changes above GeV energies are investigated with a detailed spectral analysis. Light curves generated with normal and adaptive time bins are used to study the γ-ray flux variability. Results. Non-blazar AGNs have a γ-ray photon index in the range of 1.84 − 2.86 and a flux varying from a few times 10 −9 photon cm −2 s −1 to 10 −7 photon cm −2 s −1 . Over long time periods, power-law provides an adequate description of the γ-ray spectra of almost all sources. Significant curvature is observed in the γ-ray spectra of NGC 1275, NGC 6251, SBS 0846+513 and PMN J0948+0022 and their spectra are better described by log-parabola or power-law with exponential cut-off models. The γ-ray spectra of PKS 0625-25 and 3C 380 show a possible deviation from a simple power-law shape, indicating a spectral cutoff around the observed photon energy of E cut = 131.2 ± 88.04 GeV and E cut = 55.57 ± 50.74 GeV, respectively. Our analysis confirms the previous finding of an unusual spectral turnover in the γ-ray spectrum of Cen A: the photon index changes from Γ = 2.75± 0.02 to 2.31± 0.1 at 2.35± 0.08 GeV. In the Γ − L γ plane, the luminosity of non-blazar AGNs is spread in the range of (10 41 − 10 47 ) erg s −1 , where the lowest luminosity have FRI radio galaxies (but typically appear with a harder photon index) and the highest-SSRQs/NLSY1s (with softer photon indexes). We confirm the previously reported short-timescale flux variability of NGC 1275 and 3C 120. The γ-ray emission from NLSY1s, 1H 0323+342, SBS 0846+513 and PMN J0948+0022, is variable, showing flares in short scales sometimes accompanied by a moderate hardening of their spectra (e.g., on MJD 56146.8 the γ-ray photon index of SBS 0846+513 was Γ = 1.73 ± 0.14). 3C 111, Cen A core, 3C 207, 3C 275.1, 3C 380, 4C+39.23B, PKS 1502+036 and PKS 2004-447 show a long-timescale flux variability in the γ-ray band.

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Application of the spine-layer jet radiation model to outbursts in the broad-line radio galaxy 3C 120

Cited by 14 publications

References 50 publications

Comparing 3C 120 jet emission at small and large scales

Comparing 3C 120 jet emission at small and large scales

The Connection between the Radio Jet and the γ-ray Emission in the Radio Galaxy 3C 120 and the Blazar CTA 102

Fermi-LAT observation of nonblazar AGNs

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