Constraints on the composition, magnetization, and radiative efficiency in jet of blazar
aa r X i v : . [ a s t r o - ph . GA ] M a y Draft version May 31, 2018
Typeset using L A TEX twocolumn style in AASTeX61
CONSTRAINTS ON THE COMPOSITION, MAGNETIZATION, AND RADIATIVE EFFICIENCY IN JET OFBLAZAR
Xu-Liang Fan,
1, 2
Qingwen Wu, and Neng-Hui Liao School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing, Guiyang 550025, China Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008,China
Submitted to ApJABSTRACTThe composition and energy dissipation in jets are two of the fundamental questions of jet physics that are notfully understood. In this paper, we attempt to constrain the composition, magnetization as well as radiative efficiencyfor blazar with the recently released low-frequency radio catalog of the TIFR GMRT Sky Survey at 150 MHz. Thejet power estimated from the low-frequency radio emission is much lower than that derived from spectral energydistribution fitting assuming one proton per electron. Assuming the jet power estimated from low-frequency radioemission is physical, the fraction of electron/positron pairs can be constrained with n pairs /n p ∼
10. By comparing thepower carried by magnetic field and radiation with the jet power estimated from the low-frequency radio emission,we find both relatively high magnetization parameter of σ ∼ . η ∼ . n pairs /n p , σ , and η )and the black hole mass, disk luminosity as well as Eddington ratio. No significant correlation is found, except that σ shows possible correlation with disk luminosity. Keywords: galaxies: jets — quasars: general [email protected], [email protected], [email protected]
Fan, Wu & Liao INTRODUCTIONSupermassive black holes coupled with accretiondisks are currently widely accepted as central en-gines of active galactic nuclei (AGNs). A small frac-tion of AGNs are radio loud, which are believed tohost relativistic jets (Padovani 2017; Padovani et al.2017). Until now, the jet formation and accelerationmechanisms are still fundamental open questions ofjet physics (Sikora et al. 2007; McNamara et al. 2011;Sikora & Begelman 2013; Cao 2016a). Blandford-Znajek mechanism (BZ, Blandford & Znajek 1977) andBlandford-Payne mechanism (BP, Blandford & Payne1982) are two popular mechanisms for extracting en-ergy of relativistic jets from central engines. For BZmechanism, jet energy extraction is purely electro-magnetic and directly coupled with the spin of blackhole, which is supported by several observations inX-ray binaries (XRBs, e.g., Narayan & McClintock2012, but also see Russell et al. 2013). For BP mech-anism, jet energy is extracted from the accretion diskthrough large-scale magnetic field anchored in accre-tion flow. Observationally, it is normally found thatthe radio emission appears in low-hard state of XRBs,while it will become weak or disappear in high-softstate (Corbel et al. 2001; Fender et al. 2004), whichsuggests that the accretion mode also play a role in jetformation (Tchekhovskoy et al. 2010; Sikora et al. 2013;Yuan & Narayan 2014; Cao 2016b). In AGNs, the jetproduction efficiency, defined by the ratio between jetpower and accretion power, is also found to be relatedto the black hole spin (Sikora et al. 2007) and/or thegeometrical thickness of the accretion disk (Avara et al.2016; Rusinek et al. 2017).The energy in jet is mainly carried by three compo-nents, magnetic field, radiation and kinetic energy ofmatter. In principal, energy is dominated by Poynt-ing flux at the base of jet (Kino et al. 2015). Thenmagnetic energy converts into kinetic energy along thejet. Meanwhile the jet is accelerated (Lyubarsky 2010;Komissarov 2011). At a certain distance, the radia-tive particles are accelerated and most observed ra-diation (especially high energy emission) is related tothis region. This region is also named dissipationregion. There are some arguments that jet produc-tion efficiency can exceed unity under the magneticarrested disk (MAD, e.g., Tchekhovskoy et al. 2011;Ghisellini et al. 2014). The estimation of jet produc-tion efficiency is strongly dependent on the estimationof jet power. However, the deviation between the jetpower estimated by different methods is large to oneorder of magnitude (Pjanka et al. 2017; Chen 2018).Even for the nearest FR II radio galaxy Cygnus A, the accurate value of its jet power is under debate (seee.g., Godfrey & Shabala 2013; Kawakatu et al. 2016 andreference therein).The kinetic power, or the terminal jet velocity isstrongly dependent on the composition of jet (Meier et al.2001). But the jet content is difficult to constrain. Onlythe distribution of emitting particles can be constrainedfrom observations, i.e., the non-thermal relativistic elec-trons (Dunn et al. 2006). But the number density ofthe thermal electrons and existence of protons cannot be constrained from observations directly. Thereare several indirect methods to constrain the jet con-tent for lobes of radio galaxies (e.g., Dunn et al. 2006;Kino et al. 2012; Kawakatu et al. 2016) and the dissi-pation regions of blazars in the literature (Wardle et al.1998; Ghisellini & Tavecchio 2010; Kang et al. 2014;Zhang et al. 2014). Most of these methods are basedon the constraint on the distribution of emitting elec-trons (especially the minimum energy of electrons γ min ),and an independent method to estimate the kineticjet power. Under the assumption energy equipar-tition or not, the power carried by other compo-nents (mainly protons) can be generally constrainedthrough the comparison between the electron powerand total kinetic power. Currently, most results ofblazars showed that the matter was dominated bythe electron/positron pairs on the number density,while the kinetic jet power was still dominated by pro-tons (Ghisellini 2012; Kang et al. 2014; Kawakatu et al.2016; Pjanka et al. 2017). However, the observationaland theoretical analyses of radio galaxies showed thatjet power of FR II lobes could be dominated by lep-tons, while FR I lobes needed substantial protons tosatisfy the pressure balance between the internal lobeand external environment (Godfrey & Shabala 2013;Croston et al. 2018, also see Ghisellini et al. 2010 forsimilar discussions on blazars). In addition, there aresome suggestions that the jet content is distinct fordifferent jet powers (Dunn et al. 2006), or accretionmodes (Potter & Cotter 2013). But it still lacks directcomparisons between jet content and central engines inthe literature.The magnetization parameter σ is usually used todescribe the level of the magnetic field dominance in jetwith σ = P B /P m (where P B is the power carried by themagnetic field, P m is the kinetic power of the materialin jet). σ is important on the acceleration mechanismsof the non-thermal electrons (internal shock or magneticreconnection, Sironi & Spitkovsky 2014; Sironi et al.2015). Moreover, there are several models to explainthe short-term variability or hard γ -ray spectrum (e.g.,mini-jet and current-driven instability, Giannios et al. nergy dissipation of blazar σ in blazar is usually based on spectral en-ergy distribution (SED) fitting. Ghisellini et al. (2010)and Zhang et al. (2013) calculated the power carried byeach component (namely radiation, magnetic field, non-thermal electrons, and protons whose number densityis assumed to be equal to electrons) in jet based on theresults of SED fitting. Zhang et al. (2013) found that σ of flat spectrum radio quasar (FSRQ) was close to unity,while the fraction of jet power carried by magnetic fieldwas much smaller for luminous blazars (mainly FS-RQs) in Ghisellini et al. (2010, their Figure 5). Thedeviation may be mainly due to the different mini-mum energies of emitting electrons applied in these twoworks (Zhang et al. 2013). Based on the SED fitting,it was also found that σ was different for different sub-classes of blazars, i.e., FSRQs and BL Lac objects (BLLacs). But some authors showed that σ was larger forFSRQs than that of BL Lacs (Zhang et al. 2013; Chen2018), while other results were opposite (Ghisellini et al.2010). Therefore, estimation of σ independent on thedistribution of emitting electrons is needed.The radiative efficiency η describes the fraction of thejet power dissipated into radiation with η = P rad /P j (where P rad is the power carried by the radiation, P j = P m + P rad + P B is total power in jet). The radiativeefficiency of some γ -ray bursts (GRBs) are found tobe as high as 90% (Zhang et al. 2007), which is muchlarger than the prediction of the standard shock model(Zhang & Yan 2011 and references therein). These highefficiencies suggest the energy dissipation by magneticreconnection in jet may be important (Zhang & Yan2011). The radiative efficiency of blazar was also foundto be larger than 10% (Nemmen et al. 2012; Zhang et al.2013), which is also difficult to produce under the inter-nal shock model (Zhang & Yan 2011).In this paper, we constrain the jet content, magne-tization parameter and radiative efficiency with the jetpower estimations independent on the distribution ofemitting electrons. We also compare the trends of allthese three parameters with black hole mass, disk lumi-nosity and Eddington ratio. In section 2, we presentthe method and data used in our work. Section 3shows the results of the distribution and correlationanalyses. We discuss the implications of our resultsin section 4. In section 5, we summarize the main re-sults. In this paper, we use a ΛCDM cosmology with H = 70 km s − Mpc − , Ω M =0.3, Ω Λ =0.7, consistentwith Ghisellini et al. (2014) and Ghisellini & Tavecchio(2015). METHOD AND DATAUsing the multi-wavelength SED fitting of blazar, onecan derive the distribution of emitting electrons and themagnetic field strength in dissipation region. With theassumption one proton per emitting electron in jet, thepower carried by radiation, relativistic electrons, mag-netic field and protons can be estimated for blazar zone(see Celotti & Ghisellini 2008 and Ghisellini et al. 2014for more details). The total jet power is the sum of thesecomponents with P fit = P B + P p + P e , where P B , P p and P e is the power carried by the magnetic field, protonand electron, respectively.Direct measurements of the kinetic energy in jet isderived from the observations of the large-scale struc-tures of radio galaxies (Dunn et al. 2006; Bˆırzan et al.2008; Daly et al. 2012; Kino et al. 2012). Based onthe direct measurements of jet power, some empir-ical relations between kinetic power and extendedradio emission are built (Willott et al. 1999; Punsly2005; Merloni & Heinz 2007; Cavagnolo et al. 2010;Wu et al. 2011; Godfrey & Shabala 2013; Ineson et al.2017). Although there are some arguments that the P kin - L relation has dependence on the cluster en-vironment (Hardcastle & Krause 2013), age of ra-dio lobes (Hardcastle 2018), or the composition ofjet (Godfrey & Shabala 2013), some theoretical andobservational attempts found that there was an uniformrelation for all active radio lobes (Godfrey & Shabala2013; Hardcastle 2018).Given the jet power estimated from low-frequency ra-dio emission is correct, and the energy losses betweenthe dissipation region and the large scale (extended)jets only take place via blazar radiation (ignore the ra-diation losses of large scale jets), the discrepancy be-tween the estimated jet power from SED fitting andlow-frequency radio emission means the assumption oneproton per electron overestimates the jet power fromSED fitting (Kang et al. 2014; Sikora 2016; Pjanka et al.2017). Thus the ratio between electron/positron pairsand protons can be constrained with (Sikora 2016) n pairs n p = 12 ( P p P kin − P B − P e − . (1)The magnetization parameter σ is estimated with P B from SED fitting and the jet power from low-frequencyradio emission with σ = P B / ( P kin − P B ). Radiativeefficiency η of blazar can be calculated with P rad / ( P kin + P rad ).Recently, several new low-frequency radio surveys re-leased their source catalogs, such as the TIFR GMRTSky Survey (TGSS) with Giant Metrewave Radio Tele-scope (GMRT, Intema et al. 2017), GaLactic and Extra- Fan, Wu & Liao galactic All-sky MWA (GLEAM) survey with Murchi-son Widefield Array (MWA, Hurley-Walker et al. 2017),and LOFAR Two-metre Sky Survey (LoTSS) with Inter-national Low-Frequency Array (LOFAR, Shimwell et al.2017). These recently released catalogs from low-frequency radio surveys give us good opportunities toexplore the jet power for large sample of blazars.Ghisellini et al. (2014) fitted the SEDs of 217 blazarsbased on one-zone leptonic model and calculated thepower carried by each component ( P rad , P B , P p , and P e ).They also listed three groups of black holes mass whichwere based on the virialized estimation of three emissionlines (H β , Mg ii and C iv ), respectively. In our work, theblack hole mass estimations based on the H β measure-ments are favored, as H β is the best calibrated line withreverberation mapping method. The data based on C iv are least favored, as the calibration of C iv is less reli-able (Shen et al. 2011). The disk luminosity estimatedby line luminosity in Ghisellini et al. (2014) is used. TheEddington ratio is calculated with L disk /L Edd , where L Edd is Eddington luminosity. We cross-match theTGSS ADR1 catalog (Intema et al. 2017) with the sam-ple of Ghisellini et al. (2014) within the distance of 3 ′′ .This results in a sample of 133 objects. We estimatetheir jet power with the 150 MHz radio flux from TGSSADR1 and the P kin - L relation in Godfrey & Shabala(2013) P kin = 3 × ( L W Hz − sr − ) . erg s − . (2) RESULTSThe jet power estimated from SED fitting versus thatfrom low-frequency radio emission is plotted in Figure 1.It shows that P fit > P kin for all the 133 blazars, whichmeans that the assumption one proton per electron in-deed overestimates the jet power in the emission zone ofblazar. Among these 133 objects, there are 79 objectswhich we can calculate the fraction of electron/positronpairs with Equation 1. The unreasonable results for re-maining objects can be due to the uncertainties of jetpower estimation either from the SED fitting or the P kin - L relation, or the energy losses from pc to kpc scaleduring the growth of extended structures (we will discussthis in details in Section 4). In the following analyses,we just consider the 79 objects with composition esti-mations. The detailed information of these 79 objectsare listed in Table 2 in the Appendix.The distributions of n pairs /n p , σ and η for our sampleare shown in Figure 2 (also see Table 2 in the Appendix).The mean value of n pairs /n p is 9.79, with majority con-centrates in range 1 to 100 (left panel of Figure 2). σ spans in the range 0.03 to 7.86, with the mean value
42 43 44 45 46 47 48Log P kin
Log P f i t Figure 1.
The jet power estimation from low-frequencyradio emission and SED fitting. The solid line shows theequation line. The jet power estimated from SED fitting islarger than that from low-frequency radio emission for all the133 objects. η is 0.42 with the range 0.05 to 0.94(right panel of Figure 2).We further explore the evolution of jet content, mag-netization parameter, and radiative efficiency along withthe black hole mass, disk luminosity and Eddington ra-tio. Before correlation analysis, we firstly compare thedistributions of black hole mass, disk luminosity andEddington ratio between our sample and the sampleof Ghisellini et al. (2014). The Kolmogorov-Smirnov(K-S) tests show no evidences for distinct distributionsbetween our sample and the Ghisellini’s (with proba-bilities larger than 0.22), which suggest that our re-sults can reflect the general trends for the parent samplein Ghisellini et al. (2014).The Spearman rank correlation test is used to explorethe correlations. It is taken as correlation when the sig-nificance is larger than 95% (P < . − /e )objects from our sample and derive the correlation re-sults for the sub-sample, this process is performed for10000 times. We record the percentages which could beconsidered as correlations (Peterson et al. 1998).The top panels of Figure 3 show the scatters of n pairs /n p and central engines. The results of the cor-relation test are summarized in Table 1. No correlationis shown between n pairs /n p and black hole mass, diskluminosity, or Eddington ratio. Table 1 also lists thepercentages from the bootstrapping technique. The re- nergy dissipation of blazar -2 0 2 4 6Log n pairs /n p N u m be r -2 -1 0 1 2Log σ N u m be r -1.5 -1.0 -0.5 0.0 0.5Log η N u m be r Figure 2.
From left to right are the distributions of n pairs /n p , σ , and η , respectively. −20246 Log n pa i r s / n p −2−101 Log σ BH −1.5−1.0−0.50.0 Log η
42 44 46 48Log L disk −2 −1 0 1Log L disk /L Edd
Figure 3.
The correlation between energy dissipations of jet and central engines. Left: Black hole mass. Middle: diskluminosity. Right: Eddington ratio. The top label is the correlation between n pairs /n p and central engines. The middle label isthe correlation between σ and central engines. The bottom label is the correlation between η and central engines. sults of bootstrapping confirm that no correlation existsbetween composition and central engine.It seems that σ has weak correlation with disk lumi-nosity (middle panels of Figure 3, Table 1). The resultsof bootstrapping find that 24% of the sub-samples canderive correlations between these two parameters. Nocorrelation is found for σ versus black hole mass, and σ versus Eddington ratio. The radiative efficiency alsoshows no correlation with black hole mass, disk lumi- nosity, and Eddington ratio (bottom panels of Figure 3,Table 1). DISCUSSIONSGodfrey & Shabala (2013) defined a normalizationfactor g to reflect the uncertain physics in lobes, such asthe composition, magnetic field strength, electron spec-trum, jet speed, electron Lorentz factor. The value of g can vary from 1 to 8 for different situations (theirFigure 1). As suggested by Godfrey & Shabala (2013) Fan, Wu & Liao
Table 1.
The results of correlation analysis. Columns 1 and2 are the two parameters which are applied for correlationanalysis, respectively. ρ is the correlation coefficient of theSpearman correlation test. P is the chance probability ofno correlation. The last column lists the percentage fromthe bootstrapping technique for which can be considered ascorrelation. Par A Par B ρ P Per n pairs /n p M BH n pairs /n p L disk n pairs /n p L disk /L Edd -0.08 0.51 0.01 σ M BH σ L disk σ L disk /L Edd -0.07 0.57 0.01 η M BH η L disk η L disk /L Edd -0.06 0.57 0.01 from some observational concerns, g = 2 is used in ourEquation 2. Willott et al. (1999) also defined f factorto consider the similar uncertainties in P kin - L rela-tion. They argued that 1 ≤ f ≤
20. For our analysishere, another uncertainty comes from the energy losseswhich could be used to form the large scale structureafter the power leaving the dissipation region of blazar.This can lead to an underestimation of P kin in blazar re-gion about a factor of a few (Hardcastle & Krause 2013).Considering these uncertainties for different conditions,we try several other relations in the literature for ouranalyses. Firstly, we add another factor of 2 in Equa-tion 2 to account for the underestimation due to en-ergy losses from structure expanding. The number ofsources whose pair fraction can be calculated increasesto 110 . The mean values of n pairs /n p , σ and η are5.16, 0.33 and 0.33, respectively. Interestingly, we notethat the correlation between σ and disk luminosity getsmore significant, with P = 1.50 × − . Then we considerthe relation P kin = f / × ( L W Hz − sr − ) / in Willott et al. (1999) with f = 5 (Hardcastle 2018)and f = 10, and P kin = 5 × ( L W Hz − sr − ) . in Ineson et al. (2017). The mean values of n pairs /n p , σ and η range from 6.71 to 12.59, 0.39 to 0.59, and 0.35 to0.47, respectively. The results are well consistent withthose from Equation 2. The uncertainty of jet power for a small parts of the133 objects may come from the SED fitting, e.g., the elec-tron spectrum (Chen 2014), or the duty cycle of blazar activity(Liodakis et al. 2017).
Figure 1 shows that the jet power estimated from thelow-frequency radio emission is lower than that fromSED fitting assuming one proton per electron. As-suming the jet power estimated from the low-frequencyradio emission is correctly reflect the real jet power,we constrain the jet composition by comparing the jetpower derived by these two methods. The results mani-fest that the jet of blazar contains an important frac-tion of eletron/positron pairs, with n pairs /n p ∼ P kin / Γ (where Γ is the bulkLorentz factor of jet) for FSRQs and BL Lacs had simi-lar distributions, which also supported that the materialenergy of jets was independent on accretion mode.Using the jet power estimated from low-frequency ra-dio emission and the magnetic power estimated fromthe SED fitting, we find σ ∼ . σ & − ), the particle ac-celeration would be suppressed (Sironi et al. 2015, butalso see Baring et al. 2017). Meanwhile, the accelera-tion through the magnetic reconnection would be effi-cient (Sironi & Spitkovsky 2014). Our results indicatethat the magnetic reconnection may be the main sourceto accelerate non-thermal particles in blazars (Sikora2016). Janiak et al. (2015) computed the theoreticalSEDs of blazars and concluded that σ ≪ n p /n e = 1. Once eletron/positron pairs exist in jets,the jet production efficiency would reduce. Thereforethe high Compton dominance can be produced even σ & σ shows a possible cor-relation, although very weak with disk luminosity (Fig-ure 3, Table 1). If this is intrinsic, it would suggest thatthe dissipation region in brighter disk is closer to thecentral engine, because σ decreases with the distance nergy dissipation of blazar σ ∝ r − α (although the de-tailed value of α is under debate, e.g., Kirk & Mochol2011; Granot et al. 2011; Takata et al. 2017). This canbe caused by the increasing cooling with the higher diskradiation due to the external Compoton process.The radiative efficiency η ∼ . η can be as high as 90% (Zhang & Yan 2011).The high efficiency also suggests that magnetic recon-nection is important to power the radiation of blazars,which is consistent with the strong magnetization in jet.It also needs to note other possibilities for the dis-crepancy of the jet power estimations between differentmethods. These include that the jet power estimated bythe low-frequency radio emission is underestimated dueto the intermittent activity of jet (Sikora 2016), or theremnant sources in the sample (Hardcastle 2018). If thisis the fact, n pairs /n p , σ and η should be overestimated.But for our sample, the Eddington ratio is still high( > . SUMMARYThe composition, magnetization and radiative effi-ciency are important to constrain the mechanisms of jetformation, particle acceleration and energy dissipation of blazar. In this work, we explore these issues withthe recently released TGSS ADR1 catalog at 150 MHz.Our results manifest that, 1) The leptons are dominatedon number density in blazar zone, with the ratio be-tween electron/positron pairs and protons about 10. 2)The magnetization parameter of blazar is close to unity.The radiative efficiency is about 40%, which is muchlarger than prediction of shock model. Both the strongmagnetization and high efficiency suggest that magneticreconnection process may be important to power the ra-diation of blazars. 3) No significant correlation is foundbetween the composition, magnetization parameter, ra-diative efficiency and black hole mass, disk luminosity aswell as Eddington ratio, except that the magnetizationparameter shows possible correlation with disk luminos-ity.We are grateful to the anonymous referee for construc-tive comments and suggestions that greatly improvedthis manuscript. We thank Xin-Wu Cao and LiangChen for useful discussions. This research has made useof the VizieR catalogue access tool, CDS, Strasbourg,France. The original description of the VizieR servicewas published in A&AS 143, 23. This research is sup-ported by National Natural Science Foundation of China(NSFC; grants 11573009, 11622324 and 11703093) andGuizhou Provincial Key Laboratory of Radio Astron-omy and Data Processing.
Facilities:
GRMT (TGSS ADR1)REFERENCES
Avara, M. J., McKinney, J. C., & Reynolds, C. S. 2016,MNRAS, 462, 636Baring, M. G., B¨ottcher, M., & Summerlin, E. J. 2017,MNRAS, 464, 4875Bˆırzan, L., McNamara, B. R., Nulsen, P. E. J., Carilli,C. L., & Wise, M. W. 2008, ApJ, 686, 859Blandford, R. D., & Payne, D. G. 1982, MNRAS, 199, 883Blandford, R. D., & Znajek, R. L. 1977, MNRAS, 179, 433Cao, X. 2016a, ApJ, 833, 30—. 2016b, ApJ, 817, 71Cavagnolo, K. W., McNamara, B. R., Nulsen, P. E. J.,et al. 2010, ApJ, 720, 1066Celotti, A., & Ghisellini, G. 2008, MNRAS, 385, 283Chen, L. 2014, ApJ, 788, 179—. 2018, ApJS, 235, 39Corbel, S., Kaaret, P., Jain, R. K., et al. 2001, ApJ, 554, 43Croston, J. H., Ineson, J., & Hardcastle, M. J. 2018,MNRAS, 476, 1614 Daly, R. A., Sprinkle, T. B., O’Dea, C. P., Kharb, P., &Baum, S. A. 2012, MNRAS, 423, 2498Dunn, R. J. H., Fabian, A. C., & Celotti, A. 2006, MNRAS,372, 1741Fan, X.-L., Bai, J.-M., & Mao, J.-R. 2016, Research inAstronomy and Astrophysics, 16, 173Fender, R. P., Belloni, T. M., & Gallo, E. 2004, MNRAS,355, 1105Ghisellini, G. 2012, MNRAS, 424, L26Ghisellini, G., & Tavecchio, F. 2010, MNRAS, 409, L79—. 2015, MNRAS, 448, 1060Ghisellini, G., Tavecchio, F., Foschini, L., et al. 2010,MNRAS, 402, 497Ghisellini, G., Tavecchio, F., Maraschi, L., Celotti, A., &Sbarrato, T. 2014, Nature, 515, 376Giannios, D., Uzdensky, D. A., & Begelman, M. C. 2009,MNRAS, 395, L29
Fan, Wu & Liao
Godfrey, L. E. H., & Shabala, S. S. 2013, ApJ, 767, 12Granot, J., Komissarov, S. S., & Spitkovsky, A. 2011,MNRAS, 411, 1323Guo, F., Li, H., Daughton, W., & Liu, Y.-H. 2014, PhysicalReview Letters, 113, 155005Hardcastle, M. J. 2018, MNRAS, 475, 2768Hardcastle, M. J., & Krause, M. G. H. 2013, MNRAS, 430,174Hurley-Walker, N., Callingham, J. R., Hancock, P. J., et al.2017, MNRAS, 464, 1146Ineson, J., Croston, J. H., Hardcastle, M. J., & Mingo, B.2017, MNRAS, 467, 1586Intema, H. T., Jagannathan, P., Mooley, K. P., & Frail,D. A. 2017, A&A, 598, A78Janiak, M., Sikora, M., & Moderski, R. 2015, MNRAS, 449,431Kang, S.-J., Chen, L., & Wu, Q. 2014, ApJS, 215, 5Kawakatu, N., Kino, M., & Takahara, F. 2016, MNRAS,457, 1124Kino, M., Kawakatu, N., & Takahara, F. 2012, ApJ, 751,101Kino, M., Takahara, F., Hada, K., et al. 2015, ApJ, 803, 30Kirk, J. G., & Mochol, I. 2011, ApJ, 729, 104Komissarov, S. S. 2011, Mem. Soc. Astron. Italiana, 82, 95Liodakis, I., Pavlidou, V., Hovatta, T., et al. 2017,MNRAS, 467, 4565Lyubarsky, Y. E. 2010, MNRAS, 402, 353McNamara, B. R., Rohanizadegan, M., & Nulsen, P. E. J.2011, ApJ, 727, 39Meier, D. L., Koide, S., & Uchida, Y. 2001, Science, 291, 84Merloni, A., & Heinz, S. 2007, MNRAS, 381, 589Nalewajko, K., & Begelman, M. C. 2012, MNRAS, 427,2480Nalewajko, K., Sikora, M., & Begelman, M. C. 2014, ApJL,796, L5Narayan, R., & McClintock, J. E. 2012, MNRAS, 419, L69Nemmen, R. S., Georganopoulos, M., Guiriec, S., et al.2012, Science, 338, 1445Padovani, P. 2017, Nature Astronomy, 1, 0194 Padovani, P., Alexander, D. M., Assef, R. J., et al. 2017,A&A Rv, 25, 2Peterson, B. M., Wanders, I., Horne, K., et al. 1998, PASP,110, 660Pjanka, P., Zdziarski, A. A., & Sikora, M. 2017, MNRAS,465, 3506Potter, W. J., & Cotter, G. 2013, MNRAS, 436, 304Punsly, B. 2005, ApJL, 623, L9Rusinek, K., Sikora, M., Kozie l-Wierzbowska, D., &Godfrey, L. 2017, MNRAS, 466, 2294Russell, D. M., Gallo, E., & Fender, R. P. 2013, MNRAS,431, 405Shen, Y., Richards, G. T., Strauss, M. A., et al. 2011,ApJS, 194, 45Shimwell, T. W., R¨ottgering, H. J. A., Best, P. N., et al.2017, A&A, 598, A104Sikora, M. 2016, Galaxies, 4, 12Sikora, M., & Begelman, M. C. 2013, ApJL, 764, L24Sikora, M., Stasi´nska, G., Kozie l-Wierzbowska, D.,Madejski, G. M., & Asari, N. V. 2013, ApJ, 765, 62Sikora, M., Stawarz, L., & Lasota, J.-P. 2007, ApJ, 658, 815Sironi, L., Keshet, U., & Lemoine, M. 2015, SSRv, 191, 519Sironi, L., & Spitkovsky, A. 2014, ApJL, 783, L21Takata, J., Tam, P. H. T., Ng, C. W., et al. 2017, ApJ, 836,241Tchekhovskoy, A., Narayan, R., & McKinney, J. C. 2010,ApJ, 711, 50—. 2011, MNRAS, 418, L79Urry, C. M., & Padovani, P. 1995, PASP, 107, 803Wardle, J. F. C., Homan, D. C., Ojha, R., & Roberts, D. H.1998, Nature, 395, 457Willott, C. J., Rawlings, S., Blundell, K. M., & Lacy, M.1999, MNRAS, 309, 1017Wu, Q., Cao, X., & Wang, D.-X. 2011, ApJ, 735, 50Yuan, F., & Narayan, R. 2014, ARA&A, 52, 529Zhang, B., & Yan, H. 2011, ApJ, 726, 90Zhang, B., Liang, E., Page, K. L., et al. 2007, ApJ, 655, 989Zhang, J., Liang, E.-W., Sun, X.-N., et al. 2013, ApJL, 774,L5Zhang, J., Sun, X.-N., Liang, E.-W., et al. 2014, ApJ, 788,104 nergy dissipation of blazar F an , W u & L i a o Table 2 . The source information.