Recent progress on VLBI study of the jets in Narrow - line Seyfert 1 galaxies

1. RecentprogressonVLBIstudyofthejetsinNarrow-lineSeyfert1galaxiesRecentprogressonVLBIstudyofthejetsinNarrow-lineSeyfert1galaxies Minfeng Gu (SHAO) Collaborators: ZhiqiangShen, Yongjun Chen (SHAO); Weimin Yuan (NAOC);S. Komossa, J.A. Zensus (MPIfR); Hongyan Zhou (USTC); K. Wajima (KASI); 2017-12-04 East-AsiaAGNWorkshop2017 Kagoshima,Japan

2. Outline • Introduction radio-loudAGNs narrow-lineSeyfert1galaxies(NLS1s) • Theradio structure of radio-loud NLS1s progress VLBAobservations comparisonwithotherAGNs scenarios • Ongoingandfuturework • Summary

3. AGN structure and radio-loud • Radio loudness: R>10 radio-loud; <1 radio-quiet; 1<R<10 radio intermediate (Kellermann et al. 1994) • Radio luminosity: (Miller et al. 1990) only 10%–20% were qualified as radio-loud objects in optically selected samples (e.g., Kellermann et al. 1989; Hooper et al. 1995). Urry & Padovani (1995)

4. Narrow Line Seyfert 1 galaxies (NLS1s) • Balmer lines broader than forbidden lines but narrower than normal type 1 AGNs (FWHM < 2000km/s) • Peculiar properties: softer X-ray spectra, fast X-ray variability, strong optical Fe IIs • Relatively small black hole mass 106-8 M(e.g. Collin & Kawaguchi 2004), however still controversial: viewing angle, radiation pressure … • High accretion rate Lbol >> 0.1 LEdd (up to Lbol/Ledd ~ 1) • Accretion possible via slim disk (e.g. Abramowicz et al. 1988; Mineshige et al. 2000) Boroson (2002)

5. Radio-loud NLS1s (RLNLS1s) • NLS1s were long thought to be radio-quiet. Radio-loud NLS1s are rare, but they do exist (Siebert et al 1999 ; Grupe et al. 2000; Zhou & Wang 2002; Zhou et al. 2003; Whalen et al. 2006; Komossa et al. 2006; Yuan et al. 2008). • RL NLS1s sample from SDSS: >100 out of ~2000 NLS1s (Zhou et al. 2006) – RL (R>10) fraction = 7%; very radio-loud (R>100) NLS1s: very rare – 23 from SDSS DR5 (Yuan et al. 2008). • Outof11101 NLS1s:555detectionsinFIRST(5%),378radio-loud(3.4%)(Rakshitetal.2017) • Komossa et al. (2006): the radio loud NLS1 galaxies are generally compact, steep spectrum sources. • Several of the radio loudest NLS1 galaxies displayblazar characteristics and harbor relativistic jets (Doi et al. 2007; Zhou et al. 2007; Yuan et al. 2008) • Flat radio spectra, large-amplitude flux and spectral variability, compact radio cores, very high variability brightness temperatures, enhanced optical continuum emission, flat X-ray spectra, and blazar-like SEDs.

6. Compact at arcsec scale • Arcsecond-resolution observations have resolved the structures of only a few NLS1s because they are generally quite compact (e.g. Ulvestad et al. 1995, Moran et al. 2000, Stepanian et al. 2003, Doi et al. 2012). • Kpc-scalestructurehasbeedetectedinonlyelevenNLS1s(Doi+12,Richards&Lister2015,Mrk783-relic,Congiuetal.2017)

7. Host galaxies • Almost all the low redshift NLS1s are hosted by spiral galaxies (Crenshaw et al. 2003, Deo et al. 2006)

8. Host galaxies of RLNLS1s:unclear • 1H0323+342:HSTandNOTimages–one-armedgalaxymorphologyoracircumnuclearring–thespiralarmofthehostgalaxyortheresidualofagalaxymerger(Zhouetal.2007,Antonetal.2008,LeonTavaresetal.2014) • A bulge-disk-bar(pseudobulge) morphology in PKS 2004-447 (Kotilainen et al. 2016) • A barred lenticular galaxy (SB0), pseudobulge in FBQS J1644+2619 (Olguin-Iglesias et al. 2017) • SDSSimages Zhou et al. (2007), Foschini (2011)

9. RLNLS1sinoverallAGNs • Relativelysmaller MBH,and larger accretion rate. • Two sequences on R - Eddington ratio plane (Sikora et al. 2007).

10. Jetformation • Jets in BHBs and AGNs:similar? • Jet-production related parameters: black hole mass, spin, host galaxy, accretion rate, environments … Fender et al. (2004) Yuan & Narayan (2014)

11. Progress of VLBI studies • Fiveradio-loud NLS1s: RXS J16290+4007, RXS J16333+4718, and B3 1702+457 (VLBA Gu & Chen 2010, Doi et al. 2011, JVN Doi et al. 2007), RX J0806.6+7248 (JVN Doi et al. 2007, VLBA Doi et al. 2011), B2 1111+32 (EVN, VLBA Chen & Gu in prep.). • Sixgamma-ray NLS1s: compact at kpc scale, but resolved at pc scale (SBS 0846+513, PKS 1502+036 and PKS 2004-447, VLBA D’Ammando et al. 2012, Orienti et al. 2012,2015); SDSS J094857.31+002225.4 (VLBA Doi et al. 2006, Foschini et al. 2011, global e-VLBI Giroletti et al. 2011), 1H 0323+342 (VLBA Zhou et al. 2007), FBQS J1644+2619 (JVN Doi et al. 2007, VLBA Doi et al. 2011). • In total, only about 11 RLNLS1s(outof117) have published VLBI images. • Fourteen RLNLS1swithFIRST1.4GHzflux>10mJy(VLBA, Gu et al. 2015),includingtwogamma-raysources:SDSSJ1443+4725,SDSSJ1305+5116(Liaoetal.2015,2017tobesubmitted),andSDSSJ1246+0238(D’Ammando et al.2016) • NineteenRLNLS1swith FIRST 1.4GHzflux density >=3.5 mJy(VLBA,Guetal.tobesubmitted) • Onegamma-raysource:SDSSJ1222+0413(Yaoetal.2015,MOJAVE) • VERA observations of 12 NLS1s at 22 GHz (Doi et al. 2016)

12. Early studies • Theexistenceofrelativisticjets(e.g.highbrightnesstemperature),either intrinsicallyradioloud(e.g.steep-spectrumsources),orapparentlyradioloudduetojetbeamingeffect(e.g.flat-spectrum,highbrightnesstemperature)(Doietal.2007; Gu & Chen 2010; Doi et al. 2011) gamma-raydetection (D’Ammando+16)

13. Gamma-ray RLNLS1s • Core-jet structure,highbrightnesstemperature,superluminalorsubluminalmotions,flatspectrum(D’Ammando+16,Lister+16,Schulz+16) • Basedonthesuperluminalmotion,atleastsomesourceshaveLorentzfactorsinexcessof10,andviewingangleslessthan10degree(Lister+16) • However,seeSDSSJ1443+4725,J1305+5116andJ1246+0238inoursample

14. PMN J0948+0022 • A bright and compact component with an inverted spectrum, and a faint jet feature. • Beaming effect indicated from the variable emission and high brightness temperature. • First Fermi-detected NLS1s - third class of gamma-ray AGNs. • Superluminalmotion:11.5c(MOJAVE,Lister+16) 15 GHz VLBA (Foschini et al. 2011) 22 GHz global e-VLBI (Giroletti et al. 2011)

15. SBS 0846+513(z=0.5835): (D’Ammando et al. 2013) • Strong γ -ray flares; an apparent superluminal velocity of (5.84± 0.88)c (MOJAVE,Lister+16). • Blazar-like; at the low end of the blazar’s black hole mass distribution.

16. PKS 1502+036 • High frequency peakers (HFPs) selected by Dallacasa et al. (2000), but rejected due to the variability (Orienti et al. 2008). • Apparentspeed:1.14c(MOJAVE,Lister+16)

17. PKS 2004-447 • Compact steep spectrum source: a steep spectrum at high frequency (above 8.4 GHz), the absence of significant flux density variability, and unresolved atarcsecond-resolution (e.g. ATCA) (Gallo et al. 2006). • Included in the CRATES catalog of flat spectrum objects (Healey et al. 2007) due to its flatter spectrum below 4.8 GHz. • 1.5 GHz VLBA image8.4GHzTANAMIimage(Schulz+16) (Orienti et al. 2012).

18. 1H 0323+342: hosted in a spiral galaxy?core + weak extended (MOJAVE source, 1.2 pc/mas) (propermotion:9.02c,MOJAVE,Listeretal.2016) Zhou et al. (2007), Foschini (2011)

19. SDSSJ1222+0413 • Atthehighestredshift(z=0.966,Yao+15) • Apparentspeed:0.94c(MOJAVE,Listeretal.2016)

20. Results of ourVLBA observations(Gu et al.2015,ApJS, 221, 3,Guetal.2016,AN,Gu2017,IAUS) • Thelargestsampleof117RLNLS1s(R>10)hasbeenconstructedby combining various samples available so far, which are mostly from our own work. • Fourteen RLNLS1swithFIRST1.4GHzflux>10mJywere observed with a total of 15 hours at 5 GHz using VLBA on Oct. and Nov., 2013. • Theadditional 19 RLNLS1s with FIRST flux density >=3.5 mJyhavebeenobservedwithVLBAinatotalof 24 hoursinNov.andDec. 2014, yielding the biggestVLBI sample of 33 sources. • Thisisthe firstandlargest systematic high resolution radio study of RLNLS1s. • Thejetphysics:thejetformationintheseaccretionsystems. • Theaccretion–jetrelation:earlystagesinbothactivities? • Feedback:jet–cloudinteractions?

21. Sample

22. Morphology • Generally compact: seven sources show compact core only, and other seven objects have core-jet structure. Coreonly

23. Core-jet

24. Radiospectra • Fromthe multi-bandradio data, seven sources show flat or even inverted spectra, while steep spectra are found in restobjects. Steepradiospectrum–resembletoCompactSteepSpectrumsources Flatradiospectrum–blazarlike (seealsoOrientietal.2015forVLBAimages)

25. Polarization • Thehigher fractional polarization in jets:the strong Faraday rotation in nuclei region due to the highplasma density, and/or depolarization due to the complex core structure. • Fractional polarization variations in the jet:the jet-ISM interactionat the locations of high fractional polarization due to the jet bulk motion

26. Gamma-ray sources • 1)SDSSJ1246+0238:flat-spectrum, • coreonly,logTb=9.7(K), • TS=79, Γ=2.59±0.09(D’Ammando et al.2016) • 2)SDSSJ1443+4725:logTb=10.3(K),thefirstRLNLS1withgamma-rayemissionathighsignificancefromFermi/LATandwithradiopropertiessimilartocompactsteep-spectrumsources(TS~70,Liao+15,+17).

27. 3)SDSSJ1305+5116:steepspectrum(151MHz–4.85GHz),andcompact(<10kpcfromFIRSTimage)3)SDSSJ1305+5116:steepspectrum(151MHz–4.85GHz),andcompact(<10kpcfromFIRSTimage) • Core-jetstructure:corelogTb~10.8K;TS~28.5

28. Brightnesstemperature • The core brightness temperature ranges from 108.4to 1011.7K with a median value of 1010.1K,indicatingthatthe beaming effect is generally not significant. • Typicalblazars have 1011 - 1013 K with a medianvalue near 1012K (Kovalev et al. 2005, 2009). • Thebulk jetspeed may likely be low in our sources(seealsoAngelakiset al. 2015,Richards & Lister 2015). • The Lorentz factors obtained for 1H 0323+342 and SBS 0846+513 are at the lower end of the blazar Lorentz factor distribution(Fuhrmann+16) Kovalevetal.2009

29. ComparisonstotypicalCSSs:VLBImorphology • Mosthigh-powerCSSsshowdoubleortriplemorphologies(O’Dea1998,Dallacasaetal.2013)

30. Core and core-jet in low-power CSSs • Thecompactcoreonly,orcore-jetstructurehavebeendetectedinrelativelylow-powerCSSsources(Kunert-Bajraszewska et al. 2006; Kunert-Bajraszewska & Marecki 2007)

31. Evolution • Oursources occupy thespace below the main evolutionary path of radio objects(An&Baan2012). • However,thedifferenceisthatoursourceshavesmallblackholemassandhighaccretionrate.

32. Scenario: lowjetspeed • a)The outflows/jets accelerated from the hot corona above the disk by the magnetic field and radiation force, with high mass loss rate but low speed (Cao 2014). • TheMBH - Γcorrelation:the faster moving jets are magneticallyaccelerated by the magnetic fields threading the horizon of more rapidly rotating black holes(Chai,Cao&Gu 2012). • b)The low jet speed could bedue to the low spin,supported by low/intermediate average spins (a < 0.84) from compositebroad Fe K line (Liu et al.2015).

33. Summary • Powerful jets may present in systems with small MBH and high accretion rate, e.g. NLS1s. • The jet propertiesofradio-loudNLS1s are diverse on mas scale, interms of themorphology and spectral shape. • The jet speed in these sources is likely low, which is due toeither thejetaccelerationbythemagneticfieldandradiationforce,orlowspininBZmechanism. • The slow jet speed ormildly relativistic jet, in combination with the low kinetic/radio power, couldbe responsible for the compact VLBA radio structure in most sources. • Thegamma-rayemissionhasbeendetectedin both flat- and steep-spectrumNLS1s. Thanksforyourattention!