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Understanding Seyfert Jets: Markarian 78 Reveals Jet-Gas Interactions in AGN

Explore jet-gas interactions, jet properties, physical processes, and energies in Markarian 78, providing insight into Seyfert jets. Analyzing emission line data and radio images unveils key components and behaviors of these jets.

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Understanding Seyfert Jets: Markarian 78 Reveals Jet-Gas Interactions in AGN

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  1. Seyfert Jets : weak, slow & heavy Mark Whittle (Virginia) David Rosario (Virginia) John Silverman (Virginia/CfA) Charlie Nelson (Drake) Andrew Wilson (Maryland) • Markarian 78 provides ~ideal access to : • Jet-gas interactions • Nature of jets in radio quiet AGN AJ papers – I: Data, II: Ionization, III: Jet properties

  2. JET Overall Context } • Several inter-dependent components : Jet flowrelativistic material “Lobe”ionized line-emitting gas ISMthermal (low density) gas LOBE Relativistic gas : Line Emitting gas : ISM Thermal gas :

  3. Overall Context • Several physical processes : • entrainment of ISM by jet • acceleration of line-emitting gas • lobe expansion into ISM

  4. Available Data • Emission Line image : [OIII] (HST) • Radio image : 3.6cm (VLA) • Emission Line kinematics (HST-STIS) • Briefly review this 

  5. E-fan E-fan W-knot W-lobe Overlay : Radio (contours) & [OIII] (image)

  6. 4 STIS Slit Positions

  7. STIS low dispersion spectral data

  8. STIS high dispersion [OIII] 5007 data

  9. Slit B : kinematic measurements Peak Velocity FWHM -2 -1 0 +1 +2 +3 East Nuc West

  10. Extinction Density Line flux Mass Momentum KE

  11. Region Properties 3 regions : W-knot / E-fan / W-lobe Age~ size/velocity : ~ 0.4 / 4 / 8 Myr Ionized gas : Mass : ~ 0.4 / 1.0 / 1.1 x 106 Msun Filling factor : ~ 30 / 1.5 / 0.5 x 10-4 Covering factor : ~ 0.5 / 0.5 / 0.5

  12. Pressures : Prel, Pem, Prad • High: 1-few x 10-10 dyne cm-2 • All decrease with radius (~ r -1) • both consistent with presence in bulge ISM • Prel~ Pem (~ Prad) : • pressure balance between relativistic & ionized gas • Prelcan drive lobe expansion into ISM at V[OIII] • Prel & Prad can’tquite accelerate ionized gas • may need dynamical (ram) pressure of jet

  13. Energies & Luminosities : For each region, independently : LUV(intercept) ~ 1000 x 1040 erg s-1 Lem~ 10L[OIII]~ 1000 Lmec~KE/age ~ 1 Lrel ~ Erel/age ~ 1 (Lexp~1) Lradio~ 0.2 • NLR ionized by nuclear UV (not shocks) • Nuclear photon power dominates all others • KEgas & Eexp come from radio-emitting flow

  14. The Jet Flow • Jet properties are illusive – but important • Radio provides some access : • pressures, stored internal energy • Emission lines very useful : • estimate jet’s luminosity & momentum • We follow approach of Bicknell et al (’98) • But, with different starting assumptions • these lead to very different jet properties

  15. Starting Assumptions • Jet Luminosity : • B98 : Lj~ Lem~ 100L[OIII] (since shock generated) • W04 : Lj~ (EKE+αeErel)/age ~αeElobe/age • Lj(W) ~ 10-3 Lj(B) [~1040.5 erg s-1] • Jet Momentum Flux : • B98 : Fj/Aj ~ Pram~ ρemV2sh~ ρemV2[OIII] • W04 : Fj/Aj ~ Pram ~ αmGem/age /Aj • Fj(W) ~ 10-2Fj(B) [~1033.5 dyne]

  16. JET LUMINOSITY Emission Lines : Lem Bicknell et al ‘98 Shock Lj Lj~Lem~100 x L5007 Our analysis EKE ~ Σ½M V2 Lj ~1040.5 erg s-1 Elobe~ PV ~ αeErel Lj~(EKE + αeErel)/tage αe~ αsyn αad αff ~ 2 – 10 For Mkn 78 & other Seyferts : Lj (us) ~ 10-3 xLj (B98)

  17. Bicknell et al ‘98 Shock nem~ 103cm-3 ρemVsh Pram~ ρjVj2 2 Emission Line Cloud ρjVj2 ~ ρemVsh 2 Impulsive acceleration JET MOMENTUM FLUX Vsh~Vem~ 500 km/s Our analysis Gem ~ ΣM V Fj Gradual acceleration Fj~αmGem / tage ~1033.5dyne αm~ αdrag αlcf ~ 2 – 5 For Mkn 78 & other Seyferts : Fj (us) ~ 10-2 xFj (B98)

  18. Starting Assumptions • Jet Luminosity : • B98 : Lj~ Lem~ 100L[OIII] (since shock generated) • W04 : Lj~ (EKE+αeErel)/age ~αeElobe/age • Lj(W) ~ 10-3 Lj(B) [~1040.5 erg s-1] • Let Momentum Flux : • B98 : Fj/Aj ~ Pram~ ρemV2sh~ ρemV2[OIII] • W04 : Fj/Aj ~ Pram ~ αmGem/age /Aj • Fj(W) ~ 10-2Fj(B) [~1033.5 dyne] • Our jets are much weaker

  19. Derivation of jet properties } Model jet as 2 component system : 1 : Relativisticratio defined by filling factor : 2 : Thermalffrel = (1– ffth) assume pressure balance : Pth= Prel~ B2min/8π • Energy : Ej~KEth+(5/2) Pth+4Prel [KErel ~ 0] • Momentum : Gj~ Gth+ Grel~ Gth [Grel ~ 0] • Use estimates of Ej Gj Bmin Aj tage : to derive many jet properties

  20. Jet Properties • Jet energy (~1040.5 erg s-1) & momentum fluxes (~1033.5 dyne)both dominated by thermal gas • RKE = KEj/Eint= 10 / 2 / 1 (≡Mj2) • decrease suggests KE converted to internal • Ram pressure : Pram=Fj/Aj= 30 / 7 / 4 x Prel • Pram(W04) ~ 10-2 – 10-3 Pram(B98) • Our jet is gentle • Pram is significantly greater than Prel & Prad • hydrodynamic acceleration of ionized gas • shocks in ionized gas are slow~ 10-50 km s-1

  21. Jet Properties • Jet velocity : Vj= 2Lj/ Fj (1 + Rke-1) • Vj ~ 0.3 – 3 x 103 km s-1 ~1 – few x V[OIII] • cf. Vj (B98) ~ 15 – 90 x 103 km s-1 • our jet is slow • Jet density : ρj=Fj/PramAj~0.1–5cm-3 ~ρISM • consistent with entrained ISM • our jet is dense : η = ρj /ρISM ~ 1 • future simulations should consider η ~ 1 jets

  22. Jet Properties • Jet temperature & Mach # : • Tth ~ Pj /knth106.5– 107.5 K • temp ~ 0.2 – 0.7 fully virialized (cf. Pram >Prel) • Mj~ 5 / 2.5 / 1.5  jet istransonic  efficient entrainment & decollimation • Jet mass transport : Mth~Fj/ Vj~0.5 Msun yr-1 • Mthtage~ 106Msun ~thermal content of lobe • Jet supplies lobe’s thermal component ? · ·

  23. Jet Properties • Jet synchrotron efficiency : • Rsyn ~ Lradio /Lj~ Lradio tage /Elobe ~ 0.1 Fff P-103/4 t6~ 1-few % • similar to other radio sources (e.g. CSS & FR-I,II) • not obvious why : very different types of jet • cf. Rsyn(B98)~ 10-4 [ <<Rsyn(us)] •  sub-equipartition fields, or •  low ffrel  thermal component dominates

  24. Jet Base / Inner Jet • Previous analysis applies to scales > 100pc  thermally dominated flow; slow & dense • Is the flow created like this? • could it start with ffrel = 1.0, then entrain thermal gas • probably not : need Fj-b ~ Fj-kpc Lj-b > Lj-kpc S8Ghz < 3mJy • implies Vj-b~ c and Lj-b ~ 1043erg s-1 • Most energy lost in core  bright radio  not seen • Jet created with thermal component may define nature of radio quiet jets note : can’t be pure thermal (Rsyn too high)

  25. Conclusions • Mkn 78 gives excellent access to jet properties • Must combine radio and emission line data  pressure, internal energy, KE, momentum, age • For three regions, we find : • Age sequence; ~106 Msun; low ff; high cf; • P ~ PISM; Prel ~ Pem ~ Prad; lobe expansion ;V[OIII] • LUV & Lem dominate; shocks ; Erel~ EKE • Model jet as 2 component : relativistic & thermal • follow Bicknell et al ’98 but don’t use shocks • instead, take Lj ~αeElobe/tage ; Fj ~ αmGem /tage • derive jet properties 

  26. Conclusions • The jet is weak : Lj ~ 1040.5 erg/s; Fj ~ 1033.5 dyne • Thermal gas dominates jet energy & momentum • Pram~ 4 - 30 Pint: gentle jet • adequate to accelerate ionized gas • drives slow shocks into ionized clouds (10-50 km s-1) • Jet velocity~ 1-few V[OIII] : relatively slow jet • Jet density~ ρISM : dense jet • Transonic : Mj~2-5 ; Tth~106.5K ; Rsyn~normal • Thermal content may fill radio lobe • Jet base : jet created with thermal component

  27. New HST Project : 1 or 2 slits on six other objects with evidence for JGI.

  28. Comparison : Ours is a kinder, gentler jet. Maybe more plausible ?

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