Jet-Gas Interactions in Seyfert Galaxies

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Jet-Gas Interactions in Seyfert Galaxies

• Mark Whittle (Virginia)
• David Rosario (Virginia)
• John Silverman (Virginia)
• Charlie Nelson (Drake)
• Andrew Wilson (Maryland)

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Outline

• Brief review of
• AGN Jets Emission lines
• Reasons to study jet-gas interactions
  (JGI)
• Case study of Seyfert Galaxy Mkn 78
• Observations data overview
• Heuristic description of JGI
• Ionization analysis
• Dynamical analysis

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Active Galaxies

• All galaxies have nuclear black holes
• Those currently accreting are active
• Accretion energy released in two forms

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A Photons

• Thermal non-thermal processes
• Broad SED Optical / UV / X-ray
• Large range in luminosity
• LINER ? Seyfert ? QSO

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AGN Spectral Energy Distribution (SED)
Radio far-IR optical
EUV X-ray
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Seyferts (NGC 4151) Low Luminosity
Quasars High Luminosity
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B Bipolar Outflows (Jets)

• Origin uncertain (MHD driven ?)
• Velocity uncertain
• Some relativistic, others not
• Content uncertain (pe- or ee- ?)
• Relativistic component e- B ? radio
• Other (thermal) components ?
• Large luminosity range
• Radio loud (radio galaxies/QSRs)
• Radio quiet (Seyferts/QSOs)

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(No Transcript)
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Seyfert Galaxy Mkn 573 Flux few mJy Radio Quiet
Radio Galaxy 3C 296 Flux few Jy Radio Loud
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Emission Lines

• From ionized gas
• Te 104 K, ne 102 109 cm-3
• Ionization mechanism ?
• Photoionization (yes)
• Shock related (maybe with jets?)
• Profiles reveal (Doppler) velocities
• BLR (R 10-2pc, V2 GMBH/R)
• NLR-1 (R 1 kpc, V2 GMbul/R)
• NLR-2 (R 1 kpc, V jet related)
• Nested emission line regions
• BH ltlt AD ltlt BLR ltlt NLR ltlt Gal
• r/c min hr week 103 yr 104
  yr

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Why study JGI in Seyferts ?

• Jet-gas interactions occur in many contexts
• AGN (ISM/IGM)
• Stellar jets (DMC/ISM)
• Starburst winds (ISM/IGM)
• Laboratory for astrophysical hydrodynamics
• Seyfert ELRs allow important diagnostics
• Gas mass, velocity, KE, momentum, pressure
• Complements radio source pressure/energy

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Mkn 78 jet-gas archetype

• Early ground based data suggest
• prominent JGI
• Luminous triple radio source
• Strong double OIII profile
• FWHM gtgt gravitational velocities

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Mkn 78
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? Need HST resolution

• Unfortunately, Mkn 78 is quite distant
• cz 11,000 km/s ? 1 arcsec 700pc
• BT 15.2 MB -20.8
• Dull looking early type galaxy

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Mkn 78
KPNO 2.1m Red Continuum
30 arcsec
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Mkn 78 HST VLA Dataset

• VLA 3.6cm 8hr map
• HST images (FOC, PC, STIS, NICMOS)
• Continuum UV/green/near-IR
• Emission line OIII 5007
• HST spectra (STIS, FOS)
• 4 slits good spatial coverage
• 4 gratings low resolution UV optical
• high resolution OIII
  5007

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Near IR
NICMOS F160W
arcsec
Optical
STIS CCD clear
Dust lane
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OIII ?5007
arcsec
3.6cm radio
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OIII 5007 Image ENLR
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4 STIS Slit Positions
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STIS low dispersion spectral data
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STIS high dispersion OIII 5007 data
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Mkn 78 Case Study Jet-gas interactions

1. Heuristic description
2. Ionization study
3. Dynamical study
4. Jet properties

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Overlay Radio (contours) OIII (image)
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STIS high dispersion OIII 5007 data
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1. Heuristic Description

• Inner W-knot
• Jet ends disrupts some gas disturbance
• ? ? DMC enters disrupts flow recent
  interaction
• Eastern fan
• Jet deflected split lines blow-back
  shape
• ? ? Cloud inertia deflects jet (doesnt destroy
  it)
• ? ? Radial lateral motion induced (300 on 400)
• ? ? Intermediate age begun to disrupt cloud
• Outer W-lobe
• Components complex velocity no bow shock
• ? ? late stage dispersing cloud remnants leaky
  bubble

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2. Ionization Study

• Low dispersion spectra ? many line fluxes
• Compare line ratios with
• Ionization models (U, Am/i , Shock)
• Velocities (Vbulk FWHM)
• Location (radius)
• 4. Other things (radio/color/dust)

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Ionization mechanisms

• Three basic contexts explored
• U sequence AGN photoionization
• Am/i sequence AGN photoionization
• Shock sequence shock ionization
• Cartoon illustrates these ?

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1) U sequence
2) Am/i sequence
Neutral Back
Ionized front
Optically Thin clouds
AGN
AGN
Optically Thick Clouds Only
Optically Thick Thin Clouds
UV
UV
Ferlands, CLOUDY
Binette et al 96
Am/i Am/Ai 0.1 10
U Ni/Ne 10-2 10-3
Vsh
3) Shock sequence
shock
Collisionally ionized photo-ionized post-shock
gas
Auto-ionizing Shocks
Photo-ionized precursor
UV
Vsh 100 800 km/s
Doptia Sutherland 95, 96, 03
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Line ratios vs models

• General excitation/ionization
• Discriminators to separate Sh UAm/i
• Discriminators to separate U Am/i
• OI 6300 anomalous line
• Nuclear nitrogen enhancement

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Excitation All models OK U 10-2 10-3 A
30 90 Sh 500 300 km/s
U
Am/i
Sh
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U
Discriminators 1 Trends follow U A Dont follow
shocks
Am/i
Sh
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Discriminators 2 e.g. NeV, HeII,
OIII4363 U poor, favours Am/i trend
fits nicely Note weak NeV in Mkn
78 requires new Am/i
U
Am/i
Sh
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Ratios vs models Summary

1. Clean results because enough data to show trends
2. Current shock models are excluded
3. Photoionization by the AGN dominates
4. Gas contains both optically thick thin clouds

Now consider ratios vs gas velocity ?
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Excitation vs FWHM
Excitation vs V Vsys
Shock
Shock
Results summary ?
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Ratios vs velocity Summary

• Essentially no (v. weak) correlations
• ? ionization conditions independent of velocity
• 2. Shock model predictions very poor

Now consider ratios vs radius ?
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Excitation vs Radius

• Radius
• Strong correlation
• ? photoionization
• U drops r 1
• ? density r 1
• SII difficult to confirm
• Am/i drops with r
• ? more thin _at_ small r

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Final check UV Luminosity

• Check photoionization
• Can UV luminosity power emission lines ?
• But UV is invisible/obscured ?!
• Take FIR luminosity reprocessed UV
• LUV LFIR 4pd2FFIR 4pd2 2.6S60 S100
• Check
• LUV Lem 10 x L5007 as observed
• U NUV/ne 10-2.5 as observed

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3. Dynamical Study

• To go beyond heuristic description
• Need physical properties
• Aim to evaluate these throughout regions
• First consider ionized gas
• Then consider other components

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Slit B kinematic measurements
Peak Velocity
FWHM
-2 -1 0 1
2 3
East Nuc
West
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Extinction
Density
Line flux
Mass
Momentum
KE
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Simple Properties

• Three regions Inner knot / East fan / West lobe
• Region Age
• 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

Consider other components ?
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The Various Components
Thermal gas nth Pth Tth
Relativistic gas ffrel Prel B2/8p
Line Emitting gas ffem nem Pem Vem
ISM nism 1
Assume/show Prel Pth Pem Pism
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Pressures Prel, Pem, Pth, Prad

• Log P/k 6.5 / 6.0 / 5.5 K cm-3
• Quite high gt radio galaxy lobes
• All components deep within galaxy ISM
• All pressures drop with radius ( r -1)
• As expected for galaxy ISM context
• Approximate pressure balance between
• different components Prel Pem ( Pth)
• Relativistic radiation pressure too low
• to accelerate ionized gas (by x10)
• Need dynamical (ram) pressure of jet

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Energy Comparisons

• Relative energies in different parts
• UV (FIR) 1000 (1043 erg/s)
• Emission lines 1000
• Kinetic 1
• Relativistic 1
• Expansion /lobe 1
• Radio 0.2

Simple inferences ?
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Conclusions from energy comparisons

• Photons dominate by x1000 Lem LUV
• ? supports photo- over shock ionization
• ? should not derive Ljet from Lem (see
  later)
• 2. Expansion / KE / Relativistic all similar
• ? flows can accelerate gas power radio
  source

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4. Jet Properties

• Estimating jet energy and momentum
• Use emission line lobe properties
• Ej KEem ae Elobe 2-5 Elobe
• ae synchrotron loss adiabatic loss ffrel
• Lj Ej/Tage 2-5 x 1040 erg/s
• Gj am Gem 2-5 Gem
• am covering factor loss drag loss
• Fj Gj/Tage 2-5 x 1033 dyne

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JET LUMINOSITY
EKE S½M V2
Lj
Elobe PV aeErel
Lj (EKE aeErel )/tage
JET MOMENTUM
Gem SM V
Fj
Fj amGem / tage
am adrag alcf 2 5
ae asyn aad aff 2 10
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Jet Properties (model)

• Components
• Relativistic thermal ratio defined by ffrel
• Both move at Vj
• Pressure balance Prel Pth
• We know Prel from radio physics Bme/8p
• Energy Ej KEth Wth Wrel
• Wrel (4/3)Prel Wth (5/2) Pth
• Momentum Gj Gth Grel Gth
• Relativistic component has zero inertia

2
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Jet Properties (derived)

• Use Lj Gj Pj Aj to derive many properties
  (gt100pc)
• Thermal material dominates jet energy and
  momentum
• Relativistic gas has little/no momentum
• KEj/Uj Fj/Aj/Pj 10 / 3 / 2 ? KE
  dominates energy
• Jet velocity 1-few x Vgas
• 2Lj/Fj Vj 300 3000 km s-1
• Ram pressure dominates Pram 30 / 7 / 4 x
  Prel
• Can accelerate to Vem over Tage for Ncol
  1021 cm-2
• Only mild shocks Pram ?emVsh2 ? Vsh 10-50
  km s-1
• Not acceleration by impulsive shocks maybe
  wind/ablation

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Jet Properties (derived)

• Jet density (thermal) 0.1 - 5 cm-3
• Consistent with entrained ISM
• Jet temperature Tj Pj/njk 106 K
• 0.1-0.7 Temperature from thermalized Vj
• again consistent with entrained ISM
• Jet Mach number 5 / 2.5 / 2 ? transonic
• Consistent with entrainment and decollimation
• Jet mass flux Mem over region lifetime
• Could be entrained ISM
• Could become thermal component of lobe

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Comparison with previous work
Many partial interpretations One thorough
analysis ? Bicknell, Dopita Sutherland
98 They use shocks to infer jet properties, in
particular jet energy momentum
This yields significantly different results
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JET LUMINOSITY
EKE S½M V2
Our analysis
Lj
Elobe PV aErel
Lj (EKE aErel )/tage
Emission Lines Lem
Bicknell et al 98
Shock
Lj
Lj Lem 100 x L5007
For Mkn 78 other Seyferts Lj (them)
1000 x Lj (us)
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JET MOMENTUM
Our analysis
Gem SM V
Fj
Gradual acceleration
Fj aGem / tage
Bicknell et al 98
VshVem 500 km/s
Shock
nem 103 cm-3
?emVsh
Pram ?jVj2
2
Emission Line Cloud
?jVj2 ?emVsh
2
Impulsive acceleration
For Mkn 78 other Seyferts Fj (them) 100
x Fj (us)
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Comparison Ours is a kinder, gentler jet.
Maybe more plausible ?
Jet Property Our Jet Bicknell et al
Energy flux Lj x 1 x 1000
Momentum flux Fj x 1 x 100
Velocity Vj 300 3000 km/s (1 few Vem) 15 90 x103 km/s (0.05c 0.3c)
Density nj 0.1 5 cm-3 0.1 5 cm-3
Ram pressure Pj x 1 x 100
Cloud shock Vsh 10 50 km/s 500 1000 km/s
Temperature Tj 106 K 109 K
Mach No. Mj 2 5 1 few
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Summary

• Jet-gas interactions (JGI) are important
• VLA HST data on Seyfert with dominant JGI
• Inspection reveals likely JGI scenario
• 3 regions suggest temporal development
• Ionization study rejects role of shocks
• AGN photoionization of thick thin components
• Data provide information on jet properties
• relatively low power, low speed, transonic,
  dense jet
• dominated by thermal gas, at Tj 0.5 x T(Vj)
• ram pressure 2-10 x internal pressure
• Overall context thermal jet/wind driven ablata

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