the inner part of agn: suzy collin observatoire de paris-meudon, france i.the inner region of agn :...

THE INNER PART OF AGN:THE INNER PART OF AGN:

Suzy Collin Suzy Collin

Observatoire de Paris-Meudon, FranceObservatoire de Paris-Meudon, France

I.I. The inner region of AGN : a phenomenological viewThe inner region of AGN : a phenomenological view

II.II. Some comments about the methods for studying the WASome comments about the methods for studying the WA

I. THE INNER REGION OF AGNI. THE INNER REGION OF AGN

What we do not know:What we do not know:

hot spherical corona, or (patchy) corona sandwiching the hot spherical corona, or (patchy) corona sandwiching the cold disk?cold disk?

turbulent viscosity in the cold disk and non-local magnetic turbulent viscosity in the cold disk and non-local magnetic heating of the corona?heating of the corona?

limits of the hot corona?limits of the hot corona?

etc…. etc….

1. The accretion disk1. The accretion disk

What we know:What we know:

radiative coupling between a cold and a hot mediumradiative coupling between a cold and a hot medium

2. The BLR2. The BLR


- Photoionized medium with ionization parameter (- Photoionized medium with ionization parameter ( =L/nR =L/nR22) ) 1 1 (depends on the spectral distribution and the limits)(depends on the spectral distribution and the limits)

- Density 10- Density 1099-10-101212 cmcm-3-3, ,

- CD: 10- CD: 102222-10-1024 24 cmcm-2-2, ,

- Coverage factor > 0.1, - Coverage factor > 0.1,

- Distance 10- Distance 1033-10-1055 Rg, ionization stratification, Rg, ionization stratification,

- Velocities close to Virial, - Velocities close to Virial,

- Small micro-turbulent velocities. - Small micro-turbulent velocities.


- What is the dynamics of the BLR (probably dominated by - What is the dynamics of the BLR (probably dominated by rotation for LILs + outflows for HILs)rotation for LILs + outflows for HILs)

- What is the structure of the BLR? Is it continuous or clumpy?- What is the structure of the BLR? Is it continuous or clumpy?

- What is the origin of the BLR? Thermal instabilities in a hot - What is the origin of the BLR? Thermal instabilities in a hot dilute medium, bloated stars, accretion disk, wind…dilute medium, bloated stars, accretion disk, wind…

- Are the BLR clouds confined (gas, magnetic pressure…) or - Are the BLR clouds confined (gas, magnetic pressure…) or transient?transient?

- What governs the size of the BLR? Wind corona, dust - What governs the size of the BLR? Wind corona, dust sublimation, or simply LOC model…? sublimation, or simply LOC model…?

- What controls the low and high cut-off of the velocity? - What controls the low and high cut-off of the velocity?

- What is the explanation of some very high FeII intensities?- What is the explanation of some very high FeII intensities?

Etc…Etc…

A paradox concerning the BLRA paradox concerning the BLR

There is no absorption counterpart to the BLR (cf. later)There is no absorption counterpart to the BLR (cf. later)

But the BLR must absorb at least 10% of the ionizing radiation, But the BLR must absorb at least 10% of the ionizing radiation, so it must have a covering factor of the central source > 0.1,so it must have a covering factor of the central source > 0.1,

and we should see BLR clouds in absorption, unless…and we should see BLR clouds in absorption, unless…

The disk must be either The disk must be either warpedwarped, or, or inflated inflated

(illumination by back scattered radiation is unlikely)(illumination by back scattered radiation is unlikely)

The BLR is not located on the line of sight The BLR is not located on the line of sight of the central sourceof the central source

The lines must be produced in the same The lines must be produced in the same plane as the disk or just above itplane as the disk or just above it

3. The NLR3. The NLR


Density 10Density 1044-10-1066 cmcm-3-3 , CD: 10, CD: 102020-10-1022 22 cmcm-2 -2 , coverage factor < , coverage factor <

0.01, very small filling factor,distance 100.01, very small filling factor,distance 1066-10-1088 Rg, Virial (or larger) Rg, Virial (or larger) velocities, small micro-turbulent velocities, conic structurevelocities, small micro-turbulent velocities, conic structure

AND: WHY IS THERE NO EMISSION BETWEEN AND: WHY IS THERE NO EMISSION BETWEEN

THE BLR AND THE NLR (except a small ILR)?THE BLR AND THE NLR (except a small ILR)?


- What is the origin of the NLR?- What is the origin of the NLR?

- Is it outflowing?- Is it outflowing?

- Is the velocity dispersion of NLs equal to that of the bulge? (No..)- Is the velocity dispersion of NLs equal to that of the bulge? (No..)

- How to explain the anti-correlation of [OIII] with FeII/H- How to explain the anti-correlation of [OIII] with FeII/Hand and with L/Ledd)?…with L/Ledd)?…

4. The Warm Absorber4. The Warm Absorber


- Photoionized region; with an Ionization parameter - Photoionized region; with an Ionization parameter = 10-1000 = 10-1000

- Several components in pressure equilibrium- Several components in pressure equilibrium

- Covering factor - Covering factor (by statistics and by emission lines)~0.5; (by statistics and by emission lines)~0.5; - Column density Nh= 10Column density Nh= 1021- 23 21- 23 cmcm-2-2 (by photoinization modelling); (by photoinization modelling); - Outflow velocity 500-1000km/s (much larger in some NLS1s); Outflow velocity 500-1000km/s (much larger in some NLS1s);

- Density (by He-like emission lines, coronal lines, and - Density (by He-like emission lines, coronal lines, and variability): not well constrained; variability): not well constrained;

- Distance: (from density and variability): not well constrained- Distance: (from density and variability): not well constrained

- Clumpiness: probably small filling factor, but under discussion- Clumpiness: probably small filling factor, but under discussion

- As a result: we do not know Mout, neither Lkin of the flow- As a result: we do not know Mout, neither Lkin of the flow


A clumpy flow with a small filling factor is compatible with a A clumpy flow with a small filling factor is compatible with a modest Mout (generally smaller than Macc), and with the modest Mout (generally smaller than Macc), and with the

momentum due to radiation pressure momentum due to radiation pressure (cf.Blustin et al. 2004).(cf.Blustin et al. 2004). The The WA is thus located WA is thus located close to the NLRclose to the NLR (except in PGs) (except in PGs)

reverberation mapped objectsreverberation mapped objects

On the contrary, a continuous flow should be made of “sheets”, On the contrary, a continuous flow should be made of “sheets”, with a large surface (to account for emission lines) with a large surface (to account for emission lines)

and a very small thicknessand a very small thickness

IMPOSSIBLE!

101

103

105

107

109

1011

1013

0,01 0,1 1

10Lopt/Ledd

At these distances, the density is very smallAt these distances, the density is very small

Clumpy model, with momentum due to radiation pressure

A way to constrain the density: A way to constrain the density:

OPTICAL AND IR CORONAL LINESOPTICAL AND IR CORONAL LINES

(Porquet, Dumont, Collin, Mouchet 1999)(Porquet, Dumont, Collin, Mouchet 1999)

formed in a photoionized medium with same properties as the WAformed in a photoionized medium with same properties as the WA

OVII edgeOVIII edge

n=108 n=1012

An example of resultsAn example of results

(with Laor et al continuum, and average OVII and OVIII edges, (with Laor et al continuum, and average OVII and OVIII edges, average EW of coronal linesaverage EW of coronal lines

But the computations were made with an isotropic and not radial primary which But the computations were made with an isotropic and not radial primary which overestimates emission/absorption, and not enough lines: overestimates emission/absorption, and not enough lines: a work to be done again with better data and a better code!a work to be done again with better data and a better code!

The models favor high densities The models favor high densities to avoid too large EW of the coronal lines.to avoid too large EW of the coronal lines.

SO, AS A CONCLUSION ON THE WA:

The biggest unknown is the distance to the central source and the density, therefore the amount of outflowing mass

5. The UV absorption lines (NALs)5. The UV absorption lines (NALs)

What we knowWhat we know

- Photoionized region; - Photoionized region;

- Covering factor - Covering factor (by statistics and by emission lines)~0.5; (by statistics and by emission lines)~0.5;

- Column density Nh= 10- Column density Nh= 1018 - 21.5 18 - 21.5 cmcm-2-2 (by photionization modelling); (by photionization modelling);

- Density (by fine structure lines and variability): not well - Density (by fine structure lines and variability): not well constrained, but probably small constrained, but probably small

- Outflow velocity up to 2000km/s (much larger in BALs of course) - Outflow velocity up to 2000km/s (much larger in BALs of course)


- Is it the a dilute medium in equilibrium with the NLR - Is it the a dilute medium in equilibrium with the NLR (Crenshaw (Crenshaw 2005) 2005) or with the BLR or with the BLR (Elvis 2002)? (Elvis 2002)? Or with nothing?Or with nothing?

- Is it a less ionized part of the WA flow - Is it a less ionized part of the WA flow (Mathur et al. 1994 and (Mathur et al. 1994 and subsequent works)? subsequent works)? Certainly, at least in some objectsCertainly, at least in some objects

6. The torus6. The torus

warm dust, but is it really a torus? warm dust, but is it really a torus?

(a warped disk is also possible)(a warped disk is also possible)

We have to wait for the results of theWe have to wait for the results of the

VLTI observations of NGC 1068…VLTI observations of NGC 1068…

Galacticbar ? ? ?

Galactic bar

6

Narrow Lines

UV-NALs?Warm Absorber?BALs?

THE DIFFERENT COMPONENTS THE DIFFERENT COMPONENTS (without the jet)(without the jet)

Elvis model (2000-2004)

WHERE ARE THESE COMPONENTS LOCATED?WHERE ARE THESE COMPONENTS LOCATED?

WHAT ARE THE INTER-RELATIONS BETWEEN THEM?WHAT ARE THE INTER-RELATIONS BETWEEN THEM?

Interesting empirical model in many respects Interesting empirical model in many respects

BUTBUT

The structure depends indeed on other parameters than the The structure depends indeed on other parameters than the inclination: the Mass, the Accretion rate (or the Eddington inclination: the Mass, the Accretion rate (or the Eddington factor), the environnement (a starburst for instance), etc…factor), the environnement (a starburst for instance), etc…

GRAND UNIFICATION IS NOT LIKELY FOR AGNGRAND UNIFICATION IS NOT LIKELY FOR AGN

(and I do not believe in Ocam’s razor for complex objects) (and I do not believe in Ocam’s razor for complex objects)

Examples of the influence of other parametersExamples of the influence of other parameters

1. Dominance of self-gravity of the disk1. Dominance of self-gravity of the disk

1000

104

105

106

10-3 10-2 10-1 100

L/Ledd

6

7

8

9

2D simulations

For Q=1, For Q=1, R=RR=Rcritcrit

For R > RFor R > Rcritcrit ( (~5~5Rsg), Rsg),

the disk is gravitationally unstablethe disk is gravitationally unstable

Collin & Huré 2001

Reverberation mapped objects:Reverberation mapped objects:

In large L/Ledd objects, the BLR is in the In large L/Ledd objects, the BLR is in the gravitationally gravitationally unstable regionunstable region

10-1

100

101

102

10-3 10-2 10-1 100

10Lopt/Ledd

Collin et al. in prep.

Some consequences of gravitational instabilitySome consequences of gravitational instability

1. The disk is cut: it is broken into clumps1. The disk is cut: it is broken into clumps

2. Possible extra (non-radiative) heating (FeII?); the system is 2. Possible extra (non-radiative) heating (FeII?); the system is inflatedinflated

3. The disk becomes strongly self-gravitating, so star formation, 3. The disk becomes strongly self-gravitating, so star formation, but the disk will disappear but the disk will disappear (Shlosman & Begelman 1989)

4. The disk stays marginally unstable, then formation and rapid 4. The disk stays marginally unstable, then formation and rapid growth of massive stars and explosions of SN leading to strong growth of massive stars and explosions of SN leading to strong enriched winds enriched winds (Collin & Zahn 1999)

5. High turbulence helps the accretion process

2. Launch of a wind2. Launch of a wind

A radiatively accelerated wind depends on M(BH) and A radiatively accelerated wind depends on M(BH) and OXOX (Proga & Kalmann 2004)(Proga & Kalmann 2004)

“Toy model “of K. Leighly, 2004

It fits well the “failed wind “ of D. Proga (2005), the Murray & It fits well the “failed wind “ of D. Proga (2005), the Murray & Chiang “hitch hicker” model, and the opt-X observationsChiang “hitch hicker” model, and the opt-X observations

II. SOME COMMENTS ON METHODS II. SOME COMMENTS ON METHODS

FOR STUDYING THE WAFOR STUDYING THE WA

How is modelled the WA?How is modelled the WA?

(a naive vision)(a naive vision)

The first step: extracting the data:The first step: extracting the data:

the continuum, the line EWs, the RRC, Vout…the continuum, the line EWs, the RRC, Vout…

The curve of growth method is sometimes used to determine the The curve of growth method is sometimes used to determine the turbulence and the ionic abundances. It is imprecise, unless there turbulence and the ionic abundances. It is imprecise, unless there are several lines from the same lower level of the same ion, with are several lines from the same lower level of the same ion, with

different oscillator strengths, and lines not saturated different oscillator strengths, and lines not saturated (i.e. in the Doppler part of the COG)(i.e. in the Doppler part of the COG)

EW/EW/ V Vturbturbln(ln())It gives VIt gives Vturbturb

Crenshow et al. 2003, from Kaastra et al. 2002Crenshow et al. 2003, from Kaastra et al. 2002

OVIIIseries

A good caseA good case

EW/EW/ It gives NIt gives Nii

For larger column densities For larger column densities (>10(>101818cmcm-2-2) and smaller V) and smaller Vturb turb it it

is not possible to determine is not possible to determine both quantities preciselyboth quantities precisely

CompleteAbsorption

Outwardemission

coverage factor ~1 coverage factor < 1

PartialAbsorption

Outwardemission

Primary source

reflection

There are There are three spectral componentsthree spectral components of the WA. The emission is of the WA. The emission is generally important and should be taken into account. If the generally important and should be taken into account. If the

medium is outflowing, the emission lines aremedium is outflowing, the emission lines are less blueshifted less blueshifted than than the absorption lines. The reflection lines are mainly the absorption lines. The reflection lines are mainly redshiftedredshifted. .

It is difficult to disantangle these components. It is difficult to disantangle these components. The WA can also cover the BLR emission.The WA can also cover the BLR emission.

A typical P Cygni profile of LA typical P Cygni profile of L(OVIII) obtained for a unique shell (OVIII) obtained for a unique shell with absorption and emission from a cone of 50° (no reflection): with absorption and emission from a cone of 50° (no reflection):

0 100

5 104

1 105

1,5 105

2 105

18,9 18,95 19 19,05 19,1

( )A

:4 /outflow km s :5°opening angle :coverage factor

emission

absorption

final profile

emission and absorption are intimately mixed. emission and absorption are intimately mixed.

0 100

2 108

4 108

6 108

8 108

1 109

620 625 630 635 640 645 650 655 660

x100c22n10o3783v300

νFν

hν( )eV

pure absorption

+absorption emission =5°opening angle :coverage factor unity

The emission The emission contribution is different contribution is different

for different linesfor different lines

0 100

1 109

2 109

3 109

4 109

5 109

550 555 560 565 570 575 580

νFν

hν( )eV

z

+X Yw


normaldirection

OVII triplet

=n

cm-3

pure absorption

x100c22n10o3783v300-R400

0 100

1 106

2 106

3 106

4 106

5 106

550 555 560 565 570 575 580

νFν

hν( )eV

z

+X Yw

normaldirection

=n7cm

-3+absorption emission

=5°opening angle :coverage factor unity

pure absorption

x100c22n7o3783v300-R400 Forbidden lines appear Forbidden lines appear only in emissiononly in emission

and their ratio depends and their ratio depends on the column density, on the column density, the temperature and the temperature and

the density the density (cf. Coupé (cf. Coupé et al 2003)et al 2003)

0 100

2 108

4 108

6 108

8 108

1 109

730 740 750 760 770 780

x100c22n10o3783v300

νFν

hν( )eV

pure absorption

OVII edge


The emission changes The emission changes the temperature deduced the temperature deduced

from the RRCfrom the RRC

Emission and absorption Emission and absorption do not respond similarly to do not respond similarly to

a change of Vturba change of Vturb

The second step: photoionization modellingThe second step: photoionization modelling

Basic underlying assumptions:Basic underlying assumptions:

stationarity (not valid if the density is small)stationarity (not valid if the density is small)

only radiative heating (although possibility of additional only radiative heating (although possibility of additional modes of energy release)modes of energy release)

generally motionless, without dynamical effects (not generally motionless, without dynamical effects (not necessarily valid for a wind)necessarily valid for a wind)

generally constant density (not necessarily valid, generally constant density (not necessarily valid, pressure equilibrium may be more appropriate, cf. A. pressure equilibrium may be more appropriate, cf. A. Rozanska and A. Concalves talks)Rozanska and A. Concalves talks)

Many parameters:Many parameters:

ionization parameter, column density, spectral ionization parameter, column density, spectral distribution of the incident continuum (most important), distribution of the incident continuum (most important), abundances, micro-turbulence, density, geometry of the abundances, micro-turbulence, density, geometry of the medium, clumpiness, coverage factor of the source…medium, clumpiness, coverage factor of the source…

PROBABLY NOT A UNIQUE SOLUTION!PROBABLY NOT A UNIQUE SOLUTION!

Presently three photoionization codes for the WA:Presently three photoionization codes for the WA:

XSTAR XSTAR (Kallmann),(Kallmann), ION ION (Netzer),(Netzer), Cloudy Cloudy (Ferland)(Ferland)

Now: Now: also Titan also Titan (A-M Dumont)(A-M Dumont)

1.1. transfer treatment: transfer treatment:

Titan is betterTitan is better: :

it has it has real transferreal transfer for lines and continuum (ALI cf. L.Chevallier) for lines and continuum (ALI cf. L.Chevallier)

other codes: use other codes: use escape probabilitiesescape probabilities for transfer of lines and for for transfer of lines and for recombination continuarecombination continua

but a strong dranwback of Titanbut a strong dranwback of Titan: :

large running time, because many layers are necessary (at least large running time, because many layers are necessary (at least 500), to get a correct line transfer for thick lines500), to get a correct line transfer for thick lines

2. Atomic data:2. Atomic data:

Titan is worseTitan is worse: :

only 1000 lines are treated (XSTAR: 19000)only 1000 lines are treated (XSTAR: 19000)

A quick look on the escape probabilities (EP)A quick look on the escape probabilities (EP)

EP (first level, used in these codes): decoupling the statistical equations of the levels from the transfer Equation, by identifying the “NRB”:

with the probability of the photon to escape in a single flight from the medium: for instance for a Voigt profile with CRD (Collin et al. 1981):

1.1. the probability to escape from both sides is taken into account the probability to escape from both sides is taken into account

2.2. A fraction of line photons is absorbed on the spot in the continuum A fraction of line photons is absorbed on the spot in the continuum (different approximations are used) (different approximations are used)

3.3. The escaping line photons are treated as continuum photonsThe escaping line photons are treated as continuum photons

Why is the use of the EP worse in X-ray emitting media than in the BLR?

Because more lines are superposed on an optically thick underlying continuum, and the media are more inhomogeneous

(T from 107 to 104 K).

Note that some EP methods are as sophisticated as real transfer but they are not less time consuming (cf. Elitzur 2005)

So, in each layer, line photons which do not escape are used on the spot to ionize and heat the medium (i.e. homogeneously in the given layer). Those which escape are treated as continuous photons out of the layer, whose thickness is not related to the given line. So the LOCAL treatment is approximate with respect to the REABSORPTION OF THE LINE PHOTON IN THE CONTINUUM.

Moreover the EP are computed with GLOBAL quantities (o) which are used in a LOCAL treatment. This is inappropriate for an INHOMOGENEOUS MEDIUM.

Some results concerning line Some results concerning line intensities in the emission intensities in the emission spectrum of a WA spectrum of a WA (Collin, (Collin, Dumont, Godet, 2004).Dumont, Godet, 2004).

the emission the emission spectrum displayed spectrum displayed for for FWHM=10000km/sFWHM=10000km/s

G =(x+y+z)/w of OVII is 2.5 G =(x+y+z)/w of OVII is 2.5 times too large with the EPtimes too large with the EP

Finally, a last question:Finally, a last question:

Is the Sobolev approximation more adapted to the WA?Is the Sobolev approximation more adapted to the WA?

- It applies to situations where the gradient velocity scale is smaller than the scale of the physical properties

- In the line EP, o(total) is replaced by o(RVD/V)

- It is adapted for a continuous medium or a clumpy medium with a large velocity gradient and many clouds on the line of sight

-It is also an “escape probability” method. It requires absolutely to take into account the line overlap (cf Chelouche & Netzer and apparently also Phoenix (cf. Casebeer’s talk)

- It acts like a strong micro-turbulence

If Vturb is proved to be small, I am not sure that Sobolev - or improvement of it - need to be used

CONCLUSION

THOUGH ALREADY BIG ACCOMPLISMENTS,

THERE ARE MANY THINGS STILL TO UNDERSTAND,

AND MUCH WORK TO DO!

Some naive questions that I would like to ask to T. Kallman

- Why is only LINE radiation pressure taken into account in the total pressure, and how is it computed?

- Is es taken into account (apparently yes, but why then no absorption at some frequencies for es of the order 1)?

- How is taken into account the variation of VD across the slab to compute the EP?

- Is it a two-stream or a one-stream computation (apparently a two-stream, but ambiguity)?

- Is the line blanketting treated and how?

- Is XSTAR used as an infinitely thin layer by people who compute the thermal and ionization equilibrium in their “slab” model?

the inner part of agn: suzy collin observatoire de paris-meudon, france i.the inner region of agn :...

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