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The jet: component of the standard modelLess than 10% of galaxies have an active nucleus. 10% of AGN haveRadio jets (« Radio-Loud »)Every galaxy has a black holebut the activity time-scale isshort, ~ 10-40 million yrs
According to the angle of the line of sight: the jet is seen, or relativisticg j ,motions, broad lines exist, or arehidden by the molecular torus( 2 i l i i )(type 2, scattering, polarisation)
2
Distinction between jet and windThe wind comes from the heated disk, which can,evaporateOr the magnetic pressure
jet wind is too strong
Turbulence in the disk
jet wind
Turbulence in the diskMRI instability
starBH
disk
magnetic lines
3
Activity cycles
Separation of lobes ~ 100 kpc,
V ~ 1000 km/s
age t ~ 108 yrs
Several cycles?
Other way to estimate the duration of the activity cycles of AGN t ~ (galaxy life)(% active time)
10 8
4
~ (1010 yrs)(1% of galaxies active with jets) ~ 108 yrs
Two types of morphologies for the radio jetsFR II (left) & FR I (right) High luminosity
3C 219
3C 31Low luminosity
3C 33.1 3C 313C 296
3C 47
Hot spots in the centerHot spots at
3C 465the end
5
Why only one jet?3C133Image VLAImage VLA
Faraday depolarisation~2
3C133Polarisation The visible jet is alwaysPolarisation j y
towards the observer
Eliminated hypothesis--The jet is alternatively on oneside or the other
6
side or the other--Absorbing mediumLaing, 1988
Relativistic aberration, Doppler boostReference frame of the fluidIsotropic emission
Reference frame of observerLorentz transformation
Isotropic emission
Already aberration at small speed (ex. rain) -- For AGN ~5
7Flux multiplied by D2
Total relativistic Doppler effectDoppler factor ~5 v/c ~ 0.98, D ~ 9.9
Aberration, Flux multiplied by D2
Effect of time dilatation, Flux multiplied by D , p y
Time 1Time 2 Source at rest STime 3
Source in
S
Time 1 Source in motion
Time 2Time 3
Doppler effect on frequencies, Flux in (synchrotron = 1)Flux multiplied by D3+ ~D4 ~ 9600
8
Some up to 100, D~200, and D4 ~ 16 108 !!
Superposition with Radio
Jet radio: contoursJet radio: contours// optical jet (HST)
67kpc long
HST+Merlin 10
HST ChandraMerlin
3C273 the most nearby quasar3C273, the most nearby quasarJet detected at allwavelengthsg
Superposition of optical jet(HST) in X-rays (Chandra)and in radio cm (Merlin) 11
Jets can be super-luminalP at velocity v, with respect to Oy = r sin t = r/v
Light coming from P reaches us in less time than light
C27
9
coming from O.Time observed for the object to go from O to Pdans
3C
from O to P tapp = t - x/ctapp = (r/v) - (r/c) cos t = (r/v) (1 cos )et
radi
o
tapp = (r/v) (1 - cos )V apparent on the sky
vapp = y/tapp
J
app y appvapp = (v sin )/(1 - cos )
For v << c =v/c ~0 v = v sin
To observer
For v << c, =v/c 0 vapp = v sinFor v ~ c, vapp >> v and even larger than c
Black hole in rotation: origin of Radio jets?
If the black hole is rotating, energy can be extracted from it,by the Penrose process 15
Mechanism of Blandford-ZnajekThe goal is to extract energy and angular momentum from the black holein rotation. The electromagnetic field around the hole is perturbedby magneto spherical currents which produce a torqueby magneto-spherical currents, which produce a torque Slow down the black hole
Poloidal B field, and B same senseDescribed by the potential
Pair creatione+ - e-
Described by the potentialvector A
H HorizonParticules in T can onlyfall in the hole
disk
The positrons are quicklyabsorbed by the hole,The atmosphere is of
17
negative charge
Electromagnetic extraction of rotational energy
horizonhorizon
ergospherePlasma dominated
S
ergosphereby magnetic energy
B
SS
Flux of Poyntingvector B
S
Blandford and Znajek 1977Equatorial plane B
19
Extraction MHD and not only MD
horizonSPlasma dominated horizon
ergospherev
Plasma dominatedby magnetic energy
ergosphere
BS
v
v
Flux of vectorof Poynting
SS
v
vy g
B
Region dominatedby particules
v
Negative flux of particules
v
Punsly & Coroniti 1990
BSof particulesEquatorial plane
20
Torque slowing down the black hole: Jx BTorque slowing down the black hole: Jx B
Meridian plane
21Angular momentum L Punsly & Coroniti 1990
Numerical simulations: MD & MHD
Monopole field (Komissarov 2001, McKinney 2005)
H
a=0.1•Le flux of Poyntingcorresponds to model
a=0.9
corresponds to modelof Blandford-Znajekstationnary state
Z
a=0.5y
L t f t 0t=120
i il
Lorentz factor
RZ
0
MHD very similarto MD modelThe energy is extracted from
BH, the introduction of particulesMHD d t h th
a=0.9 from 0 to 14
MHD does not change thephenomenon MD
R 22
Ergosphere and B field in simulations
Simulations MD, uniform field (Komissarov 2004)
B2 – D2 h All field lines entering theErgosphere are in rotation
horizon
g pup to 0.5 times of hole
ergosphere The dissipative layer in the equatorial plane is the sourceof energyof energy
Dissipative layer
The energie is extracted from the region betweenThe energie is extracted from the region between horizon and ergosphere (=processus of Penrose)
23
Jets are confined by magnetic fieldsJets are confined by magnetic fields
Collimationover 8 ordersover 8 ordersof magnitudein scales
24
MHD and jet confinementMHD and jet confinement
The differential rotationtwists the field lineswhich slows down rotationand allows more accretion
Magnetic pressure andthermal pressurethermal pressure accelerate the jet
Uchida et al 1999Magnetic tension collimates
25
Ejection mechanisms
Magnetic A black hole in rotation (a~1) accretes ionized and magnetized gas
field lines
Ergosphere
The gas falls in the hole, and someElectromagnetic energy is ejected along the rotation a is Ergosphere
Black hole
rotation axisThis energy flux (Poynting) will be chargedwith particules, to form a relativistic jet Black holewith particules, to form a relativistic jetSimilarity with the processus of Blandford-Znajek
The reaction of the magnetic fieldis to accelerate the plasmain counter rotation of the holein counter-rotation of the hole
26Koide et al 2002
Arrival of L < 0
Galaxies host Cen A
of FR-Is and FR-IIs
The radio galaxies FR I and FR II areGiant ellipticalswith dust laneswith dust lanes
The FRI are often cD galaxies at the center of rich clusters
M87
28
The majority of quasars are observed in galaxy mergers galaxy mergers
Violent gas shocks fueling of the black hole
Ejection of plasma: radio lobesin ellipticals results of merersin ellipticals, results of merers
Cygnus A Image radio, VLA
Optical mage , HST 30
A double quasar, just merging: 3C75, z=0.023Image radio, VLA
O i l i HSTOptical image HST
25,000 ly
31
Radio lobes, galaxies in motionGalaxies move at a velocity up to1000k / i l l
3C1291000km/s in galaxy clusters
3C4653C465
32
Origin of radio mission :P l t d i ith f ( l 0 t l• Power-law spectrum decreasing with frequency (slope 0 at nucleus,
then -1)• linearly polarised emission (at least 30% which is a lot) linearly polarised emission (at least 30%, which is a lot)
Synchrotron radiation emitted by electrons in relativistic motion in a magnetic fieldF l t f
11 γavec γ 2
22cv
ecmE For an electron of energy
Hzγ1024 26 B
The characteristic frequency of emissionis
Hz γ102.4~ Bc
With B in Gauss
35
Emission gamma (TeV) from a blazarVery high energy photons are emitted by radio AGN, when their jet isoriented towards the observer blazar & « Flat Spectrum Radio Quasar » (FSRQ) Doppler factors of 20-50!
36Marscher 2005
Jets in Gamma: high variability
Radiation mechanisms:Radiation mechanisms: synchrotron, SSC(synchrotron self-Compton)( y p )& EIC (external inverseCompton)At low power: SSCAt low power: SSCAt high power: EIC
Variability on time scales down to minutesdown to minutes
37
The blazar sequence
The highest luminosityblazars have the softestblazars have the softestspectra
Electrons of high energyIn low power objects“injection” betweenmin =104-5 to 106-7
At high L is smallerAt high L, min is smaller
38
Mechanisms of photons in culture
B-field
3. Compton 2. Pair3. Compton scattering
pscattering
5 Compton
production
1 Seed high 5. Compton scattering4. Pair
production
1. Seed high-energy photon
Multiplication of high energy rays, as soon as(1) high energy photons are injected(2) there exists a B field transverse or chaotic(3) an isotropic radiation field (BLR at 1017 cm)
39
( ) p ( )(4) the Lorentz factor of the jet ~4-10Stern & Poutanen (2006, 2008)
Why some AGN have radio jetsy jand not others?
Frequency and circumstances: Most AGN have no jet,90% are « Radio-Quiet »
10% of « Radio-Loud »: a true dichotomie
Are these different phases of anuniversal evolution?universal evolution?
Centaurus ABlue: X-rays
40
Blue: X-rays Red: Radio
Kellerman 1989R=Radio/Optical
Criteria for radio jetsCriteria for radio jets
1) Th R i h h i1) The parameter R increases when the accretionrate Lacc/LEdd decreases
2) This is verified for both sequences « radio-loud » d di iand « radio-quiet »
3) A saturation of the parameter R occurs at lowaccretion rate λ < 10-3
44
The micro-quasars in our Galaxy: nearby, variable athuman time-scalehuman time scale
SS433: micro-quasar
Objects of stellar massesThe end of life for massive starsThe end of life for massive starsRotation of the BH 1000 timesper second
46
Micro-quasar GRS 1915
superluminalsuperluminalvelocity Scale: one monthy
X-Rays: redGamma-rays: grennRadio : blue
Ejection cycles ofEjection cycles ofabout one hour
A dizain per day48
Radio versus X for micro-quasarsSradio
SXSX
For low accretion rates, the radio luminosity increases with the accretion rate (LX) like LR∝LX
0.7 (Gallo et al. 2003)But for higher accretion rates ≥ 0 01 Edd the jet productionBut for higher accretion rates ≥ 0.01 Edd , the jet production becomes intermittent (Fender et al., 2004) 49
The accretion phases vary forThe accretion phases vary forexample Cyg X-1
Accretion High (H)(small truncation
di )
H L
radius)Accretion low (L)(higher truncation(higher truncationradius)TransitionsEnergy emittedin photons Compton
50
The different phasesFender 1999 Micro-quasars & AGN
The hard X are correlated withThe hard X are correlated withthe radio emission
InstableIntermittent
1.0?In the high luminosity phase, the disk radiates efficiently,
d l t t itt d
Intermittent
and electrons are not emitted
In the low phase, ADAFDi i In the low phase, ADAFTruncation of the disk, formation of a corona where photons are
Disque mincePas de jet nide couronne
comptonized(hard X-rays)Disque tronqué
C
51The corona is the jet baseCouronneet jet continu0.1?
Several phases for the SeyfertSeveral phases for the SeyfertSeyferts 1 in general accrete at the Eddington limit
– this corresponds to a high accretion rate, unstable -- oscillation time-scale of ~ 2 yr (M/106 M)
Some Seyfert galaxies have no longer broad lines “Narrow Line S1” example NLS1 PKS 2004-447p
– M = 5 106 M; could become a classical S 1 in < 10 yr– A brighter AGN , broader lines
52
b g te GN , b oade es
Criteria for radio jetsCriteria for radio jets
For AGNs as for micro-quasars, LR and Lacc are related for the low accretion rates, and for high accretion rates, the production of jets become intermittent (e g Merloni et al 2003 Nipoti et aljets become intermittent (e.g., Merloni et al., 2003, Nipoti et al., 2005)
But the relations are verified separately for spirals and ellipticals, as for two parallel relations
there exists an other parameter, related to the formation of these galaxies, and of their central black holegThe spin of the black hole?
53
The role of the black hole spinpIf jets are produced by the extraction of the rotational energy of
black holes and if elliptical galaxies have more luminous radioblack holes and if elliptical galaxies have more luminous radio jets
-- does this mean that ellipticals have not enough gas to stop the jets?
-- or ellipticals have higher spin parameters (a)?
Ellipticals are formed by mergers of smaller galaxies, but more frequently by major mergers
A large number of minor mergers could arrive in the same finalA large number of minor mergers could arrive in the same final mass state, but the spin would be cancelled statistically
54
Minor & major mergersMinor & major mergers
id l i i dA residual spin is expectedfor the black hole resultingfrom a major merger
The final angular momentumcoming from several BH
55
from a major mergerof random orientation cancels out
Simulations ofjet formationjet formation
kBrinkmann& CamenzindLSW 2004
Brinkmann &Camenzind 2004
LSW 2004
56
ConclusionsProperties of jets-- relativistic boost, disymmetry, y y-- superluminal jets-- analogy with micro-quasars-- The radio power is 3 orders of magnitude largerin ellipticals relative to spirals
How are jets formed?-- Extraction of the rotational energy of the BH (Blandford-Znajek)gy ( j )(processus of Penrose + B field)
h di i h h i d-- the radio power increases when the accretion rate decreasesEllipticals have black holes with a larger spin ( a~1)Could be due to their formation in major mergers
59
Could be due to their formation in major mergers