1High Energy Emission from AGN Jets
活動銀河核の高エネルギー放射
活動銀河核の高エネルギ 放射

片 岡 淳 (Jun(J KATAOKA)
東工大 → 早稲田大学理工学研究所/物理学及応用物理学専攻
kataoka.jun@waseda.jp
On behalf of the Fermi/LAT collaboration

2Outline
AGN jet: on “various scales”,
across the EM spectrum.
lobe,,
hotspotM
Mpc
kpc

relativ.
jet

centralBH

sub-pcmpc

Large scale jets
- Physics of FRI jets
- Physics of FR II jets
BlBlazar
regioni- Classical view
- Modern view in Fermi
Fermi--era
Jet Launching & particles- DiskDisk--jet connection.
- LongLong-term monitoring.
I b ?
Isobe?

3Jet on kpc
kpc--Mpc

3

4

FR I and FRII

3C 465 (FR I)

z Low power (1042-44 erg/s)
z Low Γz Core brightenedz Bending (ram pressure)z Decelerating(mass entrainment)

3C 438 (FR II)z High power (1044-46 erg/s)
z High Γz Edge brightenedz Collimated, straight jetz Deceleration negligible?

AGN Jet =Acceleration Site
M87 in optical10”

Arp & Lorre 1978

The jet-like feature in M87 was first reported in Curtis 1918 (!) .
Electron synchrotron life times in equip fields topt ~ 100 yr,
whilst ,the projected length of jet much larger, D ~ 1.5 kpc.
This suggests in situ acceleration within “knots”.
9 internal shock due to velocity irregularities in the beam (Rees. 1978)

5

6

FR--I: M87 w/ Chandra
FRA

Synchrotron© D.E. Harris

Wilson + 2000

Single SED can fit radio to X-ray: Electron sync model can work.
→ X-ray emitting electrons: Ee = 10~ 100 TeV for Beq ~ 100μG.
But, we should always keep in mind various assumptions;(1) “B ~ Beq” to get various jet parameters.
(2) emitting volume is “same”
same for all wavebands
wavebands.
(3) filling factor ~ 1 and uniformity… etc

FR--I: XFR
X-ray Flare in M87

7HST-1Chandra 2keV
HESS 1 TeV
VLA 15GHz
VLBA 1,7 GHz

TeV flare

The outburst of HST-1 was detected, w/
increased X-ray intensity of factor ~50.
1’’ corresponds
d ~ 77 pc att M87 didistancet- emission region must be very compact
or “knotty”.

H i + 2006
Harris+2006, ChCheung++ 2007

VLBA observation discovered superluminal
radio features within HST-1, that could be
associatedi t d with
ith excess TeV
T V emissioni ireported by H.E.S.S.

8Inner Knot X-ray Emission ?
Centaurus A

Jetcenter

Hardcastle+ 2003

JK + 2006

Not only bright X-ray knots, but continuous, diffuse emission
between knots have been observed.
For the nearest FR-I Cen-A, “double-horn” profile in trans. direction.
9 Stratified jet – fast spine & slow sheath ?
9 Turbulent acceleration (Fermi II) at work over the jet volume ?

9FRI: Velocity Shear
Shear layer model

3C31Observation

Bridle & Liang 2002

Decelerated jet modeling w/ shear layers successfully explain
observation of 3C 31 and 3C 315..
“Velocity gradient” is naturally expected via the Jet-Env. interaction.
9 Entrains ambient medium.
9 Transfers
Tfmomentumt
andd energy tot ambient
bi t medium.
di9 Mixing layer, deceleration of jet …

10MHD simulations

K l i -Helmholtz
KelvinKelvin
H l h lt iinstabilityt bilit

Relativistic flow
De Young 1986, Aloy+ 1999, Leismann+ 2005, Mizuno+ 2008

Mass entrainment works very effectively via K-H instability.
Even in relativistic jets, 3D simulation shows development ofshear/mixing layers w/ turbulent B field.

11Turbulent Acceleration
spinelayer

Stratified jet – “spine” + “layer”.

CRUnlike Fermi
Fermi-II, turbulent acceleration(Fermi II) can produce very hard electrondistribution.
If field is very turbulent (ξ∼ 1), electrons“pile-up” as it never escape from the region.
3le
tacc~
ctesc~ 3c
VA

2~ 5x109 γ8 B-1100μV-2A,8 [s]L 2c~ 6x1015 γ8-1 B100μL2100pc [s]
VA le

32 -1
tesc/tcooll ~ 107 (B100μG100 G) (l100pc100 ) ξ

where ξ= UB/UTOstrowski
Otki 2000,2000 Stawarz
St& Ostrowski
O tki 2002
Stawarz & Petrosian 2008

FR II/QSOs: bright XX-ray jet
PKS0637-752

X-ray:y radioRadio: contour
Tavecchio+ 00, also Sambruna+ 2004

Ull iXjUltra-luminous
X-ray
jets:
• NOT smoothly connecting w/ radio-optical synchroron.
• IC/CMB isi more lik
likelyl if Γjet ~10
10 on Mpc
M scalel (∝( Γjet2 UCMB).
)
Consistent w/ VLBI observation (βapp ~ 13.3: Edwards+ 06)
More and more samples: http://hea-www.harvard.edu/XJET/

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13

FR II: Hotspots

StStawarz++ 2007
Cygnus-A

HS_D

HS_ASpitzer

X-ray emission of hot-spots in high-power FR II jet is consistent w/synchrotron self
self-Compton
Compton (SSC) model close to Ue ≈ UB.
The hot-spots in low-power jets is too bright in X-ray, suggesting
instead synchrotron in origin (Hardcastle et al. 2004).
Multiple structures often observed; relic? swing of jet-head?

14

FR II: XX-rays from Lobe
Pictor APrediction
from Ue =UBHardcastle & Croston 2005

X-ray emission is most likely due to IC/CMB under approximate
q pequipartition
between Ue and UB ((0.3 < BIC/Beq < 1.3))
Several “warnings”, however, due to (1) extrapolation of radio
spectrum to lower energy, (2) unknown filling factor,(3) contamination of cluster gas (see discussion in Worrall et al. 2009)

15

Suzaku Obs. of Fornax A Lobe

© N.Isobe
NI b

Hard X-ray signal was successfully detected from the west lobeof Fornax A up
p to 20 keV. ((Tashiro+ 2008))
Hard X-rays are produced by same electrons of γ ~ 5,000(or E ~ 2.5 GeV) that emit synchrotron in GHz band.
BIC =1.4 μG, almost consistent w/ equip. B value of Beq =1.6 μG.

Systematic Study

16

JK & Stawarz 2005

Distribution of 44 AGNs (56 knots, 24 hotspots, 18 radio lobes).
A very simple assumption that apparent deviation from equipartition isdue to Doppler enhancement, i.e. beaming factor δ.
Actually, extremely X-ray bright knots can be explained if δ ~ 10,whichhi h iis consistenti t t w// PKS0637
PKS0637-752752 (classified( lifi d alsol as blazars.)bl)Warning Signal (I)17Uchiyama+y2006,, also Jester+ 2006
spitzer

3C273
In X-ray

IR imaging of the jet of 3C 273 by SPITZER clearly confirms that
optical jet emission is dominated by the 2nd, high E component.
Both the radio and optical components are linearly polarized to asimilar degree of ~ 15% - “double” synchrotron???
SSmoothh connection
i b
between X
X-ray andd optical:
i l same origin?
i i ?

18

Warning Signal (II)JK+ 0808aradioX-ray

The 4th strongest FRII radio galaxy in 3C catalog.
First clear detection of “X-ray counter-jet” by Chandra.
9 If jet is highly relativistic, δ ≈ 1/Γj, hence Doppler “de-beamed”.
Again, “double Sync” or “Sync tail” more likely?
9 Ee ~ 200 (Γj /10) TeV ; presence of ultra rela electrons.

19Warning Signal (III)JK+ 0808a
Radio: contour
X-ray: blue

Nucl.

Various jet structure visble:
z transversal
9 narrow X-ray
X ray jet.
9 spine vs sheath visible ?
z longitudial
9 peak offset: ~ 5 kpc.
9 sync cooling? NO!
Much more complicated than
we have originally thought …

20

Calorimetry & Jet ContentFeretti+ 1995

thermalFR I jet

Thermal pressure [pa]Pth > Pnon-thHardcastle & Worrall 2000
10-8

Pth > Pnon-th

10-10
10-12

10-14

FR II lobe
10-14
10-12
10-10
10-8
Non-thermal pressure [pa]It has oftern been suggested that min. pressure in FRI /FRII jets
is normally below that of external X-ray emitting medium.
Maybe significant contribution from protons and/or thermal electrons,
but still premature (e.g., Croston+ 08).
IIndependent
dd t approachh ffrom ““cocoon-dynamics”
di ” alsol suggests
tinvisible matter in FR II jets (e.g., Ito+ 08).

Jet on subsub-pc

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22Blazars
Fossati+ 98, Kubo+98

QHB
LBL

HBLBlazars: jet closely aligned to our line of sight.
• SL motion
motion, one
one-sided
sided jetβjet ~ 0.99
0 99 c or Γjet ‫ ذ‬10
“Double peaks” over two decades in ν.
Inv. Compton
Compton, but wide variety• Sync + Inv

HBL,HBL LBL,
LBL QHB• Most powerful objects peaks at low ν“Blazar Sequence”

23

Now We have Fermi !
205 preliminary bright LAT sources ( >10 σ)

57 QHBs, 42 BL Lac (HBL+LBL), 6 unID, and 2 radio galaxies.
Note, EGRET found fewer than 30 sources above 10 σ in its lifetime.
Typical 95 % error is less than 10’ .

Katagiri’s talk24

Internal shock in blazars
e.g., Mrk 501

QHBHBLΓfastNon
Non-thermal
NonNon-thermalemissionemissioni iΓslow
collisionl（shock）

BLRor torus

2001 Tanihata+ 2001,
2001 2003
JK+ 2001,

Rapid variability suggests: R ~ c tvar δ ~ 10-3 pc.
Only little variability below tvar <<1d : “InternalInternal shockshock”• Modulation of relativistic outflows : D ~ 10 Γjet 2 Rg ~ 0.01 pc
sub-pcp jjet ((the first site of E-dissipation)p)• “Jet power” & “seed photons” control the blazar sequence.

Spectral Evolution of HBL

25

Tramacere+ 2009 (also Tanitaha+ 2004 etc)
Swift XRT (0.2-10 keV)

HighMedLow

Swift UVOT

Mrk 421Significant evolution *only* at X-rays, i.e., no significant variation
at UV-optical:
Ep ~ 1 keV → 10 keV.
Usually, this has been argued as sudden increase of electron γmax .
(e.g., Takahashi + 1996, 2000, JK+ 1999, 2000)

factor vs: shock speed)νmax ∝ ξ-11 δ vs2 (ξ: gyro factor
factor, δ: beaming factor,
Is it really expected???

Revealing “Variable” Component
Ushio+ 2009 submitted, (poster #P6)
Mrk421-High

Mrk421-Low“Variable component”: Γ1 = 1.6, Γ2 = 2.1, Ebrk ~ 3 keV
9 Fresh electrons “being accelerated” .
3 4 r ) region
9 InnermostIt (D ~ 103-4i off ththe jjet.
tg“Steady component”: Γ ~ 2.0, Ep << 1 keV (exp cutoff)
9 AlreadyAl d cooledl d electronsl t
att largeldidistance.
t
9 Fermi II (stochastic acceleration) at work ?

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Ultra Fast Variability of HBL

27

Aharonian+ 2007

HESS
PKS2155-304

Aharonian et al. 2007

PKS 2155-304: HBL, z=0.116• July 2006 flare: ∼7 Crab, VHE strongly correlated with X-rays.
• Ultra-fast variability as short as min scale by H.E.S.S.
Fermi Campaign:
ATOM RXTE (+ Swift)• 11 nightly obs
obs. using HESSHESS, ATOM,• Constraints on spectral shape, especially EIRB.

28

Fermi Observation of HBL
S b itt d tto ApJ
Submitted
A JSSC model fitting
VHE: ∼0.2 Crab, Γint ≈ 2.5
HE: ΓL=1.61±0.16, Γh=1.96±0.08,
Eb=1.0±0.3 GeV
X-ray:y ΓL=2.36±0.01,,
Γh=2.67±0.01, Eb=4.4±0.5 keV

Fermi

Model parameters(3component power-law):
power law):(3-component
p0=1.3, p1=3.2, p2=4.3 wheredn/dε ∝ ε−pbreak energies: ε1=7.4GeV,7.4GeV,
ε2=120GeVR=1.5×1017cm, δ=32, B=0.02G

Some thought…
thought• X-rays are produced by highest energy electrons, ε > ε2
• HE and VHE are produced by electrons with ε1 < ε < ε2
• X-rays
X rays can vary independently of VHE emission (cf.
(cf July 2006 flare)
Contact Author: J.Chiang

Suzaku observation of QHB (1)29

JK+ 08b“Seed”
Seed for the ERC process is UV photons reflected by the BLR.
Ediff ~ 10 eV, Ldiff ~ 1046 erg/s
Before the “blazar zone”, fast /slow shells up-scatter UV via
the“bulk-Comptonization”
th “blk Ct i ti ” tto EBC ~ ΓBLK2 Ediff ~ 1 keV.
k V
BC luminosity depends on the jet composition : LBC ∝ (ne/np) Ljet
Γ ~ 20, r ~ 1pc, ne/np ~ 10, B~ 0.6 G, Le/Lp ~ 0.05

30

Suzaku observation of QHB (2)W tWatanabe+b + 09

Nothing in this case !

A distant QHB at z = 2.98 (Sambruna+ 06)
Non detection of BC component , but useful UL on particle
contents in jets: ne/np ‫ ػ‬7.3.
73
But, still mystery…the lack of BC emission in general may mean:(1) jets cannot be fully formed/accelerated too close to the BH?
(2) cold electrons cannot carry bulk of the jet power?

Note on the Blazar region ?

31Marscher+ 2008

Bright feature in the jetcauses a “double
double flareflare”::(1) optical to TeV flare
w/ 240o PA rotation.
(2) delayed radio flareflare.
BL Lacertae

First flare:plasma pp
passingg
through the helical B field,(towards the observer)
Second flare:plasma crosses a
standing shock ?
Jet may not fully beformed/accelerarted
in blazar zone?

Fermi Observation of QHB
3C454.3 at z = 0.859
Detected by EGRET, AGILE.
Very active since 2000.

32

Submitted to ApJ
ppreliminary

Fermi-LAT data show rapid, quasisymmetric, flares on a time scaleof ~3 days.
First observation of a spectral breakabove 100MeV.
A possible interpretattion:
Direct signature of an intrinsic breakin the energy distribution of theradiating particles?

preliminary

Fermi

Contact Author: G.Madejski & B.Lott33

Non--blazar type AGN?
Non
3 monthth iimage (2008(2008.8-10)
8 10)

Cen ANGC1275

2 radio galaxies, NGC 1275 and Cen A have already been
detected above 10 σ level.
N surprising
Noti i – detections
dioff severall RG
RGs reported
d byb EGRET.
EGRET

EGRET Detection of RGs

34

Hartman+ 2008

Reanalysis of EGRET data significantly increases the number of AGNs
d t t d att > 100 MeV
detected
M V (Nandikotkur+ 07, but see Casandjian & Isabelle 08)
Centaurus A, 3C 111, NGC 6251 were detected, indicating close
similarity of the SED w/ blazars.
blazars(Hartman+ 08; Mukhergee+ 02; Sreekumar+ 99)

New Comer: NGC 1275 ?

35

3C84 (Per A)
NGC1275

Perseus clustere.g., X-ray: Fabian+ 03
Radio: Pedlar+ 90, Asada +06

Perseus cluster hosts the giant elliptical galaxy NGC 1275 at its center.
Shocks and ripples are clearly evident in deep Chandra image
image.
In radio, NGC 1275 hosts the exceptionally bright radio source Per A,
also known as 3C 84.
84
AGN, or dark matter annihilation ?

SED and LongLong-term Trend
preliminary

36

Submitted to ApJ

preliminary

Clear detection but Fermi LAT, but tight UL given by EGRET.
→ significant variability on time-scale of years to decades.
→ could be associated with ejection of new radio knot?
Either one-zone SSC (Γj = 1.8) or decelerating jet flow (Γj = 10 → 2)model represent s the data well
well.
Contact Author: J.Kataoka

RGs as a GammaGamma-ray Emitter

37

Ghisellini+ 05,
05 also Chiaberge+ 2000

RGs may/should be “mis-aligned” blazars• low power FR I
BL Lacs• highhi h power FR IIQHBQHBs

SED modeling on-goingSpine
S i dominatedd i t d ….. Blazars
BlLayer dominated ….. RGs

Summary
I have reviewed most recent observational highlights
fll jjetst & blazars
blid att highhi h energies.
i .
fromlarge
scale
viewedenergies
Recent survey of large
large--scale jets with CXO have brought us
new insights on the kpc/
kpc/Mpc scale jet - jet structures, turbulent
acceleration, ultra relativistic electrons above 100 TeV
TeV..
Unprecedented sensitivity of Fermi/
Fermi/Suzaku
Suzaku provides newchallenges to the blazar physics - Unification of blazars andradio galaxies are being more common.

More will come soon w/ Fermi!

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