2011 Sep. 三鷹AGN/ CTA 研究会

Fermi-LAT observations ofMisaligned AGN: Towards AGN Unification

Jun KATAOKA (Waseda Univ.)
Special thanks to: L.Stawarz, C.C.Cheung, B.Lott,On behalf of the Fermi-LAT collaboration1

Outline
Introduction- 2FGL catalog and AGN statistics

Misaligned AGN- Radio Galaxies- Radio Lobes- Galactic Bubble- BLRGs and Seyferts - towards AGN unification

Summary2

AGN: unified viewblazarRadio Galaxy(BLRG, NLRG)

Osterbrock 1989; for local universe• Quasars(~10-7 Mpc-3)- Radio-quiet or radio-loud quasars• BL Lacertae Objects (~10-7 Mpc-3 )• Radio Galaxies(~10-6 Mpc-3)- Broad or narrow line radiogalaxies (BLRGs, NLRGs)- Fanaroff-Riley class I or II… many more…
• Seyfert Galaxies(~10-4 Mpc-3)- Seyferts type 1 - 2- Narrow-Line Seyferts

Seyfert(type I +II)

Urry & Padovani 1995 for a review• Low-Luminosity AGN (>10-3 Mpc-3)- Low-Ionization Nuclear EmissionLine Region Galaxies- “Regular” spiral like Sgr A*…
3

2nd LAT AGN Catalog - “2LAC”• 24 month data set• 1749 TS>25, |b|>10° sources• 2LAC:• ~950 associated(Passoc>80%) AGNs

Census:• 360 FSRQs• 420 BL Lacs (~ 60% w/ measured z)• 160 of unknown type
• ~20 other AGNs, including RGs
4

Misaligned AGN (Radio Galaxies)
FR = Fanaroff & Riley

3C 31 (FR I)
BL Lac?

• Low power (1042-44 erg/s)• Low G
• Core brightened• Bending (ram pressure)• Decelerating

3C 438 (FR II)
FSRQ ?

• High power (1044-46 erg/s)• High G• Edge brightened• Collimated, straight jet• Deceleration negligible?
5Fermi-LAT detections of MAGN
Abdo, A. A. et al. 2010, ApJ, 720, 912(based on 15 month data)• 7 FRI radio galaxies• 4 FRII radio sources(2RGs and 2 SSRQs)• MAGN less luminous
than blazars consistent w/
the Unified Model• FRI RGs distinct from BLLacs
in the (L g, G) plan

• 4 Radio-Loud Narrow-Line
Seyfert 1 (NLSy1)+ Fornax A and Cen B (2FGL; preliminary)6Gamma-ray Radio Galaxies
LAT provides precise γ-ray localizations, radii (95%) ~ 1.5 – 5’ (vs. ~30’in EGRET) correspond to ~5-25 kpc for sources within 100 Mpc
Name

D/Mpc

MeV/GeV Detection

VHE?

NoteCen A

3.7

EGRET, LAT 2010

yesLobes

M87

16

LAT 2009

yes

TeV VarFornax A

18

LAT 2011

Preliminary

Cen B

56

LAT 2011

Preliminary

Per A

75

LAT 2009 (COS-B?)

yes**

Variable GeV + TeV

IC310

80

LAT 2010 (Neronov+)

yes

Head-tail, TeV Var?**

NGC6251

106

EGRET, LAT 2010

3C78

124

LAT 2010

3C120

142

LAT 2010

BLRG*

3C111

213

EGRET, LAT 2010BLRG*

FR I > FR II* See, Kataoka et al, 2011
7First “big” Surprise: NGC 1275
Perseus Cluster(Chandra X-ray image)

Abdo et al. 2009 (CA: J.Kataoka)

Kataoka et al. 2010

Clear g-ray excess exactly at the position of FR I radio galaxy 3C84
at the center of NGC 1275 in Perseus Cluster
About an order of magnitude brighter than EGRET UL– significant brightening on decade time scale
g-rays comes from 3C84, not from Perseus cluster
8

NGC 1275: Variability
2009 Apr-May

3.4 Jy3.7 Jy4.8Jy2010 Jul-Aug

LAT >0.8 GeV

MOJAVE VLBA 15 GHzBrown & Adams 2011

10 pc
1 mas = 0.35 pc• Flaring in 2009 with >GeV hardening(Kataoka et al. 2010)• Brighter flare in 2010 (Donato+ Atel 2737)
with VHE detection by MAGIC (in prep)
9

NGC 1275: SED

One zone SSC fit the data, but d ~ 2-3 (viz d ~10 for blazars)
Jet power close to the power required to inflate the lobes against
the pressure of the hot cluster gas : (0.3-1.2)x 1044 erg/s
Maybe, jet emission dominated not by a “spine” (Gj ~ 10), but by theslower jet “boundary layers”? (Gj ~ a few)
10

M87 nucleus: GeV-TeV connection
Abdo et al. 2009ApJ 2009, 707, 55(CA: Cheung, McConville)

Comparable with previous EGRET UL of 2.18x10-8 ph/cm2/s- no significant variability on decade time scale?
LAT spectrum smoothly connects with low-activity level of the TeV
emission. Again, only mild beaming required : d ~ 2 - 4
11Note: Limb-brightened jet

Kovalev+ 2007

VHE

X-ray

radioAcciari+ 2010

Jet on ~100 pc scale resolved:“Limb-brightened” jet.
Ejection of a new-radio knot
triggered TeV flare?
12

Cen A nucleus (I)Abdo et al. 2010 (CA: Finke, Fukazawa)

Steep LAT spectrum of G = 2.67±0.10, with detectable variability(apparently correlated with Swift-BAT)

A single, one-zone SSC fit the MW data from radio to GeV, but fails toexplain non-simultaneous HESS data
g-rays may be originated from slower portion of the jet, i.e., sheath13

Cen A nucleus (II)Abdo et al. 2010
(CA: Finke & Fukazawa)B = 0.45 G
d = 1.8 1.0
R = 3.0x1015 cm
Pj = 3.1x1042 erg/s

The green curve is a synchrotron/SSC fit to the entire data set. The dashed green curveshows this model without γγ attenuation. The violet curve is a similar fit but is designed tounder fit the X-ray data, and the brown curve is designed to fit the HESS data while notover-producing the other data in the SED. The blue curve is the decelerating jet model fit(Georganopoulos & Kazanas 2003).

14

Stratified Jet?

15

Laing & Bridle 02, Chiaberge 00+ Ghisellini+ 05

RGs may/should be “mis-aligned” blazars• low power FR I
BL Lacs• high power FR IIFSRQs

SED modeling on-going

Spine dominated ….. Blazars
Layer dominated ….. RGs
15

FRI vs FR IIof 4 Radio Samples

 P. GrandiBlazar
Radio Galaxy

FRIFRII
16

Rate of LAT Detected AGNs
FRI P. Grandi

FRIIIn press

17Stratified Jet – FR I and FR II P. Grandi

g-ray emission in FRII jets is dominated by the inner fast
collimated regions. Two effects could be contribute toreduce the number of FRIIs observed by Fermi:i) the absence/reduction of feedback between different
jet layers (particularly efficient mechanism in FRI withlarge inclination angles)ii) the g-ray narrower beaming cone of External
Compton scattering (EC) when compared to that of thesynchrotron-self processes (SSC).

18

Cen A lobe: g-ray imaging (I)Nearest radio-loud AGN
Radio source extent ~10O
At D=3.7 Mpc, L=600 kpc

O

LAT resolution = 0.8 at 1GeV

can image lobes
γ-ray color (purple)
with optical galaxy

NASA/DOE/Fermi LAT Collab., Capella Obs.
2011 May 1019

Cen A lobe: g-ray imaging (II)Over ½ of the total >100 MeV observed LAT flux in the lobes

LAT>200 MeV

WMAP
20 GHz0.8O resolution at 1 GeV

Background & point sources subtracted

From Nils Odegard (GSFC)

2010 Science, 328, 725 (CA: Cheung, Fukazawa, Knodlseder, Stawarz)
20

Why important? – (I) acceleration
Fermi-LAT

Good IC (CMB+EBL) fits of LAT spectra with B ~ 0.9 μG in both lobes.
(close to equipartition: Ue ~ UB)
tcool < R/c for GeV emitting electrons: acceleration all over the volume.
Stochastic acceleration like Fermi-II ?

21

22

Why important? – (II) relation to CRs
Pierr Auger collaboration. 2007
CenA

× neaby AGN○ E>5.7x1019 CRs

Anisotropic distribution of E > 5.7x1019 eV Cosmic Rays
Highest energy CRs may be accelerated in nearby AGN(see, also in this context, Hardcastle et al. 2009)22

IC g-rays from Fornax A lobe?
IC/X-ray lobe B-field ~1.5 μG (Feigelson et al. 1995, Isobe et al. 2006)

High EBL

Low EBLLAT 68% and 95% confidence ellipse
on radio image

Georganopoulos et al. (2008)

LAT team leads: McConville, Georganopoulos
23IC g-rays from NGC6251 lobe?
Associated with
3EG J1621+8203(Mukherjee et al. 2002)
with large error circle
Large radio galaxy(1.2 deg ~ 1 Mpc)
so LAT capable ofspatially separating
lobe from AGNemission

LAT 68% and 95% confidence ellipse on radio image

Lobe equipartition
B-field ~0.3 μG(Mack et al. 1996);
cf. ~1 μG for Cen A

1FGL/15-month LAT analysis in 2010 ApJ 720, 912(CA: P. Grandi) also Migliori et al., submitted
24

NGC 6251 lobe: X-ray follow-up
Premilinary

Premilinary

Fermi-LAT(from 2FGL)

B ~ 0.4 mG

Takeuchi, Kataoka et al. in prep (2011)
Suzaku follow-up observations of NGC 6251 lobe region(ON/Off src; 40 ksec each)
After removing all suggestive background, there still remained somediffuse X-ray emission, but relation to gamma-ray lobe is still underinvestigation25

Galactic Haze: nearest g-ray lobe

26

Origin of “g-ray bubble”

Fermi: 2GeV<E< 5GeV27

Su et al. 2010

WMAP: 23 GHz
Fermi-LAT reveals large g-ray bubbles,extending 50o above/below Gal. plane
Correlated w/ WMAP haze, suggesting
IC/CMB in origin

Similar to Radio Lobe in AGN- past activity of Sgr A* ?
27

Past Activity of Sgr A* (1)• “Ω Lobe” is a well-known structure inradio (Haslam +82; see also Haslam +74,Sofue 77, 84, 94, 00)• Proposed to be related to an explosion
which took place around the Galactic
Center ~ 10 Myr ago(with the total energy Etot ~ 1055 - 1056erg), and which formed a shock in theinterstellar medium• Two scenarios have been proposed:- explosion was driven by the central
starburst (Sofue 77)- jet-like activity of SMBH (Oort 77)• Similar structure is seen in X-ray,known as “North Polar Spur”

28

Past Activity of Sgr A* (2)Koyama et al. 2008

~300 pc

X-rays from Sgr A* take 300 years to reach a large molecular cloud
Sgr B2, suggesting Sgr A* must be much brighter in the past.
Indeed, brightness of Sgr B2 faded substantially in just 5 years!
29

Past Activity of Sgr A* (3)Senda et al. in prep••

About ~10 knotty structures
knot1-3… aligned on a straightline• Non-thermal PL spectra• Similar geometry, size, direction-> Evidence for past Jet activity inthe center of our Galaxy?

Sgr A*

Γ= 0.9 (-0.4 – 1.2)Chandra ACIS 3.42-6.30 keV30

Toward AGN unification; BLRGs
blazarRadio Galaxy(BLRG+NLRG)

A long debated problem in ourunderstanding of SMBHs is to unify
different types of AGN

Broad line radio galaxies (BLRGs)
are ideal targets, since they exhibit
both the disk-related “Seyfert-like”
and the jet-related “Blazar-like”
radiative signature, without being
obscured by large amounts of gas(e.g., Wozniak+98, Grandi+02, Kataoka+07,
Grandi & Palumbo 08, Sambruna+09 … )Seyfert(type I +II)

Our primary goals are to examine
the g-ray properties of BLRGs aspotential g-loud AGN, in a broad
context of AGN unification scheme

Urry & Padovani 1995 for a review
31Fermi-LAT observations; samples
All the BLRGs observed by modern X-ray astronomy satellites,
for which data are available at energies above 2 keV
A representative sample of Sy-1 galaxies with known radio fluxes
and BH mass
18 BLRGs + 9 Sy-1s of high-accretion-rate
Already known g-ray sources: 3C111, 3C120 … and more ???
Hartman+ 2008 (EGRET), Abdo+ 2010Abdo+ 2010 (Fermi-LAT)

32

Analysis of 2yr Fermi-LAT data
3C111?

Fermi

3C111

3C120

Kataoka et al. 2011

No statistically significant detection
except for 3C111 and 3C120
1/20 of EGRET flux for 3C111. g-ray
emission is most obvious during
first 6-month, coinciding with abright sub-mm flare (Chatterjee+2011)33

Pictor A; another candidate
Fermi-LAT (>200 MeV)

1.4GHz radio imageof Pictor A radio galaxy(Perley et al. 1997)
Kataoka et al. 2011, ApJ

Fermi-LAT TS map centered on Pictor A, showing the presence ofmultiple g-ray peaks in the field. The peak near the center of the map(TS=20) is almost exactly coincident with the position of Pictor A
Although not yet detected, formal detection (TS >25) of this source
by Fermi-LAT in the near future is quite likely
34

Which BLRGs are detected in GeV ?
BLRGs (total radio)
BLRGs (radio NC)

Sy-1s

What appears to differentiate 3C111 and 3C120 (and possiblyPictor A) from the sources not yet detected in g-rays is thestrong nuclear flux density in the radio35

Multi-wavelength Diagnostic Planes
Kataoka et al. 2011, ApJ“Radio-loudness”( jet efficiency)“Eddington Ratio”( accretion rate)

Brightest GeV sources (3C111, 3C120 & Pictor A) do not stand out
in these diagnostic planes. Most important parameter for GeV
detection is radio nuclei power/flux!
36

A “Hybrid” model: jet+disk
Templatefor “jet”“Mixing” parameter: h  A/B(high h is “blazar like” andlow h is “Seyfert like”)(Soldi et al. 2008)

AB

Template for“disk&corona”(Koratkar & Blaes 99)

Using “templates” for a blazar (3C273) and Sy-1 SEDs, we try todisentangle the jet and the accretion disk contributions to thebroad-band emission spectra of BLRGs
37

Application to SEDs: 3C111, 3C120
Kataoka et al. 2011, ApJ, 740, 29
3C111(h=0.35)

3C120(h=0.15)

Total observed luminosities of the accreting matter and of
the nuclear jets in BLRGs are roughly comparable (h ~ 0.1-1),
while that of the Sy-1 is very small (h < 0.001)
38

Application to SED: BLRGs(1)B3 0309+411B

Pictor A39

Application to SED: BLRGs(2)3C390.340

Application to SED: BLRGs(3)PKS2153-69

3C445

41

42

How about “Seyferts”?

Mundell+ 2003, Ulvestad+ 2005
240-pc jet in NGC 4151 (Seyfert 1.5) is two-sided and highly collimated(diameter < 1.4 pc)
Knotty morphology seems to be related to shocks formed as the jetinteracts with small ISM clouds
LR ~ 1037 erg/s. No evidence for relativistic bulk velocities(knots’ velocities < 0.03c at 0.1-10 pc scales)
42

Application to SED: Sy-1s(1)43Application to SED: Sy-1s(2)Fairall 9Note, radio emission fromFairall 9 is not detected
and thus only upper limit isprovided in the SED.

44

Mixing “Jet” and “Disk” components
3C273 modelBlazars: h ~1

BLRGs: h ~0.1

Sy-1s: h < 0.001

Conversion efficiency of accretion matter to the jet determine whether
the object can be “radio-loud ” or “radio-quiet”

Probably, this conversion efficiency is tightly related with a rotation ofthe central BH
45

“Disk vs Jet” contribution
Kataoka et al. 2011, ApJ, 740, 29

BLRG

Sy-1

Distribution of mixing parameter h for BLRGs and Sy-1s. Relative
contribution of the nuclear jets to the accreting matters is > 1 % for
BLRGs, whilst < 0.1 % for Sy-1 galaxies
46

Future LATdetection; more thought
95% UL for Lg

BLRG
95% UL for Lg

The g-ray-to-radio energy
flux ratios for the two BLRGs(and of Pictor A) detected byFermi LAT are of the order of100, while the corresponding
UL for all other objects aremuch above this value
BLRGs are in principle g-ray
loud, but their detections ing-rays are at present justlimited by the sensitivity of
Fermi-LATSy-147

AGN related g-rays from Seyferts?
Most γ-ray points are upper limits!!!

NGC 1068

BAT hard X-ray
Seyfert Sample

Lenain et al. (2010)

Preliminary*CA: Bechtol , Hayashida, Madjeski, Stawarz(ApJ, submitted)

Most BAT Seyfert sample
provides only UL
But, g-ray emission alreadydetected from a few Sy-2s?
48

g-ray Emission from Sy?
Lenain et al. 2010

Preliminary
Abdo et al. 2011, submitted“Jet model” applied in Lenain et al. (2010)
Both g-ray detcted Sy-2s, NGC 1068 and NGC 4945, strong
starburst activity. Therefore, it may be possible that observed
g-ray is due to SB rather than non-thermal jet emission
Same applied for possible association of ESO 323-G077, NGC 681449

Conclusion
After 3 years of successful operation, Fermi-LAT provided various
new insights into the physics of AGN Jets

Not only blazars, but misaligned radio galaxies are now being
important g-ray source population. In this context, observations
and detections of several BLRGs are particularly important totest the AGN unification scheme(i.e., viewing angle, radio-loud/quiet classification)
Further new surprise is the detection of g-ray lobe, both in ourGalaxy as well as in nearby radio galaxy. The g-ray imaging ofthese extended lobes may provide clues to the high energy
cosmic-ray acceleration in extragalactic sources50