2016.12.16 CTA‐Japan conference“The extreme Universe viewed in very‐high‐energy gamma‐rays 2016”

Recent Fermi results of extragalactic
objects and CTA

Yasushi Fukazawa
Hiroshima University

Contents• Recent LAT source/AGN catalogues• Blazars• Blazars‐related topics• Other AGNs

• Recent LAT source/AGN catalogues

The High Energy γ‐ray Sky

Fermi LAT
7 Years

Liz Hays, Gamma 2016

rd
3FGL (3 LAT source catalog)
3033 sources
48 months
E>100 MeV

7‐year catalog and diffuse
model in development.

Liz Hays, Gamma 2016

Recent LAT source catalogs
Coming next

3FHL
2FHL
3FGL

1FHL

Cataloging Hard Sources• Angular resolution is verygood• Background is very low• Source confusion mostly
not an issue• Transition in types ofsources found

3FGL

2FHL
BL LacLiz Hays, Gamma 2016

2FHL

3FHL

A >50 GeV all‐sky Fermi survey is a perfect complement tofuture large are surveys performed by CTA
Ackermann+15(240h)

CTA 240h

Sensitivity Improvement• Blazars

BL Lac (HBL)
TeV BLAZAR

Synchrotron
Self-Compton

Nearby, Low-L
SED peak : UV/X, TeV

FSRQ(flat spectrum radio-loud quasor)
GeV BLAZAR

Distant, High-L
SED-peak : IR/Optical, MeV/GeV

External Compton

BLAZAR emisson
Leptonic model

Torus
Broad LineRegion

Accretion
disk

Synchrotron Self-Compton

BL Lac, FSRQ

SSC
EC

External Compton

Seed photons: disk (UV),
broad line region(UV,Opt),
Torus(FIR)
FSRQ

BLAZAR Sequence

Fosatti+99
Radio

FR‐II

GeV
LBL

・ｍ
FR‐I

X‐ray

FSRQ

・ｍ high
FR‐I

Optical

ＴeV

FSRQ
. .

mm

LBL

HBL・ｍ low

PeVHBLGamma ray

Blazar Science expected with Fermi
Continuous gamma‐ray monitoring and multi‐wavelength campaign
Catch big flares(understanding flares, extracting important parameters,one‐zone or two‐zone, interesting phenomena ….)
Successful and Progressed !

Where is gamma‐ray emitting region ?

Progressed but not‐yet fully resolved

Emission mechanism : leptonic or hadronic ?
Progressed but not‐yet resolved

Evolution of blazars
logN‐logS, luminosity function,
Progressed but not‐yet fully resolved
extragalactic gamma‐ray background
Probe of distant universe

Progressed

New population of gamma‐ray AGNs other than blazars ?
Found and Progressed !

3LAC (3rd AGN Catalog)

All
1444
FSRQ
34%
BL Lac52%
Unknowns 14%

Ackermann+15

3LAC

Most of gamma‐ray blazars follow the canonical blazar sequence.

3LAC
Gamma‐rayphoton index

Synchrotron peak frequency

Gamma‐rayphoton index

Gamma‐ray luminosity

1LAC

Distribution of gamma‐ray photon index
FSRQs
rms: 0.19

LAT range
FSRQs
HSP‐BLLacs
LSP‐BLLacs
ISP‐BLLacs
ISP‐BLLacs
rms: 0.22

F

Number of sources

LSP‐BLLacs
rms: 0.15

HSP‐BLLacs
rms: 0.14

Photon index

3C279 (Hayashida+14)

Continuous GeV gamma‐ray
Monitoring of blazars
Track various low/high states.
Track the gamma‐ray spectral slope.
Find flares to trigger MW obs.
140 daysTorus

Where is GeV gamma‐ray emitting region ?
Broad LineRegion (BLR)

Both regions are possible for some objects.

Inside or outside of BLR ?

Accretion
Disk

3C279 (Hayashida+14)

SED of GeV flares(inside BLR)

3C279 in 2015: Minute-scale variability byFermi-LAT
Hayashida+15

flux reached ~5x10-5 ph cm-2 s-1

the > 100 MeV flux doubled in ~ 5 minutesminute-scale variability

Hayashida+15

variability time scale: 5 minutes•

rdyn (emission region size) ~ 10-4 (/50) pc (~3x1014 cm)•Rlocation (emission location) ~rdyn/o 0.005 (/50)2 (o)-1 pc (~1016cm)(RBLR (broad line region size) ~ 0.05 pc)

 very near to BH (inside BLR) ~ 100(/50)2Rg(Rg ~ 5x10-5 pc @ 5x108Msolar)

3C454.3 in 2014 : 10‐30 minutes variability
Britto+16

Inside or around BLR

Spectral breaking around GeV in FSRQ
Gamma-ray absorption with He Lyman continuum photons in BLR
Poutanen & Stem 2010

Not Ly α for GeV- breakFSRQa are sometimes detected up to TeV
Outside BLR ?
FSRQ 4C+21.35

Tanaka+11
Aleksic+11

3C279 (Hayashida+14)

PKS1222+21(MAGIC 2011)
PKS1510‐089(MAGIC )Optical polarization swing with gamma-ray flare-ray (LAT)-ray photonindex (LAT)
X-ray

3C279(Abdo+10)

20 days rotation
Outside BLR ?

optical-UV

Kanata, KVA

optical polarization
degree (PD)
optical polarization
angle (EVPA)
Near-InfraredRadioTeV Blazars
Typically, one‐zone model fits SED.
Paneque+14

But. Multi‐wavelength variability often indicates not simple one‐zone !
CTA is important.
Fractional variabitity

Phton Frequency

From D.Panique’s slides

Leptonic or Hadronic ?

CTA
From D.Panique’s slides

Gamma‐ray from Gravitationally‐lensed blazar
Provide one tool to probe the emission region
B0218+357 (z=0.944)
Cheung+14

Delay 11.46+/‐0.16 days

Delayed gamma‐ray was not detected unlike radio.
Different emission sites between radio and gamma‐ray ?

Gamma‐ray variation due to microlensing was also suggested.
High‐z TeV Blazars are interesting.
PKS1830‐211 (z=2.507)

Expected delay : 25 days

20daysAbdo+15

Quasi‐periodic (2.18yr) gamma‐rays from blazar
PG1553+113 (BL Lac)

Ackermann+15

1bin=45days

1bin=20days

Periodic optical emission is also suggested.

Optical polarization and gamma‐rays

KANATA telescope, RoboPol, andso on have provided a richamount of optical polarization
monitoring data for GeV blazars.

Important to understand themagnetic field structure in jets

Itoh+16

Optical polarization degree in flares well correlates withgamma‐ray luminosity or gamma‐ray to optical flux ratio.
Different alignment in jets between FSRQ (FR‐II) and BL Lac (FR‐I) ?
Itoh+16

• Blazars‐related topics

Extragalactic gamma‐ray background update
Approaching to 1 TeV.
Ackermann+15

Using 2FHL to Resolve the Extragalactic
BackgroundAckermann+16

Point sources (blazars)
explain 86 (+16 ‐14)% ofthe EGB above 50 GeV

Can constrain cosmological dark
matter emission.
Ajello+15

Constraining high‐E neutrino sources

Starburst galaxies are not ??
Bechtol+15

TeV extragalactic gamma‐raybackground can give furtherconstraints.
Inoue+16

Gamma‐ray absorption by Extragalactic background light (Opt/UV)
Fermi has obtained evidences of absorption
Ackermann+12, Dominguez+1５

More constraint has been progressing with continuous survey.
Combined constraing with TeV is important.
Ackermann+16 (2FHL)B

Constraint of intergalactic magnetic field

Correlation length og B

1

 E De  10 
 cm e+e-のmean free path
 10TeV 23

D: Halo extension sizeB  De

B  De

2

 E   B  ext  R  3 10   16 L
 10TeV   10 G 1322EBDe B
5B
 5 10  ext   16 RL 10TeV   10 G  1kpc De4

 BIGMF > 10‐15 G(Neronov & Vovk 2010; Tavecchio et al. 2010)

 BIGMF > 10‐18 G
Considering time
(Ｄｅｒｍｅｒ 2011)variability, various EBL
models.

1ES0229+200

Finke+15(Ｄｅｒｍｅｒ 2011)• Other AGNs

Non‐blazar objects and Misaligned AGNs (Radio galaxies) @ 3LAC

Several types of AGNs
Some are hard.

Narrow-Line Radio-loud Seyfert galaxy (NLSy1)
New‐type of gamma‐ray AGNs
PMN J0948+0022Gamma‐ray L ~1048 erg s‐1• small-mass BH (106.7-108.2 M.) with high accretion rate (～90% Eddington)（Blazar, radio galaxies: 107-1010M.）• Found in spiral galaxies, unlike blazars and radio galaxies.
•Very compact radio core.

SED: SSC+EC
Jet power: middle between FSRQ
and BL Lac

Important to probe jet andaccretion

D’Ammando+15

D’Ammando+16

NLSy1

TeV: not yet detected.

Radio galaxies
Parent population of Blazars
Misaligned jet  weak beaming
EGRET: Cen A and some radio galaxies were detected.
3EG catalog: Hartman et al. (1999)
see also Sreekumar et al. (1999)

他に、3C111 and NGC6251?

TeV gamma-ray was first detected from M87 in 2000s.
Probe the jet structure with a various viewing angle

Fermi detected three famous radio galaxies in 3 months.
NGC1275(Per A)

M87(Vir A)

Cen A(NGC5128)

3LAC
Radio galaxies

SED fitting parameters ; Comparison with other radio galaxies
All the fittings were done by the one‐zone SSC model (Finke+08)
Lower bulk Lorentz factors compared to those of typical blazars
Fukazawa+15

Radio Galaxies (FR‐I)
Possible TeV AGNsTeV‐detected …. NGC1275/M87/Cen A
Some radio galaxies have a hard GeVspectrum.
Fukazawa+15
PKS0625‐354(3)Cen A

3C78

Cen A

excess hard TeV tail2nd SSC ?, Decelerating jet ?
DM ?, others ?

Sahakyan+13
Brown+16

3C120 GeV Flaring associated with radio knot ejection
Tanaka+15

GeV emission region is
inside the 43GHz unresolved
core (<0.5 pc from BH),
0.1‐0.3 pc
outside the BLR.

Cen A gamma-ray lobe
In‐situ acceleration ?

Abdo+10

SAS‐3limit

2nd example of gamma‐ray lobe : Fornax A
Broadband spectral model for lobes
LAT 1‐ 300 GeV

Leptonic
Hadronic

IC/CMBIC/EBLAckermann et al. 2016

Hadronic emission could explain
excess, but requires unexpectedly
high total cosmic‐ray energy forFornax A lobes

Summary• Fermi sensitivity is being better; compatible with CTA.
‐‐‐‐ PASS‐8, Increasing Photon Statistics• Fermi‐LAT Catalogs based on all‐sky survey are very
useful for CTA.
• Finding transient objects with Fermi‐LAT are also
important to trigger MW obs. with CTA.

MAGIC : TeV min‐scale variability from radio galaxy IC 310
Low beaming factor

Black hole lightning at subhorizon scales
Aleksic+14