Leptonic Blazar Model Overview

daughterduckUrban and Civil

Nov 15, 2013 (3 years and 8 months ago)

141 views

Dermer Gamma
-
Ray Galaxies Workshop


11
-
14 Apr 2011

Leptonic Blazar Model Overview

Chuck Dermer

Naval Research Laboratory

Washington, DC USA

charles.dermer@nrl.navy.mil

Beamed and Unbeamed Gamma
-
Rays from Galaxies

Hotel Olos, Finland

12 April 2011

1.
Blazar sequence

2.
Black hole engine: accretion vs. rotation power

3.
Synchrotron/SSC model: TeV (HSP) BL Lacs and FR1 radio galaxies



Unification



Variability

4.

EC models


break in FSRQ GeV spectrum

5.

Spectral fitting of TeV blazars and the IGMF (1ES 0229+200)



B
IGMF

>10
-
18

G



Additional spectral component with
n
F
n

peak > 1 TeV



EBL

(
g

ray perspective)

Dermer

Gamma Ray Galaxies, Lapland

Selection Biases

(100 MeV


100 GeV)


Photon index = 2 is vFv
peak


Spectral change at


L
g

縠㄰
46

erg s
-
1


Fermi Blazar Divide:
change in accretion
regime?
(Ghisellini et al. 2009)


Construct diagram for X
-
ray, TeV … wavebands


red: FSRQ


cyan: LSP BL Lac


gray: ISP BL Lac


blue: LSP BL Lac


magenta: radio galaxies + others

z = 0.2

0.5

1.0

Abdo et al. (2010) (1LAC)

Misaligned Radio Galaxies and Blazars

Abdo et al. (2010) (MAGN)

Abdo et al., Science, 2010

Cen A Lobes with Fermi


Core vs. lobe dominance


Unification


Two classes
of
g
-
ray galaxies
:


1. blazar/radio galaxies


2.
starburst/star
-
forming



(or 3? cf. Dermer & Gehrels 1995:


soft vs. medium
g

rays)


Where are the shocks?

Abdo et al. 2010

(starbursts)

Spectral Index

Rotation/black
-
hole
-
powered

SNR
-
powered

TeV

Where do RLNL Sy 1s fit in?

PMN J0948+0022

z=0.585

Abdo et al. 2009, ApJ, 699, 976

Blazar Sequence


Inverse correlation between
E
peak

and luminosity
(Fossati et al.
1998)


Selection/incompleteness
biases
(Giommi et al. 1999;
Padovani et al. 2003, Padovani 2007)


Cooling model with external
radiation for FSRQs
(Ghisellini et
al. 1998)


Physical model for sequence


Galaxy evolution through
reduction of fuel from
surrounding gas and dust
(B
ö
ttcher and Dermer 2002)


BZ effect and galaxy evolution


(Cavaliere and d’Elia 2002)

Foschini et al. (2009)

GeV

(scale in units of L
Edd
)

Black
-
hole engine


Accretion vs. black hole rotation as main source of energy?


Mechanisms for collimation


Event horizons

Ergosphere radius

(thanks to Maxim Barkov)

Black
-
hole engine


Accretion vs. black hole rotation as main source of
energy?


Mechanisms for collimation


Radiant accretion luminosity:



L
rad

=

Edd

L
Edd



10
47

M
9


Edd

erg/s




Edd

includes mass accretion rate and
radiant luminosity


Eddington luminosity
L
Edd




Black
-
hole engine


Accretion vs. Black Hole Rotation as main source of
energy?


Mechanisms for collimation


Radiant accretion luminosity:



L
rad

=

Edd

L
Edd



10
47

M
9


Edd

erg/s




Edd

includes mass accretion rate and
radiant luminosity


Eddington luminosity
L
Edd



Blandford
-
Znajek power:


collimating geometry?

Blandford
-
Znajek Process


Find solutions for steady state magnetosphere


Condition of a force
-
free axisymmetric magnetosphere


With Znajek regularity condition

Levinson 2006

Dermer & Menon 2009

Angular velocity of
the event horizon


Hypothesis/guess


Extraction of energy through black
-
hole rotation
collimates jet outflow with



Implies beaming factor



Jet opening angle


M
a
jet
/
cos


)
/
(
1
M
a
f
b


)
/
(
1
2
M
a
jet



Edd
iso
L
L
,
2
1
g


Edd
iso
iso
Edd
L
L
when
L
L
M
a



,
,
,
1
g
g
Edd
BZ
iso
b
abs
L
dt
d
L
f
L




|
,
g
3C 454.3


Reached apparent isotropic luminosities of 2
×
10
50

erg/s


Black hole mass estimates: 0.5 < M
9

< 4
(Bonnoli et al. 2010)


Therefore L
g
,iso
/L
Edd

>~ 1000


a/M > 0.999


23
2
1000




min



14 from
gg
opacity arguments

Smaller value of a/M

for BL Lac objects?

(Abdo et al. 2011, Nov11 flare, ApJ in press)

PKS 2155
-
304


X
-
ray selected BL Lac; z = 0.116, d
L

= 540 Mpc


August 2006: bright flares, detected by


Swift (Foschini et al. 2007) (3 ks/day)


HESS (Aharonian et al. 2007)


TeV variability timescale: ~5 minutes




Also Mrk 501 (with MAGIC; Albert et al. 2007)

Mrk 421 2010 flare

gg

opacity and

min

for PKS 2155
-
304

Model

d
D

B

[mG]

t
var

[s]

L
j

[10
47


erg s
-
1
]

6

895

2.5

30

4.5

8

390

3.0

300

2.7

16

261

81

30

0.5

18

139

57

300

0.4

Lower EBL

(g

min
= 100 )


Radio galaxy core emission well fit by
sync./SSC model with
d





few



(e.g., Cen A, M87, NGC 1275, NGC 6251)


The
d
-
unification problem


--

Decelerating Jet Model



(Georganopoulos & Kazanas 2003)


--

Spine and Sheath Model



(Ghisellini et al. 2005)


--

Colliding Shell Model



(Saas Fee lecture, in preparation)


Standard one
-
zone synchrotron/SSC model

Doppler factor
d

㸾100du物湧r晬f物湧r
数楳潤敳e
d

㸠60晲o洠
gg

op慣楴礠
慲杵浥m瑳㬠䉥g敬浡ne琠慬t2008)

(e.g., Finke et al. 2008)


3 parameters: B,
d
ⰠR


Dermer

Gamma
-
Ray Galaxies Workshop, Finland, April 11
-
15, 2011

ν
F
ν

for MJD=55152
-
55261


MJD=55280
-
55300

Fit : BPL, LogPar, Expcutoff

No strong evolution of E
b

is found

The
Peculiarly Constant

GeV Spectral Break in 3C 454.3

Abdo et al. (2010)

(talk by B. Lott on Thursday)

Dermer

Gamma
-
Ray Galaxies Workshop,
Finland, April 11
-
15, 2011

Intrinsic spectral break in electron
energy distribution with Compton
-
scattered accretion disk and broad line
region radiation
(Finke & Dermer 2010)


Robust solution, independent of
dissipation radius, within BLR with
wind
-
density (disk
-
wind)


gg

attenuation from H (13.6 eV) and He
II (54.4 eV) recombination radiation
deep within the BLR
(Poutanen & Stern
2010)


Finke and Dermer (2010)

Models for Spectral Break

Dermer

Gamma
-
Ray Galaxies Workshop,
Finland, April 11
-
15, 2011

Intrinsic spectral break in electron
energy distribution with Compton
-
scattered accretion disk and broad line
region radiation
(Finke & Dermer 2010)


Robust solution, independent of
dissipation radius, within BLR with
wind
-
density (disk
-
wind)


gg

attenuation from H (13.6 eV) and He
II (54.4 eV) recombination radiation
deep within the BLR
(Poutanen & Stern
2010)


Finke and Dermer (2010)

Models for Spectral Break

Dermer

Gamma
-
Ray Galaxies Workshop,
Finland, April 11
-
15, 2011

Bonnoli et al. (2009)

GALEX and UVOT observations of strong Ly
a
㨠2
×

45

erg s
-
1

Emission region size from reverberation mapping studies



䕮敲杹gd敮獩瑹eo映䉌删

)
2
.
10
(
/
1
.
2
)
(
*
eV
E
GeV
GeV
E
KN

Break due to Compton
-
Scattered Ly
a

Radiation?

Dermer

Gamma
-
Ray Galaxies Workshop,
Finland, April 11
-
15, 2011

Bonnoli et al. (2009)

GALEX and UVOT observations of strong Ly
a
㨠2
×

45

erg s
-
1

Emission region size from reverberation mapping studies



䕮敲杹gd敮獩瑹eo映䉌删

)
2
.
10
(
/
1
.
2
)
(
*
eV
E
GeV
GeV
E
KN

Break due to Compton
-
Scattered Ly
a

Radiation?

Use log
-
parabola?

Dermer

Gamma Ray Galaxies, Lapland

Measurement of the Intergalactic Magnetic Field B
IGMF

Neronov & Vovk (2010)

QCD

IES 0347
-
121

inflation

Recombination

Electroweak

IES 0229+200

Origin of the
Intergalactic
Magnetic Field
(
B
IGMF
):

Primordial

Early universe
physics

Biermann battery

Galaxy dynamo

other


Dermer

Gamma
-
Ray Galaxies Workshop,
Finland, April 11
-
15, 2011

Geometry for Compton
-
gg

䍡獣s摥

Apply to 1ES 0229+200

z = 0.1396


0.14

GeV
IGMF
L
T
B
E
G
B
r
15
10
/
/





Dermer

Gamma
-
Ray Galaxies Workshop,
Finland, April 11
-
15, 2011

TeV Data

E (TeV)

VERITAS data preliminary

Perkins et al. 2010

Aharonian et al. 2007

Dermer

Gamma
-
Ray Galaxies Workshop,
Finland, April 11
-
15, 2011

GeV/TeV Data

Marginal
Fermi LAT
detection:

Orr,
Krennrich,
Dwek 2011

Dermer

Semi
-
analytic Model of Cascade

cascade

Pair injection from EBL absorption

Compton (Thomson) spectrum

from cooling electrons

g

慴awhi捨敬散瑲on猠慲攠d敦e散瑥eou琠o映b敡e

g
(
D
t
eng
): time for electrons

to cool to
g

during

activity time
D
t
eng

of

central engine

kinematic term

CD, Cavadini, Razzaque, Finke, Chiang, Lott 2011

Dermer

t
gg

and

gg

gg
gg
t

d

1ES 0229+200

z


0.14

Dermer

Gamma Ray Galaxies, Lapland

Persistent Jet Emission Hypothesis

(Neronov & Vovk 2010; Tavecchio et al. 2010, Dolag et al. 2011)


j

= 0. 1

Dermer

Gamma Ray Galaxies, Lapland


j

= 0. 3

Pair halos:
Ando &
Kusenko
2010;
Neronov et al.
2010



Halo emission
more
pronounced
for large
opening
angle,
persistent jets

Dermer

Gamma Ray Galaxies, Lapland


j

= 1.0

Limit on

j

~<
0.4 for
persistent TeV
jets

Dermer

Jet activity for time t
engine
: B
IGMF

= 10
-
19

G


j

= 0. 1

Finke et al.

(2010)

EBL model

Dermer

Gamma Ray Galaxies, Lapland

Jet activity for time t
engine
: B
IGMF

= 10
-
18

G

t
engine
= 3162 yr


t
engine


= 1 yr


Gamma Ray Galaxies, Lapland

Cascade for different B
IGMF

Gamma Ray Galaxies, Lapland

Cascade spectrum for different

deabsorbed source spectrum

Note TeV

feature for

strong

source flux

(also found

In numerical

results;

Dolag et al.

2011)



B
IGMF

>

10
-
18

G

Notes

1.
Origin of spectral component peaking at >TeV energies



Synchrotron/SSC models imply large
d
D



If EC, require low
-
energy target photon source (e.g.


CMB): weakly variable TeV emission



(B
ö
ttcher et al. 2008)



Photo
-
pair generated cascade from UHECRs




Essey, Kusenko, Beacom et al. 2010, 2011





2. Impact of EBL model on conclusions

Dermer

EBL Models

(courtesy of Justin Finke)

Dermer

Gamma Ray Galaxies, Lapland

z = 0.044

z = 0.047

z = 0.129

z = 0.139

z = 0.186

z = 0.188

z = 0.538

z = 0.44

Finke et al. (2010)

Dermer

Gamma Ray Galaxies, Lapland

z = 0.044

z = 0.047

z = 0.129

z = 0.139

z = 0.186

z = 0.188

z = 0.538

z = 0.44

variable

Dermer

Gamma Ray Galaxies, Lapland

Dermer

Dermer

Invalid > 10 TeV

Dermer

Gamma
-
Ray Galaxies Workshop,
Finland, April 11
-
15, 2011

Leptonic Models: Summary


Black hole energization


Blazar sequence


Spectral breaks in FSRQs



New primary spectral component peaking at >> TeV energies


synchrotron/SSC makes double
-
humped spectrum with cascade
radiation


weak B
IGMF



Synchrotron/SSC models incomplete without the addition of the cascade

component (or statement of minimum B
IGMF
)



Photopion
-
generated emission from UHECRs or extended jet
emission is non
-

or weakly variable


Any other way for leptons to emit distinct TeV emission
component?


Hadronic processes in TeV BL Lacs?





(more likely if they are sources of UHECRs)



Dermer

Gamma
-
Ray Galaxies Workshop,
Finland, April 11
-
15, 2011

Conclusions


Large range of primary source spectra match data


Minimalist model implies B
IGMF

>~ 10
-
18

G


All require an emission component with
n
F
n

peak >~ 5 TeV



Question: Origin of this spectral component?


Leptonic or hadronic (UHECR?)


Spectral shoulder at 1 TeV implies hard primary emission



Halo emission likely for large opening angle, persistent TeV jet
sources

Gamma Ray Galaxies, Lapland

Local (z<<1) MFPs for electron energy loss and
gg
attenuation


Evidence of UHECRs?


New component could be leptonic or hadronic


Must explain dependence of break energy on z

B
ö
ttcher et al. 2008: Leptonic Model for 1ES 1101
-
232

Leptonic Blazar Model Overview

Chuck Dermer

Naval Research Laboratory

Washington, DC USA

charles.dermer@nrl.navy.mil

Beamed and Unbeamed Gamma
-
Rays from Galaxies

somewhere above the Arctic circle,

Lapland, Finland

April 12, 2011

CTA


Beginning with the simplest relativistic jet synchrotron/SSC model and its application
to analysis of the SEDs of radio
-
loud AGN,


I consider complications of internal
photon opacity, gamma
-
ray absorption and reprocessing in the EBL, and more
complicated shell geometries. Questions about the rapid variability in PKS 2155
-
304
and Mrk 501 are addressed in terms of unification scenarios between BL Lacs and
FR1 radio galaxies. The addition of external soft photons forms the external Compton
gamma
-
ray component thought to account for the gamma
-
ray luminous FSRQs. I
conclude with questions of the location of the gamma
-
ray emission site and the
validity of and explanations for the blazar sequence.