Extragalactic jets: a new perspective
G. Ghisellini in coll. with F. Tavecchio INAF-OABrera
Almost every galaxy hosts a BH
99% are silent
1% are active
0.1% have jets
FRI-FRII & Blazars
Blazars: Spectral Energy Distribution
Radio IR Opt UV
X
MeV
Inverse
Compton
(also possible
hadronic models)
Synchro
GeV
FSRQs
BL Lacs
LBL and HBL
Fossati et al. 1998; Donato et al. 2001
The “blazar sequence”
Fossati et al. 1998; Donato et al. 2001
2
gpeak
nB
By modeling,
we find
physical
parameters in
the comoving
frame.
TeV BL Lacs
EGRET
blazars
gpeak is the
energy of
electrons
emitting at
the peak of
the SED
Low power
slow
cooling
large gpeak
Big power
fast cooling
small gpeak
Power of
jets in
blazars
Power of
jets in
blazars
Power of
jets in
blazars
The power of blazar jets
G
Lr = radiation
Le = relat. electrons
Lp = protons
LB = B-field
R
Rdiss ~1017 cm
Ghisellini, Foschini, Tavecchio, Pian 2007
AGILE!
3C 454.3
Swift
Celotti & Ghisellini 2007
High power
If one p per e-
Relat. electrons
Magnetic Field
Radiation
Celotti GG 2008
Celotti GG 2008, Maraschi et al. 2008
Jet power vs disk Lum.
Ldisk
Pjet
Photon
trapping
e-p
decoupling
Disk accretion rate (Eddington units)
Pause
•
•
•
•
Jet power is large. More than Ldisk
Matter dominated. Not many pairs
LB is small
Powerful jets must be radiatively
inefficient
• Powerful jets do not decelerate
A new blazar sequence
• Old one: based on 1 parameter: the
observed luminosity
• Now: info on mass and accretion rate (spin?
not yet)
• Info on jet power vs disk luminosity
• Info on location of dissipation: must be at
some distance from BH. One zone is
dominant (internal shocks?)
The key ideas
• Rdiss proportional to MBH
1/2
• RBLR proportional to (Ldisk)  UBLR=cost
• For Ldisk/LEdd < Lc  no BLR (BL Lacs)
Ghisellini & Celotti 2001
Ledlow & Owen
The key ideas
• Rdiss proportional to MBH
1/2
• RBLR proportional to (Ldisk)  UBLR=cost
• For Ldisk/LEdd < Lc  no BLR (BL Lacs)
• LB = eB Pjet  B propto R-1
• Le = ee Pjet
•LB = eB Pjet  B propto R-1
Celotti & Ghisellini 2008
•Le = ee Pjet
The key ideas
• Rdiss proportional to MBH
1/2
• RBLR proportional to (Ldisk)  UBLR=cost
• For Ldisk/LEdd < Lc  no BLR (BL Lacs)
• LB = eB Pjet  B propto R-1
• Le = ee Pjet
 gpeak propto U-1; U-1/2
The key ideas
• Rdiss proportional to MBH
1/2
• RBLR proportional to (Ldisk)
• For Ldisk/LEdd < Lc  no BLR (BL Lacs)
• LB = eB Pjet
• Le = ee Pjet
 gpeak propto U-1; U-1/2
The key ansatz
• Pjet always proportional to M
M
Ljet propto Ldisk
M2
1/2
Ljet propto Ldisk
ADAF
(Narayan et al.)
Simple consequences
• Rdiss propto M;
RBLR propto (Ldisk)1/2
Low M, High L  Red quasar
BLR
High M, Low L  Blue quasar
Simple consequences
• Small M, small Ljet, large B, red
BLR
UBLR ~ the same
Large UB
Give me MBH and
Ldisk (or LBLR) and
I will tell you the
SED of the jet
and its power
Conclusions
•
•
•
•
•
•
•
Pjet > Ldisk
Jets are matter dominated
Link between M, M and observed SED
“Blue” FSRQs may exist
“Red” low power FSRQs may exist
Implications about evolution
GLAST + Swift + M + Ldisk (or LBLR)
Swift
AGILE
GLAST
Fossati et al. 1998; Donato et al. 2001
CT
Swift
AGILE
GLAST
Fossati et al. 1998; Donato et al. 2001
CT
Celotti & Ghisellini 2007
Low power
If one p per e-
Relat. electrons
Magnetic Field
Radiation
Subluminal motion for all TeV sources?
bapp~ 0.03 – 0.1 (+-0.06)
H1426+428 bapp~ 2.09 (+-0.53)
Mkn 501
bapp~ 0.05 – 0.54 (+-0.15)
1959+650
bapp~ 0
2155-304
bapp~ 0.93 (+-0.31)
2344+514
bapp~ 0 – 1.15 (+-0.5)
Piner, Pant & Edwards 2008
Mkn 421
1015 cm
Cospatial fast spine & slow layer
DRl~1016 cm
DRs~1014 cm
More seed photons for both
G’ = GlayerGspine(1-blayerbspine)
 The spine sees an enhanced Urad coming
from the layer
 Also the layer sees an enhanced Urad
coming from the spine
 The IC emission is
enhanced wrt to
the standard SSC
model
BL Lac
Radiogalaxy
layer
Ghisellini Tavecchio Chiaberge 2005
Tavecchio Ghisellini 2008
Power of jets
Coordinated variability at different n
Mkn 421
TeV
PDS
MECS
LECS
G=10-20
Dissipation
Yes!
here?
~10
17
cm
Leptonic models:
Maraschi Ghisellini Celotti 1992
Dermer Schlickeiser 1993
Sikora Begelman Rees 1994
Blandford Levinson 1995
Ghisellini Madau 1996
Dissipation
NO!
here?
RBLR~10
18
cm
But see e.g.:
Mannheim 1993;
Aharonian 2002;
Rachen 2000 for
proton models
Importance of
g-rays
If g-g important
too many Xrays
dx,g>1 (>10)
Rblob large enough (>1016 cm), but
tvar<1day
Rblob <2.5x1015 tvard cm
Blob away from accretion disk X-ray
corona (>1017 cm)
Energy transport in inner jet
must be dissipationless
Ravasio et al. 2000
Fossati et al. 1998
Gamma-ray
blazars
EGRET: ~60 blazars
Cherenkov: 21 blazars (+1 Radiogal)
GLAST
HESS+
MAGIC
The Universe
becomes opaque
at z~0.1 at 1TeV
at z~2 at 20 GeV
The VHE extragalactic gamma-ray sky
20 BL Lacertae (18 HBL + 2 LBL))
1 radiogalaxy (M87, 16 Mpc)
1 FSRQs (3C279, z=0.536)
Name
Redshift
Mkn 421
0.03
Mkn 501
0.03
1ES 2344+514
0.044
Mkn 180
0.045
1ES 1959+650
0.047
PKS 0548-322
0.069
BL Lacertae
0.069
PKS 2005-489
0.071
RGB 0152+017
0.080
ON231 (W Comae) 0.102
PKS 2155-304
0.116
H1426+428
0.129
1ES 0806+524
0.138
1ES 0229+200
0.140
H2356-309
0.165
1ES 1218+30
0.182
1ES 0347-121
0.185
1ES 1101-232
0.186
1ES 1011+496
0.212
PG 1553+113
0.25-0.78
Extragalactic jets:
a new perspective
G. Ghisellini in collaboration with F. Tavecchio
INAF – Osservatorio Astronomico di Brera
o The blazar sequence
o Power and content of jets
o A new perspective
tcool  1/(gpeak U) = R/c
g  gpeakU = const
2