Post on 22-Jun-2020
Blazars: GeV-TeV connection
F.Tavecchio
INAF-OAB
GeV-TeV connection in FSRQs
GeV-TeV connection in extreme HBL
Foss
ati et
al.
1998
; Don
ato
et a
l. 20
01
CT
AGILE
Fermi
The “blazar sequence”
Foss
ati et
al.
1998
; Don
ato
et a
l. 20
01
CT
AGILE
Fermi
The “blazar sequence”
Abdo et al. 2011
Mkn 421Aleksic et al. 2012
Nice description of the HE bump
Abdo et al. 2011
Mkn 421Aleksic et al. 2012
Nice description of the HE bump
Di!erent integration
times!
GeV and TeV emission of FSRQ
e-!
e-
e- !!
B
Dermer et al. 2009Ghisellini, FT 2009Sikora et al. 2009
Accretion disk
BLR
DU
ST
Y T
OR
US
Setting the stage
Bonnoli et al. 2011
Huge optical depth of BLR
FT & Mazin 2009
FT et al. 2012
GeV TeV
The breakthrough: the FSRQ 1222+216
tdouble~10 min!
cm
Location of VHE emission? Difficult inside BLR!
Strong absorption (E>30 GeV within BLR, E>1 TeV outside) (e.g. Liu et al. 2008, Reimer 2007, FT & Mazin 2009)
Decline of the IC scattering efficiency (e.g. Albert et al. 2008, FT & Ghisellini 2008)
General
Model dependent (not applicabile to
hadronic)
RBLR
!
!b
RIR
Tavecchio et al. 2011
External emission?
“Standard” SED
Variable VHE
Tavecchio et al. 2011
e.g. Ghisellini et al. 2008, 2009
Giannios et al 2009
Marscher & Jorstad 2010
Possibilities to reconcile large d and rapid variability
Minijets from fast reconnection
Magnetocentrifugal acceleration
Possibilities to reconcile large d and rapid variability
Minijets from fast reconnection
Magnetocentrifugal acceleration
Too high B? (>100 G, Nalewajko +2012)
E/B~26
Possibilities to reconcile large d and rapid variability
Minijets from fast reconnection
Magnetocentrifugal acceleration
Large IC cooling!
Too high B? (>100 G, Nalewajko +2012)
E/B~26
Possibilities to reconcile large d and rapid variability
Radiative
efficiency
Bromberg & Levinson 2009
"=0.27
2d, semianalitic calculations “Focusing”
RMHD simulations by G. Bodo
Low cool. High Cool.
Dermer et al. 2012
UHE Neutral beams?
neutrinos
An “exotic” scenario: photon-axion oscillation
Tavecchio et al. 2012, submitted
Standard
Axions
GeV and TeV emission of extreme HBL
FT et al. 2009
B>0
Effective B-field
The reprocessed flux is diluted within a larger
solid angle
B>0!
FT et al. 2010
Neronov et al. 2010Dolag et al. 2010
Dermer et al. 2011
Vovk et al. 2012
LAT 3 years!Reprocessed?
Direct?
Bonnoli et al., in prep
A population of IGMF probes?
SUMMARY
LBL-HBL: nice description of IC bump
(caveat: long LAT integration)
FSRQs: unexpected and challenging VHE emission:
need for more examples!
Extreme HBL: probes for EBL and EGMF