Multi-messenger Transients in the CTA Era
Susumu Inoue (RIKEN)
on behalf of many collaborators

CTA
Tran
Coor

MAG
Tran
Conv

Nov 2012

Gamma Ray Bursts

VHE Neutrinos

Gravitational Waves?
Fast Radio Bursts

AGN Flares

The Unknown

Multi-messenger Transients Now
Susumu Inoue (RIKEN)
on behalf of many collaborators

CTA
Tran
Coor

MAG
Tran
Conv

Oct 2018

Gamma Ray Bursts

VHE Neutrinos

Gravitational Waves?
Fast Radio Bursts

AGN Flares

The UnknownElectroweak Transients Now
Susumu Inoue (RIKEN)
on behalf of many collaborators

CTA
Tran
Coor

MAG
Tran
Conv

Oct 2018

VHE Neutrinos

AGN Flares

outline
1. electroweak observations of TXS 0506+056 / IC-170922A
IceCube, Fermi, MAGIC+, 2018, Science 361, eaat1378

2. interpretation via pγ scenarios (one-zone)
a. internal photons as targets Cerruti, Zech, … SI+; 1807.04335
b. “external” photons: jet-sheath (structured jet) scenario
MAGIC Coll., ApJ 863, L10; 1807.04300(Bernardini, Bhattacharya, SI, Satalecka, Tavecchio)c. external photons: radiatively inefficient accretion flow
Righi, Tavecchio, SI; 1807.10506

d. brief comparison with other work
3. summary

Keivani, Murase+c. external photons: radiatively inefficient accretion flow

m cosmic-ray interactions withinere. Although atmospheric neunant at energies below 100 TeV,lls steeply with energy, allowing
utrinos to be more easily identiergies. The muon-neutrino as-

angle in IceCube is of astrophysical origin. This
probability, the so-called signalness of the event(14), was reported to be 56.5% (17). Although
IceCube can robustly identify astrophysical neutrinos at PeV energies, for individual neutrinos
at several hundred TeV, an atmospheric origin

Following the alert, IceCube performed acomplete analysis of relevant data prior to
31 October 2017. Although no additional excess
of neutrinos was found from the direction of TXS
0506+056 near the time of the alert, there areindications at the 3s level of high-energy neutrino

ν observation of IC-170922A(B)

Probability Density

a zenith angle 5:7þ0:50"0:30 degrees below the horizon.

E

2.00 (90% lower limit: 200 TeV, peak: 311 TeV)

E

2.13 (90% lower limit: 183 TeV, peak: 290 TeV)

E

2.50 (90% lower limit: 152 TeV, peak: 259 TeV)

1.5

1.0

IceCube, Fermi, MAGIC+,
2018, Science 361, eaat1378

Downloaded from http://science.sciencemag.org/ on July 12, 2018

play forceCubeme at which asignal isolor of the hit,or earliest hits
test. Timesve to the firstng to the tracknd earlier andhown with the
he first andctively. The
ent took tor is ~3000 ns.
ored sphere is
he logarithm
light
DOM, withorresponding
The total
is ~5800 photoelectrons. Inset is an overhead perspective view of the event. The best-fitting track direction is shown as an arrow,

Cosmic (deca)Pevatron?

- EHE event: 56.5% probabilityof being astrophysical ν- alert after 43s- well localized, <<1 deg- Eν~290 TeV(183 TeV - 4.3 PeV 90% C.L.)
assuming -2.13 spectrum

0.5

0.0
101

102

T and MAGIC observations of IceCube-170922A’s
sition of IceCube-170922A in J2000 equatorial coordinates

103

104

Neutrino Energy (TeV)105-> possible cosmic proton
accelerator with
10
Ep>~20Eν~several PeV
6pixel, using detected photons with energy of 1 to 300 GeV in a 2° by 2°region around TXS0506+056. The map has a pixel size of 0.02° and was

m
C

f
+ ,

ewu

f
+,

/
f

ν + EM observations of IC-170922A/ TXS*0506+056
à
C

+ ,

(2008 d1

Fermi-LAT

+,
2017

10

)

il

MAGIC

]
Fermi-LAT:- coincident with blazar TXS 0506+056 in bright state%(0.5 yr-long)- significance of association ~3σ-> possible source of possible astrophysical high-energy neutrino
MAGIC:- ~6σ detection >~100 GeV, <day timescale flaring- steep spectrum (Γ~-3.5 - -4.0), no significant time-dependence-> crucial contraints on physical conditions of source

- Sig
-> B
p
- ν luν + EM observations of IC-170922A / TXS 0506+056
2009

2013

2017

IC-170922A
15 Sep 17 01 Oct 17 15 Oct 17

MAGIC<day timescalevariability

Fermi-LAT
Swift

opticalradio

IceCube, Fermi, MAGIC+, 2018, Science 361, eaat1378

ν + EM observations of IC-170922A / TXS 0506+056
2009

2013

2017

IC-170922A
15 Sep 17 01 Oct 17 15 Oct 17

MAGIC<day timescalevariability

Fermi-LAT
Swift

opticalradio

IceCube, Fermi, MAGIC+, 2018, Science 361, eaat1378

ν + EM observations of IC-170922A / TXS 0506+056

MAGIC Coll., ApJ 863, L10 (1807.04300)

ν + EM observations of IC-170922A / TXS 0506+056

参照
z=0.3365+-0.0010

1/0.5 yr

Fermi-LAT
Γ~-2.0SwiftΓ~-2.0 - -3.0

assuming Eν-2

MAGIC
Γ~-3.5 - -4.0
NuSTAR
Γ~-1.7γ: clear

1/7.5 yr

ν: uncertainflux
X: concave
breakintermediate- or low-frequency peaked BL Lac object

IceCube, Fermi, MAGIC+, 2018, Science 361, eaat1378

blazars

AGN with relativistic jet viewed near-axis
spectra consistent with mainly electron sync.+IC
sync.

IC(?)

FSRQs
BLLs

blazar sequence
Fossati+ 98

GeV TeVflat spectrum radio quasars (FSRQs): high L, strong emission lines
BL Lac objects (BLLs): low L, weak emission lines

Redman’s theorem“A competent theoretician can fit any
given theory to any given set of facts.”

QHBs—show broad optical and UV emission lines thatoriginate from the broadline regions (BLRs) found nearsupermassive black holes. The BLR also plays a role inscattering radiation emitted by the accretion disk that feeds
matter onto the black hole. In addition, the pc-scale dust
torus surrounding the galactic nucleus is a source of IR
radiation that provides target photons for very high4-1energy CRs.
γπpνIn this work, we study high-energy neutrino production in-1 of
the inner jets of radio-loud AGN andexaminetheeffectsνexternal photon fields on neutrino production in blazars. We
use the blazar sequence to derive the diffuse neutrino
intensity from the inner jets. We show that the cumulative
neutrino background, if from radio-loud AGN, is dominatedby the most luminous QHBs. This implies a cross-correlation
between astrophysical neutrinos with ∼1–100 PeV energies
and bright, luminous FSRQs found by Fermi.
In previous works on the diffuse neutrino intensity
URASE, YOSHIYUKIINOUE, AND CHARLES D. DERMER[15,16], only the jet and accretion-disk components wereconsidered
as target
photons,with
but heree accelerated, andthey shouldinteract
bothwe show that pγ

neutrino emission from blazars

neutrino production in QHBs. Fourth, there is IR emission
from the dust torus. A schematic diagram is shown in
Fig. 1, and the SEDs of blazars are shown in Fig. 2 as a

- pγ generally favored over pp in AGN jets
- target γ ε’ >~20m m c /E δ
~ 0.4 keV (E /300 TeV) (δ/20)- unlike FSRQs, BL Lacs thought to:lack bright external γ fields,
have low internal sync. γ fields-> PeV ν production inefficient?

d external-radiation
fieldsduring the
dynamical
one-zonemodels(e+pco-accel.)
nal nonthermal emission produced in the jet isinternalWesyn.
targetso as the jetwith
component.
considerthe only:
jett first.
very high Lp required
he spectrum of internal synchrotron photons is
Cerruti, Zech, Boisson, Emery,ted by a power-law, the photomeson production
Lenain,1807.04335
is estimatedSI,
using
the rectangularapproximation
tohadronic cross section to be

see also Gao+ 1807.04275! 0 "β−1tdyn 2κ Δ σ Δ Δε̄Δ 3Lsrad
Ep
Þ≈
≃
;
tpγ
1 þ β ε̄Δ 4πrb Γ2 cE0s E0bp

ð19Þ

PHYSICAL REVIEW Murase+
D 90, 02300714(2014)

FIG. 1 (color online). Schematic picture of a blazar, showing
external radiation fields relevant for neutrino production.

023007-2

QHBs—show broad optical and UV emission lines thatoriginate from the broadline regions (BLRs) found nearsupermassive black holes. The BLR also plays a role inscattering radiation emitted by the accretion disk that feeds
matter onto the black hole. In addition, the pc-scale dust
torus surrounding the galactic nucleus is a source of IR
radiation that provides target photons for very highenergy CRs.
In this work, we study high-energy neutrino production in
the inner jets of radio-loud AGN and examine the effects ofexternal photon fields on neutrino production in blazars. We
use the blazar sequence to derive the diffuse neutrino
intensity from the inner jets. We show that the cumulative
neutrino background, if from radio-loud AGN, is dominatedby the most luminous QHBs. This implies a cross-correlation
between astrophysical neutrinos with ∼1–100 PeV energies
and bright, luminous FSRQs found by Fermi.
In previous works on the diffuse neutrino intensity
URASE, YOSHIYUKIINOUE, AND CHARLES D. DERMER[15,16], only the jet and accretion-disk components wereconsidered
as target
photons,with
but heree accelerated, andthey shouldinteract
bothwe show that pγ

neutrino emission from blazars

neutrino production in QHBs. Fourth, there is IR emission
from the dust torus. A schematic diagram is shown in
Fig. 1, and the SEDs of blazars are shown in Fig. 2 as a

- enhanced pγ efficiency via
external γ fields in BL Lacs?
I. sync. from sheath in structured jets
MAGIC Coll. 1807.04300
II. radiatively inefficient accretion flows(RIAFs) Righi+ 1807.10506
focus on one-zone models
PHYSICAL REVIEW Murase+
D 90, 02300714(2014)(electron+proton co-accelerated)
FIG. 1 (color online). Schematic pictureof a blazar, showing
external radiation fields relevant for neutrino production.
- questions
d external radiation fields during the dynamical
1. accompanying
hadronic
nal nonthermal
emission producedin the jetemission
is023007-2o as the jet consistentcomponent. We
the jetwithconsider
observedSED?
t first.
2. accompanying γγ absorption
he spectrum of internal synchrotron photons is
consistent
with observedSED?
ted by a power-law,
the photomeson
production
is estimated3.usingrole theof rectangularexternal approximation
Comptontohadronic cross section to berelative to SSC?
! energy0 "β−1s
protonmaximumtdyn 4.
E
2κ σ Δε̄3LradpÞ≈≃ Δ Δ Δ
;
2
0
0b
tpγ
1 (UHECRþ β ε̄Δ 4πraccelerator)?
Γ
cE
E
b
s
p
ð19Þ

3a. pγ scenarios with internal photons only
model description

Cerruti, Zech, …
SI+ 1807.04335

leptonic part
- emission region: spherical with radius R,
magnetic field B, Doppler factor δ- electron distribution: broken power-law γe,min, γe,max, αe1,αe2- leptonic emission: synchrotron, SSC
hadronic part follow Cerruti+ 15, Zech+ 17- proton distribution: power-law γp,min=1, γp,max (or η), αp1=αe1- hadronic emission
SOPHIA: Mücke+ 02,03
p+γLE→N+ π0, π+- photo-meson�
π+-→µ+-+ν→e+-+3ν π0→2γµ+-+B→µ+-+γ muon synchrotron
Kelner &+p+γLE→p+ e e photo-pair (Bethe-Heitler)�
Aharonian 08
γ+γLE→e+eelectron-positron
e+e-+B→e+e-+γ sync. cascade
p+B→p+γ

proton synchrotron- hadronic emission: photomeson cascade, BH cascade, muon+proton sync.

Man
Müc
Ahar

Lepto-hadronic
Lepto-hadronicsingle-zone
single-zonemodels
modelsforforthetheγ γandandν νemission
emission
of of
TXS
TXS
0506+056
0506+056

thethecentralcentralengineengineforfortypicaltypicaljetjetopening
opening
angles.
angles.
AsAs
is usuallyis usually
Table
Table
1. 1.
Parameters
Parameters
used
used
forforthethehadronic
hadronicmodelsmodelsfound
found
forfor(lepto-)hadronic(lepto-)hadronicmodels,models,thetherequired
requiredjetjet
power
power
is is
relatively
relativelyhighhighandandlargelylargelydominateddominated
byby
that
that
in in
protons.
protons.
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Proton-synchrotron Lepto-ha
Lepto
Solutions
Solutionsin inthethe
proton-synchrotron
proton-synchrotron
scenario
scenario
arearegenerally
generallyless
lessdemandingdemanding
in in
this
this
respect,
respect,
and
and
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can
can
find
find
parameterparameter
z z
0.337
0.337
0.33
0
Energy
(eV)
5
8
20 21
2sets
11sub-Eddington
14
17
δ
δ
35
−
35
50
−
50
30
−
30
sets
likelylikelycorresponding
correspondingtotosub-Eddington
luminosity.
luminosity.
It
It
is
is
10
10
10
10
10
10
10 10
16 cm]
16 cm]R [10
R [100.10.1− 9.7− 9.7
0.2 0.2−
importantimportanttoto
underline
underlinethatthat
ouroursolutionssolutionsarearecharacterized
characterized⋆τ ⋆τ [days]
0.01
0.01
− 1.0
− 1.0
0.020.0−
obsobs [days]
byby
αp,1
αp,1= =
2.02.0andand
γ p,min
γ p,min
==
1, 1,
and
and
arearethus
thus
conservative
conservative
in in
47
10
terms
terms
of of
thethe
total
total
power
power
in in
hadrons.
hadrons.
AA
lower
lower
luminosity
luminosity
cancanB B
0.80.8− 32− 32
0.130.13−⋆ u⋆ u[erg−3 ] −3 ]bebeachievedachieved
if if
γ p,min
γ p,min
≥≥
1 or
1 or
αp,1
αp,1
≤≤
2.0.
2.0.
Lower
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luminosities
luminosities
cmcm
0.02
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− 0.16− 0.16
6.5 6.5
× 10×−4
1
B B [erg
can
can
also
also
bebe
achievedachieved
if theif thephotons
photons
that
that
serve
serve
as as
targets
targets
forforγe,min500500500p-γp-γinteractions
interactions
originateoriginateoutsideoutsidethethejetjet
(see
(see
Ahnen
Ahnen
et et
al.al. 46 γe,min
10γe,break
γe,break
= γ=
γ
=
γ
=
γ
e,m
e,min
e,min
2018).
2018).
4] 4]γe,maxγe,max[10[100.60.6− 1.0− 1.0
0.8 0.8
−
The
The
two
two
scenarios
scenarios
shouldshouldin inprinciple
principle
bebe
distinguishable
distinguishable
αe,1
αe,1
= α=p,1αp,12.02.0
2.0
with
with
futurefuturevariability
variability
studiesstudies
of of
this
this
source.
source.
While
Whilethetheleptoleptoαe,2αe,2= α=p,2αp,23.03.0
3.0
hadronic
hadronic
scenario
scenario
predicts
predicts
a strong
a strong
correlation
correlation
betweenbetweenthethe−3 −31045 K eK[cm6.36.3
− 9.1
− 9.1
× 10
×3103
9.5 9.5
× 10×310−
e [cm] ]⋆ u⋆ u[10[10−5 erg−5 erg−3 ] −3 ]low-energy
low-energy
andandhigh-energy
high-energy
spectral
spectralbumps,
bumps,
as as
in in
any
any
SSC
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cmcm
0.40.4− 15.1− 15.1
2.2 2.2
× 10×310−
e e
scenario,
scenario,thethe
proton-synchrotron
proton-synchrotron
scenario
scenario
would
would
imply
imply
de-deγ p,min
γ p,min1 1
1lays
laysbetween
betweenvariations
variations
in inthethetwo
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due
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thethe
9] 9]
+γ
[10
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=
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=
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=
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=
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44 γ p,break
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diﬀerent
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andandcoolingcoolingtime
time
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AA
delay
delay
is alsois also109] 9]
γ p,max
γ p,max[10[100.40.4− 2.5− 2.5
0.060.0−
expected
expected
betweenbetweenthethe
hard
hard
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X-ray
component
component
andandthethehighhighη η
20 −
2050
− 50
10
energyenergypeak
peakflux
fluxin inthethelepto-hadronic
lepto-hadronicsolutions.
solutions.
In In
both
both
−3
−3
4
4
3
K pK[cm
10.4
10.4
− 2.0
− 2.0
× 10
× 10
3.5 3.5
× 10× 10−p [cm] ]scenarios,
scenarios,
thethetime-averaged
time-averaged
SED
SED
duringduringthethe
high
high
state
state
of of 43 ⋆ u⋆p u[erg−3 ]−3 ]cmcm
0.70.7− 45− 45100100−1
p [ergthethesource
source
is is
well
well
reproduced
reproduced
byby
thethemodel,
model,
while
while
a rapida rapid10⋆ u⋆ u/u B
1.01.0− 89− 89
3.9 3.9
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−
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flux
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over
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thetheVHE
VHE⋆ L⋆[10
46
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−1
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L
[10
erg
erg
s
s
]
]
0.8
0.8
−
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35
−
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3
band,
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would
would
requirerequiretime-dependenttime-dependent
modelling.
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arysolutionssolutionspresented
presented
here
here
arearehowever
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with
with
a a
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10−−30.2− 0.2
0.110.1
−
16
18
20
26
28
30
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24
⋆ν ⋆ν
−1 ] −1 ] 2.42.4
−5
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10 variability
10
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10
10
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variability
time
time
scale
scale
of
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one
day.
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[year
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×
10
×
10
−
−
1.7
×
10
×
10
0.008
0.00
−
183−4300
183−4300
TeV
TeV
ν (Hz)
InIn
thetheproton-synchrotron
proton-synchrotron
scenario,
scenario,
protons
protons
cancanreachreacha maximuma maximum
Lorentz
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factorfactorof of10910, 9close, closeto tothethehighesthighestob-obTheThe
luminosity
luminosityof theof theemitting
emitting
regionregionhashasbeen
been
calculated
calculatea
2222
servedservedenergies
energiesof ofultra-high-energy
ultra-high-energy
cosmiccosmic
rays,
rays,
when
when
taktakL =L2π=R
2π cΓR bulkcΓbulk(u B(u+Bu+e u+eu+p ),u pwhere), where
Γbulk
Γbulk
= δ/2,= δ/2,
andandu B ,u Buinginginto
intoaccount
account
Doppler
Dopplerboosting.
boosting.
Maximum
Maximum
protonprotonenerenerandandup u, pthe, theenergyenergydensities
densitiesof theof themagnetic
magnetic
field,
field,
thetheelectroelec
andandthetheprotons,
protons,
respectively.
respectively.
The
The
quantities
quantities
flaggedflagged
with
with
as
gies
gies
arearelow
low
byby
a factora factorof oftentenin inthethelepto-hadronic
lepto-hadronic
scenario,
scenario,
⋆ )(⋆
(
are
)
are
derivedderivedquantities,
quantities,
and
and
not
not
model
model
parameters.
parameters
but
but
the
the
protonprotondensitydensity
is is
much
much
higher.
higher.

proton sync.-dominant case (+pγ cascade)
10-9

10-4

10-1

10-10

ν L ν (erg s-1 )ν Fν (erg cm-2 s-1)

Cerruti, Zech, … SI+ 1807.04335

psyn

10-11

10-12

γe

-13

10

10-14
10

10

1012 1014γπ- EM SED reproduceable with proton synchrotron dominating γ rays,pγ cascade non-negligible at VHE- BUT neutrino flux too low to be viable
4 CONCLUSIONSCONCLUSIONS
References
References-> detection of 4single
ν provides crucial discriminant
After
Afterintroducing
introducinga afew
fewsimplifying
simplifyingconstraints
constraints
based
based
onon
generalgeneralphysicalphysicalconsiderations,considerations,
wewe
have
have
explored
exploredthethefullfullparameterparameterspace
spaceof ofthethelepto-hadronic
lepto-hadronic
one-zone
one-zone
model
model
forforAcero
Acero
F.,F.,
et etal.,al.,
2015,
2015,
ApJS,
ApJS,
218,
218,
23 23
AharonianAharonian
F. F.
A.,A.,
2000,
2000,
New
New
Astron.,Astron.,5, 3775, 377Ahnen
Ahnen
et al.
et al.
2018,2018,
in press
in pressin ApJLin ApJL

the central engine for typicalthe central
jet opening
engineangles.
for typical
As is usually
jet opening angles.
usually usedTable
TableAs
1. isParameters
for the1.hadronic
Parametersmodelsused for the hadronic models
found for (lepto-)hadronic
foundmodels,for (lepto-)hadronic
the required jet models,
power isthe required jet power isrelatively high and largely
relatively
dominatedhigh byandthatlargelyin protons.
dominated by that in protons.
Proton-synchrotron
Lepto-hadronic
Proton-synchrotron
Lepto
Solutions in the proton-synchrotron
Solutions in the
scenario
proton-synchrotron
are generally scenario are generally
less demanding in this respect,less demanding
and one incanthisfindrespect,
parameterand one canz find parameter
z
0.337
0.337
0.337
0
δluminosity. It isδ
35 − 50
30 −3550− 50
30sets likely correspondingsets
to sub-Eddington
likely corresponding
luminosity.
to sub-Eddington
It is
Energy(eV)
16 cm]
16 cm]R 17[10
R [100.1− 9.7
0.2 0.1
− 1.5
− 9.7
0.2
8are characterized
20 21
importantto underline
importantour 5solutions
to underlinethatarecharacterized
-4
-1
2that
11 our solutions
14
10
10
10
10
10
10
10
10
10
10
⋆τ
⋆
[days]
τ
0.01[days]
−
1.0
0.02
0.01
−
0.3
−
1.0
0.0
obs
obs
by αp,1 = 2.0 and γ p,minby= α1,p,1and= 2.0
areandthusγ p,min
conservative= 1, andinare thus conservativeinterms of the total powerterms
in hadrons.
of the A
total
lower
power
luminosity
in hadrons.
can A lower
luminositycanBB
0.8 − 32
0.13 −
0.80.65
− 32
0.13
47
⋆ u [erg−3⋆−3−4
be achieved if γ p,min ≥ be
1 orachieved
αp,1 ≤ 2.0.
if γ p,min
Lower≥ luminosities
1 or αp,1 ≤ 2.0. Lower
luminosities
10cm ]u B0.02[erg−cm
0.16 ]
6.5 × 100.02−−0.017
0.16
6.5 × 1B
can also be achieved if thecanphotons
also be that
achieved
serveifas
thetargets
photons
for that serve as targets for
γe,minγe,min 500
500500p-γ interactions originate
p-γoutside
interactions
the jetoriginate(see Ahnen
outsideet al.the jet (seeAhnen et al.
γe,break
γe,break= γe,min= γe,max= γe,min=γ2018).
2018).
41.0
46
γe,max [104 ]
γ
0.6
[10
−
]
0.8
0.6
−
1.7
−
1.0
0.8
e,max
The two scenarios shouldThein principle
two scenarios
be distinguishable
should in principle be distinguishable10
αe,1 = αp,1
αe,1 = α2.0
2.0 2.0p,1
with future variability studies
with futureof thisvariability
source. Whilestudiesthe ofleptothis source.αWhilethe leptoαe,2 = α3.0
3.0 3.0e,2 = α p,2p,2hadronic scenario predicts
hadronic
a strong
scenario
correlation
predicts
betweena strong
the correlation
betweenthe−3
3−
K e [cm ]K e6.3[cm− −3
9.1] × 103
9.5 × 106.3
− 2.6
9.1 ×× 101053
9.5 × 10
⋆ u as[10−5any−3 ] 45⋆ u 0.4
−5
−3 ]
30.4
3
low-energy and high-energy
low-energy
spectralandbumps,
high-energy
as in any
spectral
SSC bumps,
in
SSC
erg
cm
[10
−
15.1
erg
cm
2.2
×
10
−
43
−
15.1
×
10
2.2 × 10ee+-would imply de-scenario would imply de-10
scenario, the proton-synchrotron
scenario, thescenario
proton-synchrotron
γ p,min due to theγ p,min 1
1 1
lays between variations lays
in thebetweentwo components
variations induetheto twothe components
γ p,break [109 ]γ p,break= γ p,max[109 ]= γ=
γ p,max=γp,max
diﬀerent acceleration anddiﬀerent
cooling acceleration
time scales. A
and
delay
coolingis alsotime scales. A delay9 is also
γ p,max [10 ]γ p,max
0.4[10−92.5]
0.060.4
− 0.2
− 2.5
0.0
expected between the hard
expected
X-ray between
component
the andhardtheX-ray
highcomponent and the high1044ηη20 − 50
10
20 − 50
energy peak flux in theenergy
lepto-hadronic
peak fluxsolutions.
in the lepto-hadronic
In bothsolutions.
3 −−6.6
K p [cm−3 ]In both
Kp
10.4
[cm
−−3
2.0
] × 104
3.5 × 10
10.4
2.0××10104 4
3.5 × 10
scenarios, the time-averaged
scenarios,
SED theduringtime-averaged
the high state
SEDofduring thestateof⋆ u high
−3
⋆
−3
[erg
cm
]
u
[erg
0.7
−
cm
45
]
100
−
0.7
1400
−
45
100
p
p
the source is well reproduced
the sourceby theis wellmodel,
reproduced
while a rapid
by the model, while a rapid⋆ u /u⋆ u /u1.0 − 89
3.9 × 104 1.0− 79−×89104
3.9 × 10p in
B the VHEp
B
flux increase over a few nights,
flux increase
potentiallyover aseen
few innights,the VHEpotentially seen1043
⋆ L [1046 erg s−1 ]⋆ L [10
46
−1
0.8
−
erg
170
s
]
35
−
0.8
350
−
170
35
band, would require time-dependent
band, would modelling.
require time-dependent
The station- modelling. The station⋆ν [year−1 ] with a
⋆ν5.7
−1−3
−3 − 0.2
ary solutions presented ary
heresolutions
are however
presented
consistent
here withare howeveraconsistent
[year
× 10
] − 0.2
0.11
5.7 ×−10
3.0
0.1
⋆
−1
⋆
−5
−3
−1
−5
variability time scale of variability
one day. time scale of one day.
ν183−4300 TeV [year ]2.4ν×183−4300
10 −TeV
1.7 ×[year10]
2.40.008
× 10− 0.11
− 1.7 × 10−3
0.00
10
16
18
20proton-synchrotron
26 scenario,
28
30
32
34reach35
12 proton-synchrotron
thescenario,
10 In 101014 10
10 In the101022protons
1024 can10 reach10
10 protons
10 can10 10
99ν (Hz)oba maximum Lorentz factor
a maximumof 10 , close
Lorentz
to thefactorhighestof 10ob, close toThetheluminosity
highestof the emitting
The luminosity
region has ofbeen
thecalculated
emitting regionashas been calculate
2
2 tak2served energies of ultra-high-energy
served energies
cosmicof ultra-high-energyrays, when tak- cosmicL rays,= 2π RwhencΓbulk(u B + ue + Lu p=),2π
where
R 2 cΓbulk
Γ
(u
=
δ/2,
+
u
and
+
u
u
),
where
,
u
,
Γ
e
p B
e
bulk Bbulk = δ/2, and u B
ing into account Doppler
ingboosting.
into accountMaximum
Doppler
protonboosting.
ener- Maximum
ener- densities
and u pproton, the energy
andofuthe,themagnetic
energyfield,
densities
theelectrons,ofthemagnetic
field, the elec
p
and
the
protons,
respectively.
and
The
the
protons,
quantities
respectively.
flagged
with
The
a
star
quantities
flagged withgies are low by a factor ofgies
tenarein thelow lepto-hadronic
by a factor of ten
scenario,in the lepto-hadronic scenario,⋆ ) are derived quantities, (and⋆ ) are(notderivedmodel
quantities,
parameters.
and
not
model
parameters
but the proton density isbutmuch
the higher.
proton density is much higher.

SSC-dominant case (+pγ cascade)
10-9

10-10

10-11

10-12

10-13

10-14

ν L ν (erg s-1 )ν Fν (erg cm-2 s-1)

Cerruti, Zech, … SI+ 1807.04335

SSC

γe

γπ

psyn

- EM SED reproduceable with SSC dominating γ rays,
non-neglible: pγ cascade at VHE, BH at X-ray- BUT requires rather extreme parameters, e.g. Lp~1048 erg/s, γe,min~500
4 CONCLUSIONS
References
References- hard4After
νCONCLUSIONS
spectraalso
constrained
by
IC
point
sourcesearchintroducing a fewAftersimplifying
introducing
constraints
a few simplifying
based on constraints
on ApJS,
Acero F., based
et al., 2015,
Acero
218,F.,
23et al., 2015, ApJS, 218, 23
general physical considerations,general physicalwe haveconsiderations,
explored the full
we haveAharonian
explored F.
theA.,full
2000,
New
Aharonian
Astron.,F.
5, 377A., 2000, New Astron., 5, 377-> scenarios
withexternal
photons
likelymorefavorableparameter space of the parameter
lepto-hadronic
spaceone-zoneof the lepto-hadronicmodel forone-zone
forin pressAhnen
Ahnen etmodelal. 2018,
in ApJLet al. 2018, in press in ApJLZechA., Boisson
CerrutiC., Inoue
M., ZechS., 2015,
A., Boisson
MNRAS,
C.,
448,
Inoue
910S., 2015, MNRAS, 44
the spectral energy distribution
the spectralof energy
the 2017
distribution
high stateof theCerruti
2017 M.,
highstate
Cerruti M., Benbow W., Chen
CerrutiX.,M.,
Dumm
BenbowJ. P.,
W.,Fortson
Chen X.,
L. F.,
Dumm J. P., Fortson

jet-sheath (spine-layer) structure
3b. pγ scenarios with “external” photons from jet sheath

C. Righi
et al.: High-energy emitting BL Lacs and h
MAGIC Coll.
1807.04300- jet structure with slower sheath (layer)
Thereforsurrounding faster jet (spine)
given
HBL i
Γ
flux, F = ksumption is-> supported by observations,who found t
2FHL sourc
numerical simulationspfaster jet- synchrotron photons from sheath seen
3. CalculaΓ
The Second
Doppler boosted in jet frame
ermann et a
slowersheathabove 5-> enhanced target for pγ ν production, EC Fig. 1. Sketch of spine-layer geometry. A faster inner core, or spine, is gies
over 80 mon
c.f. Tavecchio+ 14, 15 2FHL closel
surrounded by a low-velocity layer. Both regions emit low-energy syn- nent produc- caveat: spectrum of sheath radiation
chrotron photons. Due to the relative motion, the low-energy emission
previous
Righi&frameTavecchio
17photo- theof the layer is amplified
in the spineand dominates the
good
proxy
meson cooling of high-energy protons.
not well defined a-priori
for each soul⌫sNagai+ 14

limb-brightened
structure inradio galaxies
e.g. 3C84 (NGC 1275)

where tp0 (Ep0 ) = [c hn0ph (✏ 0 ) p (✏ 0 , Ep0 )K(✏ 0 , Ep0 )i] 1 , p being
the cross section, K the inelasticity and n0ph is the target photon
number density.
The total, energy integrated, neutrino luminosity can be expressed as:L⌫ = ✏p Q0p 4s ,where the total CR injected power is:Z0Qp =Q0p (Ep0 ) dEp0 ,and the averaged efficiency ✏p is:Z1✏p = 0fp (Ep0 ) Q0p (Ep0 ) dEp0 .
Qp

(3)

(4)

F⌫,tot ⌘

(6)

X

F

i

in which we
all sources.
from HBL (sThe next
source, F⌫i ,(5)

In general, the IC (i.e., high-energy -ray) luminosity can be formally expressed in exactly the same way:
L = ✏e Q0e 4s ,pected flux o
The contotal neutrin
due to the cSince the neto the corres

F⌫i =

Z E2
E1

where the inassume thatsion

jet-sheath model description

MAGIC Coll. 1807.04300

leptonic part follow Tavecchio+ 14, 15- emission region: cylindrical with radius R, length dR=R,
magnetic field B, Lorentz factor Γj, viewing angle θv- electron distribution: broken power-law Ee,min, Ee,br, Ee,max, s1,s2- photons from sheath with Lorentz factor Γs, broken power-law spectrum- leptonic emission: synchrotron, SSC, EC
hadronic part follow Böttcher+ 13, Cerruti+ 15- proton distribution: power-law Ep-2 with exp. cutoff Epmax- hadronic emission
p+γLE→N+ π0, π+- photo-meson�
π+-→µ+-+ν→e+-+3ν π0→2γµ+-+B→µ+-+γ muon synchrotronp+γLE→p+ e+e- photo-pair (Bethe-Heitler)�
γ+γLE→e+eelectron-positron
e+e-+B→e+e-+γ sync. cascade
p+B→p+γ

SOPH
Kelner &Aharonian 08

proton synchrotron- hadronic emission: photomeson cascade, BH cascade, muon+proton sync.

Man
Müc
Ahar

jet-sheath model for electroweak emission

MAGIC 1807.04300“lower VHE”

synsheath

γe+-

EC

γπ
SSC

- large no. of parameters but reasonably constrained- SED predominantly leptonic, γ-rays EC (not SSC)
- photopion+photopair cascade subdominant
but non-negligible in X (+VHE)-> crucial constraint on proton population- photopion efficiency fpγ(Ep~6 PeV)~10-4-> τγγ(Eγ~12 GeV)~0.1 -> τγγ(Eγ~100 GeV)~1
consistent with observed GeV-TeV breakνµ0.06/0.5 yr(0.21-6.3 PeV)
R=dR=1016 cm
B=2.6 GΓj=22, Γs=2.2
θv=0.8°(δj=40)
E’pmax=1016 eV
Le=1.6x1042 erg/s
Lp=3x1045 erg/s(?)(LB=1.2x1045 erg/s)

implications: maximum proton energy

MAGIC 1807.04300“lower VHE”

Epmax dependence- maximum ν yield for E’pmax~1016 eV (comoving)- E’pmax~1016-1018 eV: higher Eνpk, lower Lp from X-ray limits
lower EHE ν rate, but not too low to be ruled out (>~0.01/0.5yr)(simultaneously PS ν not too high, ~<0.05/0.5yr)-> unclear whether UHECR accelerator or not4.1. Cyclosynchrotron Emission and the Radio-Submillimeter Spectrum
The radio to submillimeter spectrum is deÐned by three quantities : (1) the luminosity of the radio spectrum,
maximum (peak) frequency beyond which the spectrum falls o† exponentially, and (3) the slope of the radio spectru
treat each of these separately.
In the optically thin limit, the spectrum of cyclosynchrotron radiation by an isotropic distribution of relativistic telectrons is given by (Mahadevan, Narayan, & Yi 1996 ; Narayan & Yi 1995b)

3c. pγ scenarios with external photons from RIAFs

radiatively
4nn le M(x ) ,Msynch
- expected at low accretion rates (ṁ=Ṁ/ṀEdd~<0.01),
K (1/h )2einefficientthe extreme relativistic expression for M(x ) given byM
inferred for SMBHs hostingwhere
BLwe useLacs
accretion flows
0.40 0.5316B
4.0505 A
1]]
exp ([1.8899x1@3) ,M(x ) \
M
x1@4
x1@2
x1@6
M
M
M optically- radiatively inefficient -> hot,andgeometrically thick,thin MeB
2l<-> standard accretion disk for high ṁ
,
l 4
.
x 4
b 2nm cM 3l h2eb e- broadband spectrum from radioto X-rays
The cyclosynchrotron
photons in these plasmas are self-absorbed and give a blackbody spectrum, up to a critical fre
l . The frequency at which this occurs, at each radius r, is determined by evaluating the total cyclosynchrotron emissioc- strong dependence of UV-soft
X intensity on ṁv

dl \ 4.43 ] 10~30

ṁ=(3,6,12,24)x10-4

Mahadevan 97
Ho 08

FIG. 1.ÈSpectrum produced by an advection-dominated disk with a \ 0.3, b \ 0.5, m \ 5 ] 109, and m5 \ (3, 6, 12, 24) ] 10~4. The plots are cnumerically by the method described in ° 5.1.1. The three labels correspond to the three cooling processes : synchrotron cooling (S), Compton coolingrate
RIAF model for neutrino emission from BL Lacs EHE(0.06-10 PeV)

Righi, Tavecchio, SI 1807.10506- plausible relation between Pjetand ṁ of central SMBH
among LBL/IBL/HBL subclasses- RIAF model spectra well-defined- effective pγ target only for LBLs-> potential explanation for why
TXS 0506+056, not Mrk 421/501- hadronic γ modeling to be done[/7yr ]RIAF ν
TXS 0506+056
~1
syn ν

LBL
3.5x10-5
IBL

syn ν
Mrk 421/501

HBL
LBL/IBL/HBL
parameterized
spectra9x10-63 ⇥ 103 ⇥ 105
n/a
n/a
n/a
n/a
n/a
n/a

T [K]
T 0 [K]↵↵"0min [keV]"0min [keV]"0[keV]"0maxmax
[keV]

3

3

n/a
2

n/a
2

3

3
0.05

2

2

5
3d. brief comparison with other work Keivani, Murase,
Petropoulou+ 1807.04537- generic internal/external photon scenarios
0.05
5Note—See
Table
5 for
parameter
definitions,for parametercommonto allIn
LMs.
In LMBBthe external
Note—See
Table
5 for
parameter
definitions,and and
TableTable
6 for 6parametervaluesvalues
commonto all LMs.
LMBB
models,models,the external
photon photon0
0 0 and "0field
is blackbody-likewithcomoving
temperature
T , whilein LMPLmodels,is a power-law
betweencomoving
max ,
field
is blackbody-likewithcomoving
temperature
T 0 , while
in LMPLmodels,it is a it
power-law
betweencomoving
energiesenergies"0min and"min"max ,
00withphoton
index
↵.
In
all
cases,
uisthecomoving
energydensityoftheexternal
photonfield.
Note
that
the
isotropic-equivalent
with photon index ↵. In all cases, uext is
extthe comoving energy density of the external photon field. Note that the isotropic-equivalent
4=
0 .4 L0 .
cosmic-ray
protonluminosityLpcosmic-ray
protonluminosity
is Lis=Lppp- hadronic-dominant scenarios difficult, likely leptonic-dominant- X-ray cascade constraints, γ-ray absorption constraints crucial- EHE rate <0.01/yr -> 1-zone models severely constrained if not ruled out
10−11 10−111047 1047
10−10
10−10

(max)(max)pp(max)(max)
p
p

L L
2× 2×
L L

LMBB1a LMBB1a
LMBB1b LMBB1b
LMBB1c LMBB1c
LMBB2a LMBB2a
LMBB2b LMBB2b
LMBB2c LMBB2c
LMPL1a LMPL1a
LMPL1bLMPL1bLMPL2aLMPL2aLMPL2bLMPL2b
HM3
HM3

LM LM

10−12 −12
10
10

44

10−13
10−12
10−13
10−12
103

104

10

10

0

3

10

10

100

105

5

4

10

10

1043

5

10

10ε5[eV]1010
ε [eV]

1045

10

44

1015

10−12 10−12

10−13

10−13

Keivani+
1043

1015

εν Fεν [erg cm−2 s−1]1045εν Fεν [erg cm−2 s−1]ε Fε [erg cm−2 s−1]ε Fε [erg cm−2 s−1]

10−11
10−11

ε Lε at z=0.33 [erg s−1]

ε Lε at z=0.33 [erg s−1]

1046 1046

10−14

10−14102
102

notable differences- choice of data set: different X-ray + UV, no VHE- degree of optimism (~personal preference)- internal/external photon scenarios

104

106
108
6
10
εν 10
[TeV]
εν [TeV]4108

Figure 4.
Leptonic Model (LMBB2b) for the
TXS
0506+056(Ep. 1). Model
Two SEDcases (grayFigure4. flareLeptonic(LMBB2b)for the Figure 5. Upper limits on the all-flavor neutrino (⌫ + ⌫¯)lines)
areplottedagainsttheobservations(coloredpoints,TXS 0506+056 flare (Ep. 1).
Two SED cases (gray fluxesFigure
predicted
our modelingof thethe SEDin theneutrino
leptonic (⌫ + ⌫¯)
5. forUpper
limits on
all-flavor
showing
allowedrangesat90%
confidence),onewithlines) are plotted against the observations (colored points, (LMx)and hadronic
fluxespredicted(HMx)for ourmodels.
modeling of the SED in the leptonic
hadronic
component
set
to
the
maximumallowedprotonshowing allowed
ranges at 90% confidence), one with(LMx) and hadronic (HMx) models.
(max)
50
1
luminosity
L
⇡
2
⇥
10
erg
s
(solidgray),
andthephadronic component set to the maximum allowed proton

Multi-messenger SED

X-ray (+UV) data
Red = Flare 1
Blue = “Low state”
Grey = archival
Line = neutrino

Keivani+
1807.04537
data used in
MAGIC paper
EB for MAGIC | EHE-170922A | 19/10/2017 | Page 5

MAGIC Coll.: select only X dataquasi-simultaneous with MAGIC
Keivani+: average over all available
X datatime coverage sparse, no strong
reason to prefer one over the other;choice of data set subjective(~personal preference)

2014-2015 (orphan) neutrino flare IceCube, 2018, Sci. 361, 147
13+5 events, ~3.5σ excess
ΔT~150 days
ICECUBE-170922A:EN>~30
EUTRINOS AND PHOTONS
TeVν
10 7 cm 2 s 1

2009
4

2010

2011

2012

2013

2014

2015

2016

2017

Fermi-LAT (E >100 MeV)

2

P. Padovani
200 200
P. Padovani
et al. et al.
0
IC40

IC59

IC79

IC86a

IC86b

IC86c

5

− log10 p

4

IceCube-170922A

2017
Gaussian Analysis

34σ2014-15

Box-shaped Analysis

2
1
0

2009
T. Kintscher

2010

2011

2012

2013

2014

Searching Transient Neutrino Sources with IceCube

2015

viable3σinterpretation
via pp?
2σmodeling 1σongoing,
2016
2017
stay tuned

Padovani+ 18
Figure 9.
The hybrid
neutrino
SED of TXS
The red The
points
15 GHzandGHzASAS) areVsimultaneouswith neutrinos,
grey
Figure9. Thephoton
hybrid –photon– neutrino
SED 0506+056.
of TXS 0506+056.
red(OVRO
points at
(OVRO
at 15
andVmag
ASAS
with neutrinos,
greymag ) are simultaneous21

diffuse high-energy neutrinos:
Aartsen et al.
constraints on blazar contribution

azar

g

-12

-12

-12

-12

-12

g

0-9

0-9

0-9

0-9

0-9

IceCube 2017

IceCube, ICRC 2017
2LAC: blazar contribution <7-27% of diffuse ν flux
2FHL: blazar contribution <4-6% of diffuse ν flux

Figure 5. 90% C.L. ﬂux upper limits for all 2LAC blazars in comparison to theobserved astrophysical diffuse neutrino ﬂux. The latest combined diffuse
neutrino ﬂux results from Aartsen et al. (2015b) are plotted as the best-ﬁt powerlaw with a spectral index of −2.5 and as a differential ﬂux unfolding using 68%
central and 90% U.L. conﬁdence intervals. The ﬂux upper limit is shown using
both weighting schemes for a power law with a spectral index of −2.5 (blue).
Percentages denote the fraction of the upper limit compared to the astrophysicalbest-ﬁt value. The equal-weighting upper limit for a ﬂux with a harder spectral
index of −2.2 is shown in green.

blazars strongly constrained as main sources of diffuse HE ν
5.4. The Maximal Contribution to the Diffuse
Astrophysical Flux

see however Palladino+ 1806.04769

Astrophysical neutrino ﬂux is observed between 10 TeV and2 PeV (Aartsen et al. 2015b). Its spectrum has been found to becompatible with a single power law and a spectral index of

summary electroweak observations/interpretation of TXS 0506+056

observations- IceCube: detection of ~300 TeV neutrino, high signalness, well localized- Fermi-LAT: bright BL Lac TXS 0506+056 associated at 3σ CL- MAGIC: <1 day variability, steep spectrum above ~100 GeV
interpretation via pγ scenarios, one zone (e+p co-accelerated)- internal target photons only: challenged by required high proton power- “external” photons from jet sheath: plausible & consistent- observed SED predominantly leptonic (sync.+external Compton)- hadronic subdominant, critically constrained by X-ray (+VHE)- GeV-TeV break consistent with γγ absorption entailed bypγ production of ~300 TeV neutrino
for o- proton max energy ~<1018 eV (comoving) possible in principle
but not well constrained -> may or may not be UHECR accelerator- external photons from RIAFs: also promising but only for LBLs-> potential explanation for why TXS 0506+056 and not HBLs
- addition of single neutrino to MWL SED provides crucial new insightdawn(?) of electroweak astronomy

summary electroweak observations/interpretation of TXS 0506+056
questions- relation to other blazars: why TXS 0506+056 and not HBLs, FSRQs?
- origin of 2014-2015 neutrino flare during low gamma-ray state (if real)- contribution to diffuse flux, origin of dominant source(s)…
future- more neutrino+EM observations necessary, especially:- X-rays for constraining cascade emission- VHE for constraining pγ target density via γγ absorption -> CTA- more comprehensive modeling- the game has just begun, further exciting times ahead!

for oQ: MAGIC vs CTA?

Q: MAGIC vs CTA?

MAGIC IMAGIC IIMAGIC III

Q: MAGIC vs CTA?

CTA LST -1

CTA LST 0

CTA LST 1

Q: MAGIC vs CTA?

MAGIC ICTA LST -1

MAGIC II
CTA LST 0

CTA LST 1
MAGIC III

A: MAGIC+CTA LST 1
as much as possible:
win-win no-brainer!