Neutrino Emission from
Blazars
Yoshiyuki Inoue (RIKEN)

Multi-Messenger WS @ Chiba Univ., 2018-03-26

Contents• Blazar Observation• Photon Emission Mechanism• Neutrino Emission• Cosmological Evolution• TeV Gamma-ray Background• SummaryActive Galactic Nuclei (AGNs)
Blazar• >106 solar mass @ galactic center

Seyfert(no jet)

Black
Hole

• Correlate with various physicalRadio
Galaxyparameters of host galaxies• Gas accretion -> brighter than thegalaxy (active galactic nuclei: AGNs)• Various population• Relativistic jet

Accretion
Disk
imaginary picture of
AGN

Relativistic
Jet• Ultra-high-energy cosmic

rays / high-energy neutrinos (?)• The SMBH of our galaxy does not©NASAshow strong activities

Blazars
Cyg A© NRAO• AGNs whose relativistic jets

pointing at us.

• Variable (⊿t ~ 1 day)• ~10% polarization
Abdo+’10

Individual Blazar Spectra
Blazar Spectral
Energy Distributions Flat-Spectrum Radio Quasars (FSRQs):
BL Lacs:
FSRQs: cutoffs at GeV with VHE episodes

Spectral Energy Distributions
emission
toBlazar
VHE/TeVenergies
spectrum
FSRQs:
cutoffs atcutoff
GeV withat
VHEGeVepisodesBL Lacs: emission
to VHE/TeV
energies
BL Lacs: emission to VHE/TeV energies

z = 0.033

Mrk 501

Abdo et al. 2011az = 0.859 3C 454.3

Abdo et al. 2011aMrk 501

3C 454.3
z = 0.859

Abdo et al. 2009

Abdo et al. 2009z = 0.033

Abdo et al. 2011bAbdo et al. 2011b

Mrk 421z = 0.031

VHE (> 100 GeV)VHE (> 100 GeV)

Mrk 421z = 0.031

3C 2793C 2793C 279z = 0.538
3C
279
z
=
Hayashida et zal.=2012
0.538 0.538
Hayashida et al. 2012z = 0.538

LSP, ISP, HSP

LSP, ISP, HSP© C. Dermer

Typical Spectra of Blazars
49

FSRQ

Log10 νLν(erg s-1)

Log10 (νLν [erg/s])

48• Non-thermal emission

from radio to gamma-ray

47• Two spectral humps

46
45➡relativistic particles andintense photon fields

44
43

BL Lac • Luminous blazars (FSRQs)

42
41

-5

0

5
Log10 Eγ (eV)[eV])
Log10 (Energy

10Fossati+’98, Donato+’01, YI & Totani ’09

tend to have lower peakenergies(Fossati+’98;Kubo+’98;Donato+’01;Ghis
ellini+’17)

Blazar Emission Mechanism• Leptonic model• 1st hump: non-thermal e- synchrotron

Nonthermal γ rays ⇒ relativistic particles +intense photon fields• 2nd hump:

Leptonic jet model:• Synchrotron-Self-Compton (SSC)
Nonthermal synchrotron paradigm
Associated
SSC Comptonand EC component(s)• External
Inverse(EIC)
Location of emission site
• Lepto-Hadronic model
Hadronic jet model:• 1st hump:
Secondarynuclear production
non-thermal
e- synchrotron

pN → πο, π± → γ, ν, n, e±• 2ndProton
hump:and ion synchrotron radiationpB→γ• proton (ion) synchrotron
Photomeson production

pγproduction→ π ,π →γ, ν, n, e±• photomeson(cascade)ο±High energy γ-ray component from γγ′ → e± → γ byCompton or synchrotron processes

Leptonic Scenario
The Astrophysical Journal, 736:131 (22pp), 2011 August 1

Abdo et al.

-8

10

Mrk 421

-9

-10

10

-1

-2

νFν [erg s cm ]

10

-11

10

-12

10

-13

10

-14

10

8

10

11

10

10

14

17

10

20

10
ν [Hz]

10

23

26

10

10

29

Abdo+’11

Figure 11. SED of Mrk 421 with two one-zone SSC model fits obtained withdifferent minimum variability timescales: tvar = 1 day (red curve) and tvar = 1
hr (green curve). The parameter values are reported in Table 4. See the text for
further details.

data: the model describes very satisfactorily the entire measured
broadband SED. The model goes through the SMA (225 GHz)
data point, as well as through the VLBA (43 GHz) data
3Cpoint
279
for the partially resolved radio core. The size of the VLBA
core of the 2009 data from Mrk 421 at 15 GHz and 43 GHz
is ≃0.06–0.12 mas (as reported in Section 5.1.1) or using theconversion scale 0.61 pc mas−1 ≃ 1–2 ×1017 cm. The VLBA
size estimation is the FWHM of a Gaussian representing thebrightness distribution of the blob, which could be approximatedas 0.9 times the radius of a corresponding spherical blob
(Marscher 1983). That implies that the size of the VLBA core iscomparable (a factor of about two to four times larger) than thatof the model blob for tvar = 1 day (∼5 × 1016 cm). Therefore,
it is reasonable to consider that the radio flux density from the
VLBA core is indeed dominated by the radio flux density of theblazar emission. The other radio observations are single dishmeasurements and hence integrate over a region that is orders
9. Top panel: spectralenergydistributions
3C 279 during
the brightest γ-rayConsequently,
ﬂares—FlareHayashida+’15
1 (Period B, redpoints) and Flare 3 (Period D, blue points)—seeof Figuremagnitudelargerthan
theofblazar
emission.
we
Section 4.1 for discussion. Bottom panel: SEDs during two NuSTAR pointings—Period A (orange points) and Period C (magenta points)—see Section 4.2 fordiscussion.
Solidasand upper
dashed lineslimits
show SED models
obtainedwith the leptonic code Blazar. Model parameters are listed in Table 5. Black and gray lines show
treat
them
for themodel.
historical data and SED models from Hayashida et al. (2012). Black dashed line shows the composite SED for radio-loud quasars (Elvis et al. 1994) normalized toinset theillustrates
schematically thejet
decompositionof each SED model
into contributions
from individual radiative mechanisms: (in order ofLThe= 6 × powers
10 erg s . Theofdifferent
components
derivedfromincreasing peak frequency) synchrotron, SSC, ERC(IR), and ERC(BLR). The axes and line types are the same as in the main plot.
the model fits (assuming Γ = δ) are also reported in Table 4.
Estimates for the mass of the supermassive black hole inMrk 421 range from 2×108 M⊙ to 9×108 M⊙ (Barth et al. 2003;
12
Wu et al. 2002), and hence the Eddington luminosity
should be46
47−1
between 2.6 × 10 and 1.2 × 10 erg s , that is, well above
the jet luminosity.
It is important to note that the parameters resulting fromthe modeling of our broadband SED differ somewhat fromthe parameters obtained for this source of previous works(Krawczynski et al. 2001; Błażejowski et al. 2005; Revillot
et al. 2006; Albert et al. 2007b; Giebels et al. 2007; Fossati
et al. 2008; Finke et al. 2008; Horan et al. 2009; Acciari et al.
2009). One difference, as already noted, is that an extra break isrequired. This could be a feature of Mrk 421 in all states, but we−1• Radiation from accelerated electrons in inner jets
Table 4
Parameter Values from the One-zone SSC Model Fits to the SED fromMrk 421 Shown in Figure 11d45• shock? turbulence? reconnection? shear?

Parameter

SymbolRed CurveGreen Curve

Variability timescale (s)aDoppler factor
Magnetic field (G)Comoving blob radius (cm)tv,minδ
BR

Low-energy electron spectral index
Medium-energy electron spectral index
High-energy electron spectral index
Minimum electron Lorentz factor
Break1 electron Lorentz factor

p1
p2
p3
γmin
γbrk1

8.64 × 104
21
3.8 × 10−2
5.2 × 1016

3.6 × 10350
8.2 × 10−2
5.3 × 1015

• One (multi)-zone synchrotron/SSC/EIC
2.2
2.7
4.7
8.0 × 102
5.0 × 104

2.2
2.7
4.7
4 × 102
2.2 × 104

• target photon: synchrotron, broad line regions (BLRs), dust torus, accretion disk

E2dN/dE [erg/cm2/s]

Spectral Fitting w/ a Leptonic Model

E2dN/dE [erg/cm2/s]

Mrk 501

1ES 2344+514

1ES 1959+650

PKS 0548-322

PKS 2005-489

RGB J0710+591

14 -2 010-2100 102 104 106 108101010121010
10 102 104 106 108101010121014
Energy [eV]
Energy [eV]

10-10
10

-11

10

-12

10-13
10-10
10-11
10-12
10
E2dN/dE [erg/cm2/s]

Mrk 421

-13

10-10
10-11
10-12
10-13

best fit
γ’min=1
ηg=1
MAXI/GSC
10 12 14

10-2100 102 104 106 10810 10 10Energy [eV]

Swift/BAT
Fermi/LAT
IACTs
NED
YI & Tanaka ‘16b

Maximum Proton Energy from HBLs
• HBLs are not efficient

1016

Ep, max [eV]ηg vs Ep,max

accelerators having ηg ~5x104.

1015• consistent with previous
10

individual source studies

14(Inoue & Takahara ’96, Sato+’08, Finke+’08)

Our Sample• the maximum proton energy
1013 2
10

10

3

4

10
ηg

10

5

10

6

YI & Tanaka ‘16bfrom low-luminosity HBLs is<1015 eV.

Lepto-Hadronic Scenario

A hadronic origin for UHBLs

3

10 102 101

5

104 106

10

8

107 10RGB J0710+591

-2

1045

10-11

1044

-10 10

10

10-1

1

3

10 102 105104 106

10

8

107 10

9

10

10

10

13

1011 1012 10ν L ν (erg s-1 )10-2 10-1

Photomeson cascade Energy (eV)ν Fν (erg cm-2 s-1)

10-10Energy (eV)9101310 10 1011 1012 10ν L ν (erg s-1 )ν Fν (erg cm-2 s-1)

Proton-Synchrotron

RGB J0710+591

1045

-11

10

1044

10-12

10-12

1043

1043
-13

10-13

10

1042

1042

10-14

10-14
13

1012 10151014 10

16

10

18

1017 10

19

10

20

10

23

1021 1022 10251024 10• Proton (Ion) Synchrotron

26

10

28

1027 10
ν (Hz)

13

15

16

18

19

20

23

25

26

28

1012 10 1014 10 10 1017 10 10 10 10211022 10 1024 10 10 1027 10
ν (Hz)

Cerutti+’14• p + B -> p + γ• Photomeson interaction (cascade)• p+γ -> p/n, π -> p/n, ν, γ, e
• But, requires super-Eddington jet Pjet ~100 LEdd ?(Sikora+’09, Zdziarski & Bottcher ’15)

to as INTENSITY
the jet component.
We INNER
considerDIFFUSEreferred
NEUTRINOFROM THE… the jet

PHYSICAL REV

component first.
0radio lobes, but their contribu
frame, andWhen
we takeeVinternalas the typicalenergyoftheE spectrum
synchrotron
photonsis
BL ≈ 10.2of
typically small due to their low
broadline
emission. Thanks
to various
resonances production
andapproximatedby a power-law,
the photomeson
some exceptions. CRs escaping f
multipion
production,
the aboveis valideven
efficiency
is estimatedusingexpression
the rectangularapproximation
2
galaxies and galaxy assemblies
at energies
above
E 0bp ≈ 0.5mcross=E 0BL . Noteto thephotohadronic
to be that unlessp c ε̄Δsection& DermerproduceYI,
neutrinos[11]. ‘14
Another
CRs lose energy through adiabatic losses as the blob Murase,!
"s
expands, they shouldtdyn
undergopγ3Linteractions
E 0p asβ−1 vicinity of the accretion disk o2κ Δ σfurther
Δ Δε̄Δrad0≈ the BLR
≃ or dust-torus region; density could be higher. But γ raypγ ðE p Þ inlong as theyfremain
0b thetpγ
1 þ β ε̄Δ 4π rb Γ2 cE 0s (seeE psuch compact regions, so we donext subsection). The corresponding neutrinoenergyis
ð19Þ
core models
in thisonline).
work. Differe
crudely estimated to be
FIG. 9 (color

Photomeson Production in Blazars   

trinos produced in the blazar z

210−28 0cm2 , κ Δ ∼ 0.2, ε̄Δ ∼ 0.34 GeV,
∼
5
×
σ
Δ
E 0bwhere≈
0.05ð0.5mc
ð24Þ
C. Neutrinos
the BLdust
torus (solid).from
The muonnep ε̄Δ =E BL Þ ≃ 0.78 PeV;
ν
0b
2
2
0
Δε̄Δ ∼ 0.2 GeV, and E p ≈ 0.5Γ mp c ε̄Δ =E s . For example,s ¼ 2.3 and ξcrCRs,¼ 100,includinwith neIf high-energys45
parametersof BLofLac
objects
with Ldecay
From top to bottom, the cu
althoughusing
detailed
calculations
pion
and muonare erg=s
rad ∼ 10
blazars,
then the CRs have to beparameters given in Table I (seandsee
E 0s the∼ 10
eV, shape
we haveneeded toexact
of neutrino spectra.

sources.
The CRs fromthe accele
4
correspondingtoL
5 GHz ¼ 10With these approximations, the neutrino spectrum isinteract
withforexternal
radiationfi
0−4 s−4 0−1
0
−1


shown
the BLR/dust
torus
ðE
Þ
∼
7.8
×
10
L
Γ
δt
ðE
=10
eVÞ
f
pγ
p
s
given by5
rad;45 1
in theluminosities
BLR and dust[26]. wI
lack torus
interactions# 0 0b βh −100bÞðE p ≦0bE pTHE
Þ INNER … power-law CR spectraPHYSICAL(cf. Ref. [R! ðE ν =EINTENSITYDIFFUSE NEUTRINO
0 2ν
0 FROMð20Þfraction f ¼ ð1 − min½1; t =t
× f pγ0 E ν0b β −1ðE ν ≦0bE ν Þ 0
0
l
esc
dyn
Þ 10.2 eVðEEðE νE =E0 ν≈
LE 0νwe∝ takeð25Þ of
p <
p Þ;


radio
lobes,
but
their
contr
frame,E  νandas
thetypicalenergy02−s0b0
cooling time scale). Although thiðE ν < E ν Þ
f pγ EBLν
typicallyto theirif
to various resonances andof escape, broadline  emission. Thanks
it smallcan bedue
realized
1.5 and βhthe∼ 2.5
are expression
the low-energy
and evenhigh- some exceptions. CRs escapin
where βl ∼multipion
production,above
is valid
without additional significant lo
and roughly
describes
thenumerical
neutrino
spectraof2
0 Note that contribuphoton
respectively.
galaxies and galaxy assembli
atenergy
energies
aboveindices,
E 0bp ≈ 0.5m
ε̄
c
=E
.
Note
that
unlessp
Δ
BL in Figs. 9
cooling.
Such a scenario is also inluminoustions
QHBs
in
the
PeV
range,
asplottedfromenergy
variousthroughresonancesandmultipion
production
produceneutrinos [11]. Anot
CRs loseadiabatic
losses
as
the
blob
0
02
ing
PeV
neutrinos
and/or TeV
0
and 10. The
dependence
E
L
∝
E
is
suggestedfromtheEundergoν furtherνvicinity of the accretion dis
become they
crucialforν hard
photonindicesof β ≲ 1. The
expands,
shouldpγ interactionsasinteractionsin intergalactic
spacγ
decay kinematics
ofremainchargedpions[63].
InE 0baddition
to PeVdensitycould
behigher.
But
neutrino
energycorrespondingislong
as theyin theBLR
ortodust-torus
region(seethepsiblesuchfeaturesof sucha system,e.gneutrino
production,∼0.1–1
EeV
neutrinos
are produced
compact
regions,so wenext subsection). The corresponding neutrinoenergy isescape,ormodels
direct inor thisdiffusiveesca
via interactions
between to
CRbeprotons and0b
2 IR
0 photons−1fromcore
work.
crudelyE 0b
estimated
ð21Þ
inner
jet photons
ν ≈ 0.05E p ≃ 80 PeV Γ1 ðE s =10 eVÞ ;tdyn , may
generate spectra of esca
the dust torus. Using
the peak photon energy 2.82kT IR, the0b
2 roughly0
to accurately
representfrom
the themeenergy isestimated to be ð24ÞE neutrino
C. Neutrinos
BLR
photons
pg → D+ → p + characteristicNν ≈ 0.05ð0.5mp c ε̄Δ =E BL Þ ≃ 0.78 PeV;
which is typically higher than 1 PeV and the Glashowspectrum [25,26] or to explain
If high-energy CRs, inclu
resonanceenergy
at
6.3
PeV
(for
electronantineutrinos),
0b−1
specific
properties of this system d
E
≃
0.066
EeVðT
=500
KÞ
:
ð26Þ
IR
dust
photonsalthoughν detailed calculations
IR of pion and
0 muon decay areblazars,
then the CRs have to
except toforseeHSP
BL
Lacshape
objectswithE s ∼spectra.
1 keV. Notingmagnetic field
properties, and theneededtheexactofneutrino0sources.
The
CRs from the acc
that
Eimportanceis lowerfor
moreblazars,
we concludes theseprocessesthatrequirefura
The relativeof thejet luminous
component
compared
to iseration
With
approximations,the neutrino
spectrum
FIG. 10(coloronline).
Same©withK. Muraseinteract
external
radiatioPhotomeson Production Efficiency
C.D. Dermer et al. / Journal of High Energy Astrophysics 3–4 (2014) 29–40

BL Lacs

4

FSRQs

Photopion Production Efficiency

10
develop as
theLLGRB,
jet becomes closer to the outer edge ofttering zone. Calculationsof γ -ray and neutrino SEDs enΓ=2
2
4
LGRB
action-rate10
factor (1 − β µ) SGRB
that reduces the importanceofHz)
photons.
The assumptionof isotropy is a good first approx2
5
0
SGRB
Γ
=
10
0well
10 the radiation reprocessing
withinregion, but should
BL Lac, quiescentΓ=5
xed in further studies.
-2
10transformationof an isotropic monochromatic external raLGRB
field with energy density u 0 and photon energy ϵ0 to-4d frame is10easily
performed using the transformation law
LLGRB,′ ) = u (ϵ , Ω)/[
Γ (Γ1=+30β µ′ )]3 for the specific spectral energy-6u (ϵ , Ω) (see2009). For
BL Lac, flaring
10 Eq. (5.24) in Dermer and Menon,
Γ = 100
y relativistic (Γ ≫ 1) Γflow,
spectral energy= 103 one obtains theϵ ′ u ′ (ϵ ′ ) ≈10(u-80 /2Γ )(ϵ ′ /ϵ0 )3 H (ϵ ′ ; 0, 2Γ ϵ0 ), after integrating
14
15
16
17
19
20
21
gle. Substituting
Eq.18 (1),(3)
10 this10expression
10
10into 10
10noting
10 Eq.10′ , gives the eﬃciency
ltiplying by t dyn

Dermer, Murase, & YI ’14

E (eV)!

p"
Production
efficiency (= effective(1• +ln y u )σ̂ u 0 R optical depth)
Fig. 3. Minimum photopion production eﬃciency as a function of escaping proton
η0 Fig.
1 −2. Photopion production
H ( y u − 1),
η0 ≡
,
(8)
eﬃciencypresented
2 in terms of
yu

f

⇠n 

me c ϵ0renergy E p for parameters typical of quiescent and flaring states of FSRQs. The eﬃ

the ratio of •the dynamicaland energy-losspp ptimescales using ciency for interactions with synchrotron radiation is determined by the dynamica2′′∼
y u parameters≡ (4ϵ0 γ p /ϵ̄frompathlength! R ext(LGRBs),
through shortthetimescale t dyn= R ext /(c Γ ) for exter= Γ t var , using values from Table 1, and t dyn
Tablethe1 forlong soft RGRBs
thr ) andprocesses, using values for the physical extent R ext = 0.1 and 1 pc of the BLR
adiation
fieldofLacsextentR. The comoving
energy-loss
rate
ext
hard GRBs
low-luminosity
GRBs(LLGRBs),
andbutnal• BL(SGRBs),
areinefficientneutrino
factories,
UHECRscansurvive
2
2
′
and
IR
radiation
fields,respectively. Separate contributions from photopion produc∼onswith escaping peakedenergy(HSP)E p =BLm p cLac
γ pobjects.
Γ γ pthethat= m p c For
high-synchrotrontion with Ly α radiation in the BLR, scattered accretion-disk radiation, IR radiation′
ergy
throughphotopion
processeswithphotonsofalocallyeﬃciency
calculations,tdyn = Γtphotopionand synchrotron
photons are shown separately. The differing internal synchrotron
var = δD tdue
var forto• FSRQsaremoreefficientexternal
photonfield
c externalradiation
fields synchrotron
is therefore photons.
given byeﬃciency for the quiescent and flaring cases are plotted by the long-dashed andproduction
with internal<latexit sha1_base64="eAIfIO5TFVL2F9bItI+rX1dCyhk=">AAACKnicbVDLSgMxFM34rPVVdekmWARXZaYI6q7oxmUFawudMtxJM21okglJRihD/8Of8Bfc6t5VcSd+iOkD1NYDgZNzzuUmJ1acGev7Y29ldW19Y7OwVdze2d3bLx0cPpg004Q2SMpT3YrBUM4kbVhmOW0pTUHEnDbjwc3Ebz5SbVgq7+1Q0Y6AnmQJI2CdFJWqSZSrsAdCwCg0TGAZzW44HIBSECmn9gT8pHRUKvsVfwq8TII5KaM56lHpM+ymJBNUWsLBmHbgK9vJQVtGOB0Vw8xQBWQAPdp2VIKgppNP/zbCp07p4iTV7kiLp+rviRyEMUMRu6QA2zeL3kT814vFwmabXHZyJlVmqSSzxUnGsU3xpDjcZZoSy4eOANHMvR2TPmgg1tVbdKUEixUsk0a1clUJ7s7Ltet5OwV0jE7QGQrQBaqhW1RHDUTQE3pBr+jNe/bevbH3MYuuePOZI/QH3tc3h0So8w==</latexit>#∞

short-dashed curves, respectively. Also plotted by the thin green dotted curve is th!
"• have a ν spectral
peak
at
~PeV
due to BLRphotopion
photonseﬃciency for energy loss by a proton or neutron traveling rectilinearlc σ̂ γ p(1 + ln ȳ u )ϵ u (ϵ )through the BLR radiation field. (For interpretation of the references to color in thi
,
γ )=
dϵ
1−
(9)

Neutrino SEDs
Target Photon SED

48

49

47

log(E ’νLE’ [erg s-1])

48
47

ν

log(E’LE’ [erg s-1])

BLR/Dust Torus
Blazar Zone

49

50

46
45
44

46
45

quasar-hosted
blazars

44
43
42
41

43

40

42

39

41

Neutrino SED

50

51

BL Lacobjects

38

3-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13log(E’ [eV])• Luminous blazars are brighter in ν
• pγ with internal rad. field:• pγ with external rad. field:• because

0.5
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4

5

6

7

log(E ’ν [GeV])

8

9

10

11

Murase, YI, Dermer ‘14

fp / Lph,int ) L⌫ / L

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assumed fro
the convent
indices una
budgets, w
power law C
relax source
The third
Lcr/Lγ = 50
explain the
UHECRs, ato the first athat the ph
Lcr/Lγ = 3
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differential
−8
3
×
10
G
EeV
PeV
1044 f pγ;−1 eCR loading
Murase, YI, Dermer ‘14 factor to ex
our simple• Difficult to explain
FIG. 14 (color
online).
Same
Fig.blazars
13, but for s ¼ 2.0. Here
IceCuberesults
onlyasby0Lξcr ¼ 3 (thick), and ξcr ¼ 50 (thin). Note that the former value is
rad are ass
shooting th
motivatedbybyBLR
the &AGN-UHECR• Spectral structure
Dust Torus hypothesis.
emissionmodel cons
neutrino an• NormalizedHowever,by UHECRs
EeVthreeν detectablein future
there areissues. First,
this model cannot
complicatedexplain sub-PeV neutrino events. This is because broadline
lose their enormalized by the observed UHECR energy generation rate.
The atmospheric muon neutrino background is also shown(dotted dashed).

Cosmic TeV-PeV Neutrino BackgroundHE Neutrinos from AGN Jets: Constraints

Blazar Models vs. Data

Standard simplest jet models as the cosmic n origin: many constraints…
- Blazars: power-law CR spectra & known SEDs→ hard spectral shape

10-6

2

-2 -1

-1

E Φ [GeV cm s sr ]10-5various diffuse n predictions

HZ97 (Blazar)
MPERS03 (LBL)
MPERS03 (HBL)
PPGR15 (BL Lac)
MID14 (Blazar w. ξcr=3)
MID14 (Blazar w. ξcr=50)

leptonic
BL Lacs + FSRQ
(enhanced by BLR/IR photons)
lepto-hadronic norm.
BL Lacs (w.o. external fields)

10-7

10-8

leptonic w. UHECR norm.
BL Lacs + FSRQ

IC-79/86
IceCube 16 ApJ

10-9 410105

106
E [GeV]

107

108© K. Murase

HE Neutrinos from AGN Jets: Constraints

Blazar Models vs. Data

Standard simplest jet models as the cosmic n origin: many constraints…
- Blazars: power-law CR spectra & known SEDs→ hard spectral shape
IceCube 9-yr EHE analyses give a limit of <10-8 GeV cm-2 s-1 sr-1 at 10 PeV
many existing models have been constrained

10-6

2

-2 -1

-1

E Φ [GeV cm s sr ]10-5various diffuse n predictions

HZ97 (Blazar)
MPERS03 (LBL)
MPERS03 (HBL)
PPGR15 (BL Lac)
MID14 (Blazar w. ξcr=3)
MID14 (Blazar w. ξcr=50)

×
×
× ×

10-7

ICRC 201710-8

leptonic w. UHECR norm.
BL Lacs + FSRQ

IC-79/86
IceCube 16 ApJ

10-9 410105

leptonic
BL Lacs + FSRQ
(enhanced by BLR/IR photons)
lepto-hadronic norm.
BL Lacs (w.o. external fields)

106
E [GeV]

107

108© K. Murase

Can Blazars Explain the IceCube Data?

Can Blazars Explain the IceCube Data?
© K. Murase
E2 Φ [GeV cm-2 s-1 sr-1]

10-5

from KM 2015

Blazar (DMI14)
Blazar (MID14)
Blazar (PPGR15)
AGN Core (KMT15)
AGN Core (S05)

10-6
10-7
10-8
10

-9

10-10 3
10

104

105

106
E [GeV]

107

108

109

Can blazars dominantly explain the IceCube data? – challenging- Need a cutoff or steepening around a few PeV (ex. stochastic acceleration)- Medium-energy (<100 TeV) data cannot be explained by proposed models
Can blazars dominantly explain the UHECR data? – maybe- But the simultaneous explanation for the IceCube data is challenging

Fermi Blazars Contribution

IceCube ‘17• Blazars are rare (~1-10 deg-2)• Fermi/LAT blazars can explain <7-27 % of the IceCube flux
• Note: Fermi/LAT is not sensitive to MeV blazars (most powerful blazars)

and extreme HBLs (highest energy blazars)

F100 300000 MeV [10 6 cm 2 s 1 ]Neutrinos From Flaring Blazars
2010 2010.5
2.5

2011 2011.5

2013 2013.5• Kadler+’16

2• IceCube: HESE-35 (2 PeV)

1.5
1

• PKS B1424-418 (z=1.52)

0.5
0
55200
5

55400

55600

2011-11-13
2
1 (12pp), 2017 September 10
ournal, 846:121
0.5
Flux Density [Jy/beam]

2012 2012.5

55800 56000
MJD

56200

56400

Kadler+’16

2012-09-16

2013-03-14

Lucarelli et al.

• Lucarelli+’17

0.2
0.1
0.05
0.02
0.01
0.005
0

• Association level: ~2σ

56600

1 mas

Figure 1: a) -ray light curve of PKS B1424 418. The Fermi/LAT data are shown as two-week binned

photon fluxes between 100 MeV and 300 GeV (black), the Bayesian blocks light curve (blue), and the IC 35

ime stamp (red line). The first three years of IceCube integration (2010 May through 2013 May) and thencluded outburst time range are highlighted in color. b) TANAMI VLBI images of PKS B1424 418. The• ICECUBE-160731 (several hundred

TeV?)• 1RXS J141658.0-001449

mages show the core region at 8.4 GHz from 2011 Nov, 2012 Sep and 2013 Mar in uniform color scale.

1 mas corresponds to about 8.3 pc. All contours start at 3.3 mJy beam 1 and increase logarithmically byactors of 2. The images were convolved with the enclosing beam from all three observations of 2.26 mas ⇥Lucarelli+’17• Association level: ~4σ

D intensity map in (ph cm-2 s-1 sr-1) zoomed-in around the ICECUBE-160731 position, in the time interval (T0 - 1.8; T0 - 0.8) days. The
0.79
at respectively,
a position angleof 9.5, whichis showneventin theleft.
Thepeakofflux
increasesfrom AGL J1418+0008. Theagainmasshow,
the 90%c.r. ofthe ICECUBE
andbottom
the 95%
C.L.
contourthedensity
AGILE-GRID
detection
ositions of several e.m. candidates found during the MWL follow-up. Cyan cross: HAWC best archival search result(Taboada 2016); blue
1 (2011in
1 (2013XRTJysources
Evans
et al. Jy(2016a,yellow
1.95
beam reported
Apr)
to 5.62
beam 2016b);Mar).boxes: two optical sources (one steady, one transient) detected by the Global

IceCube 170922A• Initial alert by AMON
• Eν ~ 300 TeV• Flare of TXS 0506+056, located inside the error region• Fermi ATel #10791 (Tanaka+)• MAGIC ATel #10817 (Mirzoyan+)• Swift GCN #21930, ATel #10942 (Keivani+)• NuSTAR ATel #10861 (Fox+)• Kanata, Subaru, and so on,,,• ?? True association ??

•Blazars, star-forming galaxies and radio galaxies can explain the intensity
and the spectrum of the EGB

Components of Cosmic Gamma-ray Background

Preliminary• FSRQs

YI +’15
As usual: it does not include the systematic uncertainty onAjello,the EGB!
(Ajello+’12)(Ajello+’14)(YI’11), BL Lacs, Radio gals.
, & Starforming gals. (Ackermann+’12) makes almost 100% of CGB from
0.1-1000 GeV.

Blazars inThethe
CosmicGamma-ray
Background
AstrophysicalJournal Letters,
800:L27 (7pp), 2015 February
20

Ajello, YI+’15•

Padovani+’93; Stecker+’93; Salamon & Stecker ‘94; Chiang + ‘95; Stecker & Salamon ‘96; Chiang & Mukherjee ‘98; Mukherjee & Chiang ‘99; Muecke & Pohl ‘00;
Narumoto & Totani ‘06; Giommi +’06; Dermer ‘07; Pavlidou & Venters ‘08; Kneiske & Mannheim ‘08; Bhattacharya +’09; YI & Totani ‘09; Abdo+’10; Stecker & Venters‘10; Cavadini+’11, Abazajian+’11, Zeng+’12, Ajello+’12, Broderick+’12, Singal+’12, Harding & Abazajian ’12, Di Mauro+’14, Ajello+’14,Singal+’14, Ajello, YI, +’15,• Blazars explain ~50% of CGB at 0.1-100 GeV.
• explain ~100% of CGB at >100 GeV.

1
10

1.5

-13
-3

10

-2

10

-1

10
1
48
L γ[10 erg s -1]

10

2
Γ
0
-3

-2

10

2.5

3

-1

10

10
1
48
L γ[10 erg s -1]

-8

10

-2 -1

F100 [ph cm s ]10-7

Cosmological Evolution of Blazars
Figure 3. Observed redshift (upper left), luminosity (upper right), photon index (lower left), and source count (lower right) distributions of LAT BL Lac objects. The
continuous solid line is the best-fit LDDE model convolved with the selection effects of Fermi. The error bars reflect the statistical uncertainty including (for theupper plots) the uncertainty in the sources’ redshifts. Error bars consistent with zero represent 1σ upper limits for the case of observing zero events in a given bin (seeGehrels 1986).

gure 3. LF of the Fermi FSRQs in different bins of redshift, reconstructed using the Nobs /Nmdl method. The lines represent the best-fit LDDE model of Section 4.2.
highlight the evolution, the LF from the next lower redshift bin is overplotted (dashed lines).
color version of this figure is available in the online journal.)

FSRQs

BL Lacs

respect to the PLE and PDE models. The fit with τ = 0 (all10-4LogL =45.6 -- 46.9
-7
10
luminosity
classes evolve in the same way) already provides alogL γ =43.8 -- 45.8
-5=46.9 -- 47.5
10
representation of the data, which is as good as theLogLbest-fit
PLE
logL γ =45.8 -- 46.9
-8model10(seeTable 3). If we allow τ to vary, theLogLfit=47.5
improves-- 47.9
10-6
further with respect to the baseline LDDE1 model(TS = 30,logL γ =46.9 -- 47.4
LogL =47.9 -- 49.4
i.e., ∼5.5σ).
Figure
3
shows
how
the
LDDE
model
reproduces
10-7
3
-9
logL γ =47.4 -- 48.4
10
the observed distributions.
10-8
The -10improvement of the LDDE2 model with respect to the
PLE310model can be quantified using the Akaike information
10-9
criterion (AIC; Akaike 1974; Wall & Jenkins 2012). For each
10-10
-11
10
model, one can define the quantity AICi = 2npar − 2 ln L,
where npar is the number of free parameters and −2 ln L is
10-11
-12 log-likelihood value as reported in Tables 2 and 3. The
twice10the10-12
relative likelihood of a model with respect to another model can
0
0.5
1
1.5
2
2.5
3
3.5
−AICi ) 2
0
1
2.5
3comes3.5
min1.5be evaluatedas0.5p = e0.5(AIC, zwhere AIC
from
min
z
Ajello+’12
Ajello+’14
the
model
providingtheminimalAIC
value.
Accordingtothisgure 4. Growth and evolution of different luminosity classes of FSRQs. Note that the space density of the most luminous FSRQs peaks earlier in the history of
Figure 4. Growth and evolution of BL Lac objects, separated by luminosity
e universe while the bulk of the population (i.e., the low luminosity objects) are more abundant at later times. The range of measured distribution is determined by
test,
the
PLE
model
has
a
relativelikelihoodwithrespect
toquiring at least one source within the volume
3 (lower left) and sensitivity limitations of Fermi (upper right).
class. The gray bands represent 68% confidence regions around the bestcolor versionof
thisfigureisavailable
intheonlinejournal.)•theFSRQs,
Lacs
show
evolution.
LDDE2 modelluminousof ∼0.0024. Thus,BL
the model
LDDE
fitting LDDE LF
model (for each Monte Carlo sample). Both data points and2 whose positive
band errors include uncertainties for the source redshifts as well as statisticalparameters are reported in Table7 3 fits the Fermi data better
uncertainty. All but the least luminous class have a redshift peak near z ≈ 1.5;(∼3σ) than the PLE3 model.
the lowest luminosity
BL Lac objects
increase towardz = 0. AGNs.
• low-luminosity
BL Lacs
negative
evolution
unlikeother
In this representation, low-luminosity(Lγ = show
1044 erg s−1)(A color version of this figure is available in the online journal.)
sources are found to evolve negatively (p1 = −7.6). On
the other hand, high-luminosity (Lγ = 1047 erg s−1 ) sources
γ

γ

48

-3

,z) [Mpc ]γ

Φ(Lγ /10γγ

Φ(L ,z) [Mpc -3 (L /1048)-1]γLumino10
BL Lacs, 1 σ uncertainty

Blazar evolution?

1044

FSRQs, 1 σ uncertainty (Ajello et al. 2012)

0

0.5

1

1.5

2
Redshift

2.5

3

3.5

Figure 6. Luminosity density as a function of redshift produced by the Fermi BL Lac objects. The gray band represents the confidence regi
realizations of the best-fit LF to the Monte Carlo samples.
(A color version of this figure is available in the online journal.)

2.5
All redshift constraints - this work

2

BL Lacs in 2LAC with spectroscopic redshifts

dN/dz

dy known in
hift bin 4 <9M⊙ : SDSS
43.3 (Sbarratoa large numSince they are
the presence⊙ . Since thears imply that
N with similar. The comovpc3 , therefore
oud AGN perystems.
of supermasthe comoving
9
H > 10 M⊙ )ini et al. 2010nd radio-loudo et al. 2012)
y functions as
oving number
from the two
e beginning oftes (see Ghisown at z > 4
cs to continue
4, the density
sponding one

1.5

BL Lacs in BZCAT with redshift

1

0.5

0
0

0.5

1

Sbarrato+’15

z

1.5

2

2.5

Ajello+’14

Figure 7. Redshift distribution of Fermi’s BL Lac derived using all constraints of Section 3.3 compared to spectroscopic redshift distributions
Figure 4. Comoving number density of supermassive blackholeswith (Ackermann et al. 2011) and the Roma blazar catalog (BZCAT; Massaro et al. 2009). The gray band encloses the 68% of all re
2LAC
catalog
MBH > 109 M⊙ hosted in radio-quiet (blue line, derived fromthelumidistribution of the Monte Carlo samples.
nosity function by Hopkins, Richards & Hernquist 2007) and radio-loud(A color version of this figure is available in the online journal.)
quasars (orange line). The radio-loud density is obtained from blazar number densities, by multiplying them by 450 = 2" 2 (" = 15). Blue data andthe light blue line are derived from the γ -ray luminosity function obtained
The observed 0.1–100 GeV luminositie
PLEno−zin Table 2) changes fairly dramatically with respect toby Fermi/LAT (Ajello et al. 2012). Red data points and the yellow
line arederived from the [15–55keV] luminosity function from Ajellothe
et al.
(2009),
present work are apparent isotropic lumi
best-fit LDDE2 model. Indeed, instead of showing a change
modified as in Ghisellini et al. (2010). All the number density
functionsin erg s−1 ). Since the jet material is moving
in the evolution with source luminosity, it displays a very mild
are derived by integrating the corresponding luminosity functions
at lumipositive
evolution for all luminosity classes. This would leadthe observed Doppler-boosted luminosities
nosities larger than what labelled in figure, to ensure that correspond toto a biased estimate of the evolution of BL Lac objects. We
intrinsic values by
MBH > 109 M⊙ . Such a cut in luminosity selects objects that are the mostthus believe that results based on BL Lac samples with scarce
L = δ p L,
luminous in their corresponding bands, other than the most massive. Green
redshiftcoverage are unreliable.
pentagons represent the state of the art before the beginning ofour project,
where L is the intrinsic (unbeamed) lumi
with four serendipitous blazars in the 4 < z < 5 bin and the single detection
kinematic Doppler factor
4.4. The Intrinsic Luminosity Function of BL Lac Objectsof Q0906+6930 at z > 5. The yellow pentagons are instead the number!
densities derived from our results. In the redshift frame 5 < z < Beaming
6, the data is known to alter the shape of the intrinsic LF (e.g.,δ=(γ−γ 2 − 1 cos θ )−point is given by the two blazars we classified at z > 5 (B2 1023+25 and• Stronger evolution in X-ray selected blazars?

• Redshifts of 50% of Fermi BL Lacs are unknown.

ions between
hisellini et al.
pentagons in
he five blazarsa (three frome two blazars• ~10 hr exposure w/ 10-m telescope for TXS 0506+056
Urry & Shafer 1984; Urry & Padovani 1991). In this section weCosmic TeV Gamma-ray BackgroundE2 dN/dE [MeV2/cm2/s/sr/MeV]

10-3

Total CGB (Fermi)
IceCube (ν per flavour)

10-4

-5

10

10-6

10-7
103

Fermi
CGB
104

105

IceCube TeVPeV ν
106107
Photon Energy [MeV]

108

109

1010

• Above 1 TeV, there is no gamma-ray data, though it isimportant for neutrino studies.

GeV-TeV Gamma-ray Connection: Cascade
TeV
Source

γ-ray

e+

γ-ray

e-

ObserverE ,i
E ,c 0.8
1 TeV•TeV gamma-ray photons are absorbed by EBL

EBL

CMB

•electron-positron pairs are created•pairs scatter CMB via inverse-Compton process• 1 TeV (primary) -> ~1 GeV (secondary)•Note: plasma instability may suppress the cascade(Broderick+’12, but see also Sironi & Giannios ‘14)2

GeV

Upper Bound on the Cosmic Gamma-ray BackgroundCascadeIntrinsic
UL

Absorbed

YI & Ioka ’12• Cascade component from the TeV background can not exceed the

Fermi data (Coppi & Aharonian ’97, YI & Ioka ’12, Murase+’12, Ackermann+’14).

• No or negative evolution is required -> low-luminosity BL Lacs show

negative evolution (Ajello+’14).

Galaxy Counts: Lower Bound on the Cosmic
Optical/Infrared Background100

νIν [nW/m2/sr]

10

Stars

1

0.1
0.1

1

Dust

10

100

λ[µm]

Madau & Pozzetti ’00 (HST)
Elbaz et al. ’02 (ISO)
Papovich et al. ’04 (Spitzer)
Fazio et al. ’04 (Spitzer)
Xu et al. ’05 (GALEX)
Dole et al. ’06 (Spitzer)
Frayer et al. ’06 (Spitzer)
Gardner et al. ’00 (HST)
Berta et al. ’11 (Hershel/PEP)
Wright & Reese ’00 (DIRBE)
Wright ’04 (DIRBE)
Levenson et al. ’07 (DIRBE)
Levenson & Wright ’08 (DIRBE)
Bernstein ’07 (HST)
Matsuoka et al. ’11 (Pioneer)
Matsumoto et al. ’11 (IRTS)
Matsuura et al. ’11 (AKARI)
CambrØsy et al. ’01 (DIRBE)
Dwek & Arendt ’98 (DIRBE)
Gorijian et al ’00 (DIRBE)
Finkbeiner et al ’00 (DIRBE)
Hauser et al ’98 (DIRBE)
Lagache et al ’00 (DIRBE)
Edelstein et al ’00 (Voyger)
Brown et al ’00 (HST/STIS)
Albert et al ’08 (MAGIC)(X, zc)=(1.0, 0.0)
(X, zc)=(50.0, 10.0)(X, zc)=(100.0, 10.0)

1000

10000

YI+’13

Known TeV sources
10-9
10

-10

10

-11

z = 0.031
Mrk 421z = 0.034
Mrk 501z = 0.044
1ES2344+514

10-12
10-13
10-9
E2dN/dE [TeV/cm2/s]

10

-10

z = 0.045
Mrk 180 (high)z = 0.048
1ES1959+650

z = 0.049
AP Librae

10-12

10

-10

sources at |b|>10 deg
from the default TeVcat
catalog.
• low-state data only

10-11
10-13
10-9

• Select 35 known TeV• 30 are blazars, 3 arez = 0.069
PKS 0548-322

z = 0.069
BL Lacz = 0.071
PKS 2005-489

10-11
10-12

radio galaxies, 2 arestarbursts• 3FGL SED data for the

10-13
10-4 10-3 10-2 10-1 100 10110-4 10-3 10-2 10-1 100 10110-4 10-3 10-2 10-1 100 101
Energy [TeV]
Energy [TeV]
Energy [TeV]YI & Tanaka ’16

GeV data.

Lower Bound on the Cosmic Gamma-ray BackgroundE2 dN/dE [GeV2/cm2/s/sr/GeV]

10-6

Total CGB (Fermi)
Resolved CGB (Fermi)
2FHL Source Counts
TeV Source Counts
Mrk 421
Mrk 501

10-7
10-8
10-9
10

-10

10-11
10-12 0
10

101

102
103
Photon Energy [GeV]

104

105

YI & Tanaka ’16• TeV source counts give lower limit on to the cosmic gamma-ray background.
• Fermi has resolved more portion of the TeV sky than IACTs do.
• CTA survey will be important (YI, Totani, & Mori 10; Dubus, YI, +’13; De Franco, YI,+’17)

Bounds on the Cosmic TeV Gamma-ray
Background10
E2 dN/dE [GeV2/cm2/s/sr/GeV]

-6

10

-7

10-8
10

-9

10-10
10

Total CGB (Fermi)
IceCube (ν per flavour)

-11

10-12
100

101

102

103
104
105
Photon Energy [GeV]

106

107

YI & Tanaka ’16• Current limit at 0.3-10 TeV is• 3x10-8 (E/0.1 TeV)-0.8 exp(-E/2 TeV) < E2dN/dE < 1x10-7 (E/0.1 TeV)-0.5 [GeV/cm2/s/sr]

Bounds on the Cosmic TeV Gamma-ray
Background10
E2 dN/dE [GeV2/cm2/s/sr/GeV]

-6

10

-7

10-8
10

-9

10-10
10

Total CGB (Fermi)
Upper Limit (Inoue and Ioka 2012)
IceCube (ν per flavour)

-11

10-12
100

101

102

103
104
105
Photon Energy [GeV]

106

107

YI & Tanaka ’16• Current limit at 0.3-10 TeV is• 3x10-8 (E/0.1 TeV)-0.8 exp(-E/2 TeV) < E2dN/dE < 1x10-7 (E/0.1 TeV)-0.5 [GeV/cm2/s/sr]

Bounds on the Cosmic TeV Gamma-ray
Background10
E2 dN/dE [GeV2/cm2/s/sr/GeV]

-6

10

-7

10-8
10

-9

10-10
10

Total CGB (Fermi)
TeV Source Counts
Upper Limit (Inoue and Ioka 2012)
IceCube (ν per flavour)

-11

10-12
100

101

102

103
104
105
Photon Energy [GeV]

106

107

YI & Tanaka ’16• Current limit at 0.3-10 TeV is• 3x10-8 (E/0.1 TeV)-0.8 exp(-E/2 TeV) < E2dN/dE < 1x10-7 (E/0.1 TeV)-0.5 [GeV/cm2/s/sr]

Summary• Blazar emission mechanism• Leptonic? Lepto-Hadronic?
• Even if blazars are neutrino emitters,• blazars can not explain the whole IceCube data
• Currently, association w/ blazars is still uncertain.
• More events & more follow-ups• We still do not understand evolution history of blazars• Can CTA/HAWC measure the TeV background?