ニュートリノ放射天体の
理論モデル
東北大学

学際科学フロンティア研究所
天文学専攻

木村成生
2023年日本天文学会秋季年会

2023年9月20日〜22日

2

目次
•

高エネルギーニュートリノ天体物理への導入•

セイファート銀河の降着流でのニュートリノ放射•

潮汐破壊現象におけるニュートリノ放射•まとめ宇宙線：宇宙を満たす高エネルギー荷電粒子
宇宙線のエネルギーと到来個数

起源天体と生成機構は100年来の• 最高エネルギーの大問題

人類の到達した最高エネルギー（LHC@CERN）

宇宙線1グラム→ 生物大量絶滅！

極限環境での物理現象を探究

1912年 宇宙線発見
ヘスの気球実験
1936年
ノーベル物理学賞

天文学辞典

3

従来の研究4

宇宙線の伝搬

地球での検出p

宇宙磁場
宇宙線起源天体
p

?

電波

電波望遠鏡

γ

宇宙線

可視光

e

γ

X線・γ線

γ

X線・γ線衛星

光学望遠鏡

ニュートリノ観測
宇宙線の伝搬

宇宙磁場
宇宙線起源天体

γ

p

?

γ線

p

5

宇宙線

地球での検出

赤外線
γ

CMB

ν

γ線

e

γ

ニュートリノ
e

ν

γ

可視光
X線・γ線

γ

X線・γ線衛星

光学望遠鏡

ニュートリノ検出器

6•

南極に建造された~ 1 km3 の巨大検出器•

ニュートリノと氷原子核の衝突で生じる光を検出天体ニュートリノの検出

7• energy
1,041 TeV
1,141 TeV
(15% resolution)• not atmospheric
IceCube 2013 PRL
at 3σ• no muons fromaccompanying
atmospheric shower
ICECAT-1• look for more•

2013年：
天体ニュートリノ検出の報告•

空の全ての方向から到来→ 宇宙ニュートリノ背景放射

宇宙ニュートリノ背景放射スペクトル

A combined fit of IceCube’s high energy neutrino data

IceCube ICRC 2023

3: Result of the com•Figure
TeV-PeVのニュートリを検出

bined fit of tracks and cascades•underSinglepower-law
diﬀerent
assumptionsと整合的
of the astrophysical neutrino• 低いエネルギーのニュートリノがflux. Solid lines represent
the多く地球に届いている
sensitive energy ranges of
the corresponding astrophysical flux models. The uncertainty band shown in blue
represents
the
68%
CL
uncer宇宙ニュートリノの起源は
tainties on the SPL fit. The
segmented
flux fit uncertain天体物理の新たな大問題
ties are obtained by profiling single-segment normalizations over all other parametersin the fit.

8

ニュートリノ天体同定の困難
1度

可視光で見た夜空
ニュートリノ望遠鏡
の分解能

9

•

光学望遠鏡の視力≲ 1秒角(すばる望遠鏡)•

ニュートリノ望遠鏡の視力~ 1度 (強度近視)•

ニュートリノ事象の到来方向を可視光で見ると多数の天体理論予言による
サポートが必須

高エネルギーニュートリノ生成過程
pp 非弾性散乱

•
νμ

p

宇宙線

μ-

π-

標的

π0

p

π

γ

μ+

+

p+p → p+p+π• π±→ 3ν+e
• π0→2γ

標的

eνe

γ

νμ

•

νμ

光中間子反応 (pγ)

p

νμ

γ

＜
〜
〜

•

宇宙線

e+

10

νe

γ
γ
γγ

π0

νμμ
ν
π+

μ+
νμ

p+γ → p+π
• π→ 3ν+e• π0→2γ•

原子核、または光子と相互作用してニュートリノ生成
ニュートリノと同時に同量のガンマ線が生成される

e+
ννee

11

ガンマ線データによる制限

γ理論
ν理論
γ観測

•

フェルミ衛星による宇宙ガンマ線背景放射の観測•

天体ではニュートリノと同時にガンマ線も生成•ν強度@10 TeV > γ線強度@100 GeVνμνμdark sources below 100 TeV not seen
in g’s?
μeπgamma rays cascadeνe energy
標的in the source to lower→ ガンマ線強度の理論予測 > フェルミデータ-→ ニュートリノ源はTeV γ線に対して不透明である必要（隠されたニュートリノ源: e.g., γ + γ → e

νデータ

Ahler & Halzen 2017
Murase et al. 2013, 2016

+

−

+e ）

p

宇宙線

p

γ

π0

γ

νμ

π+μ+

π+

νμ

e+
νe

ニュートリノ天体の探し方•

カタログとの相関解析（γ → ν）••

積分したニュートリノデータ→ ニュートリノ放射天体の同定

γ

ν








QDQRVHFRQGV







T

γ

ν
γ

[VW ]PL^

ニュートリノアラート＋ 即時追観測→ ニュートリノ放射天体同定

IceCube 2018

ニュートリノ事象の追観測（ ν → γ)•

＋ 電磁波天体のカタログ

ZPKL ]PL^

12

γ

??

ニュートリノ起源天体ニュートリノ天体の探し方•

カタログとの相関解析（γ → ν）••

積分したニュートリノデータ•

リアルタイムの解析は困難→ ニュートリノ放射天体の同定γ

ZPKL ]PL^ν

IceCube 2018








QDQRVHFRQGV







T

γ

ν
γ

[VW ]PL^

ニュートリノアラート＋ 即時追観測→ ニュートリノ放射天体同定
定常天体にも感度がある

ニュートリノ事象の追観測（ ν → γ)•

＋ 電磁波天体のカタログ

•

13

γ

??

ニュートリノ起源天体

g at Tohoku University on November 14, 2022

125 m apart response,
to form athethree-dimensionalarraycriteria(25).
We
reprocessed
these
data
uni.....................................................................................................................................................................................................................
DOMs of the DeepCore subarray,14
in the ice. Each
DOM
records
the number
of wereformly to remove data sample fragmentation,
intended
to study≲100‐GeV
neutrinos,
induced photoelectrons(charges)asdataset,a func-whichalign different data-taking conditions and calexcluded (25). Our
resultinginducedibrations, and improve event reconstructions
tion of time.is optimized for track-likeh eventsi

IceCubeのニュートリノ点源探索解析

by muon (anti-)neutrinos ðn!Þ , has a total exm
posure time of 3186 days.
We restricted our searches to the Northern
Hemisphere from declination d = −3° to 81°,
IceCube 2022
where IceCube is most sensitive to astrophysical sources. IceCube uses Earth as a passive
cosmic muon shield and as a target material
for neutrinos. Hence, by selecting only upwardgoing events, we reduced the atmospheric muon
background, which contributes <0.3% to our
final event sample (25). Declinations higher
than 81° are excluded because low-energy
events from those directions are closely alignedwith the strings of IceCube, complicating ourdistinction between the signal and background(26). The resulting loss of sky coverage is <1%.
A total of ~670,000 neutrino-induced muon•tracks pass the final event selection criteria(25). However, only a small fraction of these
events originate from neutrinos produced in•
astrophysical sources. Most arise from the decay of particles (specifically mesons) that are
Fig. 2. High-resolution scan around the most significant location. (A) High-resolution scan around theFig. 1. Sky mapof the scanpoint sourcesin theNorthernThecolorbyscale
indicates
thecontours showing its 68% (solid) and 95% (dashed)producedin thefor
interactionof cosmic
rays
most Hemisphere.
significant location
markeda whitecross, withwithlocal
nucleiin Earth’s
atmosphere.
discrimlogarithm of the
P value(Plocal) obtainedTo
from
our maximum
likelihoodtheconfidence
regions. analysis,
The red dotevaluatedshows the (withpositionof NGC 1068, and the red circle is its angular size in2
inate
neutrinos
that
originatefromindividual^
theopticalwavelength
(61).
(B)
The
distributionofthesquaredangulardistance,y, between NGC 1068 andspectral index as a free parameter) at each location in the sky. The map is shown in equatorial coordinates on
astrophysical sources from the background ofthereconstructed
event
directions.
Weestimatedthebackground(orange)andthesignal(blue)
from
M77
(NGC
1068)
a Hammer-Aitoff projection. The black circles indicate the three most significant objects in the source list
atmospheric and diffuse astrophysical neutrinos,
Monte Carlo simulations, assuming the best-fitting spectrum at the position of NGC 1068. The superposition

北天にあるニュートリノ点源を探査

近傍のセイファート銀河NGC1068 (M77) の方向から
80事象の高エネルギーニュートリノが到来→4.2 σの統計的有意度でニュートリノ源の証拠

セイファート銀河からのニュートリノ
Neutrino emission from NGC 1068

IceCube (this work)

Electromagnetic observations (26)The high-resolution scan around the most sigTheoretical ν model (52,55)
0.1 to 100 GeV gamma-rays (40,41)
nificant location in the Northern Hemisphere
Theoretical ν model (53)> 200 GeV gamma-rays (42)is shown in Fig. 2A, with NGC 1068 located−9inside the 68% confidence region. The posi10
IceCube 2022
þ22
^
¼
79
more
tion of NGC
1068
producedm#20
電波:ジェット ns
events than expected from the atmospheric
−10
10
遠赤外線
and diffuse astrophysicalneutrino
backgrounds.
赤外線：トーラス
X線 Murase, SSK +2020
Figure 2B shows the distribution of the angular separation of these events from NGC 1068.
10 −11
可視光
Among the 79 most contributing events, 63
were included in a previous analysis (23). The
10 −12^ ns is ~2 events (26).
systematic uncertainty on m
þ0:2
The measured spectral index is ^g ¼ 3:2#0:2−13
可視：降着円盤10
電波with an estimated systematic uncertainty of±0.07 (26), consistent X線：コロナ
with previous results
Y. Inoue et al. 2020(23). We estimate these systematic uncertain10 −14
ties by analyzing simulated data, assuming a
10 −1510 −12
10 −9
10 −6
10 −3
10 0
10 3
10 6
source with flux equal to the one measured forEnergy [GeV]
NGC 1068 but varying assumptions about theM77 (NGC 1068)
セイファート銀河
detector response (26). Systematic uncertainties
Fig. 4. Multimessenger spectral energy distribution of NGC 1068. Gray points show multifrequency
arise mainly from the modeling of the photon
observations (datasources listed in table S1). Dark and light green points indicate gamma-ray observations•- 銀河の中心が明るく輝く天体
propagation in the glacial ice—e.g., scattering
at 0.1 to 100 GeV (40, 41) and >200 GeV (42), respectively. Arrows indicate upper limits, and error bars
and absorption—and the efficiency with whichare 1s confidence intervals. The solid, dark blue line shows our best-fitting neutrino spectrum with thephotons are detected by the IceCube optical(活動銀河核)•dark blue shaded region indicating the 95% confidence region. We restrict this spectrum to the range
modules. Systematic uncertainties are smaller
between 1.5 and 15 TeV, where the flux measurement is well constrained (26). Two theoretical predictions
than statistical uncertainties for directional track- 超大質量ブラックホールが物質を降着
are shown for comparison: The light blue shaded region and the gray line show the NGC 1068 neutrino
reconstructions (26) but have a nonnegligible
emission models from (52, 55) and (53), respectively. The shaded region covers possible values of theeffect on the energy reconstructions.
- 重力エネルギーの解放
gyrofactor 30 ≤ hg ≤ 104 used to describe uncertainty in the efficiency of the underlying particle acceleration
The properties of the source spectrum are(55). All fluxes F are multiplied by the energy squared E2.
shown in Fig. 3, which shows
the likelihood—> 高温のプラズマ流(降着流)を形成
as a function of the model parameters (F0, g)
E 2 Φ [TeV cm− 2 s− 1 ]•15

ニュートリノγ線

どこで宇宙線が加速されているのか？

→ クーロン衝突が非効率（無衝突プラズマ）→ 宇宙線を加速することができる！

Downloaded from https://wwX線放射領域（高温コロナ）は高温で希薄

高温コロナでの宇宙線加速

ラックホールに引きつけられたガスは, 回転しながらブラックホールに込まれる (降着円盤 or 降着流).

16

スの重力エネルギーが変換され, 明るく輝き, 場合によってはジェット

出する.

巨大ブラックホール
Particle-In-Cell (PIC) シミュレーション(太陽質量の１億倍)
エネルギー天体のエネルギー源
Hoshino 2013, 2015; Riquelme et al. 2012; Kuntz et al. 2016
ジェット(赤)座X-1の想像図

降着円盤
X線で光る)

SSK+ 2016 ApJ, 2019 MNRAS; Sun & Bai 2021

磁気流体乱流の生成

Figure 7. Momentum distributions at t = 10tL in the lab frame (upper)
and the fluid flame (lower) for λini = 4. We can see a bulk motion in thelab-frame, while the bulk motion is not seen in the fluid frame.

分布関数の進化銀河(白)ブラックホール(太陽質量の10倍程度)(可視光で光る)水曜日

磁気流体 (MHD)+テスト粒子軌道計算

Figure 6. Orbits of test particles projected to the R − θ plane (upper panel)and the R − φ plane (lower panel) for λini = 4. The initial and final positionsof the particles are shown by the stars and circles, respectively. In the bottom
panel, the cyan circle and black arrows indicate the initial ring R = Rini andthe rotation direction, respectively.

電波銀河
is the unit vector of the φ direction and Vbul, φ is indewhere eφ の観測

pendent of θ. The bottom panel shows the momentum distribution
in the fluid frame, where we can see no bulk rotational motion. In
the following sections, we use the energy distribution in the fluid
frame. Note that the particle distribution is slightly anisotropic: theparticles tend to have positive pR and negative pφ . This is because
FIG. 1 (color online). Time evolutionof the magnetorotational instability. Panels (a) and (b) show the magnetic field lines (greenish
the particles tend to move radially outward along the spiral magnetic
Figure 8. Energy distribution function at t = 4tL , 10tL , and 25tL in fluidlines) and angular velocities in the background
at
Y
¼
y=λ
¼
1.91
and
X
¼
x=λ
¼
1.91
(colorcontour), and panels (c)–(e) depict thefield, as discussed above. This anisotropy becomes stronger in later
flame for λini = 4. The distribution function diffuses in the energy space.
time
and forPanels
higher energy
particles(seeatSection
3.2.3).
Since
this Panel (f): The energy spectra during the MRI
high-density regions as reddish curved
planes.
(b) and(c) arethe sametime
stage.
anisotropy
in the particle
with all fitting
the MHDfor T describes
at T orbit ¼ 0.31, 6.89, 7.18, 8.84, and14.28. appears
The dashedline issimulations
a Maxwellian
the evolution of the distribution function for the particles
orbit ¼ 7.18.
data sets, the grid spacing and resolutions are not the cause of thewith isotropic distribution in the fluid rest frame (e.g. Skilling
anisotropy.
1975; Strong, Moskalenko & Ptuskin 2007). When the terms for

乱流

分布関数の進化は

非熱的粒子分布

エネルギー空間での拡散

061101-2

configuration space and the advection term in momentum space are
negligible, the transport equation may be simplified to the diffusion
equation only in momentum space (e.g. Stawarz & Petrosian 2008):
!
"
1 ∂
∂f
∂f
= 2
p 2 Dp
.
(23)
∂t
p ∂p
∂p

磁気リコネクション
We examine evolution→of the 相対論的粒子の生成
energy distribution function in the fluid(a) and (b) show the magnetic field lines (greenish
frame. The time evolution of the energy distribution for λini = 4 is
1.91 (color contour), and panels (c)–(e) depict theshown in Fig. 8. We can see that the width of the energy distribution
大スケールの乱流場と相互作用→
さらなる宇宙線加速
Since the anisotropy in our system is not very strong, we apply thisincreases
with
time.
This
motivatesustoconsider the diffusion
stage. Panel (f): The energy spectra during the MRI
3.2.2 Diffusion in energy spacehere Fp turbulence.
is the momentum
distributionfunctionWe
computesteadystate CR spectra by solv2
dN/d"p•= 宇宙線陽子の輸送方程式
4⇡p Fp /c), D"p is the di↵usion coefficient,ing
thefollowing
Fokker-Planck
equation(e.g.,[75–78]),ool is the cooling time, tesc is the escape time, and! stochastic acceleration. "F˙p,inj is the injection term to the3ε1 ∂∂Fp waves,pthe
Fp∂Fp2
onsidering resonant
scatterings
with
Alfvenεp Dεp= 2+
Fp −+ Ḟp,inj ,i↵usion coefficientas [144–146]∂t is εrepresented∂εptp−cooltescp ∂εpGeV cm s sr ]

QSO

-1

IG. 2. Relationship between the observed X-ray luminosy, LX,obs , and the X-ray luminosity obtained by the model
alculation, LX,calc . The green squares are LLAGNs withm > 10 3 , while the blue circles are those with ṁ < 10 3 .
he dotted line represents LX,obs = LX,calc , and cyan bandndicates LX,obs /1.7 < LX,calc < 1.7LX,obs , in which all thereen squares are located.

See also SSK+ 2019; SSK+ 2021; Kheirandish, Murase, SSK 2021
We p
V. CASCADE GAMMA-RAY EMISSION
Fig. 3. A
Hadronuclear and photohadronic processes produce
a flat svery-high-energy (VHE) gamma rays through neutral pionattenuat
decay and high-energy electron/positron pairs throughelectron
MULTIMESSENGER
TESTS
OFcharged pion decay and the Bethe-Heitler process. The
VHE gamma rays are absorbed by soft photons through theγγ → eþ e− process in the RIAF, and produce
additionalGAMMA-R
V. CASCADE
MULTIMESSENGERTESTS OFpairs.
COSMIC-RAY
ACCELERATION…
high-energy electron/positron
The high-energyeþ e−Hadronuclear and photohadro
pairs also emit gamma-rays through synchrotron processes,
where raεvery-high-energy
(VHE)
gamma
pr
V. CASCADEGAMMA-RAY
EMISSION leading to We plot −2
inverseCompton scattering,and bremsstrahlung,
decay
and
high-energy
electron/
ðx
−
x
Fig.
3.
A
suff
electromagnetic cascades. We calculate the cascade emisHadronuclear and photohadronic processes
producecharged
pion
decay
Beth
thespectrHea
a flatthesion by solving the kinetic equations of photons
andandvery-high-energy (VHE) gamma rays throughneutral pion
VHE
gamma
rays are absorbedof thebycr
attenuationbelectron/positron pairs (see Refs. [87,159,160]):
decay and high-energy electron/positronγγ →pairs
eþ e−throughprocess inelectron-posit
the can
RIAF,
seecharged pion edecay and the Bethe-Heitler
process.electron/positronThe
high-energy
pairs
tabulate∂nεe
3e
VHE gamma raysþare∂ absorbed
throughthe½ðPIC þ byPsynsoftþ photons
Ppairs
þ
P
Þn
%
also
emit
gamma-rays
throughfitting f
ff
Cou εeþ − ∂tγγ → e e process∂εine the RIAF, and produce
additionalscattering,formed
inverseCompton
and
bre
w
e
þ e−
n
high-energy-4electron/positronpairs.
The
high-energy
e
ε
ðγγÞ
inj
e
LATcalcsenelectromagnetic cascades.
We
_
_
¼
n
−
þ
n
;
ð31Þ
10
ε
ε
e
e
• alsopairs
emit gamma-rays
throughsynchrotron
processes,
電磁カスケードに関する輸送方程式
tesc
with
ais 1
RQ
AGN
(this
work) the wheresion bysolving
kinetic
εγ equinverse Compton scattering,bremsstrahlung,leadingto
RQ andAGN(cascade)

(this
work)
−2
predicte
electron/positron pairsðx(see
Refs.
[
−
x
Þ
lnðx
γ -5
γ
γ We calculate
RQ AGN(thermale) electromagnetic
cascades.
thecascadeemisthe case∂n10nεγ nεγ
εγðICÞ RL AGN
ðffÞ (inðsynÞ
inj 
the
Heavisideclusters)_ εγandþ n_ εequations
þ n_ εγ þþ; ð32Þ
¼ − the− kinetic
sion by solving
ofn_ εphotons
e nγγ
better
se
∂n
∂
RL
AGN
(w.
blazars)

∂t
t
t
ε
of
the
criticaleγγ
esc Refs. [87,159,160]):
electron/positron pairs(see½ðPIC þ Pþsyn þ P
gammatotal∂εe∂t
can see flat sp-6
10 irangevalduetabulated
e nε is the differential number density (i ¼ e or n
γ),
where
∂nεe i ∂εeðγγÞ
inj a hi
e
has
_
_
¼
n
−
þ
n
;
ðxxÞ
½ðPIC þ Psyn þ Pff þ PCou Þnεe %þ
εe formu
εefitting
particle source term from the process txx
n_ εi ∂t is the
esc
flux
is to
-7 ∂εeformedwitht
10IC (inversee[xx ¼
Comptonscattering),
γγ
(γγ
pair
pron
be chall-2 -1

AGN コロナモデル

17
PHYSICALREVIEW
LETTER
Murase,
SSK, Meszaros TESTS
2020 OF COSMIC-RAY ACCELERATIONMULTIMESSENGER

FIG. 1. Schematic picture of the AGN disk-corona scenario.
Protons are accelerated by plasma turbulence generated in the(1)✓ ◆2 ⇣ ⌘2
q2
where ⇣c
Fp is
the
CR
distributionfunction,
D
≈
ε
VA
rL
εp
p /tacc2
D "p ⇡
"p ,
(9)
−1
H
c
H
is the diffusion coefficient in energy space, tp−cool = t−1
pp +

18

NGC 1068からのガンマ線・ニュートリノ放射•-6コロナモデルはガンマ線データと10

矛盾することなくニュートリノデータ
拡散的逃走とBethe-Heitler process(p+γ —> p+e++e-)が加速を止める•

pp と pγ (with X-rays) の両方がニュートリノ放射に寄与•

カスケード放射は10 MeV付近に現れる→ 将来のMeVガンマ線観測で検証可能

10
E FE [GeV cm s ]

•

-7

-2 -1

を説明可能

ν
Cascade γ

Murase, SSK+ 2020

IceCubeeASTROGAM-810

AMEGO-X-9

Fermi LAT

10

-10

10

-11

10

-4

-3

-2

-1

10 10 10 10

0

1

2

3

4

5

6

7

10 10 10 10 10 10 10 10E [GeV]

ESO 138-1
NGC 7582
NGC 1068
NGC 4945
NGC 424
UGC 11910
CGCG 164-019
NGC 1275

1
0.7
0.5
0.8
0.7
0.5
0.4
0.3

0.1 (0.02)
0.2 (0.04)
0.2 (0.05)
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0.4 (0.3)
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0.4 (0.3)
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0.3 (0.08)
0.4 (0.2)19
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Kheirandish,Murase, SSK 2021
0.5 (0.5)
0.5 (0.5)

近傍セイファート銀河からのニュートリノ
• The
コロナモデルの予言：L∝Lν
X (17pp), 2021
Astrophysical Journal, 922:45
November 20• スタッキング解析の予言（10天体）→ 明るい近傍天体をリストアップ
TeV energies, the source beneﬁts from a 100% visibility in

Table 4
KM3NeT. Therefore, the likelihood for its observation is high,and can exceed 3σ in 3 yr of operation
for thefor
stochastic
Prospects
ObservationofnearbyBrightSeyfertGalaxies
in
One
Year
• NuSTARデータとIceCubeの有効面積
acceleration scenario with High CR pressure.
As the signal events from the rest of the sources in the list
fall short of yielding
a statistical signiﬁcance in 3 yr, we now→ NGC1068
が最初に見つかるべきp-va
turn to the prospects for observation of neutrino emission in a
Sourcestacking analysis. We only consider
Visibility
Stochastic (the Modest CR pressure Stochastic (High CR Pressure)scenario in stochastic acceleration since emission under either−8
Cen Aof the other two scenarios should be identiﬁed
0.7 by IceCube. In
0.001 (9.3 × 10 )addition to KM3NeT, we consider IceCube-Gen2 for the−5
Circinus
Galaxy1.0we assume that the
0.008 (1.9 × 10 )stacking
search in this scenario. Here,effective area for IceCube-Gen2 is ∼5 times larger than the
ESO 138-1
1
0.1(0.02)
current IceCube detector.
We present the p-values expected
NGC 7582
0.7for the Modest CR
0.2 (0.04)
pressure stochastic acceleration scenario for KM3NeT together
NGC with
1068
0.5 10. We project the
0.2 (0.05)
the ones for IceCube-Gen2 in Figure
for identiﬁcation of neutrino0.8
emission from the brightNGC prospects
4945
0.5
(0.2)
sources assuming an angular resolution of 0°. 3 (solid) and 0°. 7
note that our estimation
NGC (dashed)
424 for each detector. We should0.7
0.4 (0.2)of the prospects for identifying Seyfert galaxies are quite
Figure 10. Prospectsforobservation of the bright Seyfert galaxies in the nextUGC conservative,
11910 given that an angular resolution
0.5 of 0°. 3 or better is
0.4
(0.4)
generation neutrino telescopes: KM3NeT and IceCube-Gen2. The solid•
KM3NeTとIceCube-Gen2
は5σ
で
not
that
far-fetchedfor
KM3NeT.
The
expected
improvements(dashed)lines
show
expectations
for
0°
.
3
(0°
.
7)
angularresolution
for theCGCG 164-019
0.4
0.4
(0.3)
Modest CR pressure scenario. The thick lines show the prospects forin the angular reconstruction in IceCube-Gen2 will also make it
identiﬁcation of0.4
the 10 (0.4)
nearby bright sources in Table 2 in a stacking analysis.
NGC easier
1275to identify these sources. In fact,
0.3our estimates indicate
セイファート銀河からの信号を検出可能
The thin lines show the prospects for identiﬁcation of the sources in thethat achieving ﬁner angular resolutions at ∼10–30 TeV isクエーサー (QSO): 明るい活動銀河核→ 降着流全体が無衝突プラズマ

RIAF

LLAGN

ev. Astro. Astrophys. 2008.46:475-539. Downloaded from www.annualreviews.org
by Osaka University on 12/18/13. For personal use only.

低光度活動銀河核 (LLAGN): 暗い活動銀河核→ 光学的に薄い高温降着流

1 cm

1 mm

100 µm 10 µm

1 µm

1000 Å 0.1 keV 1 keV

10 keVQSO

Ho 2008→光学的に厚い円盤＋高温コロナ
•

10 cm

46

log (νLν /ergs s–1)•

低光度活動銀河核

20

44

LLAGN x 104

42

log Lbol /LEdd ≥ 0–1 ≤ log Lbol /LEdd < 040–3 ≤ log Lbol /LEdd < –1
log Lbol /LEdd < –3

38

PHYSICAL REVIEW
9

10

11

12

13

14

15

16

17

18

log (ν/Hz)

QSO

Figure 7

Wind?

Composite SEDs for radio-quiet AGNs binned by Eddington ratio. The SEDs are normalized at 1 µm
(Adapted from L.C. Ho, in preparation.)

Turbulence?

nuclei (Ho 1999b, 2002a; Ho et al. 2000) and a substantial fraction of Seyfert nuclei (Ho & P
2001). Defining radio-loudness based on the relative strength of the radio and X-ray emis
RX ≡ ν Lν (5 GHz)/LX , Terashima & Wilson (2003b) also find that LINERs tend to be ra
loud, here taken to be RX > 10−4.5 . Moreover, the degree of radio-loudness scales inversely
Lbol /LEdd (Ho 2002a; Terashima & Wilson 2003b; Wang, Luo & Ho 2004; Greene, Ho & Ulv
Accre6on
Shock?
2006; Panessa et al. 2007; Sikora, Stawarz& Lasota 2007;
L.C. Ho, in preparation; see Figure 1
In a parallel development, studies of the low-luminosity, often LINER-like nuclei of FR I rgalaxies also support the notion that they lack a UV bump. M84 (Bower et al. 2000) and(Sabra et al. 2003) are two familiar examples, but it has been well documented that FR I n

活動銀河核降着流からのニュートリノ放射
PHYSICAL REVIEW LETTERS 125, 011101 (2020)

SSK et al. 2021
Murase, SSK+ 2020

FIG. 1. Schematic picture of the AGN disk-corona scenario.
Protons are accelerated by plasma turbulence generated in thecoronae, and produce high-energy neutrinos and cascaded
gamma rays via interactions with matter and radiation.

Coronaeγ by thermal e
RIAFs
γ by EM cascades

distributions (SEDs) are constructed from the data and fromempirical relations, and then we compute neutrino andcascade gamma-ray spectra by consistently solving particle
transport equations. We demonstrate the importance of
future MeV gamma-ray observations for revealing theorigin of IceCube neutrinos especially in the mediumenergy (∼10–100 TeV) range and for testing neutrino
emission from NGC 1068 and other AGN.
We use a notation with Qx ¼ Q × 10x in CGS units.
Phenomenological prescription of AGN disk coronae.—
We begin by providing a phenomenological disk-coronamodel based on the existing data. Multiwavelength SEDs
of Seyfert galaxies have been extensively studied, consisting of several components; radio emission (see Ref. [60]),
infrared emission from a dust torus [61], optical andultraviolet components from an accretion disk [62], andx rays from a corona [33]. The latter two components are
relevant for this work.
The “blue” bump, which has been seen in many AGN, isattributed to multitemperature blackbody emission from ageometrically thin, optically thick disk [63]. The averaged
SEDs are provided in Ref. [64] as a function of the
Eddington ratio, λEdd ¼ Lbol =LEdd , where Lbol and LEdd ≈1.26 × 1045 erg s−1 ðM=107 M ⊙ Þ are bolometric and
Eddington luminosities, respectively, and M is the
SMBH mass. The disk component is expected to have acutoff in the ultraviolet range. Hot thermal electrons in a

ν by non-thermal p
Coronae

RIAFs

FIG. 2. Disk-corona SEDs used in this work, for LX ¼ 1042,
1043 , 1044 , 1045 , and 1046 erg s−1 (from bottom to top). See text
for details.

Fig. 2 (see Supplemental Material [68] for details), whichenables us to quantitatively evaluate CR, neutrino andcascade gamma-ray emission.
Next we estimate the nucleon density np and coronalmagnetic field strength B. Let us consider a corona withthe radius R ≡ RRS and the scale height H, where R is
the normalized coronal radius and RS ¼ 2GM=c2 is the
Schwarzschild radius. Then the nucleon density isexpressed by np ≈ τT =ðσ T HÞ, where τT is the Thomson
optical depth that is typically ∼0.1–1. The standard
accretion theory [69,70] gives
heightpffiffi the coronalpscale
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiH ≈ ðCs =V K ÞRRS ¼ RRS = 3, where Cs ¼ kB T p =mp ¼
pffiffiffiffiffiffiffiffiffiffiffiffiffi
pffiffiffiffiffiffi
c= 6R is the sound velocity, and V K ¼ GM=R ¼
pffiffiffiffiffiffi
c= 2R is the Keplerian velocity. For an optically thincorona, the electron temperature is estimated byT e ≈ εX;cut =ð2kB Þ, and τT is empirically determined from
ΓX and kB T e [31]. We expect that thermal protons are atthe virial temperature T p ¼ GMmp =ð3RRS kB Þ ¼ mp c2 =
ð6RkB Þ, implying that the corona may be characterized by
two temperatures, i.e., T p > T e [71,72]. Finally, the magnetic
pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
field is given by B ¼ 8πnp kB T p =β with plasma beta (β).
Many physical quantities (including the SEDs) can be
estimated observationally and empirically. Thus, for a given•

明るい活動銀河核と暗い活動銀河核のそれぞれを理論モデル化•

多波長観測データを用いて物理パラメータを較正

•

天体ニュートリノデータを説明可能

21

その他のモデル[10]. This outer wind can propagate farther and impact
the torus [37, 54], potentially inducing strong shocks and
DSA of protons [55], for which we assume a total proton
power Lp,o . The model geometry is illustrated in Fig.1.

円盤風モデル•

弱磁場モデル

22

Y. Inoue+ 2019, 2020

S. Inoue+ 2022

ν

p

X

CoronaDisk BH

γ

UV

Shock

4

Galaxies 2021, 1, 0

FIG. 1. Schematic sketch of the model. The accretion disk
around the black hole (BH) drives an outflowing wind. Inner region: winds from the inner disk dissipate their kinetic
energy via shocks near the BH, caused by failed line-driven
winds that fall back. Protons undergo diffusive shock acceleration (DSA) and pγ interactions with photons from the disk
and corona, inducing neutrino and electromagnetic cascade
emission, modulated by γγ interactions. Outer region: successful winds from the outer disk propagate farther, partially
impact the torus and trigger shocks. Protons undergo DSA
and pp interactions with the torus gas, inducing gamma-ray
emission, affected by γγ interactions with photons from the

10 8: Corona: Corona (Screen)
GRAMS(35 days)

10 9

E 2dN/dE [erg/cm2/s]

the
e in
Inons
The
t fit
red •
nge.
TeV
neurerino
Xac46],
ntly
.
), to
ons
rved,
vely
ages
omeussedabsibly
med.
ower
at
is
more
dels
Neuthephoocirays
athe
few

: Corona (Uniform)
IceCube
4FGL
3FHL
MAGIC

10 10

10 11
AMEGO
(5 yrs)

10 12
GRAMS
(3 yrs)

10 13

10 14

10 15
106

107

108

109

1010

1011

Energy [eV]

1012

1013

1014

1015

1016

ニュートリノ天体の探し方•

カタログとの相関解析（γ → ν）••

積分したニュートリノデータ

ニュートリノ事象の追観測（ ν → γ)•

→ ニュートリノ放射天体の同定→ ニュートリノ放射天体同定•

定常天体にも感度がある•

リアルタイムの解析は困難

•

γ

ν






QDQRVHFRQGV







T

突発天体にのみ感度がある
γ

ν
γ



追観測によりカタログにはない
データの取得可能

ZPKL ]PL^[VW ]PL^

ニュートリノアラート＋ 即時追観測＋ 電磁波天体のカタログ

•

23

γ

??

ニュートリノ
起源天体

潮汐破壊現象 (TDE)とニュートリノ

24

Stein+ 2021; Reusch+ (incl. SSK) 2022

©NASA

•

潮汐破壊現象：恒星が超巨大ブラックホールに引き裂かれて明るく輝く現象だが詳細は未解明•

２例のIceCube事象が明るいTDEと相関。有意度 3.5σ？ IC191001 <=> AT2019dsg；IC200530 <=> AT2019fdr•

TDEの光度曲線のピークから 100 - 400 日後にニュートリノ検出

様々なモデル In the standard disk, for ex
25

strophysical Journal, 902:108 (13pp), 2020 October 20

ウインド
ジェット
コロナ

T
»
0.488
is
estimatedasdisk
降着流モデル Hayasaki & Yamazaki 2019
Pringle 1981), which typically- 超臨界降着モデル
case, the early-timeemissionm
Murase, SSK+ 2020
- コロナモデル
it can be reprocessed by the
SSK, Murase+ 2019
- RIAFモデル(e.g., Loeb & Ulmer 1997; S
2018). But late-time optical an• 円盤風モデル
Murase, SSK+(e.g.,2020
the disk emission
Lelou- デブリとの相互作用
2019; Wevers et al. 2019).
- 熱光子の利用
Winter & Lonardini
2022
In a corona,electrons
aredissipation,
cooledvia
theC• ジェットモデル
photons, andefﬁciently
emit
Lonardini& Winter 2016
- 立派なジェット
electron temperature in A
- 隠されたジェット
kTe ~ 10 - 100 keV. When
Senno theet al. 2016
longer thandissipation t•

TDEからのニュートリノ放射モデル

The Astrophysical Journal, 902:108 (13pp), 2020 October 20

trophysical Journal, 902:108 (13pp), 2020 October 20

26

Mura

Murase et al.

In the standard disk, for example, the inner disk temp
3
1 4

T
»
0.488
(
3
GM
M
8
ps
R
)
is
estimated
as
disk
BH
SB ISCO4. Implications for AT2019dsg
Murase+2020
Pringle 1981), which typically lies in the UV range. In the
4.1. Summaryジェット
of Observations
case, the early-time emission may not be directly observed b
it can be reprocessed by the surrounding optically thick m
discovery of AT2019dsg triggered a follow-up cam(e.g., Loeb & Ulmer 1997; Strubbe & Quataert 2009; Da
ウインドmuch before the detection of IceCube-191001A.
The
コロナ2018). But late-time optical and UV emission is often attribu
of the observations are presented in Stein et al. (2020).
the disk emission (e.g., Leloudas et al. 2016; van Velzen
we give a short summary. On April 9th 2019 ZTF
2019; Wevers et al. 2019).
ed the discovery of AT2019dsg as an optical transient of
In a corona, electrons are heated presumably by ma
extragalactic origin (Nordin et al. 2019). Spectroscopic
dissipation, cooled via the Comptonization of optical/UVations of AT2019dsg with the extended-Public ESO
photons, and efﬁciently emit hard X-rays. Observational
oscopic Survey for Transient Objects (ePESSTO+)
electron temperature in AGN coronae is foundll et al. 2019) classiﬁed it as a TDE. Radio follow-up
kTe ~ 10 - 100 keV. When the Coulomb relaxation ti
ations ﬁrst with the Arcminute Microkelvin Imager
longer than the dissipation timescale, one may expect aLA) (Sfaradi et al. 2019) and later with the Enhanced
temperature plasma, in which thermal protons have a
Murase,Network
SSK+ 2020models
ApJ
Element
Remotely
LinkedInterferometer
Figure 1. Schematic
pictureof neutrino
and gamma-ray
production
Figure 6. Most optimistic all-ﬂavor neutrino ﬂuences expected
for AT2019dsg
1
kT

5.2
MeV
(
R
30
R
)
temperature
of
,
where
R
considered
in
this
work
(not
to
scale).
Inthecore
models,theemission
regionispS•(Perez-Torres
RLIN)
et
al.
2019)
revealedradio
emisin the corona (for MBH,7 = 3), RIAF (for MBH,7 = 3), hidden wind, and hidden
降着流モデル：possible
2 , isthe corona and disk regions. In the hidden wind model, the emission regions
b
º
8
p
n
kT
/
B
coronalradius.
The
plasmabeta,
jet
scenarios.
See
also
Figure1.
Thehorizontal
lines
show
the
ﬂuencelevelppAT2019dsg
belongs
to
a
rare
type
of
TDEs
which
exhibitare sub-relativistic outﬂows that may be driven by an accretion disk or induced
needed toduced
producetooneestimate
neutrino inthe
the GFUand PS ﬁeld
channels
respectively
for an• 円盤風モデル
magnetic
strengthB.
Here,：challenging
nonthermal)
emission,suggestiveofparticle
accelerationby collisions among tidal streams. In the jet model, CR acceleration andEn-2 neutrino
spectrum. density
Note that ofthethermal
ﬂuences arelower fortheβ∼0.01−modest cases.
thenumberprotons.
For
tivistic
neutrinoenergies.
production occur inside relativistic jets. Note that the above scenarios
ジェットモデル：unlikely
expect B∼0.1–30 kG.
are not• mutuallyemission
fromexclusive.
AT2019dsg was ﬁrst detected by themodel-dependent
implications,
includingtherelationshiphidden jet model
For AGNs,
there is anempirical
betwee

he

y
m
wof
g
ncpns
he
me

TDE-neutrino paradigm の検証

and i-band observations could enable us to determine thetemperature more precisely.
• 宇宙ニュートリノ起源までの平均距離: z ∼ 0.5 − 1
We perform follow-up spectroscopic observations by
諸隈さんの講演
Gemini/GMOS.
Spectroscopy
enables 21-24
us to mag)
confirm—> 深い観測が必要(TDE@z=0.5:
whether the target is a true dffistant TDE or not, owto its broad emission lines (mainly Balmer
series)of2• ing
ニュートリノ事象の平均角度誤差:1
deg> 104 km s 1 and/or highly ionized Fe lines emerging—> 視野の広いサーベイが必要(typical TDEs
FoV: in0.03 deg2)
aroundthe H line [16]. The neutrino-detecteddicate the broad-line feature even after the neutrino detec• tion,
現在の望遠鏡群ではSubaru/i.e., more than several
months HSC
after のみが可能なサーベイ
the peak of optical lightcurves [17]. Besides, spectroscopic observations• willSubaru/HSCで青くて遅い突発天体を探せ！（2023年
前期・後期 観測提案採択済）
provide information of the host galaxy. Even if thecandidate TDE became fainter than 24 mag at the timeof spectroscopic observation, its host galaxy at z ⇠ 0.5
would be as bright as 23 24 mag. Host galaxies of ZTFdetected TDEs are mostly green valley galaxies emitting
emission lines [16]. Several-hour spectroscopic observaZTF
tions by Gemini/GMOS will detect H and [OIII] emission
lines with S/N ⇠ 5, with which we can determine its redshift. If both the candidate TDE and its host galaxy are
fainter than 25 mag, we will make photometric follow-up
observations by Gemin/GMOS to obtain the lightcurve
HSC
and color evolution for a longer time period. This may
enable us to distinguish a TDE from other type of transients.

27

まとめ

28

•

高エネルギー宇宙線と天体ニュートリノの起源は未解明の大問題•

IceCubeが近傍のセイファート銀河からのニュートリノ信号の証拠を発見•

潮汐破壊現象と相関するニュートリノ事象の報告•

ブラックホール降着流からのニュートリノ放射理論モデルを構築→これらのニュートリノデータを説明することが可能
The Astrophysical Journal, 902:108 (13pp), 2020 October 20-610

Murase, SSK+ 2020
E FE [GeV cm-2 s-1]

10-7

νCascade γ
IceCubeMurase, SSK+ 2020

4. Implications for AT2019dsg
4.1. Summary of Observations

The discovery of AT2019dsg triggered a follow-up campaign, much before the detection of IceCube-191001A. The
10-8
details of the observations are presented in Stein et al. (2020).
AMEGO-X
The Astrophysical Journal, 902:108 (13pp), 2020 October 20
Murase et al.
Below
we
give
a
short
summary.
On
April
9th
2019
ZTF
Fermi LATIn the standard disk, for example, the inner disk temperature
10-9
reported the discovery of AT2019dsg as an optical transientis estimatedof as T » 0.488 (3GM M 8ps R ) (e.g.,Pringle 1981), which typically lies in the UV range. In the TDE
likely extragalactic origin (Nordin et al. 2019). Spectroscopic
case, the early-time emission may not be directly observed because
it can be reprocessed by the surrounding optically thick material
observations of AT2019dsg with the extended-Public ESO
10-10(e.g., Loeb & Ulmer 1997; Strubbe & Quataert 2009; Dai et al.
2018). But late-time optical and UV emission is often attributed toSpectroscopic Survey for Transient Objects (ePESSTO+)
the disk emission (e.g., Leloudas et al. 2016; van Velzen et al.
2019; Wevers et al. 2019).
(Nicholl et al. 2019) classiﬁed it as a TDE. Radio follow-up-11
In a corona, electrons are heated presumably by magnetic
10
dissipation, cooled via the Comptonization of optical/UV disk
-4
-3
-2
-1
0
1
2
3
4
5
6
7 ﬁrst with the Arcminute Microkelvin Imager
observations
10 10 10 10 10 10 10 10 10 10 10 10
photons, and efﬁciently emit hard X-rays. Observationally, theelectron temperature in AGN coronae is found to be(AMI-LA)(Sfaradi
et
al.
2019)
and
later
with
the
Enhanced
E [GeV]kT ~ 10 - 100 keV. When the Coulomb relaxation time iseASTROGAM

disk

e

BH

3
1 4
SB ISCOlonger than the dissipation timescale, one may expect a two-

Murase et al.