Unveiling
Origin of Galactic Cosmic Rays
Hiroyasu Tajima
Solar-Terrestrial Environment Laboratory
Nagoya University

July 29, 2013
天文・天体物理若手 夏の学校
蔵王Outline✤ Introduction✤ Gamma-ray emissions from cosmic rays
✤ Cosmic gamma-ray experiments❖ Fermi Gamma-Ray Space Telescope❖ Imaging atmospheric Cherenkov telescopes✤ Search for origin of cosmic rays
❖ Galactic supernova remnants✤ Future prospects

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Cosmic Particle Accelerators✤ Origin of cosmic ray is one of the biggest mysteries ofastrophysics
15
Neutron starlog(B, gauss)

10
1 PARTICLEPER SQUAREMETER PER YEARKNEE
1 PARTICLEPER SQUAREKILOMETERPER YEAR

1010

1012

JENNIFER C. CHRISTIANSENRELATIVE PARTICLE FLUX (LOGARITHMIC UNITS)

1 PARTICLEPER SQUAREMETER PER SECOND

1014

1016

1018

GRB
1021 eV

LHC

5

AGN

White dwarf

Colliding galaxies

0

AGN jet1012 eVRadio lobe

1015 eV 1018 eV
Galaxycluster-5
SNR

Galaxy

12

15

-10
0

1020

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

3

6

9

18

21

24

log(size, km)
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Deflection of Cosmic Rays
✤ Cosmic rays (charged particles) are deflected by (turbulent)

Galactic magnetic field✤ Neutral particles (Photons and neutrinos) come straight to us

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Gamma-ray Emission from Electrons✤ Synchrotron radiation✤ Compton up-scattering❖ CMB (Cosmic Microwave BG)❖ Synchrotron light❖ Interstellar light

Energy Flux (E2•dN/dE)✤ Bremsstrahlung

UB/Uγ

Synchrotron
Emission

Bremsstrahlung

Compton
Up-Scattering∝E-1/3

Radio

Infra-red

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X-raysγ-rays Energy
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Gamma-ray Emission from Protons✤ Nuclear interactions with interstellar medium❖ First suggested by S. Hayakawa

γπ0pπ± → µ± → e±p (Interstellar medium)

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Gamma rays from π0 decays
Before collision

After collision

CR

proton at rest

p

p

π０

p

gas
High energy proton(E > 1 GeV)

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gamma-rays

p

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Gamma rays from π0 decays
Before collision

After collision

CR

proton at rest

p

p

π０

p

gas
High energy proton(E > 1 GeV)

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gamma-rays

p

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π0-decay γ-rays: Direct Probe of Accelerated Protons✤ γ-ray spectral shape is determined solely by dN/dp (proton

spectrum).

dN/dp ∝ p−s exp(−p/pm)

s=1.5, 2.0, 2.5, cpm = PeV ➜ dNγ /dε

π0 production
microphysics
8

photon index Γ ≃ scutoff at ε ~ 0.1 cpm(σ ~ const)

10

ε2 dNγ/dε:
hard spectrum
below 300
MeV

10 9

E2 dN/dE [erg cm 2 s 1 ]dNγ/dε:symmetric
about 68 MeV

s=2.5
s=2.0
s=1.5

Very hard spectrum below
300 MeV for any reasonable
proton index

10 10

10 11

10 12

10 13 7
10

108

109

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

1010

1011
E [eV]

1012

1013

1014

1015
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Gamma-ray Detectors
Satellite-based pairconversion telescope

Ground atmospheric
Cherenkov telescope

Experiments

EGRET, AGILE, Fermi

HESS, VERITAS MAGIC

Energy range

0.02 – 200 GeV

0.1 – 100 TeV

Angular res.

0.04 – 10 deg~0.1 deg

Collection area

1 m2

105 m2

Field of view

2.4 sr10-2 sr

Duty cycle

~95%

<10%

γ

e+

e–

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Fermi (GLAST)/LAT Overview✤ LAT (Large Area Telescope) on board Fermi Observatory✤ Satellite experiment to observe cosmic gamma rays
❖ Wide energy range: 20 MeV to >300 GeV

Si Tracker❖ Large effective area: > 8000 cm2 (~6xEGRET) 70 m2 , 228 µm pitch❖ Wide field of view: > 2.4 sr (~5xEGRET)~0.9 million channels
maintained by our groupγ✤ Pair-conversion telescope❖ “Clear” signature❖ Background rejection

Large Area
Telescope (LAT)

Anti-coincidence Detector
Segmented scintillator tiles
99.97% efficiency
Gamma-ray
Burst
Monitor

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

e+

eCsI Calorimeter8.4 radiation length
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Fermi (GLAST)/LAT Overview✤ LAT (Large Area Telescope) on board Fermi Observatory✤ Satellite experiment to observe cosmic gamma rays
❖ Wide energy range: 20 MeV to >300 GeV

Si Tracker❖ Large effective area: > 8000 cm2 (~6xEGRET) 70 m2 , 228 µm pitch❖ Wide field of view: > 2.4 sr (~5xEGRET)~0.9 million channels
maintained by our groupγ✤ Pair-conversion telescope❖ “Clear” signature❖ Background rejection

Large Area
Telescope (LAT)

Anti-coincidence Detector
Segmented scintillator tiles
99.97% efficiency
Gamma-ray
Burst
Monitor

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

e+

eCsI Calorimeter8.4 radiation length
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Fermi (GLAST)/LAT Overview✤ LAT (Large Area Telescope) on board Fermi Observatory✤ Satellite experiment to observe cosmic gamma rays
❖ Wide energy range: 20 MeV to >300 GeV

Si Tracker❖ Large effective area: > 8000 cm2 (~6xEGRET) 70 m2 , 228 µm pitch❖ Wide field of view: > 2.4 sr (~5xEGRET)~0.9 million channels
maintained by our groupγ✤ Pair-conversion telescope
LAT❖ “Clear” signature❖ Background rejection
Spacecraft
Large Area
Telescope (LAT)

Anti-coincidence Detector
Segmented scintillator tiles
99.97% efficiency
Gamma-ray
Burst
Monitor

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

e+

GBM
e

CsI Calorimeter8.4 radiation length
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Comparison with Previous Missions✤ Number of triggers way

beyond 100 billion(134x109; 26x109
downlinked)✤ Number of photons in
one year dwarfs
previous missions✤ Uptime: 99.1%✤ All data public
Processing time:
typically 5-10 hours✤ 5-year mission, no
consumables

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Comparison with Previous Missions✤ Number of triggers way

beyond 100 billion(134x109; 26x109
downlinked)✤ Number of photons in
one year dwarfs
previous missions✤ Uptime: 99.1%✤ All data public
Processing time:
typically 5-10 hours✤ 5-year mission, no
consumables

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Variable Gamma-ray Sky

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Predecessor, EGRET✤ EGRET: 1991–2000❖ 271 gamma-ray sources (Hartman et al. 1999)• Only 38% (101 sources) have clear “identifications”
EGRET all-sky (galactic coordinates) E>100 MeV

Galactc plane

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1873 sources

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1873 sources
Preliminary

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Fermi	  Highlights	
  and	  Discoveries
2009, Nature, 462, 331

GRBse+e- spectrum

Blazars	  (782)
Radio	  Galaxies	
  (12)ExStar	
  Burst	  	
  Galaxies	
  (4)Globular	
  Clusters	
  (11)

c
%
c
a
l
a
g
a
tr

LMC	
  &	
  SMC

Fermi	
  Bubbles
2010, Science, 327, 1103

SNRs	
  &	
  PWN	  (68)

Nova	
  (1)

c
%
c
a
l
a
G

γ-­‐ray	  Binaries	
  (6)Pulsars:	
  isolated,	
  binaries,	
  &	
  MSPs	  (122)

Sun:	
  ﬂares	  &	  CR	
  interacOons
TGFs

UnidenOﬁed	
  Sources	
  (600)

Scientific Impacts of Fermi✤ 225 publications (> 3300 citations for top 8 papers) as of 2013/03✤ “Breakthrough of the Year” in 2009 selected by Science magazine

1. Ardipithecus Ramidus

2. Opening up the gamma-ray sky✤ Bruno Rossi Prize 2011 awarded to W.B. Atwood, P. Michelsonand Fermi LAT Team by High-Energy Astrophysics Division of
AAS
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Scientific Impacts of Fermi✤ 225 publications (> 3300 citations for top 8 papers) as of 2013/03✤ “Breakthrough of the Year” in 2009 selected by Science magazine

1. Ardipithecus Ramidus

2. Opening up the gamma-ray sky

Nature: 3
Science: 15(as of 2013/03)✤ Bruno Rossi Prize 2011 awarded to W.B. Atwood, P. Michelsonand Fermi LAT Team by High-Energy Astrophysics Division of
AAS
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Imaging Atmospheric Cherenkov Telescope
Cherenkov Light
50photons/m2 (5 pe/m2) at 1TeV

Typical parameters
Energy range
50GeV ~ 10TeV
CR rejection power >99%
Angular resolution ~0.1 degrees
Energy resolution ~20%
Detection area
~105m2
Sensitivity ~1% Crab Flux (10-13 erg/cm2s)
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Imaging Atmospheric Cherenkov Telescope
Cherenkov Light
50photons/m2 (5 pe/m2) at 1TeV

T1

T３

T２

T４

Typical parameters
Energy range
50GeV ~ 10TeV
CR rejection power >99%
Angular resolution ~0.1 degrees
Energy resolution ~20%
Detection area
~105m2
Sensitivity ~1% Crab Flux (10-13 erg/cm2s)
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Imaging Atmospheric Cherenkov Telescope
Cherenkov Light
50photons/m2 (5 pe/m2) at 1TeV

T1

T３

T２

T４

Typical parameters
Energy range
50GeV ~ 10TeV
CR rejection power >99%
Angular resolution ~0.1 degrees
Energy resolution ~20%
Detection area
~105m2
Sensitivity ~1% Crab Flux (10-13 erg/cm2s)
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Currently Operating IACTs on Earth
MAGIC

PACT
GRAPESVERTAS

HESS

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VHE Skymap

106 sources (45 Extragalactics + 61 Galactics) in Nov 2010
Blazars, FSRQs, FR-I, Starburst galaxies
SNRs, PWNe, Pulsar, Binaries, un-IDs
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Origin of cosmic ray protons✤ Galactic SNRs (Supernova Remnants) are considered as thebest candidates for cosmic-rays below “Knee”❖ Only circumstantial evidence• CR energy sum consistent
with SNR kinetic energy(Ginzburg&Syrovatskii 1964)• Diffusive shock acceleration(Blanford&Eichler 1977)• Chemical Composition(Hayakawa 1956)❖ No observational evidence❖ Spectral index (~2.7) is difficult to explain✤ Cosmic-rays above “Knee” areconsidered extragalactic❖ Gamma-ray bursts (GRB)❖ Active Galactic Nuclei (blazar)❖ Merging galaxy clusters
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Origin of cosmic ray protons✤ Galactic SNRs (Supernova Remnants) are considered as thebest candidates for cosmic-rays below “Knee”❖ Only circumstantial evidence• CR energy sum consistent
with SNR kinetic energy(Ginzburg&Syrovatskii 1964)• Diffusive shock acceleration(Blanford&Eichler 1977)• Chemical Composition(Hayakawa 1956)❖ No observational evidence❖ Spectral index (~2.7) is difficult to explain✤ Cosmic-rays above “Knee” areconsidered extragalactic❖ Gamma-ray bursts (GRB)❖ Active Galactic Nuclei (blazar)❖ Merging galaxy clusters
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Origin of cosmic ray protons✤ Galactic SNRs (Supernova Remnants) are considered as thebest candidates for cosmic-rays below “Knee”❖ Only circumstantial evidence• CR energy sum consistent
with SNR kinetic energy(Ginzburg&Syrovatskii 1964)• Diffusive shock acceleration(Blanford&Eichler 1977)• Chemical Composition(Hayakawa 1956)❖ No observational evidence❖ Spectral index (~2.7) is difficult to explain✤ Cosmic-rays above “Knee” areconsidered extragalactic❖ Gamma-ray bursts (GRB)❖ Active Galactic Nuclei (blazar)❖ Merging galaxy clusters
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Energetics of Galactic Cosmic Rays
✤ Cosmic ray power in our Galaxy: ~ 5 x 1040 ergs/s❖ Supernovae: Q ~ 1042 ergs/s• Energy release (1051 ergs) x frequency (1/30 years)❖ Novae: Q ~ 1042 ergs/s• Accretion of matter onto white dwarf• Energy release (1042 ergs) x frequency (100/year)❖ Rotating neutron stars: Q ~ 1041 ergs/s• Majority of Galactic Fermi-LAT sources❖ Stellar winds from hot O/B stars: Q ~ 1041 ergs/s• Strong winds from radiation pressure (109 Ṁ☼)

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“Fermi Acceleration” Mechanism
Shock wave
electronwith E = 1 GeV
E = 1.01 GeV

E = 1 GeV

E = 1.03 GeV

Energetic charged particles“random walk” in turbulent
magnetic field.
Shock crossing➜ energy gain
Energy gain per one round
trip: ΔE/E ~ v/c~ 1% of original energy(for v = 3000 km/s)
After 1000 round trips:
Energy: x20,000(e.g. 1 GeV ➜ 20 TeV)
But, very few particles canmake 1000 trips➜ power law distribution

Particle Acceleration in SNR✤ Young shell-type supernova: SN1006❖ Power law spectrum from rim is best described by synchrotron

emission by ultra-relativistic electrons❖ First evidence of particles accelerated to > 1014 eVPower-law
Thermalemission

Koyama et. al
Ozaki
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Particle Acceleration in SNR✤ Young shell-type supernova: SN1006❖ Power law spectrum from rim is best described by synchrotron

emission by ultra-relativistic electrons❖ First evidence of particles accelerated to > 1014 eV
Credit: NASA/CXC/Rutgers, NRAO/AUI/NSF/GBT/VLA, Middlebury College/
F.Winkler, NOAO/AURA/NSF/CTIO Schmidt & DSS

Power-law
Thermalemission

Koyama et. al

Radio
Optical
X-ray (Chandra)

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Ozaki
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Particle Acceleration in SNR✤ Young shell-type supernova: SN1006❖ Power law spectrum from rim is best described by synchrotron

emission by ultra-relativistic electrons❖ First evidence of particles accelerated to > 1014 eV
Credit: H.E.S.S.

Credit: NASA/CXC/Rutgers, NRAO/AUI/NSF/GBT/VLA, Middlebury College/
F.Winkler, NOAO/AURA/NSF/CTIO Schmidt & DSS

Power-law
Thermalemission

Koyama et. al
Gamma ray (HESS)

Radio
Optical
X-ray (Chandra)

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Ozaki
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“Gold-Plated” Supernova Remnant✤ HESS TeV gamma-ray observation of RX J1713.7-3946❖ Evidence for particle acceleration > 1014 eV❖ Morphological similarity with X-ray observation❖ Spectral feature can not conclusively distinguish leptonic or

hadronic origin of gamma rays

Aharonian et al. 2005

Aharonian et al. 2005

HESS/ASCATeV gamma-ray

Molecular clouds

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Expected Fermi Spectrum for J1713✤ Simulated 5-year Fermi observation of RX J1713-3946❖ Fermi is expected to positively identify hadronic contribution

MC simulation

EGRET

-2

E2 dN/dE (eV cm s-1)

Funk ICRC2007

10

1
Inverse Compton/0 - decay
GLAST - hadronic 5 years
GLAST - leptonic 5 years
H.E.S.S.

10-1
108

109

1010

1011

1012

1013

Energy (eV)
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Fermi Observation of RX J1713.7-3946✤ Data from 2-year Fermi observation❖ Leptonic model may explain the Fermi spectrum better❖ Requires more statistics to distinguish hadronic or leptonic

nature of gamma-ray emissions

2011, ApJ, 734, 28
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RX J0852.0–4622: Another TeV SNR✤ B = 0.01 mG in leptonic model would be difficult to be reconciledwith X-ray measurements.
✤ Hadronic model would require a large CR content❖ 5×1050 erg for n=0.1 cm-3
Contours: ROSAT X-ray (E > 1.3 keV)Red vertical bars: statistical errors
Black caps: systematic errors

TeV Gamma-ray Image by H.E.S.S.
(Aharonian+ 2007)

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RX J0852.0–4622: Another TeV SNR✤ B = 0.01 mG in leptonic model would be difficult to be reconciledwith X-ray measurements.
✤ Hadronic model would require a large CR content❖ 5×1050 erg for n=0.1 cm-3
Contours: ROSAT X-ray (E > 1.3 keV)sync
π0 decaysIC

sync
Red vertical bars: statistical errors
Black caps: systematic errors

TeV Gamma-ray Image by H.E.S.S.
IC(Aharonian+ 2007)

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Hard Gamma-Ray Spectra✤ Hard gamma-ray can be explained by higher target density forhigher energy particles❖ Highly inhomogeneous molecular clouds interacting with SNR

TOWARD UNDERSTANDING THE YOUN

❖ Higher energy protons can penetrate into the cloud core wheretarget gas density is highwind bubble
primary shock

wind shell

ISM

synchrotron
radiation

eddy generation/
B amplification

short-time variabilityof X-rays
exploded starreflected shock

hadronic γ-rays
Inoue et al. (2011)
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dense clump/core

shocked clump/core
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Correlation with Matter Density✤ Sum of molecular and atomic hydrogen gives good correlation

with TeV gamma-ray intensity

Fukui et al. arXiv 1107.0508v4
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Young SNR Cassiopeia A✤ Last SNR witnessed by human (AD 1680)✤ Both leptonic and hadronic interpretation possible❖ Leptonic (Bremsstrahlung + IC)• B ~ 0.12 mG, We ~ 1x1049 erg• Not consistent with X-ray variability (B ~ 0.5 mG)❖ Hadronic (π0 decay)• B > 0.12 mG, Wp ~ 5x1049 erg
Leptonic model

Hadronic model I=2.4, no break
I=2.1, Ebreak = 10 TeV

Brems
IC

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Young SNR Cassiopeia A✤ Last SNR witnessed by human (AD 1680)✤ Both leptonic and hadronic interpretation possible❖ Leptonic (Bremsstrahlung + IC)• B ~ 0.12 mG, We ~ 1x1049 erg
B = 0.1 mG• Not consistent with X-ray variability (B ~ 0.5 mG)❖ Hadronic (π0 decay)• B > 0.12 mG, Wp~ 5x1049 erg

Leptonic model

MC simulation

B = 0.3 mG
Hadronic model I=2.4, no break
I=2.1, Ebreak = 10 TeV

B = 1.0 mG

Brems
IC

ASTRO-H SGD 100 ks observation
Uchiyama

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ASTRO-H Soft Gamma-ray Detector✤ Taking advantage of Japanese semiconductor detector technologies andspace technologies❖ Silicon sensors by Hamamatsu photonics❖ Space instrument assembly (Mitsubishi Heavy Industries)❖ Visualization of gamma-ray sources such as radio isotopes• Technology transfer to accelerate removal of Cs hotspots in Fukushima

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ASTRO-H Soft Gamma-ray Detector✤ Taking advantage of Japanese semiconductor detector technologies andspace technologies❖ Silicon sensors by Hamamatsu photonics❖ Space instrument assembly (Mitsubishi Heavy Industries)❖ Visualization of gamma-ray sources such as radio isotopes• Technology transfer to accelerate removal of Cs hotspots in Fukushima

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Fermi Observations of middle-aged SNRs

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Fermi Observations of middle-aged SNRs

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W44 Gamma-ray Image✤ Deconvolved image indicates shell-like gamma-ray emission✤ Maximum likelihood analysis prefer ring-like morphology rather

than disk-like morphology (> 8 σ)2010, Science, 327, 1103

Middle-aged (~ 2.0×104 yr)
mixed-morphology SNR(radio: shell, thermal X-ray: centrally filled)
Distance: ~ 3 kpc
No. 3, 2006

SPITZER SURVEY OF SUPERNOVA REMNANTS

1487

Cloud-shell interactions
CO (Seta et al. 2004)
OH maser (Hoffman et al. 2005)
Green: Spitzer IRAC 4.5 μm
traces shocked HIIReach et al. (2006)

Fig. 8.—Spitzer IRAC color image of W44. The SNR appears ‘‘green’’ in the IRAC colors because channel 2 is relatively much brighter in the SNR shell than in
the surrounding ISM (including both the surrounding molecular cloud and the H ii regions to the east and northeast).

in channel 3. But channel 3 is mixed with the eastern H ii regionand other ISM emission outside the remnant. The remnant isbarely noticeable in IRAC channel 4 due to confusion with unrelated emission.
G36.6!0.7.—There is a possible shell of infrared emission
bounding the SNR toward the north, as well as a dark filament in
the north and clumps in the west and southwest. There is no clear
evidence for emission from shock fronts.
3C 396 (G39.2!0.3): Infrared emission is detected from thisremnant in three forms. First, faint, filamentary emission is detected in the western radio shell of this remnant, with IRAC colors
clearly distinct from normal interstellar emission. In Figure 9(left), the western shell appears green; a cut through the westernshell near ! ¼ 19h 03m 56:s3, " ¼ þ05$ 25 0 46 00 yields IRAC colors(<0.08)/0.2/0.69/1, suggesting emission from shocked, ionizedgas.
Second, there are two very bright infrared filaments, at! ¼ 19h 04m 18:s5, " ¼ þ05$ 20 0 33 00 and ! ¼ 19h 04m 17:s0, " ¼
þ05$ 27 0 07 00 (each %3000 long), just inside the eastern radio

shell. The filaments are clearly separated from the recently
detected pulsar wind nebula (Olbert et al. 2003) and are locatedwithin a region of exceptionally high radio polarization. We
suspect that these bright filaments, which are highly unusual,are part of the SNR, which is the only known structure in the interstellar medium at that location. The color ratios of the filamentsare (<0.05)/0.03/0.4/1, at a location at which the 8 #m surface
brightness is 30 MJy sr!1. These colors are similar to normalinterstellar medium, so the filaments could be photodissociation
regions (e.g., compressed filaments that were shocked long ago,rather than active shock fronts).
Finally, there is faint, diffuse emission surrounding the entireradio shell, with some bright, extended regions just outside theeastern periphery. The ‘‘blowout tail’’ discussed by Patnaik et al.
(1990) from radio data extends eastward from the remnant andwraps north then back over the top of the remnant. In the infrared, the ‘‘tail’’ starts with a bright region at ! ¼ 19h 04m 26:s0," ¼ þ05$ 27 0 55 00 that is connected to an intricate set of infrared
filaments that follow the radio structure, with the infrared region

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W44 Gamma-ray Image✤ Deconvolved image indicates shell-like gamma-ray emission✤ Maximum likelihood analysis prefer ring-like morphology rather

than disk-like morphology (> 8 σ)

SPITZER SURVEY OF SUPERNOVA REMNANTS

1487

Spitzer IRAC 4.5 μm

30:00.0

30:00.0

Cloud-shell interactions
CO (Seta et al. 2004)
OH maser (Hoffman et al. 2005)
Green: Spitzer IRAC 4.5 μm
traces shocked HIIReach et al. (2006)

PSR B1853+01

Fig. 8.—Spitzer IRAC color image of W44. The SNR appears ‘‘green’’ in the IRAC colors because channel 2 is relatively much brighter in the SNR shell than in
the surrounding ISM (including both the surrounding molecular cloud and the H ii regions to the east and northeast).

in channel 3. But channel 3 is mixed with the eastern H ii regionand other ISM emission outside the remnant. The remnant isbarely noticeable in IRAC channel 4 due to confusion with unrelated emission.
G36.6!0.7.—There is a possible shell of infrared emission
bounding the SNR toward the north, as well as a dark filament in
the north and clumps in the west and southwest. There is no clear
evidence for emission from shock fronts.
3C 396 (G39.2!0.3): Infrared emission is detected from thisremnant in three forms. First, faint, filamentary emission is detected in the western radio shell of this remnant, with IRAC colors
clearly distinct from normal interstellar emission. In Figure 9(left), the western shell appears green; a cut through the westernshell near ! ¼ 19h 03m 56:s3, " ¼ þ05$ 25 0 46 00 yields IRAC colors(<0.08)/0.2/0.69/1, suggesting emission from shocked, ionizedgas.
Second, there are two very bright infrared filaments, at! ¼ 19h 04m 18:s5, " ¼ þ05$ 20 0 33 00 and ! ¼ 19h 04m 17:s0, " ¼
þ05$ 27 0 07 00 (each %3000 long), just inside the eastern radio

58:00.00

shell. The filaments are clearly separated from the recently
detected pulsar wind nebula (Olbert et al. 2003) and are locatedwithin a region of exceptionally high radio polarization. We
suspect that these bright filaments, which are highly unusual,are part of the SNR, which is the only known structure in the interstellar medium at that location. The color ratios of the filamentsare (<0.05)/0.03/0.4/1, at a location at which the 8 #m surface
brightness is 30 MJy sr!1. These colors are similar to normalinterstellar medium, so the filaments could be photodissociation
regions (e.g., compressed filaments that were shocked long ago,rather than active shock fronts).
Finally, there is faint, diffuse emission surrounding the entireradio shell, with some bright, extended regions just outside theeastern periphery. The ‘‘blowout tail’’ discussed by Patnaik et al.
(1990) from radio data extends eastward from the remnant andwraps north then back over the top of the remnant. In the infrared, the ‘‘tail’’ starts with a bright region at ! ¼ 19h 04m 26:s0," ¼ þ05$ 27 0 55 00 that is connected to an intricate set of infrared
filaments that follow the radio structure, with the infrared region

18:56:00.0

200

400

600

54:00.0800

2:00:00.0

mixed-morphology SNR(radio: shell, thermal X-ray: centrally filled)
Distance: ~ 3 kpc
No. 3, 2006

2010, Science, 327, 1103

2:00:00.0

Middle-aged (~ 2.0×104 yr)

1000
0[counts/deg 2 ]解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

58:00.0

18:56:00.0

54:00.0

Deconvolved Image(2–10 GeV; front)
200

400

600

800

1000

1200

1400

1600 1800[counts/deg 2 ]33/40

W44 Gamma-ray Image✤ Deconvolved image indicates shell-like gamma-ray emission✤ Maximum likelihood analysis prefer ring-like morphology rather

than disk-like morphology (> 8 σ)

SPITZER SURVEY OF SUPERNOVA REMNANTS

1487

Spitzer IRAC 4.5 μm

30:00.0

30:00.0

Cloud-shell interactions
CO (Seta et al. 2004)
OH maser (Hoffman et al. 2005)
Green: Spitzer IRAC 4.5 μm
traces shocked HIIReach et al. (2006)

PSR B1853+01

Fig. 8.—Spitzer IRAC color image of W44. The SNR appears ‘‘green’’ in the IRAC colors because channel 2 is relatively much brighter in the SNR shell than in
the surrounding ISM (including both the surrounding molecular cloud and the H ii regions to the east and northeast).

in channel 3. But channel 3 is mixed with the eastern H ii regionand other ISM emission outside the remnant. The remnant isbarely noticeable in IRAC channel 4 due to confusion with unrelated emission.
G36.6!0.7.—There is a possible shell of infrared emission
bounding the SNR toward the north, as well as a dark filament in
the north and clumps in the west and southwest. There is no clear
evidence for emission from shock fronts.
3C 396 (G39.2!0.3): Infrared emission is detected from thisremnant in three forms. First, faint, filamentary emission is detected in the western radio shell of this remnant, with IRAC colors
clearly distinct from normal interstellar emission. In Figure 9(left), the western shell appears green; a cut through the westernshell near ! ¼ 19h 03m 56:s3, " ¼ þ05$ 25 0 46 00 yields IRAC colors(<0.08)/0.2/0.69/1, suggesting emission from shocked, ionizedgas.
Second, there are two very bright infrared filaments, at! ¼ 19h 04m 18:s5, " ¼ þ05$ 20 0 33 00 and ! ¼ 19h 04m 17:s0, " ¼
þ05$ 27 0 07 00 (each %3000 long), just inside the eastern radio

58:00.00

shell. The filaments are clearly separated from the recently
detected pulsar wind nebula (Olbert et al. 2003) and are locatedwithin a region of exceptionally high radio polarization. We
suspect that these bright filaments, which are highly unusual,are part of the SNR, which is the only known structure in the interstellar medium at that location. The color ratios of the filamentsare (<0.05)/0.03/0.4/1, at a location at which the 8 #m surface
brightness is 30 MJy sr!1. These colors are similar to normalinterstellar medium, so the filaments could be photodissociation
regions (e.g., compressed filaments that were shocked long ago,rather than active shock fronts).
Finally, there is faint, diffuse emission surrounding the entireradio shell, with some bright, extended regions just outside theeastern periphery. The ‘‘blowout tail’’ discussed by Patnaik et al.
(1990) from radio data extends eastward from the remnant andwraps north then back over the top of the remnant. In the infrared, the ‘‘tail’’ starts with a bright region at ! ¼ 19h 04m 26:s0," ¼ þ05$ 27 0 55 00 that is connected to an intricate set of infrared
filaments that follow the radio structure, with the infrared region

18:56:00.0

200

400

600

54:00.0800

2:00:00.0

mixed-morphology SNR(radio: shell, thermal X-ray: centrally filled)
Distance: ~ 3 kpc
No. 3, 2006

2010, Science, 327, 1103

2:00:00.0

Middle-aged (~ 2.0×104 yr)

1000
0[counts/deg 2 ]解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

58:00.0

18:56:00.0

54:00.0

Deconvolved Image(2–10 GeV; front)
200

400

600

800

1000

1200

1400

1600 1800[counts/deg 2 ]33/40

“Smoking gun” Signature of π0-decay γ-rays✤ Compton up-scattering❖ Energetically completely disfavored (x100 higher radiation fields)❖ Shape not consistent with Compton up-scattering✤ Best-fit Bremsstrahlung model shows less steep decline❖ Even with abrupt cutoff at 300 MeV in electron spectrum❖ Mixed model requires Ne/Np = 0.01 (@ p = 1 GeV/c)

Gamma-ray flux E2 dN/dE (erg cm-2 s-1)

Gamma-ray flux E2 dN/dE (erg cm-2 s-1)

✤ Sub-GeV spectra of IC443/W44 agree well with π0-decay spectra/0 decay
Mixed model

10-10

Inverse Compton
Bremsstrahlung
Bremsstrahlung with Break

10-11

10-12

10-13
10-7

-5

10

-3

10

-1

10

10

3

10

5

10

7

10

9

10

IC443
10-10

W44

/0 decay
Mixed modelBremsstrahlung
Bremsstrahlung with Break

10-11

10-12

10-13
11-7 1210
10
10 10-5

Energy (eV)
解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

10-3

10-1

10

103

Energy (eV)

105

107

109

1011 1012

2013, Science, 339, 807

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“Smoking gun” Signature of π0-decay γ-rays✤ Compton up-scattering❖ Energetically completely disfavored (x100 higher radiation fields)❖ Shape not consistent with Compton up-scattering✤ Best-fit Bremsstrahlung model shows less steep decline❖ Even with abrupt cutoff at 300 MeV in electron spectrum❖ Mixed model requires Ne/Np = 0.01 (@ p = 1 GeV/c)✤ Sub-GeV spectra of IC443/W44 agree well with π0-decay spectra

Gamma-ray
E2 dN/dE
E2fluxdN/dE(erg (ergcm cm
s-1-2) s-1)

10-10

/0 decay
Mixed model

10-10

Bremsstrahlung with Break

10-11
-11
10

2

Best-fit broken power law
Fermi-LAT
VERITAS (Acciari et al. 2009)
MAGIC (Albert et al. 2008)
AGILE (Tavani et al. 2010)/0-decay
Bremsstrahlung
Bremsstrahlung with Break

-12

10

10-12

10-13
10-7

-5

10

8

-3

10 10

-1

9

10 10

10

3 10

1010

5

10

7 11

10
10

9

10

W44

10-10

IC443
10-10

-2

Inverse Compton
Bremsstrahlung-2

E fluxdN/dE(erg (ergcm cm
s-1-2) s-1)
Gamma-ray
E2 dN/dE

IC 443W44/0 decay
Mixed modelBremsstrahlung
Bremsstrahlung with Break

10-11
-11
10

-12

10

10-12

10-13
8
12
11-7 121010
10
10 10-5 1010-3

Energy (eV)Energy(eV)
解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

Best-fit broken power law
Fermi-LAT
AGILE (Giuliani et al. 2011)/0-decay
Bremsstrahlung
Bremsstrahlung with Break
9

10-1 10

10

10

3
1010

105

Energy (eV)Energy
(eV)

11

107
10

109

12
10
1011 1012

2013, Science, 339, 807

34/40

Cosmic-ray Proton Spectrum✤ s1 = 2.36±0.05, s2 = 3.1±0.1 (3.5±0.1) pbr =239±74 (22±8) GeV/c(for IC 443)
❖ Below the break: proton spectrum softer than electron spectrum(s1,e = 1.72)

W44
10-9

1049

s1

p

IC 443

p

s2
1048

10-10

1047
10-11

Fitted /0 decay model

1046

Derived Proton spectrum

10-12

VERITAS (Acciari et al. 2009)
MAGIC (Albert et al. 2008)

108

109

1010

Energy (eV)
解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

1011

Proton Spectrum E2 dN/dE (erg)Gamma-ray flux E2 dN/dE (erg cm-2 s-1)

✤ CR efficiency 1-4%. Strongly depends on assumed density1012
2013, Science, 339, 807

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Cosmic-ray Escape from W44✤ Large-scale GeV emission was found in the vicinity of W44

count map 2-100 GeV

residual map (W44 subtracted)

SRC-1/2: TS = 75/102

Subtraction of W44
Gamma-rays from W44 itself are subtracted,
assuming “radio map = gamma-ray map”
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Uchiyama et al. (2012)36/40

Large-scale GeV γ-rays vs CO map✤ W44 is known to be surrounded by a complex of molecular

clouds (CO)✤ Size ~100 pc, Mass ~106 M(Dame+1986)✤ Amount of CRs escapedFγ ≈ ρISM x ρCR❖ Wesc = (0.3 – 3)×1050 erg

depending on diffusion
coefficient
SNR W44
CO: contours

MC complex is illuminatedby a “CR halo” around W44

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Gamma-ray Evidence for Leaking CRs(c) M. Malkov (2012)

π0-decay γ-ray(and bremsstrahlung)
After leaving SNR W44, CRs diffuse along theexternal B-field direction ➜ bipolar morphology
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Future Gamma-ray Observatory✤ Cherenkov Telescope Array❖ Large number of telescopes• Large collection area (x~30)• Better angular resolution (0.03°, x~1/3)❖ Optimized telescope configuration• LST: ~23 m ϕ x 4, ~30 GeV – 1 TeV• MST: ~12 m ϕ x 20, ~100 GeV – 10 TeV• SST: 4~6 m ϕ x 40~70, ~1 TeV – 100 TeV❖ ~1000 of TeV gamma-ray sources

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Future Prospect✤ CTA will be x10 more sensitive with x3 better angular resolution❖ finer morphological comparison with X-ray (e) and interstellar gas❖ detect more RX J1713-like SNRs in entire Galaxy✤ CTA can be sensitive

up to >100 TeV❖ corresponding to CR spectrain “knee” region❖ Gamma-ray spectra
beyond Klein-Nishina regimeof Compton up-scattering✤ Explore extragalactic

CR sources❖ Active galactic nuclei❖ Gamma-ray bursts• 10,000x more sensitive thanFermi at ~30 GeV
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Supplemental Slides

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

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Fermi/LAT Collaboration
Stanford University & SLAC
NASA Goddard Space Flight Center
Naval Research Laboratory
University of California at Santa Cruz
~400 Scientific
Sonoma State University
Members (including
University of Washington
Purdue Univeristy-Calumet
96 Affiliated Scientists,
Ohio State University
plus 68 Postdocs andUniversity of Denver
105 Students)
Commissariat a l’Energie Atomique, Saclay
CNRS/IN2P3 (CENBG-Bordeaux, LLR-Ecolepolytechnique, LPTA-Montpellier)
Hiroshima University
Institute of Space and Astronautical Science
Tokyo Institute of Technology
RIKEN
Instituto Nazionale di Fisica Nucleare
Agenzia Spaziale Italiana
Istituto di Astrofisica Spaziale e Fisica Cosmica
Royal Institute of Technology, Stockholm
Stockholms Universitet
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Particle Background Environment✤ TKR trigger rate is monitored throughout South Atlantic Anomaly❖ Trigger rate saturates above ~3.7 kHz/layer

launch site

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Event Rates
Trigger rateü Overall trigger rate: ~1–4 kHzü Huge variations due to orbital
effects.

Downlink rate

Gamma-ray selectionü Downlink rate: ~0.3–0.7 kHzü ~90% from GAMMA filterü ~30 Hz from minimum bias filterü ~5 Hz from heavy ion filterü Rate of photons after the standard
background rejection cuts for source
study: ~1 Hz
ü Most of the downlinked events are infact background, final ~ 1000:1 rejection
is done in ground processing.

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JAXA ASTRO-H✤ History of Japanese X-ray satellite

1970

1980

1990

2000

2010

2020

Hakucho
Tenma
Ginga
ASCA
ASTRO-E (launch vehicle failure)
SuzakuASTRO-H??

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

Credit: ISAS/JAXA

45/40

JAXA ASTRO-H✤ History of Japanese X-ray satellite

1970

1980

1990

2000

2010

2020

Hakucho
Tenma
Ginga
ASCA
ASTRO-E (launch vehicle failure)
Soft Gamma-ray Detector
SuzakuASTRO-H??

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

Credit: ISAS/JAXA

45/40

Fermi Science Support Center✤ Fermi data have been public since 2009 August❖ data access: http://fermi.gsfc.nasa.gov/ssc/data/access/❖ analysis tool: http://fermi.gsfc.nasa.gov/ssc/data/analysis/

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Fermi Science Support Center✤ Fermi data have been public since 2009 August❖ data access: http://fermi.gsfc.nasa.gov/ssc/data/access/❖ analysis tool: http://fermi.gsfc.nasa.gov/ssc/data/analysis/

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Pion-decay cutoff in SNRs
✤ IC 443 and W44: two “brightest” SNRs in the Fermi-LAT range❖ 2FGL: IC 443: 132σ, W44: 57σ, W51C: 50σ, W28: 49σ❖ Energy range: 60 MeV - 2 GeV (energy range of main interest)
250
12

200

8
6

Galactic Latitude (deg)

8

150

4

IC443
4

100

0

Geminga

W44

IC 443

0

W44

-4

-4

Crab
196

192

188

184

50

-8
180

44

Galactic Longitude (deg)
解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

40

36

32

28
20

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W44 Spectrum✤ Simple power-law function is rejected with 14σ✤ π0-decay dominant model is most natural explanation✤ Electron bremsstrahlung cannot completely be ruled out❖ Brems: amount of electrons should be comparable to protons❖ Inverse Compton: We ~ 1051 erg or quite intense photon field needed✤ Protons need to have a spectral break at ~ 10 GeV/c❖ Fast escape of high energy

Γ1 ~ 2

particles with damping ofmagnetic turbulence dueto the dense environment(Ptuskin & Zirakashvili 2003)

WhippleΓ2 ~ 3

HEGRA
Milagro+ statistical error+ systematic error

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SNR W51C✤ Another Fermi-LAT SNR interacting with molecular clouds❖ Middle age: 3×104 yr,

Distance: 6 kpc✤ Most luminous gamma-ray source: L = 1036 (D/6 kpc)2 erg s–1✤ Spectral steepening similar to the W44 spectrum

π0-decay model can reasonably explain the data
❖ Leptonic scenarios have similar difficulties as W44❖

Contours: ROSAT X-ray(Koo et al. 1995)

π0-decay dominant model
π0-decay

Abdo et al.
(ApJ 706L 1A 2009)

shocked CO clumps(Koo & Moon 1997)
HII regions(Carpenter & Sanders 1998)
CXO J192318.5+143035(PWN?)(Koo et al. 2005)

PSF

Bremsstrahlung
H.E.S.S.
Inverse Compton

Smoothed Count Map(2–10 GeV; front)

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SNR IC443✤ SNR interacting with molecular clouds❖ Middle age: (3~30)×104 yr,

Distance: 1.5 kpc✤ IC 443 is an extended source against a point-source at >17σsignificance in the LAT band
✤ π0-decay dominant model is most natural explanation❖ Proton spectral break at ~ 70 GeV/c

π0-decay

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Fermi Observations of Middle-Aged SNR✤ Common feature of middle-aged SNRs observed by Fermi❖ Interacting with molecular clouds❖ Spectrum steepening between GeV and TeV✤ SNR observed by Fermi may give new clues on❖ Effect on cosmic ray acceleration from interacting molecular clouds✤ Ensemble of SNRs with different cutoff may explain cosmic-ray

spectral index of ~2.7

W28 Field❖ Shock acceleration @ ~2.0
❖ Softening of spectral index

by propagation effect is not
sufficient to describe differences❖ Note: #(middle aged SNRs)>> #(young SNR)

Preliminary

W44
HESS J1801−233

IC443
W51CA

B

C

HESS J1801−233
Smoothed Count Map(2–10 GeV)
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51/40

Implications of LAT-Detected SNRs
✤ Common features of LAT-detected SNRs (except for Cas A)❖ Radio-bright• Flat radio spectrum (α = 0.3 – 0.4) for W51C,W44, W28, IC 443• Radio-GeV correlation❖ Interacting with

Radio (1 GHz) vs LAT (1-100 GeV)

molecular clouds❖ Break in GeV region

Uchiyama

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Models for SNRs with Molecular Could✤ “Aharonian-type” model❖ CRs escaping from SNR and colliding with nearby MCs❖ Does not explain radio-GeV correlationγ

Molecular
Cloud

Runaway CRs
SNR
blastwave✤ Our model (Uchiyama, Blandford, Funk, Tanaka, HT, 10)❖ γ-ray coming from “cloud shock”• CRs and MC simultaneously compressed

SNR
blastwave
解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

cloud shock

radio & γ

Compressed CRs
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“Prediction” for W44✤ Re-acceleration of the pre-existing Galactic CRs results in❖ Flat radio index (α=0.37) & correlation between radio & γ-ray fluxes
Blandford & Cowie (1982)✤ GeV break as a result of Alfvén wave evanescence (damping)(Malkov+2010)❖ Spectral steepening by one power at cpbr =2eBVA/νi-n✤ Three free parameters for pre-shock cloud conditions❖ Density❖ Filling factor❖ Magnetic field

Radio

γ-ray

Uchiyama+10

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Comparison with Model Predictions✤ Inverse Compton❖ Energetically completely disfavored (x100 higher radiation fields)❖ Shape not consistent with IC✤ Best-fit Bremsstrahlung model shows less steep decline❖ Even with abrupt cutoff at 300 MeV in electron spectrum❖ Mixed model requires Kep= 0.01 (@ p = 1 GeV/c)✤ Sub-GeV spectra of IC443/W44 agree well with π0-decay spectra

IC443

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

W44

55/40

Comparison with Model Predictions✤ Inverse Compton❖ Energetically completely disfavored (x100 higher radiation fields)❖ Shape not consistent with IC✤ Best-fit Bremsstrahlung model shows less steep decline❖ Even with abrupt cutoff at 300 MeV in electron spectrum❖ Mixed model requires Kep= 0.01 (@ p = 1 GeV/c)

Gamma-ray flux E2 dN/dE (erg cm-2 s-1)

✤ Sub-GeV spectra of IC443/W44 agree well with π0-decay spectra

IC443

W44

/0 decay

10-10

Mixed modelBremsstrahlung
Bremsstrahlung with Break

10-11

10-12

10-13
10-7

10-5

10-3

10-1

10

103

105

107

109

1011 1012

Energy (eV)
解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

55/40

Comparison with Model Predictions✤ Inverse Compton❖ Energetically completely disfavored (x100 higher radiation fields)❖ Shape not consistent with IC✤ Best-fit Bremsstrahlung model shows less steep decline❖ Even with abrupt cutoff at 300 MeV in electron spectrum❖ Mixed model requires Kep= 0.01 (@ p = 1 GeV/c)

Gamma-ray flux E2 dN/dE (erg cm-2 s-1)

Gamma-ray flux E2 dN/dE (erg cm-2 s-1)

✤ Sub-GeV spectra of IC443/W44 agree well with π0-decay spectra/0 decay
Mixed model

10-10

Inverse Compton
Bremsstrahlung
Bremsstrahlung with Break

10-11

10-12

10-13
10-7

10-5

10-3

10-1

10

103

105

107

109

IC443
10-10

W44

/0 decay
Mixed modelBremsstrahlung
Bremsstrahlung with Break

10-11

10-12

10-13
11-7 1210
10
10 10-5

Energy (eV)
解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

10-3

10-1

10

103

105

107

109

1011 1012

Energy (eV)55/40

Amount of CRs Escaped from W44✤ Solving the diffusion equation in the vicinity of W44, we canestimate the energy spectrum of escaping CRs❖ Uniform molecular clouds illuminated by escaping CRs (within r<L)

• L ~100 pc, Mass = 0.5×105 M❖

Diffusion coefficient of the interstellar medium (isotropic)• D(p) = D28 (cp/10 GeV)0.6 1028 cm2 /s❖ Case 1: slow diffusion (D28 = 0.1)

• Nesc(E) = k E-2.6• Wesc = 0.3×1050 erg❖ Case 2: D28 = 1• Nesc(E) = k E-2.0• Wesc = 1.1×1050 erg❖ Case 3: fast diffusion (D28 = 3)

• Nesc(E) = k E-2.0• Wesc = 2.7×1050 erg

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

Surroundings

56/40

SNR W28

W28 Field

Preliminary

HESS J1801−233

A

B

C

HESS J1801−233
Smoothed Count Map(2–10 GeV)
解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

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SNR W28

W28 Field

Preliminary

HESS J1801−233

A

B

C

HESS J1801−233
Smoothed Count Map(2–10 GeV)
解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

57/40

Declination (J2000)

SNR W28W28–23:00:00

W28 Field

Preliminary

G6.5-0.4
HESS J1801−233
G5.71-0.08–24:00:00

A

18:04:00

B

C— RadioHESS J1801−233— Fermi 18:00:00

Smoothed Count Right
Map Ascension (J2000)(2–10 GeV)
0.1
解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

0.2

0.3

0.4

0.5

0.6

0.7

57/40

Declination (J2000)

SNR W28W28–23:00:00

W28 Field

Preliminary

G6.5-0.4
HESS J1801−233
G5.71-0.08–24:00:00

A

18:04:00

B

C—RadioCO—
HESS J1801−233—Fermi
Fermi 18:00:00—

Smoothed Count Right
Map Ascension (J2000)(2–10 GeV)
0.1
解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

0.2

0.3

0.4

0.5

0.6

0.7

57/40

Declination (J2000)

SNR W28

Source N W28–23:00:00

W28 Field

Preliminary— HESS— FermiG6.5-0.4
HESS J1801−233
HESS J1800-240

G5.71-0.08

A–24:00:00

AB

B

Source S

18:04:00

C

C—RadioCO—
HESS J1801−233—Fermi
Fermi 18:00:00—

Smoothed Count Right
Map Ascension (J2000)(2–10 GeV)
0.1
解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

0.2

0.3

0.4

0.5

0.6

0.7

57/40

(a) W28 North
Declination (J2000)

E2dF/dE (eV cm−2 s−1 )SNR W28
102

10

1

−1

10

10−1

1

10

102

3

Source N W28–23:00:00

W28 Field

Preliminary— HESS— FermiG6.5-0.4
HESS J1801−233

10Energy (GeV)

HESS J1800-240

G5.71-0.08

A–24:00:00

AB

B

Source S

18:04:00

C

C—RadioCO—
HESS J1801−233—Fermi
Fermi 18:00:00—

Smoothed Count Right
Map Ascension (J2000)(2–10 GeV)
0.1
解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

0.2

0.3

0.4

0.5

0.6

0.7

57/40

(a) W28 North
Declination (J2000)

E2dF/dE (eV cm−2 s−1 )SNR W28
102

10

1

−1

E2dF/dE (eV cm−2 s−1 )1010−1 (b) W28
1
10
South

102

102

3

Source N W28–23:00:00

W28 Field

Preliminary— HESS— FermiG6.5-0.4
HESS J1801−233

10Energy (GeV)

HESS J1800-240

G5.71-0.08

A–24:00:00

10

AB

B

Source S

1

18:04:00

C—RadioCO—
HESS J1801−233—Fermi
Fermi 18:00:00—

Smoothed Count Right
Map Ascension (J2000)(2–10 GeV)

−1

10

10−1

C

1

10

102

3

10

0.1

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手
夏の学校,
JUL 29, 2013
Energy
(GeV)

0.2

0.3

0.4

0.5

0.6

0.7

57/40

E2dF/dE (eV cm−2 s−1 )Declination (J2000)

SNR W28

Source N W28–23:00:00

W28 Field— HESS— FermiG6.5-0.4
HESS J1801−233(b) HESS J1800−240C

HESS J1800-240

10G5.71-0.08

A–24:00:00

AB

B

Source S

1

18:04:00

C

C—RadioCO—
HESS J1801−233—Fermi
Fermi 18:00:00—

Smoothed Count Right
Map Ascension (J2000)(2–10 GeV)

−1

10

10−1

Preliminary

1

10

102

3

10

0.1

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手
夏の学校,
JUL 29, 2013
Energy
(GeV)

0.2

0.3

0.4

0.5

0.6

0.7

57/40

E2dF/dE (eV cm−2 s−1 )SNR W28
Declination (J2000)(a) HESS J1800−240A
10

1E2dF/dE (eV cm−2 s−1 )

10−1
10−1

1

10

102

Source N W28–23:00:00

W28 Field— HESS
3
10 — Fermi

G6.5-0.4
HESS J1801−233

Energy (GeV)(b) HESS J1800−240C

HESS J1800-240

10G5.71-0.08

A–24:00:00

AB

B

Source S

1

18:04:00

C

C—RadioCO—
HESS J1801−233—Fermi
Fermi 18:00:00—

Smoothed Count Right
Map Ascension (J2000)(2–10 GeV)

−1

10

10−1

Preliminary

1

10

102

3

10

0.1

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手
夏の学校,
JUL 29, 2013
Energy
(GeV)

0.2

0.3

0.4

0.5

0.6

0.7

57/40

Declination (J2000)

SNR W28

Source N W28–23:00:00

W28 Field

Preliminary— HESS— FermiG6.5-0.4
HESS J1801−233
HESS J1800-240

G5.71-0.08

A–24:00:00

AB

B

Source S

18:04:00

C

C—RadioCO—
HESS J1801−233—Fermi
Fermi 18:00:00—

Smoothed Count Right
Map Ascension (J2000)(2–10 GeV)
0.1
解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

0.2

0.3

0.4

0.5

0.6

0.7

57/40

Declination (J2000)

SNR W28

Source N W28–23:00:00

W28 Field

Preliminary— HESS— FermiG6.5-0.4
HESS J1801−233
HESS J1800-240

G5.71-0.08

A–24:00:00

AB

B

Source S

18:04:00

C

C—RadioCO—
HESS J1801−233—Fermi
Fermi 18:00:00—

Smoothed Count Right
Map Ascension (J2000)(2–10 GeV)
0.1
解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

0.2

0.3

0.4

0.5

0.6

0.7

57/40

Declination (J2000)

SNR W28

Source N W28–23:00:00

W28 Field

Preliminary— HESS— FermiG6.5-0.4
HESS J1801−233
HESS J1800-240

G5.71-0.08

A–24:00:00

AB

B

Source S

18:04:00

C

C—RadioCO—
HESS J1801−233—Fermi
Fermi 18:00:00—

Smoothed Count Right
Map Ascension (J2000)(2–10 GeV)
0.1
解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

0.2

0.3

0.4

0.5

0.6

0.7

57/40

Cosmic Particle Accelerators✤ Origin of cosmic ray protons?
❖ Galactic SNRs (Supernova Remnants) are considered as the best

candidates for cosmic-rays below “Knee”• Only circumstantial evidence- CR energy sum consistent
with SNR kinetic energy(Ginzburg&Syrovatskii 1964)- Diffusive shock acceleration(Blanford&Eichler 1977)• No observational evidence
for hadronic acceleration• Spectral index (~2.7) is difficult to
explain❖ Cosmic-rays above “Knee” areconsidered extragalactic• Gamma-ray bursts (GRB)• Active Galactic Nuclei (blazar)• Merging galaxy clusters
解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

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Cosmic Particle Accelerators✤ Origin of cosmic ray protons?
❖ Galactic SNRs (Supernova Remnants) are considered as the best

candidates for cosmic-rays below “Knee”• Only circumstantial evidence- CR energy sum consistent
with SNR kinetic energy(Ginzburg&Syrovatskii 1964)- Diffusive shock acceleration(Blanford&Eichler 1977)• No observational evidence
for hadronic acceleration• Spectral index (~2.7) is difficult to
explain❖ Cosmic-rays above “Knee” areconsidered extragalactic• Gamma-ray bursts (GRB)• Active Galactic Nuclei (blazar)• Merging galaxy clusters
解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

58/40

Blazars (AGN)✤ Emission mechanisms (for HE component)❖ Leptonic (IC of synchrotron or external photons) vs hadronic (π0→γγ,

proton synchrotron)✤ Emission location❖ Single zone for all wavebands?

Gamma factor ~10✤ Particle acceleration mechanisms❖ Shocks, magnetic reconnection,

turbulence acceleration✤ Jet composition❖ Poynting flux, leptonic, ions

SMBH
107-1010M◎✤ FSRQ/BLLac dichotomy✤ Jet confinement❖ External pressure, magnetic stresses✤ Accretion disk—black hole—jet connection✤ Effect of blazar emission on host galaxies and galaxy clusters✤ Blazars as probes of the extragalactic background light (EBL)

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 201359/40

Pair Creation✤ Interaction with ambient photons❖ Cross section peaks at

E1 E2 (1cos )

2(me c2 )2E2500 [eV] for E1 = 1 [GeV]

E2

0.5 [eV] for E1 = 1 [TeV]

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

60/40

Pair Creation✤ Interaction with ambient photons❖ Cross section peaks at

E1 E2 (1cos )

2(me c2 )2E2500 [eV] for E1 = 1 [GeV]

E2

0.5 [eV] for E1 = 1 [TeV]

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 201360/40

Extragalactic Background Light✤ EBL is sensitive to star formation history, dust extinction, lightabsorption and re-emission by dust
❖ Direct measurements of the IR-UV EBL are very difficult because of

foreground subtraction✤ ~TeV gamma rays are sensitive to EBL in IR to UV band

via γγ → e+e− processν Iν (nW m-2 sr -1)❖ EBL will steepen AGN/GRB spectra above > 10 GeV
102

10

1 -1
10

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

1

10

2

10

λ (μm)

61/40

Probing EBL with AGN and GRB✤ 10–100 GeV gamma rays can probe EBL in early universe❖ Information on intrinsic spectrum✤ Requires many sources at various redshifts to untangle EBL

effect and intrinsic spectra❖ Fermi has ~100 of blazars and ~10 of GRBs with redshift

τ(E,z) = 3
Model Predictions

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

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EBL - TeV Gamma-ray Crisis✤ Observed TeV spectrum is too “hard”

dN= N0 E int
dE
Intrinsic
spectrum

e

(E)

EBL
attenuation❖ Even lowest EBL still often

Krennrich et al

yields Γint < 1.5 as low as 0.5❖ Blazars at redshifts z > 0.1
have particularly hard spectra❖ Fermi observed softer spectraat ~GeV region
Abdo et al

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

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New Approach✤ Take into account secondary photons from UHE gamma rays

to explain “hard” spectra of distant blazars❖ Use Monte Carlo to track individual photons and all secondary

particles (instead of analytical parametric approaches)❖ EBL models considered in this study• “High”: based on observed luminosity functions (Stecker et al)• "Low": based on lower limits from galaxy counts• EBL models include evolution with redshift❖ Include effects from Intergalactic magnetic field (IGMF)• Only upper limits exist for IGMF
- 10-6 – 10-12 G depending on model (Dolag et al 2004)• Strong IGMF will deflect secondaries and produce halo beyond the PSF
of Fermi or Cherenkov telescopes

0.1

B
10 14 G

4

10 eV
E
16

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

Ds
1Gpc

1/2

lc
1Mpc

1/2

64/40

Spectral Fit−2 −1

E dN/dE (GeV cm s )✤ Γint = 1.75, Emax=100 TeV assumed

10−8

1ES 0229+200
Z=0.14

Fe

rm
iu

pp

−9

er

lim

it

10

2

10−10

10−11
10−1

101

102

E(GeV)

103

104

10−9

1ES 0347−121
Z=0.188

iu
pp

IGMF: 10–18 G
er
lim
it

IGMF: 10–13 G

10−10

−2 −1

Fe
rm

E dN/dE (GeV cm s )10−8

IGMF: 10–15 G−2 −1

E dN/dE (GeV cm s )

10−8

100

1ES 1101−232
Z=0.186

Fer
m

i up

−9

per

lim

it

10

2

2

10−10

10−11
10−1

0

10

1

10

2

10

E(GeV)

3

10

4

10

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

10−11
10−1

100

101

102

E(GeV)

103

104

65/40

Parameter Scan
EBL: High ; Cutoff: 20TeV

10−11
10−12

EBL: High ; Cutoff: 100TeV

10−11
10−12

Excluded by ACT data

10−13

B(G)

B(G)

10−13

Excluded by ACT data

10−14
10−15

10−14
10−15

10−16

10−16
Excluded by Fermi upper limits

−17

10

10

10−18 0.6

10−18

0.8

1

1.2

1.4

1.6

1.8

Excluded by Fermi upper limits

−17

2

0.6



1.4

1.6

1.8

2

10−13

Excluded by ACT data

B(G)

10−13

B(G)

10−12

10−14

Excluded by ACT data

10−15

10−15

10−16

10−16
Excluded byFermi upper
limits−17

1010−18 0.6

1.2

EBL: Low ; Cutoff: 100TeV

10−11

10−12

10−14

1



EBL: Low ; Cutoff: 20TeV

10−11

0.8

0.8

1

1.2

1.4

1.6

1.8

10−17
2

10−18


解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

Excluded by Fermi upper limits
0.6

0.8

1

1.2

1.4

1.6

1.8

2


66/40

Gamma rays from Cosmic-Ray Cascades✤ Proton interaction with CMB photons

p+

CMB

p + e+ + e

p + CMBN +nm +k❖ Secondary electrons up-scatter CMB photons producing VHE
gamma rays
✤ Remainder is similar to previous study

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

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Spectral Fit with CR Origin
B = 10–15 G, Emax = 1020 eV, Γint= 2, and θjet = 6°
High EBL

101

High EBL

101

101

Fermi limit

101
102

2

102

100

103 8
10

109

1010

1011

E(eV)

1012

103 8101013

Low EBL

101

109

1010

1011

E(eV)

109

1010

1011

E(eV)

1012

1013

102

100

109

Fermi limit

101

1011

E(eV)

1012

1013

1ES 1101+232

Fermi limit

100
101
102

2

102

1010

Low EBL1012

103 810101

103 8101013

E dN/dE (eV cm 2s 1 )

102

100

1ES 0347+121

E dN/dE (eV cm 2 s1 )E dN/dE (eV cm s )

101

2

2 1

Fermi limit

1012

Low EBL101
1ES 0229+200

100

Fermi limit

2Fermi limit

1ES 1101+232

E dN/dE (eV cm 2s 1 )

1ES 0347+121

E dN/dE (eV cm 2s 1 )2

E dN/dE (eV cm2s1 )1ES 0229+200
100

High EBL101

103 8
10

109

1010

1011

E(eV)

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

1012

1013

103 8
10

109

1010

1011

E(eV)

1012

1013

68/40

Summary of CR Origin Fit✤ 95% CL limit on IGMF found to be❖ 2x10-16 G < B < 3x10-14 G ("High" EBL)
❖ 1x10-17 G < B < 8x10-16 G ("Low" EBL)ℓUHECR ≈ 3x1036 egs/s/Mpc3
nBLZR ≈ 4x10–6 Mpc–3
Source1ES0229+200

1ES0347-121

1ES1101-232

Redshift
0.14

0.188

0.186

EBL model

Lp (x1043 erg/s)

χ2/D.o.F.

Low

1.3

6.4 / 7High

3.1

1.8 / 7Low

2.7

16.1 / 6

High

5.2

3.4 / 6Low

3.0

16.1 / 9

High

6.3

4.9 / 9B = 10–15 G, Emax = 1020 eV, Γint= 2, and θjet = 6°
解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

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Test of CR Origin Model✤ Secondary gamma rays with low IGMF have some testableconsequences:❖ For B > 10-15 G halos will be present around source, moresignificant for cosmic rays
❖ Recent Fermi analysis consistent
with B ~ 10-15 G✤ Gamma-ray spectrum continues

beyond Klein-Nishina regime✤ No short scale time variability for z > 0.1❖ No variability has been observed in the TeV range❖ Some variability below 200 GeV

Essey, Ando, Kusenko 2010

✤ High energy neutrino signal should accompany gamma rays
解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 2013

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CTA Membership✤ 25 countries✤ 132 Institutions✤ 734 Scientists

解き明かされた銀河系宇宙線の起源, 天文・天体物理若手 夏の学校, JUL 29, 201371/40