フェルミガンマ線宇宙望遠鏡
で見た銀河系内天体田中 孝明（京都大学）
On Behalf of the Fermi LAT Collaboration

Content• Fermi Large Area Telescope• Supernova Remnants• GeV-Bright SNRs
• TeV-Bright SNRs
• Gamma-ray Binaries• Gamma-ray Flares from Crab Nebula• SummaryFermi Large Area Telescope
Pair-production telescope launched in June, 2008
Energy Range: from 20 MeV to > 300 GeV
Angler Resolution: < 1° (68% containment at 1 GeV)
Effective Area: 8000 cm2 (on axis at 1 GeV)
Field of View: 2.4 sr (all-sky coverage in ~ 3 hr)

γ

ACD

e+

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4x4 array of
TKR towers]

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The Fermi
Large Area Telescope
CalorimeterNews
The 2012 American Physical Society's W. H. K. Panofsky Prize in Elementary Particle Physics isFermi Large Area Telescope
Pair-production telescope launched in June, 2008
Energy Range: from 20 MeV to > 300 GeV
Angler Resolution: < 1° (68% containment at 1 GeV)
Effective Area: 8000 cm2 (on axis at 1 GeV)
Field of View: 2.4 sr (all-sky coverage in ~ 3 hr)

γ

ACD

e+

[surrounds
4x4 array of
TKR towers]

Tracker

Home Mission Instrument Collaboration Institutions Publications NASA Pictures Internale–

The Fermi
Large Area Telescope
CalorimeterNews
The 2012 American Physical Society's W. H. K. Panofsky Prize in Elementary Particle Physics is

CGRO EGRET vs Fermi LAT
LAT Specifications & Performance
Quantity

LAT (Minimim Spec.)

EGRET

Energy Range

20 MeV - 300 GeV

20 MeV - 30 GeVPeak Effective Area 1> 8000 cm 2

1500 cm 2

Field of View

> 2 sr

0.5 srAngular Resolution 2< 3.5° (100 MeV)
< 0.15° (>10 GeV)

5.8° (100 MeV)

Energy Resolution 3

< 10%

10%

Deadtime per Event< 100 µs

100 ms

Source Location Determination 4< 0.5'

15'

Point Source Sensitivity 5< 6 x 10 -9 cm -2 s -1

~ 10 -7 cm -2 s -1

1 After background rejection
2 Single photon, 68% containment, on-axis
3 1-!, on-axis
4 1-! radius, flux 10 -7 cm -2 s -1 (>100 MeV), high |b|
5 > 100 MeV, at high |b|, for exposure of one-year all sky survey, photon spectral index -2

2FGL catalog contains 1873 sources (cf. 271 sources for 3EG catalog)超新星残骸

GeV-Bright SNRs

Color: Gamma Rays by Fermi LAT
Contours: Radio Continuum by VLAW44: Fermi LAT Spectrum
Red vertical bars: 1-σ statistical errors
Black vertical bars: systematic errors

WhippleHEGRA

MilagroAbdo+ 2010

Spectral break at a few GeV
π0-decay model can explain the data well
Leptonic scenarios have similar difficulties
Bremsstrahlung: difficult to fit the radio and GeV data at the same time
IC: requires large amount of electrons (~ 1051 erg)

W44: Fermi LAT Spectrum
Red vertical bars: 1-σ statistical errors
Black vertical bars: systematic errors

WhippleHEGRA

MilagroAbdo+ 2010

Proton Spectrum: Broken PL
s1 = 1.74, s2 = 3.7, Eb = 8 GeV
Wp = 6 × 1049 (n/100 cm–3)–1 (d/3 kpc)2 erg

Kep = 0.01

Similar Case: W51C
Age: 3.0 × 104 yr, Distance: 6 kpc
Abdo+ 2009

Count Map
(2–10 GeV)

π0-decay

Brems

IC

Contours: ROSAT X-ray (Koo+ 1995)
Dashed magenta ellipse: shocked CO clumps (Koo & Moon 1997)
Green crossed: HII regions (Carpenter & Sanders 1998)
Diamond: CXO J192318.5+143035 (PWN?) (Koo+ 2005)

One of the most luminous gamma-ray sources L = 1 × 1036 (D/6 kpc)2 erg s–1
Spectral steepening
π0-decay model can reasonably explain the data
Leptonic scenarios have difficulties similar to those for W44

H.E.S.S.

combinations of π 0 decay (long-dashed curve), bremsstrahlung (dashed curve),
and IC scattering (dotted curve). The sum of the three component is shown as asolid curve.

H

H

p

H

0

be expected.
Given the interaction with a molecular cloud, we first attributethe observed gamma-rays to the decay of π 0 mesons produced
in inelastic collisions between accelerated protons (and nuclei)
boundary (a flat elliptical template) as the spatial distribution ofand target gas (Figure 3). The gamma-ray spectrum of π 0 decay
the source gamma-rays. Different spatial distributions such as a
is calculated based on Kamae et al. (2006) using a scaling
flat elliptical template reduced in size (scaled by 0.5) are tested
factor of 1.85
for helium andSTUDY
heavy nuclei(Mori2009). Note
to estimate the systematic error. No.
Our1,conservative
estimate is2009
GAMMA-RAY
OF SNR
W51C
that the scaling factor assumes the local interstellar abundance!20% in 1–6 GeV and ∼30% above 6 GeV as the systematicfor target material and the observedmomentum
cosmic-ray arecomposition.
assumed to be identical f
uncertainty attributable to the unknown shape of the source.
Contributions from bremsstrahlung protons
and inverse(IC)As we argue bel
andCompton
electrons.
scattering by accelerated electrons arealso theshown
in Figure4. DISCUSSION
reflectcharacterof 3.
magnetohydrodyna
Electron–ion and electron–electron bremsstrahlung
spectraareaccount for the radio synchrotron index α
The extended gamma-ray emission positionally coincident
computed as in Baring et al. (1999).Koo
The1994),
interstellar
radiation
we adopt
s = 1.5, though awith SNR W51C has been studied using the Fermi LAT. The
field for IC (see Table 1) is comprisedoftwodilutedblackbodys = 1.7) could be reconciled with the
gamma-ray spectrum presented in Figure 3 is not fitted by acomponents (infrared and optical) andthe thecosmicmicrowave
withinuncertainty.
The energetic parti
simple power law, exhibiting a remarkable steepening. Here, webackground (CMB). The infrared andopticalcomponents
arebe uniformly distributed in the volume odiscuss the origin of the extended emission and the underlying
adjusted to reproduce the interstellar
field radiusin the R = 30 pc. T
withradiation
an effective
particle spectra that give rise to the observed spectrum of
GALPROP code (Porter et al. 2008). Cooling effects due to eff
imply a shock velocity of vsh ∼ 400 km
photons.
ionization and synchrotron (or IC) losses, 52which introduce
1.6 × 10 erg cm3 , where ESN and n0 rep
The expanding shock waves driven by the supernova explocooling breaks in particle spectra in addition to pbr , are taken
kinetic
energyanda theinterstellar density ision are expected to be the sites of the acceleration of multi-GeV
into account assuming constant particle
injection
overperiodblast wave
is propagating,particles. To phenomenologically interpret the spectral curvaT0 ∼ 3 × 104 yr. The synchrotron cooling
becomes
important respectively. The−3ture in the LAT+TeV bands, a broken power law is adopted forin the TeV band for leptonic models.n0 ∼ 0.3 cm . The radio images indicate
the momentum distribution of the radiating electrons/protons
electronsspectrum
are smoothly
distributed in a thic
Figure 4(a) shows the radio+gamma-ray
togetherof Koo& Moonwith the radiation model that uses theparametersin4(1997a)
Table 1. suggests the pres! "−s #! "2 $−∆s/2
p
p
×−310
M% engulfed
by the blast
We adopt here MH = 2.8 × 104 M%cloud(n̄H =of10∼1cm), whichisNe,p (p) = ae,p
,
(1)
1
+
Figure 4.
multiwavelength
modeling(see quoted
cloud
canTheact total
as target
somewhatlarger thanthe value
above.
energymaterial for relativ
p0
pbrThree different scenarios for the
Table 1). The radio emission (from Moon
&
Koo
1994)
is
explainedby
50hydrogen maof the high-energy protons amountstotal
to W(atomic
× 10molecular)erg,
p = 5.2 andsynchrotron
radiation,
while
the
gamma-rayemissionismodeledbydifferent
volume is denoted by M = n̄H mp V . Not
which
is inversely(dashedproportional
where p0 = 1 GeV c−1 . For simplicity,
the indicesand thebreak curve),
combinationsof π 0 decay(long-dashedbremsstrahlung
curve), to MH , but insensitive to otherH
be expected.
and IC scattering (dotted curve). The sum of the three component is shown as aGiven the interaction with a molecular clo
solid curve.
Table 1the observed gamma-rays to the decay of πParameters of Multiwavelength Models
in inelastic collisions between accelerated
boundary (a flat elliptical template) as the spatial distribution ofand target gas (Figure 3). The gamma-ray sp
the source gamma-rays. DifferentaParameters spatial distributions such asEnergetics
is calculated based on Kamae et al. (200flat elliptical
template
reducedin size B(scaled by0.5) are tested
Model
ae /ap
∆s
pbr
n̄H
Wp
We
factorof 1.85 for helium and heavy nuclei
to estimate the systematic
error.
Ourconservative
estimate
is
−1
−3
50
50
(GeV c )(µG)(cm )(10 erg)(10 erg)that the scaling factor assumes the local in!20% in0.02
1–6 GeVand ∼30%
above406 GeV as
the systematic(a) π 0 decay
1.4
15
10
5.2
0.13
for
target material and the observed cosm
uncertainty
attributable
totheunknown
shape
of
the
source.
(b) Bremsstrahlung
1.0
1.4
5
15
10
0.54
0.87
Contributions from bremsstrahlung and inv(c) Inverse Compton
1.0
2.3
20
2
0.1
8.4
11
scattering by accelerated electrons are also
4. DISCUSSION
Electron–ion and electron–electron bremss
Notes. Seed photons for IC include the CMB (kTCMB = 2.3 × 10−4 eV, UCMB = 0.26 eV cm−3 ), infraredThe
extendedgamma-rayemission
positionallycoincident
computed
as in Baring et al. (1999). The i(kTIR = 3 × 10−3 eV, UIR = 0.90 eV cm−3 ), and optical (kTopt = 0.25 eV, Uopt = 0.84 eV cm−3 ). The
total
with
SNR
W51C
has
been
studied
using
the
Fermi
LAT.
The
−1
energy content of radiating particles, We,p , is calculated for p > 10 MeV c .
field for IC (see Table 1) is comprised of tw
gamma-ray spectrum presented in Figure 3 is not fitted by acomponents (infrared and optical) and thesimple power law, exhibiting a remarkable steepening. Here, we

Similar Case: W51C

Similar Case: IC 443
Spatially extended emission detected with the Fermi LAT
Similar spectral steepening to W51C and W44

π0-decay

Gaensler+ 2006

Abdo+ 2009

Gamma-Ray Production Site

Uchiyama+ 2010

correlated withe.g. Ohira+ 2010

Emission from the Vicinity of W44
Uchiyama+ 2012
2

Y. Uchiyama

F IG . 1.— (a) Fermi LAT γ-ray count map for 2–100 GeV around SNR W44 in units of counts per pixel (0.◦ 1 × 0.◦ 1) in celestial coordinates(J2000). Gaussian smoothing with a kernel σ = 0.◦ 3 is applied to the count maps. Green contours represent a 10 GHz radio map of SNR W44(Handa et al. 1987). 2FGL sources included in the maximum likelihood model are shown as crosses, while those removed from the model are
indicated by diamonds. (b) The difference between the count map in (a) and the best-fit (maximum likelihood) model consisting of the Galactic
diffuse emission, the isotropic model, 2FGL sources (crosses), and SNR W44 represented by the radio map. Excess γ-rays in the vicinity of
W44 are referred to as SRC-1 and SRC-2.

2012), Galactic interstellar diffuse emission, and an isotropic
component (extragalactic and residual particle background).
The Galactic diffuse emission is modeled using the standard
ring-hybrid model, gal_2yearp7v6_v0.fits, with its normalization being left free. We use a tabulated spectrum written in
iso_p7v6source.txt as the isotropic diffuse emission. The

sky model. Significant excess γ-rays are seen in the vicinityof W44; the features are referred to here as SRC-1 and SRC2. The statistical significance is found to be ∼ 9σ for SRC-1
and ∼ 10σ for SRC-2.
The residual count map depends weakly on the choice of thespatial template that describes γ-rays from W44. Our simula-ld in the filaments as nm ! 7 × 103 cm−3 and Bm ! 0.8
owing the prescription in Uchiyama et al. (2010).
mplicity we describe the energy distributions of CRs and protons in the filaments as a cut-off power law
entum: ne,p (p) = ke,p p−1.74 exp(−p/pc), where the inhosen to match the radio spectral index of α ! 0.37
etti et al. 2007). The ratio of radio and γ-ray fluxes
e /k p = 0.05. The spectral break in the LAT specreproduced by pc = 10 GeV c−1 . As shown in Fig. 2,
ctrum below a few GeV is dominated by the decays
mesons produced in the dense filaments12 , while theIG . the3.— LAT
Fermispectrum
LAT residual
count map highlighting
thetheγ-ray
partFofis contributed
largely byemission from the surroundingsof density
SNR W44.
bremsstrahlung.
The energyof Magenta
the CR contours
propresent the synchrotron 2radio map of SNR
W44.
Green
contours
3
−1
−3
ounts
to u(Jp=!
4×
10 (Msh/5 × 10over
MvelocityeV
cm!)
show CO1→0) emission
integrated
from30
to, 65esc
ould
bewithexplained
reaccelerationof GalacticCRs
km s−1
respect to by
the Local
Standard of Rest
(Dame et al.
2001),
tracing the molecularcomplexcloudthat surrounds
SNR W44.
pre-existingin a cloud
molecular(Uchiyama
et al.The−1
contours start
20 Kspecify
km s withinterval ofsource
10 K km
However,
wefromdo notthe andominantofs−1 .
Some molecular
clouds notsince
associatedwith W44
are also seenalong
ay-emitting
particles,
freshly
accelerated
CRs
the Galactic plane (dashed line) in the CO map.
so enter the filaments diffusively from the intercloudm. Provided that u p corresponds to the mean CR denhe shell of the remnant,4.thetotal kinetic energy of CRs
DISCUSSION50
3−150periphery of
0.4We
× 10
/5
×
10
M
)
erg.
have (Mdiscovered
GeV
γ-ray
sources
on
the
sh
!
esc

2
Nesc (p) structures
dominated by filamentarysynchrotron−(r−Rescof)2 /R−(r+Rescradiation)2 /R2dde radio emission− e is thought ,to (2)n(p, r,t) = al.3/2(Castelletti et4π2007).
The
Rd Resc r
arise from radiatively-compressed gas behind fast dissociawhere
tive shocks driven into molecular
clouds that are engulfed by%
the blastwaveR(Reach≡al.2 2005).
DISMAssuming(p)[t − tesctypical(p)]. magnetic (3)d (p,t)et
fields of molecular clouds, the GeV γ-ray flux relative to theThediffusioncoefficienttheenoughinterstellar
mediumradio
flux is expected
to be ofhighto accountfor theisγ-often
parameterized
as SNR W44, irrespective of the origin of theray emission fromhigh-energy particles (Uchiyama& et al. 2010).'Emission from the Vicinity of W44

Kinetic energy of theescaped cosmic rays (W )can be estimatedW=(0.3–3)×10erg
SNR W44. It has long been known that a complex of giant

cloudsfrom(GMCs)
surrounds SNRofW44;
2.molecularGamma-rays
the Surroundings
W44the spatial
extent is as large as 100 pc and the total mass of the complex
CR
distributions
in6M
thesurroundings
ofSetaSNR
W44
amounts
to ∼ 1 × 10
et al. 1986;
et al.
1998).
! (DamebeIndetermined(1)emission
how CRs
intoofthe
Figure 3, the by
γ-ray
fromarethereleased
surroundings
W44
is compared
CO diffusion(J = 1 → 0)
map (Dameal. in2001)
medium,andwith(2)athecoefficientofettheintegrated overvelocityof 30
km s−1We
appropriate
r medium,
DISMa(p)(e.g.,range
Gabiciet toal.652009).
contheprotons
GMC complex.
The regionsof excessoverlap
lyforCR
since leptonic
emissionsareγ-rays
unimporwith
surrounding
GMC complex.
ane-ptheratioof ∼ 0.01.
Also, the non-detection of
The γ-ray emission in the vicinity of W44 can be ascribedtron
radiotoemission
the GMC
complexformally
possible fromimperfectionof themaps ofindicatesgas column
ctron
bremsstrahlung
is notofthe
γ-rayproduction
densities
used in the model
themain
Galactic
interstellar
diffuseδp
2 −1
DISM (p) = 10 D28
cm
s ,
(4)
10 GeV c−1
with constants of D28 ∼ 1 and δ ∼ 0.6 based on the GCR
propagation model (Ptuskin et al. 2006). The diffusion coefficient in the close vicinity of a SNR may be different fromthe Galactic average, for example, because of Alfvén waves
generated by CRs themselves (Fujita et al. 2010). We allow
D28 to vary, but fix the index to be δ = 0.6 for simplicity.
Given that the γ-ray emission by the escaping CRs is visible against SNR W44 in the LAT image, we expect the sizeof the CR halo, RCR (p) = Rd (p,tage ) + Resc (p), is much larger
than the size of the remnant R = 12.5 pc. Since we find
RCR (100 GeV c−1 ) ! 2R for D28 = 0.1, we set D28 ≥ 0.1. Notehowever that the constraint depends on the exact choice oftage ; D28 ≥ 0.05 is obtained for tage = 20, 000 yr.
To calculate the γ-ray emission from the surroundings ofW44, we also need to specify the mass distribution. The total
F IG .of4.—
the γ-rayilluminatedemission from by
the molecular
cloud CRs
mass
theModelingcloud ofcomplexthe runaway
complex that surrounds W44. Data points
are from Fig. 2, but SRC5
is 1estimated
as
M
∼
5
×
10
M
by adding
sixwithmolecMC! spectrum
and SRC-2 are co-added.
The SRC-1+2(red uppointsular
clouds(Clouds
1–6) inSeta
et al. γ-rays(1998).
mass isstatisticalerrors)is attributable
to theπ 0 -decay
from Thethe cloudcomplex illuminatedby the CRs
that have escaped(blueof theassumedto be uniformly
distributed
withinfrom
theW44
radiuscurves). Threecasescomplex,of diffuse coefficient,
D28pc.
= 0.1,Given
1, 3, are theshown.
molecular
cloud
RMC = 50
spheriA gray curve indicates the γ-ray spectrum produced by the sea of
calGCRs
symmetryof the model, we combine the γ-ray spectra ofin the same CR-illuminated clouds.
SRC-1 and SRC-2.
Uchiyama+
2012
Effectively,model has filaments
three adjustableparameters,
D28 ,The dense ourradio-emitting
are indeed
the most
28

TeV-Bright SNRs
H.E.S.S. Images

RX J1713.7−3946
The Fermi LAT collaboration recently published the results (Abdo+ 2011)
Spatially extended source at the location of the SNR
The extent determined by a maximum likelihood fit is consistent with that of the
SNR observed in other wavelengths– 19 –

Fermi LAT count maps (> 3 GeV)

1FGL J1714.5-3830c
Source B

1FGL J1716.9-3830c

400
Source C
Source A
1FGL J1705.5-4034c
1FGL J1707.9-4110c
1FGL J1702.4-4147c
1FGL J1707.1-4158c

262.0

300

100

1FGL J1716.9-3830c

c)

200

1FGL J1714.5-3830c

200
150
100

Source B

Source C

50
0

Source A
1FGL J1705.5-4034c

262.0

Before background subtraction
1FGL J1717.9-3729c

1FGL J1718.2-3825

200

260.0
258.0
256.0
Right Ascension (J2000, deg)

1FGL J1720.7-3707c

.0

500

1FGL J1717.9-3729c-42.0

1FGL J1718.2-3825b)

600
Declination (deg)
-40.0
-38.0

a)

1FGL J1720.7-3707c

1FGL J1717.9-3729c-42.0

Declination (deg)
-40.0
-38.0

1FGL J1720.7-3707c-50

1FGL J1707.9-4110c
1FGL J1702.4-4147c-100

1FGL J1707.1-4158c

-150

260.0
258.0
256.0
Right Ascension (J2000, deg)

-200

After background (contributions from diffuse
backgrounds + other sources) subtraction

RX J1713.7−3946
Fermi LAT spectrum: Very hard with Γ = 1.5 ± 0.1 (stat) ± 0.1 (sys)Leptonic Models

Hadronic Models

The Fermi LAT + H.E.S.S. spectrum can be fit well with leptonic models
How to reconcile with the large magnetic field?
If interpreted with hadronic models, extremely efficient particle acceleration is required to fit the data
(proton index must be sp ~ 1.5 to fit the Fermi LAT spectrum)RX J0852.0−4622
Fermi LAT count maps

0.6

(b)

(a)
0.8

0.6
-46.0
0.4

-44.0

Dec [deg]-44.0

Dec [deg]

Tanaka+ 2011> 10 GeV> 1 GeV

0.5

0.4
-46.0
0.3

0.2
-48.0

-48.0
0.2

0.1

138.0

136.0

134.0

132.0

RA [deg]

130.0

128.0

0

138.0

136.0

134.0

132.0

130.0

128.0

0

RA [deg]

H.E.S.S. contours

Spatially extended source at the location of the SNR RX J0852.0–4622
The emission clearly detected in the high energy region (Hereafter we show results with events > 5 GeV)
Using a uniform disk as a spatial template, we obtain a radius of 1.12 (+0.07, –0.06) deg,
which is consistent with the extent observed in radio, X-rays, and TeV gamma rays

Modelsp

p0p[TeV c−1 ]Hadronic
Leptonic

1.8
—

50
—

(1.7 ± 0.2 ± 0.4) × 10−1186.1−11(2.8 ± 0.4 ± 0.6) × 10
102.4
−11
p
B
n
0e± 0.8 ± 0.6) × 10
(2.9
40.9
−1
−3
c and] second[µG][cm statis]
Note. —[TeV
The first
errors denotetical and systematic errors, respectively.
8.49
35.3
se147

Wp
[erg]

We
[erg]

5.2 × 1050—

3.9 × 1046
1.1 × 1048

RX J0852.0−4622
1.8
2.15

10
25

100
12

0.1
0.1

Table 2
Parameters
for the Models
Note. — Wp and We are total kinetic energyof particles
integrated above 10 MeV.
Model

sp

p0p
[TeV c−1 ]sep0e[TeV c−1 ]

B
[µG]

n
[cm−3 ]

Wp
[erg]

We
[erg]

Hadronic
Leptonic

1.8
—

50
—

1.8
2.15

10
25

100
12

0.1
0.1

5.2 × 1050—

3.9 × 1046
1.1 × 1048

Note. — Wp and We are total kinetic energy of particles integrated above 10 MeV.
sync

Tanaka+ 2011

π0 decays

IC

sync
IC

Figure 2.

Fermi LAT spectral energy distribution (SED) in 1–

AT300spectralenergy(SED)
in 1–
GeV with the
H.E.S.S. distribution
SED by Aharonian
et al. (2007b)
plottedFigure 3. Broadband SED of RX J0852.0−4622 with (a) the hadronic
together.SED
For theLAT points,
the (2007b)
vertical redplottedlines and the.E.S.S.
byFermiAharonian
et al.
model 3.
andBroadband(b) the leptonic
model.
The J0852.0−4622
radio data points arein- (a) the hadronic
blackLAT
caps represent
statisticaland systematic
errors,respectively.
Figure
SED
of
RX
with
ermi
points,thevertical
red
lines
and
the
tegrated fluxes of the SNR determined based on the 64-m Parkes
The dotted line indicates the best-fit power law obtained from themodel
and yields(b)datathebyΓleptonic
TheTheradio
data
points are int maximum
statisticaland Power-law
systematic
errors,respectively.
fit
toGeV
theband.
Fermi
LAT spectrum= 1.85± 0.05(stat)± blue0.17
radio telescope
Duncan& model.
Green(2000).
line(sys)
likelihood
fit for the entire
1–300
The buttershows thefluxes
X-ray flux
by Aharonianal. (2007b),
who
an-the 64-m
fly shapeshows
the 68%
confidence
region.
The dashedcurveis thetegrated
ofestimatedthe SNR
determined
based
on0.1
50 et
–3) Parkes
icatesthe
best-fit
powerlaw
obtained
from
the
The
hadronicmodel
requiresalarge
amountofprotons
(5
×
10
erg
for
n
=
cm
0
alyzed
ASCA
data.
The
solid,
dashed,anddot-dashedcurvesrepreπ -decay
spectrumby 1–300
BerezhkoGeV
et al. (2009).
radio
telescopefrom
data
The blue line
d fit
for theentireband. The butter0 by Duncan & Green (2000).
sent
contributionsπdecays,inverseComptonscattering,andHow to reconcile
theweakmagnetic
fieldshows
with
X-ray
filaments
inThe
the
case
of
the
leptonic
model
the
X-ray
flux
estimatedby
Aharonianetal.
(2007b),who an68%
confidence
region.
Thedashedcurve
isthesynchrotron
radiation,
respectively.
parameters
adoptedfortheton scattering, we considered the CMB as well as the interstelmodel calculation
are summarizedin Table
2.
ASCA data.
The solid,
dashed,and dot-dashed curves repreradiation field
in infraredbylarBerezhko
et al.
(2009).and optical bands. The spectrum alyzed

ガンマ線連星

Gamma-ray Binaries
Gamma-ray emitting X-ray binaries
First discovered by air Cherenkov telescopes
LS 5039

Aharonian+ (2005)

O star + ?
H.E.S.S. detected
Periodicity (3.9 days)

LS I +61° 303

Albert+ (2005)

Be star + ?
MAGIC & VERITAS detected
Periodicity (26.5 days)

Possible Scenarios
Mirabel (2006)

Particles accelerated at a jet from the compact object
orat a shock generated by interaction between stellar wind and pulsar windLS 5039 in X and TeV
Folded Lightcurves

Suzaku XIS
X-ray

HESS
TeV Gamma

Aharonian+ 2006, Takahashi+ 2007

Geometry of LS 5039
= 0.058
外合 (Superior Conjunction)

逆コンプトン散乱の確率：大ガンマ線吸収の確率：大

電子

= 0.0
近星点 (Periastron)

ガンマ線

O型星
可視・紫外光= 0.5
遠星点 (Apastron)
電子= 0.716
内合 (Inferior Conjunction)

逆コンプトン散乱の確率：小ガンマ線吸収の確率：小

ガンマ線

観測者
田中 他

天文月報よりデルでは、放射は毎周期、似たものになることが予という極めて短いタイムスケールの構造が安定しては、さらに観測を重ねることが必要であろう。

LS 5039 by Fermi LAT= 0.058
外合 (Superior Conjunction)

逆コンプトン散乱の確率：大ガンマ線吸収の確率：大

電子

= 0.0
近星点 (Periastron)

ガンマ線

O型星
可視・紫外光= 0.5
遠星点 (Apastron)
電子= 0.716
内合 (Inferior Conjunction)

逆コンプトン散乱の確率：小ガンマ線吸収の確率：小

ガンマ線

観測者

Anti-correlation between GeV and TeV flux as predicted Abdo+ (2007)

LS 5039 Gamma-ray Spectrum
E2 F(E) [ erg cm-2 s-1 ]Hadasch+ (2012)
Fermi, 30 months
H.E.S.S., SUPC, 2004/05

-10

10

H.E.S.S., INFC, 2004/05

10-11

10-12

10-13

3

10

104

5

10

6

10

107
Energy [MeV]

Cutoff energy of 2.2 GeV is too low compared to that expectedfrom γγ absorption (> 30 GeV)

1FGL J1018.6−5856
Periodic source (P = 16.6 days) found in 1FGL catalog
Follow-up observations confirmed this source is a X-ray binary

Power (photons cm−2 s−1)2

5.0×10−16−16

4.0×10

3.0×10−16

Rate (ph cm−2 s−1 ×10−7)

Ackermann+ (2012)

5.6
5.4
5.2
5.0
4.8
0.0

0.5

1.0

1.5

2.0

Phase

2.0×10−16
1.0×10−16
0.0 −3
10

10 −2

10 −1

Frequency (days−1)

10 0Radio Flux Density(mJy)

0.05 Swift XRT (0.3–10 keV)
0.04
0.03
0.02
0.01
0.00
7
6
5
4
3
2
1 ATCA 5.5 GHz & 9 GHz0
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
X−ray Count Rate(counts s−1)

X-ray & Radio Lightcurve

Orbital Phase

Suzaku observation during last summer (PI: Tanaka)

Fig. 4. X-ray (upper panel) and radio (lower panel) observations of 1FGL J1018.6 5856 foldedon the orbital period. The X-ray data are from the Swift XRT and cover the energy range 0.3 to
10 keV. For the X-ray observations the different colors indicate data taken from different 16.58
day orbital cycles. For the radio data the green diamonds indicate 9 GHz and red circles 5.5
GHz data. The radio data are from the ATCA.

1FGL J1018.6−5856

かに星雲からのガンマ線フレアFermi LAT Images

Flux > 100 MeV [ 10-7 cm-2 s-1 ]The April 2011 Flare
1

2

3 4

5

6 7 8

9

10

11

Buehler+(2012)
200~ 9 min time bins

100

55660

55662

55664

55666

MJD

55668

55670

55672

55674

✛ Synchrotron nebula brightened by a factor of ~30✛ Flux doubling time : 4–8 hours✛ No change in pulsar flux and phaseCrab SEDȷɳȯɭɈɭɳ
ԓȳɳɗɈɳ‫ܨ‬෾ɀȹɈǘȖǻ
ஈૈ೰‫ޝ‬

Spectral Evolution
102

10

3

102

3

Energy [MeV]
102

10

10

3

102

10

3

Buehler+(2012)
10

10

-9

-10

0

F [ ergs cm-2 s-1 ]

1

0

0

2

3

4

10-9

Γ = 1.26 ± 0.11
εc = 361 ± 26 MeV

10-10
5

10

10

6

10

10

7

10

10

8

10-9

Lγ ~ 1036 erg/s~ 1% of Lsd
10-10
9

10

11

Why Puzzling?
✚ Compactness
Doubling time t ~ 4-8 hours ➜ Emission region < ct ~ 3x10-4 pc(Inner ring ~ 0.1 pc)
Large luminosity (~ 1% of spindown power) from a compact region✚ Spectrum
Γ = 1.26 ± 0.11: Flare energy is carried by the highest energy
electrons εc = 361 ± 26 MeV: Appears to violate the radiation
reaction limit
synchrotron cooling time = gyroradius/c➜ Cutoff of synchrotron spectrum must be:2
εc < (9/4αF) mec = 160 MeV

Summary• Fermi LAT は順調に全天観測を進めている• いくつかの超新星残骸のスペクトルは中性パイ粒子の崩壊でうまく説明できる• 今後の低エネルギー帯域のデータ解析に期待• TeV ガンマ線源の連星系の他、新たなガンマ線連星からも GeV ガンマ線を検出• かに星雲からフレアを観測• このフレアは既存の理論では説明が困難