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ガンマ線バーストからの 高エネルギーガンマ線. (Review). K. Ioka (Osaka U.). Short review of GRBs HE g from GRB HE g from Afterglow Summary. Gamma-Ray Burst. Brightest object ~ 10 52 ergs s -1. Vela satellites (1967). Origin has been a puzzle. GRB Spectrum. Band spectrum. Non-thermal. - PowerPoint PPT Presentation
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(Review)
K. Ioka (Osaka U.)1. Short review of GRBs2. HE from GRB3. HE from Afterglow4. Summary
Gamma-Ray BurstBrightest object~ 1052 ergs s-1
Vela satellites (1967)
Origin has been a puzzle
200keV
GRB SpectrumBand spectrum
Non-thermal
200keV
Angular Distribution
Isotropic
~ 1000 events/yr
Duration
Long-softShort-hard
Long burstShort burst
Discovery of Afterglow
X-ray
Radio
Beppo-SAX (1997)
Redshift
zmax=4.5
Optical → Redshift
Summary of Observation
Luminosity
Time
GRB~ 1000 events/yrIsotropic, Inhomogeneous~ 200 keV, Non-thermal103s ~ 103s : short, long
AfterglowX-rayOpticalRadio
Redshift
>msec
Standard Model
?optically thick
→e+e
Central Engine
Internal Shock
External shock>100
ISM
Luminosity
Time
GRBAfterglow
Kinetic energy↓
Shock dissipation
Afterglow Model
reverse shockforward shock
ISM Shock emission
① Electron Fermi acceleration 2 3
int 1 , ( >10 )e e e e eU U O N
int 1B BU U O ② Magnetic field
Internal energyKinetic energy intU
⇒ Synchrotron emission
Great Success of Model
Price et al.(03)
51-54
3
10 erg
0.01 100cm0.10.01
e
B
E
n
Fitting:
,max
, , ,
, , ,
as functions of time
e B
c m a
E n
F
Synchrotron shock model
Sari,Piran&Narayan(98)
Panaitescu&Kumar(00)
Galama et al.(98)
Optical Flash
Sari&Piran(99)
Zhang et al.(03)
reverse shockforward shock
ISM Shock emission
JetJet & Relativistic beaming
1・ Relativistic beaming・ Jet
1Γ
Jet in afterglow11 ΓθΓθθ ii :sideways expansion
iθ
Energy, Event rate, Model
3 2 2 243 pE R nm c
3 8 1 2T T
Break in afterglowHarrison et al.(99)
3 8 1 8 1 8iso,520.057 dayt E n
Break time ⇒ Jet angle
Breaktime
Standard Total Energy
2 51iso 10 ergE E
Frail et al.(01)
Bloom et al.(03)
Smalldispersion
Massive Star Origin
Massive stellar collapse(Hypernova, Collapsar)
Binary NS merger
Supernova in afterglow
Bloom et al.(99)
Hjorth et al.(03)
1st example: SN1998bw-dim GRB980425
Position in host galaxyBloom,Kulkarni&Djorgovski(02)
GRB CosmologyMassive star origin High redshift GRBs⇒
Larson&Bromm(02) GRBQSO, galaxyGRBs are useful
for probing high z
Like QSOLike SNStar formationMicrolensingReionization…
Short Summary1.Cosmological (Long GRBs)2.Relativistic jet is ejected: >1003.Internal shock: GRB 4.External forward shock: Afterglow5.External reverse shock: Optical flash6.Synchrotron shock model succeeds7.Standard total energy (?)8.Massive star origin (Long GRBs)
But, …
Problems1.Fireball content: Kinetic or magnetic ?2.GRB emission mechanism: Synchro or not ?3.GRB jet structure: Uniform or not ?4.Jet acceleration: How to launch ?5.Environment: What is in front ?6.Shock parameters: Universal or not ?7.Short GRBs: What ?8.Other emissions: UHECR, HE, HE, GW ?9.GRBs & cosmology: How to use ?Etc…
GeV BurstsHurley et al.(94)
GRB940217
>10GeV photons can last for > 1hrGeV burst starts with MeV2% of total energy at 30MeV-20GeV
Earth occultation
18GeV
90min
GeV at 2.4s and 25sSpectral index –2 to GeV>MeV energy ~ <MeV one
Sommer et al.(94)
EGRET: 7GRB(100MeV<<18GeV)
Possible TeV Bursts
Atkins et al.(00)
Milagrito: Tentative (3) TeV detection in 54 bursts>50GeV fluence ~ 10×MeVbut no z
Tibet array (>10TeV): superpose 57 bursts: 6
GRAND (>10GeV): GRB971110: 2.7
Milagro (>100GeV): VHE fluence<MeV one
GRB970417a
a-ph/0311389
>MeV Tail in GRB941017
Gonzalez et al.(03)
One of 26GRBs
High energydecays moreslowly
Photon numberindex: -1 (hard)
Totani(00)
⇒ Nearby GRBs
Kneiske et al.(03)
103events/(3Gpc)3/yr~ 1event/(100Mpc)3/30yr⇒ Off-axis GRB ?
22
1IR IR, 1
0.1eV TeV
1 100 Mpce
T
m c
l n n
5GRB (z<0.5)
IR Background
Internal Shock
?optically thick
→e+e
Central Engine
Internal Shock
External shock>100
ISM
Luminosity
Time
GRBAfterglow
Kinetic energy↓
Shock dissipation
e± Pair CreationTarget photon energy
Cutoff energy
target
221TN
c t
Nphoton
~ 200keV
⇒⇒ Dim or long timescale bursts for TeV
* Scattering constraint is stronger if <mec2
TeVNtarget
target
Lithwick&Sari(01)
2 1target 2.5 TeV20 keV
1 652 2.5 21 GeVL t
Shock AccelerationTime scales
Maximum energy
① Acceleration time② Dynamical time③ Cooling time
⇒ ①Synchro ②SSC ③Proton synchro ④0 decay
2 2acc L e et r m c qB 2dynt R c t
26 1cool e T et m c B Y
20 1 2 1 2 1 2 152 2.5
14
1 220 1 4 1 4 1 4 5 2 1 252 2.5 2
10 eV
10 eV for electron
10 1 eV for proton
acc dyn e B
acc cool
e B
t t L
t t
L t Y
①
②
Vietri(95),Waxman(95)
Synchrotron
m
m max
max
∝e-p
∝e-p-1
∝e-2
∝(2-p)/2∝1/2
Electronenergyspectrum
Photonspectrum
Dim orlong burst:X-ray flash ?
3 2 1 2 1 2 2 152 2.5 2
1max 2.5
5 2 2 152 28
100 keV
10 1 GeV
10 erg cm s
m e B
m
L t
Y
F L D
Sari,Piran&Narayan(98)
F
eN
e
Synchrotron Self-Compton
Klein-Nishina:
∝1-p/2
∝1/2-p
∝1/2
2SSCe
F
SSCm SSC
KN maxSSCm
7 2 1 2 1 2 2 152 2.5 2e B L t
2 10 GeVSSCm m m
10 GeVSSCKN
max 100 TeVSSC
3 2 1 2 1 2 452 2.5 2e B L t
1 21 4 1 4 1 4 5 2 1 252 2.5 2 1e B L t Y
22SSCKN m em c
Guetta&Granot(03)
Synchrotron
SSC
SSC Luminosity
1
1syn eSSC e
syn B B B B
UU U YLYL U U U Y
1 2
if 1
if 1
e e
B B
e e
B B
Y
* For fast cooling, U ~ Usyn×ln (tdyn/tcool)1/2
(One zone)
SSC ~ Synchro
Sari&Esin(01)
Ioka(03)
Proton SynchrotronVietri(97),Totani(98)
1max, max, 2.510 1 TeVp
p ee
mY
m
m
e-synchrotronF
max, pmax,ep-synchrotron
1p
e
Y
dyn coolt t
proton injection fraction
3 2p
~ 1020eV protons emit
0 Decay0
0
,
, e
p n p
e
Waxman&Bahcall(97)Vietri(98)
15 1 2,MeV 2.50.1 10 eVp syn
N
F
1 ~ MeV ~ 1015eV
Synchrotron 0 decay
524
,MeV 2.5 2
0.2p pm
LRY Nt
GRB Spectrum
F Pair creation
MeV GeV TeV PeV
Electronsynchtrotron
SSCProtonsynchrotron
0 decay
External Shock
?optically thick
→e+e
Central Engine
Internal Shock
External shock>100
ISM
Luminosity
Time
GRBAfterglow
Kinetic energy↓
Shock dissipation
e,p-synchrotron & SSC
Zhang&Meszaros(01)
Long-dash: e-sy, short-dash: p-sy, dots: SSCTimes: trigger, 1 min, 1 hr, 1day, 1 monthE52=1, p=2.2, p=1, 0=300, z=1 flat
e=10-3, B=0.5n=100 cm-3
e=0.5, B=0.01n=1 cm-3
e=0.01, B=0.1n=1 cm-3
p-sy SSC e-sy
SSC vs p-synchrotron
Zhang&Meszaros(01)
(I’): SSC<p-syn(II’): SSC>p-synfor TeV
SSC dominatesin typical afterglow
Up ~ Ue,E52=1,n=1p=2.2,t=1hr
p-sy
SSC
,SSCc e
,SSCc e
0 Decay
Bottcher&Dermer(98)p-syn, p cascade, e+-syn, 0 decayLow energy: normalize to GRB970508 (z=0.83)E52=1, n=1 cm-3, 0=300, p=1, B=1, p=2Cascade emission decays more slowly than SSC(protons have less cooling)
E53=1,e=0.6,B=0.01,p=2.5 E52=1,e=0.6,B=0.01,p=2.5
E53=1,e=0.6,B=10-4,p=2.5 E53=1,e=0.6,B=0.01,p=2.2
f-synr-syn
solid: r-SSCdot: f-SSCdash-dot: f-IC of rdash: r-IC of f
10-100s:Reverseshockemission
Wang et al.(01)
4 IC in Early Afterglow
Off-Axis GRB
Ioka&Nakamura(01)
Fluence
Energy
-ray
X-ray
X-Ray Flash (XRF)
X-ray
-ray
Lamb et al.(03)
XRF ~ GRBexcept forsmall Epeak
& fluence
Distance Indicators
Sakamoto et al.(03)
Yonetoku et al.(03)
GRB spectrum
Energy
Peak Energy
XRF
We may selectnearby burstsquickly
SummaryIR background ⇒ Nearby bursts for TeVAfterglow is better than GRB for TeV High energy ~ Low energy
SSC, p-Synchrotron, 0 decay, etc. ⇒ Physical state, Lorentz factor, etc.
Nearby bursts ~ Off-axis ~ X-ray flash(?)Distance indicators Nearby bursts⇒