GAMMA-RAY EMISSION OF PULSARS: STATUS AND MULTI-WAVELENGTH CONTEXT · 2006-05-23 · 363rd...
Transcript of GAMMA-RAY EMISSION OF PULSARS: STATUS AND MULTI-WAVELENGTH CONTEXT · 2006-05-23 · 363rd...
363rd Heraeus-Seminar 1
GAMMA-RAY EMISSION OF PULSARS: STATUS AND MULTI-WAVELENGTH CONTEXT
Gottfried KanbachMax-Planck-Institut für extraterrestrische Physik
Garching, [email protected]
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PSR B1919+21
Pulsars are not themost prominent sourcesin radio or X-ray surveys
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GLAST simulated all-sky map (>1GeV) after ~55 days of exposure: EGRET Pulsars
Credit: M. Razzano
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Presently known pulsars
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Table of detectionsHigh-Energy Pulsars: Multiwavelength Detections
PSR P(ms)
E& /d2
rankradio opt Xlow Xhi γlow γhi
high confidence γ-ray detectionsB0531+21 (Crab) 33.4 1 P P P P P PB0833-45 (Vela) 89.3 2 P P P P P PJ0633+1746 (Geminga) 237.1 3 P? P P P ? PB1706-44 102.5 4 P ? D PB1509-58 150.7 5 P D P P PB1951+32 39.5 6 P P P PB1055-52 197.1 33 P D P P P
candidate γ-ray detectionsB0656+14 384.9 18 P P P ? ?B0355+54 156.4 36 P D ?B0631+10 287.7 53 P D ?B0144+59 196.3 120 P ?
ms -PSR γ-ray detection & candidatesJ0218+4232 2.32 43 P P PB1821-24 3.05 14 P P ?
Likely PSR - γ-ray source positional coincidenceB1046-58 123.7 8 P D D?J1105-6107 63.2 21 P D D?B1853+01 267.4 27 P D?
P = pulsed detection, P? = low significance pulsation, D = unpulsed detection
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•Maximum of Emission in the hard X- and γ-ray range
•High energy spectral cut-off
• Distinct spectralcomponents
Multi-λ Spectra of γ-ray Pulsars
(pulsed emission)
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Phase Averaged Pulsar Spectrum(Romani, 1996, ApJ 470, 469)τ = 104.5 y, B12=3, Ec=3GeV
log(ν) (Hz)
10 12 14 16 18 20 22 24
log(ν
Fν) (Jy
Hz)
26
28
30
32
34
SynchrotronThermalCurvature (full cascade)Curvature (primary)Compton Scatter
PSR spectral components (outer gap model)
radio
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Slot gap modelSlot gap model
(Arons 1983, Muslimov & Harding 2003, 2004)
|| 0E =Γ~106-7
Γ~102
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HighHigh--altitude slot gap altitude slot gap -- geometrygeometry
(Dyks & Rudak 2003, Dyks et al. 2004)
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High-Energy ParticlesRelativistic e+-e- plasma
Collective processes: oscillations, bunching, beam/plasma
coherent emission
Single particles in B- & E- & photon-fields
incoherent emissionsynch, CR, ICS
radio opt, X, γ
thermal:kT ~ keV106-107 K
neutronstar
?
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Gamma-Ray Details…
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Each ‚Goldreich-Julian‘ particle releases ~ 15 ergs of γ-luminosity,
( e.g. in GeV photons this implies 6x103 photons/G-J particle)
If the accelerator provides particles of Lorentz factor ~ 107 (~10 erg) this implies a radiation efficiency of ~ 100%!
Luminosity
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Spectral Hardness
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Pulse Components Crab and Geminga
Phase
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
even
ts
-40
-20
0
20
40
60
80
100
120
140
160
Phase
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
even
ts
-20
-10
0
10
20
30
40
Phase
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
even
ts
-20
0
20
40
60
80
Phase
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
even
ts
-20
0
20
40
60
80
100
Phase
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
even
ts
-5
0
5
10
15
20
25
30
Phase
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
even
ts
0
5
Crab, PSR B0531+21
> 100 MeV
30-70 MeV
70-150 MeV
150-500 MeV
500-2000 MeV
2-10 GeV
Phase
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
even
ts
-20
0
20
40
60
80
100
Phase
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
even
ts
-15
-10
-5
0
5
10
15
20
Phase
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
even
ts-20
-10
0
10
20
30
40
Phase
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
even
ts
-10
0
10
20
30
40
Phase
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
even
ts
-5
0
5
10
15
20
25
30
Phase
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
even
ts
0
5
PSR B0633+17 Geminga
> 100 MeV
30-70 MeV
70-150 MeV
150-500 MeV
500-2000 MeV
2-10 GeV
Fits with 2 asymmetricLorentzian peaksP1, P2
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Spectra of Components in Crab and Geminga
PSR B0633+17 Geminga: Relative Intensity of Pulse Components
Energy (MeV)10 100 1000 10000
% o
f tot
al In
tens
ity
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
P1
P2
PSR B0531+21 (Crab): Relative Intensity of Pulse Components
Energy (MeV)10 100 1000 10000
% o
f tot
al In
tens
ity
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
P1
P2
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Pulse Components Vela
Phase
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
even
ts
-20
-10
0
10
20
30
40
50
30-70 MeV
Phase
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
even
ts
-20
0
20
40
60
80
100
120
Phase
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
even
ts
-20
0
20
40
60
80
100
120
140
160
150 - 500 MeV
Phase
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
even
ts
-10
0
10
20
30
40
50
60
70
500-2000 MeV
Phase
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
even
ts
-2
0
2
4
6
8
10
12
14
16
18
2 - 10 GeV
VELA, PSR B0833-45
Phase
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
even
ts
-50
0
50
100
150
200
250
300
> 100 MeV
70-150 MeV
Empirical Fit with 2 asymmetricLorentzian peaks and a log-normal distribution: P1, P2, IP
PSR B0833-45: relative Intensity of Pulse Components
Energy (MeV)10 100 1000 10000
% o
f tot
al In
tens
ity
0.0
0.1
0.2
0.3
0.4
0.5
0.6
IP
P2
P1
V e la P 1 ,P 2 p h a s e d is ta n c e
E n e r g y ( M e V )
1 0 1 0 0 1 0 0 0 1 0 0 0 0
Pea
k P
hase
Sep
arat
ion
P1 -
P2
0 .4 0
0 .4 1
0 .4 2
0 .4 3
0 .4 4
0 .4 5
0 .4 6
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Peak separation VelaFit (30-10000 MeV): Δφ = 0.449 – 7.19x10-3 log(EMeV)
highenergy
lowenergy
Vela P1,P 2 phase distance
Energy (MeV)
10 100 1000 10000
Pea
k P
hase
Sep
arat
ion
P1
- P
2
0.40
0.41
0.42
0.43
0.44
0.45
0.46
2000, MNRAS, 319, 477
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Population Synthesis of observable γ-ray pulsars
(Sim)(Sim)
(Sim)loud: 7quiet:1
loud: 15-19quiet:7-10
loud: 37quiet:13
loud: 344quiet:276
(Gonthier et al., 2004)
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Phase Averaged Pulsar Spectrum(Romani, 1996, ApJ 470, 469)τ = 104.5 y, B12=3, Ec=3GeV
log(ν) (Hz)
10 12 14 16 18 20 22 24
log(ν
Fν) (Jy
Hz)
26
28
30
32
34
SynchrotronThermalCurvature (full cascade)Curvature (primary)Compton Scatter
Pulsars in the optical range
radio
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Shearer, 1999
3 4 5 6
25
30
35
log(
corre
cted
opt
ical
lum
inos
ity) e
rg/s
Log(magnetic field at l.c.) Gauss
0656+14
Geminga
Vela
0540-69
Crab
Optical Emission
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Shibanov, et al.,, astro-ph/0511311
Observations with the SUBARU telescope
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Shibanov, et al.,, astro-ph/0511311
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OPTIMA fibers on the Crab
One fiber: 2’’
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Nebula Polarization (OPTIMA)
Polarizationclose to pulsar:degree: 8-13%angle ~ 140°(Schmidt&Angel, 79)
8% ; 139°
6% ; 145°
8% ; 145°6% ; 144°
7% ; 138°
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Shearer, 2002
The Crab is visible at all phases
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single rotation variability studies
Crab single rotation and summed lightcurve
continuousemission
bridge
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Crab Polarization (OPTIMA)
Measure lightcurves for different positionsof the rotating polarisation filterat [φ0, φ0+90°] and [φ0+45°, φ0+135°].
Calculate Stokes-Parameters:Q=I(0°)-I(90°), U=I(45°)-I(135°)
IUQ
V22 +
=
QUarctan
21⋅=Θ
P1
P2
angle of polarization:
degree of polarization:
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Model: Dyks et al., 2004
~ Correspondence of Polarization Characteristics(note also striped wind model, Petri and Kirk, 2005)
MeasurementTwo Pole Caustic Model (Dyks etal, 2004)
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P2/P1= 0.64
Crab: single pulse statistics (A. Slowikowska et al.)
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3 4σ
Peak ratio statistics
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all
Good conditions
bad conditions
Check for atmospheric transparencyand aperture loss due to seeing variations
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Correlation of otical flux and Giant Radio Pulses(Shearer et al., Science, 301, 493, 2003)
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The main peak of theOptical emission is~3-5% brighter in a Rotation that showsA GRP !
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Conclusions:
High energy emission in young radio pulsars isthe dominant radiation process and some details arealready detectable in the brightest objects
(GLAST will detect `many` more radio pulsarsWhere many could be 50-100 depending onmodel)
Coupling between incoherent high-energy radiationsand coherent radio emissions in Crab (rad-opt) and Vela (talk by A. Lommen) start to become visible.
We should be on our way to a comprehensive model of pulsar emissions…