gamma-ray burst polarimeter – gap – aboard the solar powered sail mission

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ma-Ray Burst Polarimeter – GAP ard the Solar Powered Sail Miss isuke YONETOKU (Kanazawa UNIV.), shio MURAKAMI (Kanazawa UNIV.) uichi GUNJI (Yamagata UNIV.) tehiro MIHARA (RIKEN) d GAP Team Launch in May 18 Poster #062

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Gamma-Ray Burst Polarimeter – GAP – aboard the Solar Powered Sail Mission. Launch in May 18. Daisuke YONETOKU (Kanazawa UNIV.), Toshio MURAKAMI (Kanazawa UNIV.) Shuichi GUNJI (Yamagata UNIV.) Tatehiro MIHARA (RIKEN) and GAP Team. Poster #062. Theoretical Model. Inter-Stellar - PowerPoint PPT Presentation

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Page 1: Gamma-Ray Burst  Polarimeter  – GAP –  aboard the Solar Powered Sail Mission

Gamma-Ray Burst Polarimeter – GAP – aboard the Solar Powered Sail Mission

Daisuke YONETOKU (Kanazawa UNIV.),

Toshio MURAKAMI (Kanazawa UNIV.)Shuichi GUNJI (Yamagata UNIV.)Tatehiro MIHARA (RIKEN)and GAP Team

Launch in May 18

Poster #062

Page 2: Gamma-Ray Burst  Polarimeter  – GAP –  aboard the Solar Powered Sail Mission

Inter-StellarMedium

Internal Shock(prompt)

External Shock(afterglow)

■ Internal / External shock ■ Electron acceleration ■ Strong magnetic field (B > 104 G) ■ Synchrotron radiation

We expect to detect the strong linear polarization !!Its direct measurement is key to solve the emission mechanism.

Theoretical Model

Γ > 100

Central Engine

B

Polarization

cvJET

Prompt

Afterglow

Central engine

Lazzati et al.

Page 3: Gamma-Ray Burst  Polarimeter  – GAP –  aboard the Solar Powered Sail Mission

IKAROS(Solar Powered Sail)

Interplanetary Kite-craft Accelerated by Radiation Of the Sun

Launch on May 18, NEXT MONTH

Mission Span is 1 year20m

Radiation pressure

Page 4: Gamma-Ray Burst  Polarimeter  – GAP –  aboard the Solar Powered Sail Mission

GAmma-ray burst Polarimeter

偏光方向

E’γ+ – 1 + cos2θ

2α2 rc

2

2

dΩ =Eγ

E’γ

E’γ

■ Angular Anisotropy of Compton Scattering ■ Geometrical Symmetry

α : Fine Structure Constantrc : Compton Radius

HV Unit HV Unit

PlasticScintillatorCsI

R6041-SBR7400p analog

FPGACPU

60 m

m10

0 m

m

140mm

Polarization

140mm

We can observe(1) Polarization : 60 – 300 keV(2) Time resolution of Pol. : 1 sec(3) Time resolution of lightcurve : 125 msec

for the IPN(4) Spectrum : 30 – 300 keV

(angle)

Page 5: Gamma-Ray Burst  Polarimeter  – GAP –  aboard the Solar Powered Sail Mission

GAP Flight Model

GAP-S (Sensor)

GAP-P (Power)

6cm, 160g

20 cm, 3700g

Page 6: Gamma-Ray Burst  Polarimeter  – GAP –  aboard the Solar Powered Sail Mission

the deck of GAP and Some Electronics

The surface of GAP (Anti-Direction of Solar Panel)

Page 7: Gamma-Ray Burst  Polarimeter  – GAP –  aboard the Solar Powered Sail Mission

IKAROS

Page 8: Gamma-Ray Burst  Polarimeter  – GAP –  aboard the Solar Powered Sail Mission

KEK Highly Polarized X/Gamma-rayModulation Curve (π = 80%)

0 100 200 300Rotation Angle [deg]

Num

ber o

f Ev

ents

■ The experimental results with pencil X-ray are

consistent with GEANT-4 simulations within 2% level. ■ Comparing the experimental data and simulation,

we make effort to constrain the systematic uncertainty.

Pencil BeamM=0.446±0.028

GEANT-4 Mass Model

80keV, π=80%, pencil beam, M=0.456

Uniform irradiation (100keV)Efficiency = 0.17, M100% = 0.31

Pencil Beam (1x1mm) : 80keV, π=80%,

Page 9: Gamma-Ray Burst  Polarimeter  – GAP –  aboard the Solar Powered Sail Mission

Synchrotron “Ordered B”Synchrotron “Random B”Compton Drag

Lazzati et al. (2005)

Polarization Degree

Num

ber F

racti

on (%

)Theoretical Expectation Rate

Page 10: Gamma-Ray Burst  Polarimeter  – GAP –  aboard the Solar Powered Sail Mission

2

48

14

Expe

ctati

on R

ate

( G

RB/y

r ) (3

σ)

MDP (GRB’s Polarization Degree)

GRB rate in the entire field of viewGRB rate within the 30deg from optical axis

According to the BATSE database

Page 11: Gamma-Ray Burst  Polarimeter  – GAP –  aboard the Solar Powered Sail Mission

Summary

■ GAP has a capability to detect the polarization for GRBs, bright magnetar flares, and Crab nebula.

■ We will install the GRB Polarimeter – GAP –

aboard the solar powered sail “IKAROS”, launched in May 18.

■ We need the position information of GRBs by Swift, Fermi, IPN, INTEGRAL, Super-AGILE, MAXI, etc…

IN NEAR  FUTURE