2. nuclearimagingspectroscopyw/etcc · 2016. 6. 20. · detection significance [s] 3 4...
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Detection significance [s] 3 4 5
Conservative (SD, DD) [Mpc] 70, 55 60, 48 55, 45
Optimistic (SD, DD) [Mpc] 110, 85 95, 75 85, 65
[email protected] International Symposium on Nuclei in the COSMOS, Niigata, Japan, June 19-24, 2016
Yoshitaka Mizumura1,2, Toru Tanimori2, Atsushi Takada2, on behalf of SMILE group3
1 Unit of Synergetic Studies for Space, Kyoto University, Kyoto, Japan2 Division of Physics and Astronomy, Kyoto University, Kyoto, Japan3 http://www-cr.scphys.kyoto-u.ac.jp/research/MeV-gamma/wiki/wiki.cgi
All-sky nuclear imaging spectroscopy is a promising tool for systematic study of supernova (SN) explosions. Especially, progenitor scenarios of type Ia SNe are not well-understood yet. Here, we report an nuclear imaging telescope, Electron-Tracking Compton Camera (ETCC), and its expected performance with satellite-based all-sky imaging, which enable us to observe nuclear lines from SN Ia at a distance beyond 40 Mpc (~several SNe/years).
100 days(@40-140 d), 0.7-4.0 MeV
20 40 60 Mpc
Distance distri.
in 5 yrs
56N
i ge
nIn
clin
atio
n an
gle
20 40 60
±20%
±30%
20 40 60
20 Mpc 40 Mpc 40 Mpc20 Mpc
100keV
4MeV
2MeV
200keV
500keV
812
1561keV
480270
158
56Ni
56Co 847
1038
1238 1771
2038
2598
3253keV
750
0.7 MeV
1MeV
SD
DD
56Ni (t1/2 = 6.1 d) → 56Co (77.2 d) → 56Fe
SD
DDIR-Opt.-UV
Uncertainty from inclination
angle of the orbit
SD DD
50 keV—4 MeV
Obvious diff.b/w SD and DD
©David A. Hardy/AstroArt
Mass accretion from companion star (SD)
©NASA
Violent merger of white dwarfs (DD)Which
scenario is?
1. Progenitor scenarios of Ia SNe
A. Summa, et al., A&A 554, A67 (2013)
800
Nuclear gamma-ray is a powerful tool to distinguish SD and DD.
R. Diehl, et al., Science 345, 1162 (2014)E. Churazov, et al., Nature 406, 512 (2014)
SN2014J: SN [email protected] (Very rare: ~1/40 SN/yr)
SPIIBIS
847keV 1238
keV1038keV
INTEGRAL successfully observed 56Ni and 56Co lines,but it is difficult to resolve
the puzzle of SD vs. DD
True nuclear imaging spectroscopy and systematic
study are required!!
MeV g
MeV g
COMPTEL type ETCC type
COMPTEL type ETCC obs.
improvement
Instruments on satellite:4 x (50 cm)3 ETCC
Effective Area:240 cm2@1 MeV
PSF: 2o @1 MeV
ΔE/E: 5%@662 keV
Field of View: 2p srEffective Exposure: 33%Assumed B.G. flux:2 times of reported flux
e- Energy: Keg Energy: Eg
Eg
Ke
KeEg
cme
=
2
1cos
Details in [23-PS2.78]T. Tanimori, et al., ApJ 810, 28 (2015)
3. Detectable nuclear gamma-ray lines
Please check also SMILE balloon experiment series.Sub-MeV gamma-ray Imaging Loaded-on-balloon Experiment
Expected performance
SN Ia rate(<60 Mpc): ~2x10-5 [yr-1 Mpc-3] Dist.[Mpc]
SN rate[yr-1]
5 yrs[SNe]
15 0.28 1.420 0.67 3.440 5.4 2760 18 90
D. Maoz, and F. Mannucci,Publ. Astron. Soc. Australia 29, 447 (2013)
56Ni gen.
Incl
inat
ion
angl
e
±20%
±3
0%
Flux uncertainty:56Ni gen. 20% (SD & DD)
Inclination 30% (only DD)
4. Averaged lightcurve of type Ia SNe
SD
3.5 Mpc
20-40 Mpc (23 SNe) 40-60 Mpc (63 SNe)10
days
20-60 Mpc (86 SNe)
SD
DD
Generated #(SD, DD)
SD ratio[%]
Best fittedSD ratio[%]
0, 86 0.0 4 ± 1120, 66 23.3 23 ± 342, 44 48.8 44 ± 364, 22 74.4 76 ± 386, 0 100 90 ± 3
Can we measure co-existence ratio of SD and DD?
A puzzle of SN Ia, SD vs. DD,
can be resolved
5. Detection limits & prospects
Obs. in 50-100 d
BG subtracted BG subtracted BG subtracted BG subtracted
DD
3.5 Mpc
56Co lines will be observed from ~several SNe/years
T. Tanimori, et al., ApJ 810, 28 (2015)
Distance[Mpc]
#[SNe]
Averageddist.[Mpc]
0-20 4 14.020-40 23 31.940-60 63 51.30-60 90 44.7
Emulation of type Ia SNe
SDDD
SDDD
Random numbers
Expectation of averaged lightcurves
orCo-existence
!?
Yes!! we can measure the ratio w/ 20-30% err.
If we achieve observations of Ia SNeup to 100 Mpc, >400 SNe/5yrs are expected.
Nuclear imaging spectroscopy with ETCC enables us to try systematic observational studies of type Ia SNe, andit will open a new era of nuclear physics in the cosmos.
SD
DD
Conservative model: 2xBG, All-sky surveyOptimistic model: 1xBG, Pointing mode
days
2. Nuclear imaging spectroscopy w/ ETCC
Mpc
1 mCrab sensitivity