第２回
MeVガンマ線天文学研究会
Discussion
小高裕和 (東大)Origin of matter?
supernova

Wikipedia

neutron star merger

The findings reported here also bear upon thecontroversy concerning the nature of ACC. Initially, a single amorphous phase was reported(26). Later experiments demonstrated the existence of both hydrous ACC and anhydrous ACC(27). Other research suggested the existence of
two forms of hydrous ACC (28), as well as proto56
vateritic 56
ACC and proto-calcitic ACC (29), witheach serving as a precursor to the respective crys56
talline phase. The dense liquid phase referred
to above was recently proposed as yet anotheramorphous form. Our results call into question
whether these are fundamentally distinct phases
or whether they exist as points on a continuum.
Though certainly not conclusive, the disparate
modes of ACC dissolution observed in our study
suggest thatdoi:10.1038/nature13672
the term ACC refers to a spectrum ofstructures ranging from the dense liquid phase to
the anhydrous form, rather than a single or even56
a few closely related structures. Finally, whereas
our results clearly show that direct transformation of ACC to the crystalline phase of CaCO3
readily occurs, we confirm previous suggestions
from low-resolution optical measurements, mac8
1,9
roscopic1,x-ray
diffraction
data (12–14),
and x-ray
E. Churazov1,2, R. Sunyaev1,2, J. Isern3, J. Knödlseder4,5, P. Jean4,5, F. Lebrun6, N. Chugai7, S. Grebenev
E. Bravo, S. Sazonov
microscopy (30) that direct transformation from& M. Renaud10
ACC to calcite is unlikely. Indeed, this formation pathway has never been directly observed.
A type Ia supernova is thought to be a thermonuclear explosion
The model spectrum is binned similarly to the observed supernova
of either a single carbon–oxygen white dwarf or a pair of merging spectrum. The signatures of the 847
1,238 keVAND
linesNare
clearly seen
REand
FE RENCES
OT ES
white dwarfs. The explosion fuses a large amount of radioactive 56Ni in the spectrum (along with tracers
weaker lines of 56Co at 511 and
1. of
http://web.mit.edu/jwk/www/docs/Gibbs1875-187856
56(refs 1–3). After the explosion, the decay chain from Ni to Co to 1,038 keV). The low-energy (,400 keV)
Equilibrium_of_Heterogeneous_Substances.pdf
part of the SPI spectrum is not
56
2. S. E. Wolf,
M. Kappl,response
F. Emmerling, W. Tremel,
Fe generates c-ray photons, which are reprocessed in the expand- shown because of possible contamination
dueJ.toLeiterer,
off-diagonal
J. Am.
Chem. energies,
Soc. 130, 12342–12347(2008).
ing ejecta and give rise to powerful optical emission. Here we report of the instrument to higher-energy lines.
At these
we use ISGRI/
3. M. A. Bewernitz, D. Gebauer, J. Long, H. Cölfen, L. B. Gower,
the detection of 56Co lines at energies of 847 and 1,238 kiloelectron- IBIS data instead (Methods).
Faraday Discuss. 159, 291–312 (2012).
volts and a c-ray continuum in the 200–400 kiloelectronvolt band
By varying the assumed position4.ofA.thesourceetandflux- (2013).
F. Wallaceal., repeating
Science 341,the885–889
from the type Ia supernova 2014J in the nearby galaxy M82. The line fitting procedure using SPI data (Methods)
a 40uScience
3 40u322, 1819–1822
5. D. Gebauer,weA. construct
Völkel, H. Cölfen,
56
fluxes suggest that about 0.6 6 0.1 solar masses of radioactive Ni image of the signal-to-noise ratio in the
800–880 and 1,200–1,300 keV(2008).
were synthesized during the explosion. The line broadening gives a energy bands (Fig. 2). SN 2014J is detected
6. H. Cölfen,
M. Antonietti,
Mesocrystals
and Non-Classicalat 3.9s.d. and 4.3
s.d. in these
Crystallization(Wiley, in
SanbothFrancisco,2008).
characteristic mass-weighted
highest peaks
images.
6 ejecta expansion velocity of 10,000 6 two bands, respectively. These are7. the20
A. E. S. Van Driessche et al., Science 336,
3,000 kilometres per second. The observed c-ray properties are in
The images obtained by ISGRI at lower
energies (100–600 keV) dur- 69–72 (2012).
8. E. M. Pouget et al., J. Am. Chem. Soc. 132, 11560–11565
broad agreement with the canonical model of an explosion of a white ing the observations of SN 2014J andin October–December 2013, thatdwarf just massive enough to be unstable to gravitational collapse, is, a few months before the SN 2014J(2010).
(see Methods
for the T. Roncal-Herrero,
9. P. explosion
Bots, L. G. Benning,
J. D. Rodriguez-Blanco,
but do not exclude merger scenarios that fuse comparable amounts details of the earlier observation), areS.shownin Fig.
3. Anof (2012).
Shaw, Cryst.
GrowthDes.inspection
12, 3806–3814
56
of Ni.
10. R.that
Demichelis,
P. Raiteri,J. D. Gale,D. Quigley, D. Gebauer,
images in the 25–50 keV band shows
the fluxes
observed
in 2013The detailed physics of the explosion of type Ia supernovae (for exam- and 2014 are similar, whereas at higher
Nat. Commun.
590 (2011).
energies2,(.100keV) there isple deflagration or detonation) and the evolution4,5 of a compact object excess at the position of SN 2014J only
11. M. J. Williamson, R. M. Tromp, P. M. Vereecken, R. Hull,
in
the
2014
data.
Previous ISGRI
6–9
F.
M.
Ross,
Nat.
Mater.
2,
532–536 (2003).
towards explosion remain a matter of debate . In a majority of models, observations of this field in 2009–2012, with a total exposureof about (2012).
12. Q. Hu et al., Faraday Discuss. 159, 509–523
the ejecta are opaque to c-ray lines during first 10–20 days after the ex- 6 3106 s, revealed no significant signal
20energiesD..50
keVJ.from
M82D.
.R. Hamann, Science
13. J.at
Aizenberg,
A. Muller,
L. Grazul,
plosion (because of Compton scattering). At later times,
the ejecta become–6
A
combinationofimaging
andspectralanalysisprovidesrobustevi299,1205–1208(2003).
10
3 × fraction
IKI, MPA and INTEGRAL teamprogressively more transparent and a largeof c-rays escapes.
J. R. AsI. Leeet al., J. Am.
Chem.
Soc.sig129, 10370–10381
dence of c-ray emission from SN 14.
2014J.
expected,muchof theThis leads to a robust prediction10 of c-ray emission from type Ia superSN-2014J(2007).
nal comes from the 800–900
and 1,200–1,300
keV bands, where two
56
novae after few tens of days, dominatedthe c-ray lines of Co. Such
15. A. A. Chernov, Modern Crystallography III (Springer, Berlin,
10–5 by2 × 10–6
emission has been observed before: the down-scattered
hard X-ray con1984).
3 × 10
MPA and INTEGRAL team
16. E. Beniash, IKI,
J. Aizenberg,
L. Addadi, S. Weiner, Proc. R. Soc.
tinuum from supernova (SN) 1987A in the Large Magellanic Cloud was
SN-2014J
56
11,12
–5
LondonSer.
B
264,
461–465 (1997).
seen half a year after the explosion , and c-ray lines of Co were detected10
2 × 1017. S. Weiner, I. Sagi, L. Addadi, Science 309, 1027–1028
10–6 (type II) supernova,
several months later13,14. That was a core-collapse(2005).
10
in which the cause of the explosion is completely different from that of
18. E. M. Pouget et al., Science 323, 1455–1458 (2009).
type Ia supernovae. Type Ia events, despite being intrinsically brighter,
0
19. S.
E. Wolf et al., Nanoscale 3, 1158–1165 (2011).
5 × 10–6
300
400
500
100
200
–6
are more rare than core-collapse
and0before
2014J there
5 × 10supernovae,
20. L. Addadi, S. Raz, S. Weiner, Adv. Mater. 15, 959–970
300
400
500
100 SN 200
was not one close enough to detect. The recent type Ia SN 2011fe at a dis(2003).
21. Y. Politi et al., Adv. Funct. Mater. 16, 1289–1298 (2006).
tance of D < 6.4 Mpc yielded only an upper limit on the 56Co line flux15.
22. P. W. Sutter, E. A. Sutter, Nat. Mater. 6, 363–366 (2007).
SN 2014J in M82 was discovered16 on January 21, 2014. The recon0
23. L. O. Hedges, S. Whitelam, Soft Matter 8, 8624–8635 (2012).
structed
1517 date of the explosion is January 14.75 UT. This is the nearest
24. L. Cheng, P. Fenter, K. L. Nagy, M. L. Schlegel, N. C. Sturchio,type Ia supernova to be detected in at least four decades, at the M82
Phys. Rev. Lett. 87, 156103 (2001).
distance of D < 3.5 Mpc (ref. 18). The European Space Agency satellite
25. J. I. Kilpatrick, S.-H.1,000
Loh, S. P. Jarvis, J. Am. Chem. Soc. 135,500
190
INTEGRAL started observing SN 2014J in 2014, from January 31 to
2628–2634(keV)(2013).
EnergyApril 24 and from May 27 to June 26. We use the INTEGRAL data taken
26. L. Brečević, A. E. Nielsen, J. Cryst. Growth 98, 504–510
at 847 and 1,238 keV in the(1989).
between days 50 and 100 after the explosion, the period when the ex- Figure 1 | Gamma-ray lines from Co decay
obtainedby INTEGRAL
between
27.wasN. Koga,
Y. Yamane,
J. Therm. Anal.
Calorim. 94, 379–387
pected flux from c-ray lines of 56Co is close to the maximum10. This set of spectrum of SN 2014J. The spectrum
blue points show SPI and(2008).
observations by the SPI and ISGRI/IBIS instruments on board INTEGRAL days 50 and 100 after the outburst. Red and
ISGRI/IBIS data, respectively. The flux below 60 keV is dominated by thehas been analysed, excluding periods of strong solar flares, which cause emission of M82. The black curve shows a fiducial model of the supernova
large variations in the instrumental background (Methods and Extended 500
1,000
spectrum for day 75 after the explosion.
Inset,
lower-energy
part2014of the1162
5 SEPTEMBER• VOL 345 ISSUE 6201
Data Fig. 1). The spectrum derived assuming a point source at the spectrum (black). The expected contributionsof three-photon positronium(keV)
Energyposition of SN 2014J is shown in Fig. 1 using red and blue points for annihilation (magenta) and Compton down-scattered emission from 847
and 1,238 keV lines (green) are also shown. All error bars, 1 s.d.
SPI and ISGRI, respectively.

ear explosion
The model spectrum is binned similarly to the observed supernova
air of merging spectrum. The signatures of the 847 and 1,238 keV lines are clearly seen
adioactive Ni in the spectrum (along with tracers of weaker lines of Co at 511 and56
Ni to Co to 1,038 keV). The low-energy (,400 keV) part of the SPI spectrum is notin the expand- shown because of possible contamination due to off-diagonal response
Here we report of the instrument to higher-energy lines. At these energies, we use ISGRI/
8 kiloelectron- IBIS data instead (Methods).
tronvolt band
By varying the assumed position of the source and repeating the fluxM82. The line fitting procedure using SPI data (Methods) we construct a 40u 3 40u
Ni image ofc-ray
dioactive Cobalt-56
the signal-to-noisein thefrom
800–880
andtype1,200–1,300
emissionratio
lines
the
Ia keVdening gives a energy bands (Fig. 2). SN 2014J is detected at 3.9 s.d. and 4.3 s.d. in thesesupernova 2014J
ty of 10,000 6 two bands, respectively. These are the highest peaks in both images.
operties are in
The images obtained by ISGRI at lower energies (100–600 keV) dursion of a white ing the observations of SN 2014J and in October–December 2013, that
ional collapse, is, a few months before the SN 2014J explosion (see Methods for therable amounts details of the earlier observation), are shown in Fig. 3. An inspection ofimages in the 25–50 keV band shows that the fluxes observed in 2013
ovae (for exam- and 2014 are similar, whereas at higher energies (.100 keV) there iscompact object excess at the position of SN 2014J only in the 2014 data. Previous ISGRI
ority of models, observations of this field in 2009–2012, with a total exposure of about
ays after the ex- 6 310 s, revealed no significant signal at energies .50 keV from M82 .
e ejecta become
A combination of imaging and spectral analysis provides robust evic-rays escapes.
dence of c-ray emission from SN 2014J. As expected, much of the sigm type Ia supernal comes from the 800–900 and 1,200–1,300 keV bands, where twos of 56Co. Such
ard X-ray conanic Cloud was
Co were detectedII) supernova,
nt from that ofsically brighter,
SN 2014J there
2011fe at a dis56
Co line flux .
14. The recons is the nearest
es, at the M82
Agency satellite
m January 31 to
RAL data taken
d when the ex- Figure 1 | Gamma-ray lines from Co decay at 847 and 1,238 keV in theum10. This set of spectrum of SN 2014J. The spectrum was obtained by INTEGRAL between

28. A. V. Radha, T. Z. Forbes, C. E. Killian, P. U. Gilbert, A. Navrotsky,
Proc. Natl. Acad. Sci. U.S.A. 107, 16438–16443 (2010).
29. D. Gebauer et al., Angew. Chem. Int. Ed. 49, 8889–8891(2010).
30. J. Rieger, J. Thieme, C. Schmidt, Langmuir 16, 8300–8305(2000).

acknowledges support awarded by the U.S. Department of
Defense, Air Force Office of Scientific Research, National Defense
Science and Engineering Graduate Fellowship 32 CFR 168a,and the NSF under grant DMR-1312697. Pacific Northwest National
Laboratory is operated by Battelle Memorial Institute for the
DOE under contract DE-AC05-76RL01830.

Detection of nuclear lines

Flux (photons s–1 cm–2 keV–1)–6–6

We thank V. Altoe for the use of and assistance with the
JEOL-2100F transmission electron microscope. This research
was supported by the U.S. Department of Energy (DOE),
Office of Basic Energy Sciences, Division of Chemical Sciences,
Geosciences, and Biosciences at Pacific Northwest National
Laboratory and Lawrence Berkeley National Laboratory. TEM was
performed at the Molecular Foundry, Lawrence Berkeley
National Laboratory, which is supported by the Office of Basic
Energy Sciences, Scientific User Facilities Division. M.H.N.

Space Research Institute (IKI), Profsouznaya 84/32, Moscow 117997, Russia. 2Max Planck Institute for Astrophysics, Karl-Schwarzschild-Strasse 1, 85741 Garching, Germany. 3Institute for Space
Sciences (ICE-CSIC/IEEC), 08193 Bellaterra, Spain. 4Université de Toulouse, UPS-OMP, IRAP, Toulouse, France. 5CNRS, IRAP, 9 Avenue colonel Roche, BP 44346, F-31028 Toulouse Cedex 4, France. 6APC,
Université Paris Diderot, CNRS/IN2P3, CEA/Irfu, Observatoire de Paris, Sorbonne Paris Cité, 75205 Paris Cedex 13, France. 7Institute of Astronomy of the Russian Academy of Sciences, 48 PyatnitskayaStreet, 119017 Moscow, Russia. 8ETSAV, Universitat Politecnica de Catalunya, Carrer Pere Serra 1-15, 08173 Sant Cugat del Valles, Spain. 9Moscow Institute of Physics and Technology, Institutsky pereulok
9, 141700 Dolgoprudny, Russia. 10LUPM, Université Montpellier 2, CNRS/IN2P3, CC 72, Place Eugène Bataillon, F-34095 Montpellier Cedex 5, France.

days 50 and 100 after the outburst. Red and blue points show SPI and

www.sciencemag.org/content/345/6201/1158/suppl/DC1
Materials and Methods
Figs. S1 to S6Tables S1 to S2References (31–33)
Movies S1 to S12

Science

28 March 2014; accepted 30 July 201410.1126/science.1254051

SUPERNOVAE

Early 56Ni decay gamma rays from
SN2014J suggest an unusual explosion
Roland Diehl,1* Thomas Siegert,1 Wolfgang Hillebrandt,2 Sergei A. Grebenev,3Jochen Greiner,1 Martin Krause,1 Markus Kromer,4 Keiichi Maeda,5Friedrich Röpke,6 Stefan Taubenberger2
Type Ia supernovae result from binary systems that include a carbon-oxygen white dwarf,
and these thermonuclear explosions typically produce 0.5 solar mass of radioactive
56
Ni. The 56Ni is commonly believed to be buried deeply in the expanding supernova cloud.
In SN2014J, we detected the lines at 158 and 812 kiloelectron volts from 56Ni decay(time ~8.8 days) earlier than the expected several-week time scale, only ~20 days after the
explosion and with flux levels corresponding to roughly 10% of the total expectedamount of 56Ni. Some mechanism must break the spherical symmetry of the supernova
and at the same time create a major amount of 56Ni at the outskirts. A plausible
explanation is that a belt of helium from the companion star is accreted by the white dwarf,
where this material explodes and then triggers the supernova event.

S

N2014J was discovered on 22 January 2014(1) in the nearby starburst galaxy M82 andwas classified as a supernova of type Ia(SN Ia) (2). This is the closest SN Ia since theadvent of gamma-ray astronomy. It reached
its optical brightness maximum on 3 February,
20 days after the explosion on 22 January at 14.75
UT (3). At a distance of 3.5 Mpc (4), a detailed
comparison of models to observations across awide range of wavelengths appears feasible, including gamma-ray observations from the 56Ni
decay chain.
Calibrated light curves of type Ia supernovae(SNe Ia) have become standard tools to deter-–6

1

SUPPLEMENTARY MATERIALS

1

Max-Planck-Institut für Extraterrestrische Physik,
Giessenbachstrasse 1, D-85741 Garching, Germany 2MaxPlanck-Institut für Astrophysik, Karl-Schwarzschild-Strasse 1,
85741 Garching, Germany. 3Space Research Institute,
Russian Academy of Sciences, Profsoyuznaya 84/32, 117997
Moscow, Russia. 4The Oskar Klein Centre and Department of
Astronomy, Stockholm University, AlbaNova, SE-106 91
Stockholm, Sweden. 5Department of Astronomy, Kyoto
University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 6068502, and Kavli Institute (WPI), University of Tokyo, 5-1-5
Kashiwanoha, Kashiwa, Chiba 277-8583, Japan. 6Institut fürTheoretische Physik und Astrophysik, Universität Würzburg,
Emil-Fischer-Strasse 31, 97074 Würzburg, Germany.
*Corresponding author. E-mail: rod@mpe.mpg.demine cosmic distances and the expansion historyof the universe (5), but we still do not understandthe physics that drives their explosion (6, 7). Their
extrapolation as distance indicators at high redshifts, where their population has not been empirically studied, can only be trusted if a physicalmodel is established (5). Unlike core-collapse SNe,which obtain their explosion energy from theirgravitational energy, SNe Ia are powered by therelease of nuclear binding energy through fusion
reactions.
It is generally believed that carbon fusion reactions ignited in the degenerate matter inside awhite dwarf star lead to a runaway. This sudden
release of a large amount of nuclear energy isenough to overcome the binding energy of such a
compact star and thus causes a SN Ia. A consensus had been for years that the instability ofa white dwarf at the Chandrasekhar mass limit
in a binary system with a main-sequence or (red)giant companion star was the most plausible model to achieve the apparent homogeneity (6). However, observations have revealed an unexpected
diversity in SNe Ia in recent years (8), and increasing model sophistication along with reevaluations of more-exotic explosion scenarios haveoffered plausible alternatives. The consensus now
sciencemag.org SCIENCE

Downloaded from http://science.sciencemag.org/ on July 1, 2019

Flux (photons s–1 cm–2 keV–1)

LETTER

NatureACKN OWLED GMEN TS

of this result is that observations with C O M P T E L can be used to map out
the spatial structure of emission near 1 MeV and to more precisely pin down
the 1 MeV flux level. It may be that accurate spectral measurements near 1
MeV will require more detailed knowledge of the spatial distribution of theemission, information which only C O M P T E L can easily provide.

Transition to non-thermal

DISCUSSION
Given the spectra presented in Figure 1, it is difficult to draw any firm
conclusions about the nature of the spectrum near 1 MeV. As noted above,
the C O M P T E L data alone seems to further corraborate the conclusion that

Cygnus X-1

•

•

•

Everything eventually goes tothermal equilibrium. How?
Plasmas closest to black holes
have temperatures of a few
hundred keV, which seems likethe highest observabletemperature in the universe.
Could see what happens to theboundary between thermal andnon-thermal.

10"1. . . . . . . .

i•'•

I

. . . . . . . .

I

'

:

9 COMPTEL (thiswork)[] BATSE-EBOP (Ling et al. 1997) [11]0 0 S S E (Phlips, pdvate communication)

10.2

10.3

F

lO'

%

10 .5

I

0.1

I

I

I p ==,I

I

,

=

I

,

, ,=il=10Energy (MeV)
FIGURE 1. Contemporaneous spectra of Cyg X-1 as derived from COMPTEL,BATSE-EBOP and OSSE. Some OSSE upper limits have been removed for the sake ofclarity. Error bars are 1~. Upper limits are 2r Errors on COMPTEL data include estimates of systematic uncertainties due to spatial modeling of the COMPTEL images.

McConnell et al. 1997

832

ASTRO-H（「ひとみ」）特集（2）Polarimetry

表 1 かに星雲の軟ガンマ線偏光の主要な観測結果．
実験名エネルギー（keV）

偏光角（度）

偏光度（％）

露光時間（ks）

Hitomi/SGD
PoGO＋
AstroSAT/CZTIINTEGRAL/SPI
INTEGRAL/IBIS

60‒16020‒160100‒380130‒440200‒800

111±13131.3±6.8
143.5±2.8
117±9
110±1122±1120.9±5.0
32.7±5.828±647（＋19/−13）

5
92
800
600
1200

E(RA)

•

(Ng & Romani 2004)•

図2

Chauvin et al. 2017（7）Vadawale et al. 2018（8）Chauvin et al. 2013（5）Forot et al 2008（4）• a pure
toroidal B-ﬁeld からの携わった全ての方に厚く御礼申し上げます．
シンクロトロン放射なら約50%の偏光度
参考文献(inclinationに依存)•

パルサー自転軸: 124º

本研究（6）

開発・運用，SGD の開発・運用やデータ解析に

N(DEC)

偏光角 111º

文献

1）Tajima, H., et al., 2018, JATIS, 4, 021411
乱流磁場などがdepolarizeするので、
2）Weisskopf, M. C., et al., 1978, ApJL, 220, L117
3）Dean, A. J., et al., 2008, Science, 321, 1183
約20%の偏光度は自然と言えそう。
4）Forot, M., et al., 2008, ApJ, 688, L295）Chauvin, M., et al., 2013, ApJ, 769, 137
パルサー成分と星雲成分
6）Hitomi Collaboration, PASJ, 70, 1137）Chauvin, M., et al., 2017, Sci. Rep., 7, 7816
エネルギー依存性、場所依存性などが今後
8）Vadawale, S. V., et al., 2018, Nature Astron., 2, 55の課題9）Ng, C.-Y. & Romani, R. W., 2004, ApJ, 601, 479
10）Shibata, S., et al., 2003, MNRAS, 346, 841

かに星雲の X 線イメージ（Chandra 衛星）に今

まとめ• MeV検出器の技術は進んできた• 重要かつ多様なサイエンス• 具体的な観測の計画と期待されるサイエンスの精度の良い議論がまだなされていない→高精度の観測シミュレーション• 「難しい、難しい、、」と言っている時代は終わった。

HXIバックグラウンドシミュレーション
CdTe放射化に加えて、BGO放射化、X線背景放射、大気ガンマ線を追加

H. Odaka et al.

Nuclear Inst. and Methods in Physics Research, A 891 (2018) 92–105

linearOdaka et al. 2018
主要なラインを再現

logarithmic
連続成分も実測と非常によく一致マニアックな分野から主要な領域へ
大勢の皆さんのご参加に感謝します
第３回は？