SPICA
Mission Requirement
Document (MRD)ver. 3.5 draft

Explanatory presentation
19 May 2009
Prepared by H. Matsuhara, I. Sakon, M. Takami, T.
Wada, M. Tamura, T. Yamashita, T. Ootsubo, H.
Kataza, H. Kaneda, H. Izumiura, T. Onaka et al.

Scope of SPICA MRD• The MRD clarifies the objectives of the SPICA mission.
• The objectives of the mission are more concretely expressedby various scientific targets (plus also technical purposes).
• Based on these targets, the mission requirements, such as
required specifications of the mission instrumentations,scientific operations etc. are defined.
• Also the success criteria, by which the evaluation of themission achievement will be addressed, are clearly described.
• The mission requirements described here will give thebaseline of the study of the system requirements.
• In the future, this document will also be used to confirm thedevelopment status, system performance, and operational
results on orbit etc. are well in-line with the mission
requirements described in this document.
• The description in this document may be updated dependingon the change in the stake-holder’s opinions or external
conditions, and in such case this document will be used as thesource and reference document to estimate the effects on the
mission achievement.

The SPICA Mission Requirement

SPICAの科学目的達成に向けてのアプローチ法Approaches to perform SPICA Scientific Objectives

[1]

[2]

[3]

銀河の誕生と進化過程の解明
Resolution of
Birth andEvolution of
Galaxies

銀河星間空間における物質輪廻の解明
The Transmigrationof Dustin the Universe

惑星系形成過程の総合理解
Thorough
Understanding ofPlanetary System
Formation

遠方宇宙／初期宇宙
Distant/Early
Universe

近傍宇宙（恒星系）
Local Universe/Stellar
systemMajor Objective [1]銀河の誕生と進化過程の解明
Resolution of Birth andEvolution of Galaxies

SPICA

銀河の誕生と進化過程の解明
Resolution of Birth and Evolution of Galaxies
第1世代の星の誕生 Birth of 1st Stars
宇宙再電離 Cosmic Re-ionization

SPICA

銀河団の誕生と進化
Formation/Evolution of Cluster of Galaxies

億
１３７

光年

銀河の中で星と超巨大ブラックホールが誕
生し進化 Formation/Evolution of Stars &Super-Massive Blackholes in Galaxies

Extragalactic Science ：Objective #1• 科学目的 Objective– 銀河の誕生の解明のために重要な天体である宇宙再電離期の「種族III天体」（第一世代の星）の検出に挑む。
– We will discover “population III” objects (first generation of stars) at reionization epoch, which play an important role in the understanding ofgalaxy formation processes.

• 科学目標 Target– 「種族III天体」の候補である遠方（赤方偏移７以上）、（低金属量１０－４以下）の星からの電離輝線を、放射エネルギーが赤方偏移した赤外線領域の分光観測で検出する。これにより種族III天体の存在を明らかにする。さらに「種族III天体」の形成時の分子雲冷却にかかわる水素分子輝線（赤方偏移３以上）を赤外線分光観測で探査し「種族III天体」形成の証拠を探る。
– We will search for redshifted ionization lines (z>7) from low-metal
objects (less than 10-4) with mid-IR spectroscopy, by which we intend
to prove the existence of population III objects. We also investigate theformation of population III objects at z>3 through emission lines fromhydrogen molecules -- important cooling lines of primeval molecular
clouds -- using far-infrared spectrograph.

遠赤外線分光装置 BLISS 中間赤外線撮像・低分散分光装置 MIRACLEHα at z>7 will be detectablewith MIRACLE/SPICA
Hα (λ0=656.3nm) enters mid-IR
at 5.25μm (z=7), 8.53μm (z=12)
Emitter Search for z>7?
Star-formation Rate? Dust Extinction (with Hβ)?

25” = 150 kpc

・・・・・・・

Dispersion
direction

MIRACLE’s FoV 6’x6’• Multi-slit + wide-field MIR
imagerLyman a blob @z=3.1
SSA22 “Blob1” (Steidel et al. 2000,
Matsuda et al. 2004)

第一世代星の誕生を水素分子(H2)輝線でとらえる

Probing the 1st stars with H2Emission Lines
星間ガスの冷却関数
Cooling Function (T<104K)

元素合成が進んでいない宇宙初期の原始ガス(<0.1Zsun) は・H Lyα (T>104K)
・H2 rotation lines 回転線(T<104K)
で冷却する
これらのラインの観測が原始ガスの物理状態の理解に最も重要
Most important lines tounderstand physics of metal-poor
gas in the early universe

Extragalactic Science ：Objective #2• 科学目的 Objective– 宇宙遠赤外線背景放射の大部分を個別天体に分解するとともに、遠赤外線背景放射の空間揺らぎの起源を明らかにする。
– We will resolve the cosmic far-infrared background light into individual
objects, and reveal the origin of the cosmic far-infrared backgroundfluctuations.

• 科学目標 Target– 宇宙遠赤外線背景放射を、「あかり」の3倍以上の空間分解能により個別の
遠赤外線天体に分解する。さらに個別天体を取り除いた遠赤外線背景放射
ゆらぎを評価し、多波長相関解析等からその起源を解明する。
– We will resolve the cosmic far-infrared background light into individual
far-infrared objects with 3 times or more higher spatial resolution thanthat of AKARI. We then evaluate far-infrared background fluctuations
after removal of the individual objects, and reveal its origin throughdetailed analysis such as multi-wavelength correlation.

中間赤外線撮像・低分散分光装置 MIRACLE
遠赤外線撮像分光装置 SAFARI 遠赤外線分光装置 BLISS

Resolving capability of theCosmic Infrared Background(CIB)

With an ideal pointsource sensitivity
limited by source
confusion as a functionof telescope diameter(Dole et al. 2004)

The near-infrared background (IRTS, COBE & AKARI)• Proto-galaxies (e.g. pop-III stars, mini-quasars) at z~10?

If substantial fraction of the energy of the NIR
background is converted to dust emissions (IGM
dusts, mini-quasars(AGN), etc.), it may form the
far-infrared background.

The far-infrared background measurement with SPICAAKARI found :1) Excess brightness around 100um
Corresponding to>10^10 gals/sr for S<100 uJy
Proto-galaxies?
2) Large-scale fluctuations at 10’-30’~5% of the mean CIRB level
Very red foreground galaxies?
(Matsuura et al. 2009)Extragalactic Science ：Objective #3• 科学目的 Objective– 星間塵の影響を正しく評価し補正したうえで、星間環境の診断とダスト放射の理解を基に、塵に覆われた遠方銀河の物理化学を解明する。
– We will reveal physical & chemical condition of high-z galaxies with
precise correction for dust attenuation, based on understanding ofinterstellar environment and dust emission.

• 科学目標 Target– 赤方偏移３までの銀河について、中間・遠赤外線中分散広帯域分光観測を行ない、PAH放射や原子の電離輝線・分子輝線を効率的に捕らえ、その銀河の星間環境と星間ダストの性質を明らかにする。これにより、他波長のように星間塵の吸収補正の不定性なく、初期の宇宙（90億年前まで)の銀河の物理化学状態を明らかにする。
– We will reveal interstellar environment and dust emission
characteristics of high-redshift galaxies out to z~3 through PAH
emission as well as atomic and molecular emission lines with broadband mid- & far-IR moderate resolution spectroscopy. Theseobservations allow us to reveal the physical & chemical conditions of
dusty galaxies in the early universe (up to 9 Gyr ago) with precise
correction for dust attenuation.

MIRMES 中間赤外線撮像装置 MIRACLE
遠赤外線撮像分光装置 SAFARI 遠赤外線分光装置 BLISS

中間赤外線中分散分光装置

Interstellar dust in distant galaxies
UIR band spectra at z=0.2, 1, 2, 5Moderate resolution
Spectroscopy with SPICA(1hr, 5sigma)
MIRACLE R~50
MIRMES R~700
SAFARI Δσ=1cm-1,

SAFARIMIRMESBLISSMIRACLE

NGC6240

Spectroscopic Diagnostics ofInterstellar gas & dustout to z~3!

UIR band features at 3.3, 6.2, 7.6-7.8, 8.6, 11.2, 12.7μm
atomic ionic lines; [ArIII] at 8.99μm (27.63eV, nCe=4.8・105)[SIV] at 10.51μm (34.83eV, nCe=5.6・104)[NeII] at 12.81μm (21.56eV, nCe=5.4・105)

Numerous Atomic/Ionic Fine-structure Lines
exist in the Mid- to Far-infrared

158μm

88μm

Diagnostic tool to study the
Physical/Chemical Condition
without sufering from dust extinctionExtragalactic Science ：Objective #4•

科学目的 Objective– 銀河の進化における超巨大ブラックホール※の役割を解明するため、他の手法では観測が困難な星間塵に囲まれた形成中の超巨大ブラックホールを、初期宇宙にいたるまで探査する。
※太陽の数億個に相当する質量があると思われるブラックホール– In order to understand the role of supper-massive black holes (SMBHs) in
the galaxy evolution, we will make a survey for the forming SMBHs, that
may not be observed easily in other methods due to the obscuration by dust,
from the present to the early universe.

•

科学目標 Target– 星間塵の影響を受けない赤外線撮像・分光観測により、他の手法では観測が困
難な星間塵に囲まれた形成中の超巨大ブラックホールを、現在の宇宙から初期宇宙に至るまで広く探査し、ＴＢＤ個のサンプルを構築する。これと、銀河形成史の観測結果とをくみあわせて、銀河の進化における超巨大ブラックホールの役割を解明する。
– We will make infrared imaging & spectroscopic observations of TBD numberof the forming super-massive black holes (SMBHs), that can not be
observed easily in other methods due to the obscuration of dust, from thepresent to the early universe. Supplementing these results with the results ofobservations for the galaxy formation history, we will understand the role of
SMBHs in the galaxy evolution.

中間赤外線撮像・低分散分光装置 MIRACLE
中間赤外線中分散分光装置 MIRMES 遠赤外線撮像分光装置 SAFARI

Optically (X-ray)
selected AGN

Buried AGN

5-35 μm spectra of
ULIRGsActive Sturburst

Buried AGN

Starburst + AGN
PAH

PAH

18um
9.7um

18um

9.7um

9.7um
PAH

PAH

18um
9.7um

9.7um

18um
9.7um

With Spitzer& AKARI, only 24 micron-very-brightULIRGs(biased sample)
PAH weak Silicate abs.
strong
PAH strong
could be studied at z > 1: SPICA enables us to go to z > 3 and to
general ULIRGs at z > 1 !!

Evolution of galaxies and the growthof supper massive blackholes
4000A break strength

z=0.2-0.7

Obs. limit

z=0.7-1.0

z=1.0-1.5log( Stellar mass (M_sun))Contours : the galaxy distribution in SXDF
Blue filled (spec-z) and open (phot-z) circles : X-ray sources (AGN)At z=1.0-1.5, AGN are associated with massive star-forming galaxies, while at z=0.2-0.7,
the AGN number associated with massive red galaxies increases.
ÆDo some X-ray AGN follow the track from star-forming to red, passive galaxies (andtheir activities are going to turn off)? How about dusty obscured AGN?.
Æ SPICA/SAFARI low-resolution spectrophotometric imaging survey over ~100 sq.
deg!!
Subaru XMM deep survey field (SXDS) (Akiyama et al.天文月報２００８年１月号 )Extragalactic Science ：Objective #5• 科学目的 Objective– 銀河の星形成史・質量集積史を、銀河団や大規模構造の形成過程と銀河進化への影響との関わりの中で、解明する。
– We will reveal the star-formation & mass assembly history of galaxies
in relation to the forming processes of the galaxy clusters and thelarge scale structures, as well as the environmental effect on thegalaxy evolution.

• 科学目標 Target– 星形成活動のピーク(70－100億年前、z=1~2)があったとされる時代の宇宙において、放射エネルギーが赤方偏移してきた赤外線領域で、大規模構造をトレースできるほどの広い天域（~300メガパーセク相当)をサーベイし、銀河団や大規模構造を観測する。これにより、宇宙星形成史・質量集積史
および銀河進化に対する環境効果を解明する。
– In the early universe where the star forming activities was at a peak,
we will undertake imaging wide-area survey and observe the galaxy
clusters and the large scale structures at infrared wavelength, to which
the redshifted emitting energy shifts. The large survey area
(corresponding to ~300 Mpc) can trace the large scale structures, andwe will reveal the star formation history in the early universe (up to 9
Gyr ago) as well as the mass assembly history and its environmental
effect on the galaxy evolution.

中間赤外線撮像装置 MIRACLE 遠赤外線撮像装置 SAFARISPICAMIR-cam (JWST MIRIの２０倍)で探る宇宙の質量集積史z = 30z=5

6.6’×6.6’

z=3

MIRI

MIRI

MIR-cam

MIR-camz=2

6.6’×6.6’z=1

6.6’×6.6’

z=0

MIRI
MIR-cam
A Massive Cluster (6×1014 M◎), 20×20Mpc2 (co-moving)

Yahagi et al. (2005)

Environmental Effect in distant
Cluster revealed with AKARI &Subaru(RXJ1716 z=0.81 Koyama et al. 2008)

塵に覆われた宇宙の星形成史の解明
星形成率密度 Star formation rate density（ M◎yr-1 Mpc-3 )Understanding the Cosmic Star-Formation History Obscured by
Dust
Extra
succes
s

Full
Succe
ss

FIR~Submm(prediction)
遠赤外～サブミリ（予想）

可視光 Optical（塵による減光補正後）With extinction correction
可視光（塵による減光補正前）
7Gyr ago
７０億年前
０

１

9Gyr ago
９０億年前
２

赤方偏移 redshift

１２０億年前３

４

５
Blain et al. 2002

Major Objective [2]銀河星間空間における物質輪廻の解明
The Transmigration of Dustin the Universe

SPICA

Life Cycle of Dust
HST/WFC image ofthe active galactic nuclei of NGC 4261
~ a gas and dust disk

AKARI 9μm image of
Hickson Compact Group 31~ the site ofgalaxy interactions
and the Formation of
Tidal Dwarf Galaxies

VLA image of J1148+5251~the most distant quasar at z~6.4
One of the most interesting object to discuss
the evolution of dust in the early universe(CREDIT: ESA and NASA)

Diffuse ISM
Evolution
Destruction(CREDIT: NRAO/AUI/NSF)

Formation-- where the dust is formed-- how they are ejected into the interstellar space-- how they evolve in the interstellar space in a galaxy-- where and how the dust is destroyed-- how they enrich the universe

Life Cycle of dust：Objective #1•

科学目的 Objective– 大質量星終焉のダスト形成過程を解明し、初期宇宙のダスト起源を探る。
– The dust formation scenarios by massive stars are examined to explore theorigin of interstellar dust in the early universe.

•

科学目標 Target– 25Mpc以内の近傍銀河内で起こるダスト形成の兆候が見られる超新星(~5個以上)について、爆発後から１～２年間に複数回のデータ取得を行う。これにより、超新星放出ガスからダストが新たに凝縮する過程、また、それらが既存の星周ダス
トの温度(数百度K)に冷える過程の中間赤外スペクトル変化を調べ、超新星
ejecta中で形成されるダストの組成、サイズ分布、質量を詳細に制限する。
– Observations of several (>~5) dust-forming supernovae in nearby (<25Mpc) galaxies
are required several times within 1-2 years after the explosion. Changings in midinfrared spectra of the supernova during the processes in which the dust is newly
condensed in the SN ejecta gas and then it is cooled down to the temperature of
circumstellar pre-existing dust (~ a few hundred K) are examined to specify its
composition, its size distribution and its total mass.

中間赤外線低分散分光装置 MIRACLE
遠赤外線分光撮像装置 SAFARI

中分散分光装置 MIRMESDust formation process by massive stars
SCIENTIFIC BACKGROUND・ Dust Formation in the ejecta of core-collapse supernovae (SNe)-> Important to explore the origin of dust in the early universe

e.g., The amount of 0.1Msolar dust formation is needed for a core-collapse supernova
to account for the dust content of high red-shift galaxies (Morgan & Edmunds 2003).
The dust condensation in the ejecta of core-collapse SNe is theoretically suggested(Kozasa et al.1991; Todini & Ferrera 2001).

・ Observational Evidence for the dust formation in SN ejecta- Type II SN2003gd; 0.02Msolar (Sugerman et al. 2006)-> 4x10-5Msolar (Meikle et al. 2007)- Type II SN1987A ; 7.5x10-4Msolar (Ercolano et al.2007)- Cas A ; 0.003Msolar (Hines et al. 2004) or 0.02-0.054Msolar (Rho et al. 2004)

Æ much smaller amount of dust formation

A gap still remains in produced dust mass in core-collapse SN ejecta between thoseobservational results and theoretical prediction of 0.1 - 1Msolar (Nozawa et al. 2003)

ISSUES TO BE SOLVED-- Dust formation mechanisms in the SN ejecta
・Processes of transitions among SN ejecta gas, precursor molecules and SN dust
・Geometry of the newly condensed dust; newly formed dust forms in clumpy structures?
-- Relation between the SN types and dust formation.
・Differences in compositions and size distributions of newly condensed dust in the SN ejecta.
・How much fraction of dust formed in SN ejecta can survive to become the interstellar dust.

Dust formation process by massive stars
Example of the Latest Results on the Dust Formation by Core-collapse SNe
10

(b)

1

Modeled spectrum (total)- amorphous carbon ; T=800K- amorphous carbon ; T=320K

AKARI/IRC observations of SN2006jc(a) Three false-colors composite image of
the SN2006jc on epoch 220 days and thehost galaxy UGC4904 taken with AKARI/IRC[3μm(blue), 7μm(green) & 11μm(red)]

0.1(b) Near- to mid-infrared spectral energy
distribution of SN2006jc on epoch 220 days.
The gray solid line shows the result of model
0.01
calculation for dust thermal radiation. This
0
2
4
6
8
10
12
14
Wavelength (μm)
reveals that 300K amorphous carbon dust
Observed Results
Model Calculation Results (green solid line) exists in addition to 800K
MAGNUM telescope
300K amorphous carbon
amorphous carbon dust (red dotted line).
NIR photometric data
800K amorphous carbon
AKARI satellite(see Sakon et al. 2009)
total
NIR/MIR photometric data
AKARI satellite
NIR spectroscopic data

Æ Dust condensation not only in the SN ejecta itself but also in the mass loss wind associatedwith the prior events to the SN explosion could make a significant contribution to the dust
formation by a massive star in its whole evolutional history (Sakon et al. 2009).

Excellent sensitivity (>10 times better than AKARI/IRC) and wider wavelength coveragein the mid-infrared (5-40μm) achieved by MIRACLE low-resolution spectroscopy enable
us to detect 10-5M☉ of dust which is cooled down to a few hundred Kelvin even at the
distance of 25Mpc.
Æ providing strong constraints on the composition and the mass of newly formed dustin the ejecta of various types of SNe in nearby galaxies

Dust formation process by massive stars
Understanding transitions among the SNe ejecta gas, precursory molecules
and Newly Formed Dust
IR lines including a population of silicate particle *[FIV] 25.83μm[OIV] * 25.89μm[FeII] * 25.99μm[SiII] * 34.82μm[NeII] 12.8μm[NeIII] 15.5μm[OIII] 51.8μm[NIII] 57.3μm[PII] 60.6μm[OI] 63.2μm[OIII] 88.4μm[NII] 121.9μm[CII] 157.7μm[OI] 145.5μm

Spitzer LH spectrum of SN1987A aroundthe [FeII] 25.99μm line. [OIV] 25.89μm
and [FeII] 25.99μm are not well resolved
due to the contribution of [FIV] 25.83μm.
(Bouchet et al. 2006)

Æ R>1000 is required to decompose
the lines of [FIV], [OIV] and [FeII](from Reach et al. 2000)

Important molecules
formed in the ejecta
SiO (8.1~8.6μm; 28Si16O 1-0)
Precursor of silicate dust
(MgSiO3, Mg2SiO4 and SiO2)(Schneider et al. 2004)
CO (4.74μm 1-0 P(8))
C is bounded in CO if C<O(Clayton et al. 1999)[FeII], [SiII] ;Vaporization of pre-existingsilicate dust is indicated[OIII] / [OI] ; the density and temperature of
the emitting region is constrained

High-dispersion (R>1000) spectroscopic abilities in the mid- infrared (10-36μm)
with MIRMES and in the far-infrared (35-200μm) with SAFARI is indispensable fordemonstrating the transitions from the SN ejecta gas to the SN dust.

Life Cycle of dust：Objective #2• 科学目的 Objective– 中・小質量星によるダスト形成過程を解明し、天の川銀河中のダスト、即ち現在の宇宙のダストの起源における中小質量星の役割を探る。
– The dust formation processes by low- to intermediate-mass stars are examined
to explore the origin of dust in the Milky Way and, thus, in the current universe.
• 科学目標 Target– 系内、及びマゼラン雲中のAGB星、惑星状星雲、新星など進化した中小質量星約30個の星周の希薄なダストシェルを空間分解し、撮像情報から過去の質量放出とダスト形成の歴史を調べる。また星周の分子・ダストシェルの中間赤外~遠赤外分光データ
から、分子・ダストシェルの組成を調べ、放出ガスから形成されたダストの性質を制限する。
– Spatially well-resolved observations of faint dust shells around ~30 low- to intermediatemass evolved stars (e.g., AGB stars, planetary nebulae, novae etc) in the Milky Way and in
the Magellanic clouds are required to investigate their mass-loss histories and the dustformation processes. Mid- to far-infrared spectra of spatially-resolved molecular and dust
shell are obtained to identify the constituents of the molecular/dust shells and theproperties of dust formed in the mass-loss gas.

中間赤外線撮像装置 MIRACLE

中分散分光装置 MIRMES
中間赤外線高分散分光装置 HIRES
遠赤外線分光撮像装置 SAFARIDust formation processby low-to intermediate mass stars
SCIENTIFIC BACKGROUND
Chemical evolution models for dust budgets in the Milky Way (Dwek 1998)
Silicate dust; Type II SNe, red supergiants, O-rich AGB stars
Carbonaceous dust; mainly in low-mass (2-5M☉) C-rich AGB star
Metalic iron; Type Ia SNe
Observations (Waters 2004; Cohen & Barkiw 2005)
Asymptotic Giant Branch (AGB) stars with C/O<1 in their envelope
・・・presense of several silicate dust species
Asymptotic Giant Branch (AGB) stars with C/O>1 in their envelope
・・・presense of amorphous carbon, SiC, MgS, and in some cases PAHs
PAH features in the mid-infrared appear after the AGB phase and are observed in
C-rich Planetary Nebulae
ISSUES TO BE SOLVED-- Identifying some of the molecules in the MOLsphere (Tsuji 2000) of redgiants
to explore the driving force of mass ejection and to understand the formation
process of MOLsphere.
-- Demonstrating how the dust is formed around the AGB stars and how it isejected into the ISM at the evolutionary end phase of the AGB stars

Dust formation processby low-to intermediate-mass stars
High spatial resolution (~0.37”) and excellent sensitivity in the mid-infrared (5-40μm)
achieved by MIRACLE multi-band imaging enable us to examine the detailed structureof the circumstellar dust shells around the evolved low- to intermediate-mass stars.
・Possible dust shell around the
AGB stars are quite faint due tothe deficiency of ultra-violet
photons from the central star.
・Only a few bright PNe haveever been spatially resolved in
the mid- to far-infrared using
ground-based facilities.
100”

AKARI 90μm image of afamous red-giant U Hydra.
The dust in the shell wasformed about 104 years ago.
(ISAS/JAXA)

1”

Subaru COMICS 11.7μm
image of Galactic planetarynebula BD30+3639. Image
size is 10”.64 x 10”.64.
(Matsumoto et al. 2008)ÆHigh spatial resolution andhigh sensitivity in the mid- to
far-infrared with MIRACLE
and SAFARI can demonstrate
the dynamical and chemical
process in which circumstellar
dust is ejected into the interstellar space.

Dust formation processby low-to intermediate mass stars
UIR bands in the ISO SWS spectrum of carbon-rich
AGB star TU Tauri (Boersma et al. 2006)
TU Tauri has, so far, been the only AGB star that is known
to have PAHs; the presence of the UIR bands in TU Tau is
attributed to UV photons originating from the A2 companion.

Excellent sensitivity (>10 times of AKARI/IRC) and wide wavelength coverage in the
mid-infrared (5-40μm) achieved by MIRACLE low-resolution spectroscopy are quite
useful to detect the faint dust features dominantly powered by soft optical radiations in
the circumstellar dust shells around the AGB stars.
Æ Possible detection of PAHs features in the envelope of AGB stars, which should be
the first direct observational evidence for the formation of PAHs in the AGB phase
High-dispersion (R>10000) spectroscopic abilities in the mid-infrared (4-20μm) with
MIRHES is crucial to examine the properties of molecules in MOLsphere of redgiants.
Moderate-dispersion (R>600~1000) spectroscopic abilities in the mid-infrared (1036μm) with MIRMES and in the far-infrared (35-200μm) with SAFARI is crucial toexamine the physical conditions and chemical composition of the circumstellar gas,
molecules and dust grains around the evolved low- to intermediate-mass stars.

Life Cycle of dust：Objective #3•

科学目的 Objective– 低温高密度分子雲中におけるダスト形成・成長の過程を探る。
– Dust formation and grain growth in the cold dense molecular clouds are
examined.

•

科学目標 Target– 系内の若い星を内包するcold dense molecular cloudsの中間~遠赤外分光観測
によってiron sulphideの赤外バンドを検出し、Inter planetary Dust Particles(IDPs)中に見られるGlass with Embedded Metals and Sulfides (GEMS)とInterstellar dustの関連を解明する。これによって低温高密度分子雲中におけるダスト粒子の成長のシナリオを探る。
– Mid- to Far-infrared spectroscopic observations of cold dense molecular
clouds with embedded young stellar objects in the Milky Way are required todetect the infrared bands of iron sulphide grains and to demonstrate the link
between the Glass with Embedded Metals and Sulfides (GEMS) in
Interplanetary Dust Particles (IDPs) and the interstellar grains. Then thegrain growth scenario in cold dense molecular clouds are explored.

中分散分光装置 MIRMES
中間赤外線高分散分光装置 HIRES
遠赤外線分光撮像装置 SAFARI

Detection of iron sulphide grains
in cold dense molecular clouds
A Linkage between the Glass with Embedded Metals
and Sulfides (GEMS) in Interplanetary Dust Particles(IDPs) and the interstellar silicate grains

Glass with Embedded Metals and Sulfides (GEMS)
in IDPs (Bradley et al. 1999)

Infrared spectra of troilite (FeS) andsulphide-rich IDPs compared to “23.5μm”
feature in ISO SWS spectra of two youngstars AB Aurigae, HD163296 after
subtracting the model spectra composedof amorphous silicates, metallic Fe andcarbonaceous materials and water ice.
(Keller et al. 2002, Science, 417, 148)

The theory of Superparamagnetic (SPM)
grain alignment
Superparamagnetic (SPM) hypothesis;
Grains can align sufficiently quickly if the imaginary part of the magnetic susceptibility is greatly
enhanced over that found in paramagnetic materials (Jones & Spitzer 1967)
The required enhancement can be provided quite easily by the presence of small clusters or
inclusions of ferromagnetic materials such as metallic iron and iron oxides and sulphides.
The spacing of embedded “superparamagnetic”(SPM) inclusions in GEMS particles in IDPs;
・・・ the spatial frequency of ~0.1μm(Goodman & Whittet et al. 1995)
Æ consistent with the Mathis’s “cutoff size” ofa’~0.09μm, below which no grains are aligned
If the resemblance between the infrared spectroscopic properties of the GEMS in IDPs andthose of interstellar metal sulphides obtained in the spectra of cold dense molecular clouds,
the “superparamagnetic” inclusions in particles of GEMS in IDPs are expected to bepreserved for interstellar grains.
Æ dust formation and grain growth in cold dense molecular clouds are suggested.

Dust formation and grain growthin the cold dense molecular clouds are examined.
Enhanced depletion of sulphur in cold dense molecular clouds (Joseph et al. 1986)
Æ cold dense molecular clouds with embedded young stellar objects in the Milky
Way are favorable places to look for iron sulphide grains.
(left panel) The ISO/SWS mid-infrared
spectra of young stars AB Aurigae,
HD163296, and the evolved star M2-43
after subtracting the model spectra
composed of amorphous silicates,
metallic Fe and carbonaceous materials.
(right panel) Infrared spectra of troilite(FeS) and of pyrite (FeS 2 ) calculated
from oprical constants, and of pyrrhotite(Fe1-xS) from laboratory measurements.
(Keller et al. 2002, Science, 417, 148)

Moderate-dispersion (R>~1000) spectroscopic abilities in the mid-infrared (10-36μm)
with MIRMES and in the far-infrared (35-200μm) with SAFARI are crucial to identify
the mid-infrared features of iron sulphide grains at 23.5, 34, 38 and 44μm.
High-dispersion (R>10000) spectroscopic abilities in the mid-infrared (4-20μm) with
MIRHES is crucial to examine the properties of molecules in cold dense molecular
clouds with embedded young stellar objects in the Milky Way

Life Cycle of dust：Objective #4••

科学目的 Objective– 銀河物質進化への超新星の影響、特にダスト生成・破壊及び周囲の星間物
質へのエネルギー供給過程を明らかにする– Elucidate the effects of supernovae on the material evolution; theformation and destruction of dust grains, and energy supply processes tothe ISM
科学目標 Target– これまで赤外線で検出されている超新星残骸（系内外あわせて約30個）について、計300 時間(TBD)の中間赤外線・遠赤外線イメージ分光を行い、生成
ダスト・組成・量、衝撃派の影響・ISMへの影響を調べる。Objective#5で検出されたSNRについても同様の詳細観測も行う（約100-200 時間）– About 30 SNRs so far detected in the infrared as well as those detectedin Objective #3 will be observed with Imaging spectroscopy in the mid-to
far-infrared to investigate the composition/amount of formed dust, shock
effects, and effects on the ISM (In total about 400 to 500 hours).
中間赤外線低分散分光装置 MIRACLE 中分散分光装置 MIRMES
遠赤外線分光撮像装置 SAFARI (low-res. & high-res.)Supernovae in infrared
Information on the formation and destruction of dust by SNe as well as theinteraction with the ISM can most effectively obtained in infrared observations
SNRs in our Galaxy are located mostly on the Galactic plane, where the confusionon the line-of-sight is significant. SNRs in external galaxies provide a better
situation with respect to the confusion, but they are smaller in size and thus
requires high-spatial resolution observations, particularly in the far-infrared, which issignificant in the estimate of mass of the dust grains associated with SNRs.

SNRs in the
LMC of AKARI7, 11, & 15μm
color images(Seok et al.
2008, PASJ,
60, S453)

Supernovae – place for fast dust
production in the Universe
Despite the significance of supernovae for dust formation, the composition and amountof dust formed is not yet fully understood. This largely owes to the poor spatial
resolution of current facilities in mid-to far-infrared. It is indispensable for the study of
SNRs to separate individual components (ejecta and circumstellar matter).
Because of emission lines and multi-component
nature a wide range spectroscopy is important

AKARI Observations of G292.0+1.8 (L) 7, 15,
24μm color (R) 15/24 ratio (Lee et al. submitted)

Spitzer IRS spectra of G292.0+1.8(Ghavamian et al. ApJ in press)

Signature of dust formed in SNe
Infrared spectra have so far been obtained for only a handful of SNRs, most of whichindicate the presence of a broad hump around 15 – 25μm, depending of objects.
The diversity may indicate the evolution of dust grains.
Emission lines provide information on the physical conditions and abundance
120

400
350

A similar humpis also seen in
massive starforming regions,indicating therelation to SNe

100

300
250

80

200

60

150
100

Cas A

50
0
15

20

25

Wavelength (μm)

30Kepler

40
35

20
10

15

9

6 10

N132D
(Tappe etal. 2006)

20

25

30

Wavelength (μm)

3540Several materials
have been
proposed, but moredata are clearlyneeded for detailed
investigations

9

5 10

9

4 10

9

3 10

9

2 10

Carina nebula

9

1 10

0
10

15

20

25

30

Wavelength (μm)

3540Onaka et al. (2009)

Life Cycle of dust：Objective #5• 科学目的 Objective– 銀河内外の物質の流れを捉え、銀河スケールで物質の進化を理解する。
– We understand the physical processing and chemical evolution of the
ISM in galactic scales in view of material circulation for nearby galaxies.

• 科学目標 Target– 「あかり」サンプル近傍銀河50個に対し、計600時間の中間・遠赤外線イメー
ジ分光により、ガス診断とダスト(バンド)観測を行う。SNR、HII領域、巨大分子雲、銀河中心、ハローなど、物質の生成・破壊場所を空間分解し、大きな循環と銀河内gradientを捉える。系内物質循環の詳細研究(#1-#4)と相補的。
– By mid- to far-infrared imaging spectroscopy (600 hrs in total), we
spectrally decompose and spatially resolve emission from the ISM in 50
nearby galaxies of our AKARI sample, to track galactic-scale material
circulation from sources to sinks of the ISM in galaxies, which
complements the objectives #1-#4.

中間赤外線低分散分光装置 MIRACLE 中分散分光装置 MIRMES
遠赤外線分光撮像装置 SAFARI (low-res. & high-res.)3-D picture of ISM distributions in various gas
phasesMIRACLE & SAFARI (low-res.) enable spatially(a) 9um

resolved spectroscopic studies of dust and gas
in disks & haloes for face-on & edge-on galaxies.
Example: NGC253(a) AKARI 9um (PAH+old stars) (b) 18um (warm dust)(c) VLA 20 cm continuum→ discrete radio sources: SNRs? HII regions?
(d) AKARI 90um in color, ROSAT X-ray in contours→ dust outflow entrained by X-ray superwinds(b) 18um

3’(c)Ulvestad 2000

3’(d) 90um

3’
Kaneda et al. 2009

Galactic nuclei & Influence of their activities on
ISM
MIRMES & SAFARI (high-res.) probe central regions of galaxies by detailed
gas line diagnostics, even revealing the kinematics of material circulation flow.
Example: (left) NGC1316: AKARI/FIS images overlaid on AKARI 11um image.
→ Energy feedback outflow from a central dust reservoir (?)(right) NGC1052: a LINER elliptical.
65um

90um

The spectral gap
filled by SPICA

saturation

1’

Kaneda et al. 2008

140um

160um

Why SPICA?
• Low FIR background thanks to the cold telescope enables faint extended
emission to be detected from nearby galaxies, which Herschel cannot detect.
• Small and simple PSFs in the MIR-FIR thanks to the monolithic 3.5m mirror
can reliably resolve various dust and gas components in nearby galaxies.

Requirements for SPICA(1) MIR-FIR continuous spectral coverage is crucial for dust physics, maximizing
outputs from the cold telescope; this would make SPICA unrivalled.
(2) MIR-FIR spectroscopic imaging capability with low - moderate spectral
resolution is essential for spatially-resolved studies of nearby galaxies.
(3) For efficient mapping, we need the capability of raster mapping with variable
integration time at different positions.
(4) For better calibration of extended sources, [SiII] 34.8 um line should beobserved by both SAFARI and MIR instruments with matched spectral
capabilities. Two different modes are compared: imaging FTS and long-slit
spectral mapping.

AKARI MIR images

M51

M101

NGC2403

Life Cycle of dust : Objective #6
科学目的 Objective
天の川銀河系の恒星分布、ダスト供給源分布、ダスト分布を明らかにし、大局的な物質循環を探る。
Census of red clump giants, dust producing objects, and dust extinction in the Galactic plane to
explore the global dust circulation in the Galaxy.
科学目標 Target
天の川銀河系の、銀経－90°から＋90°、銀緯－2°から＋2°の範囲 （いわゆる銀河面）を近・中間赤外線域で撮像と分光の両面から網羅的に探査する。レッドクランプ星、長周期変光星により銀河系中心を超えて銀河系円盤部の反対側の端まで見通すことで、銀河系円盤部の恒星質量分布を得る。また、ダスト供給源である高い質量放出率を示す各種天体の分布、星間ダストの分布を得る。
これらにより、銀河系内の物質循環の具体的描像を得る。
A complete survey of objects lying in the Galactic plane area of -90d < l < 90d and -2 < b < 2d in
the near- and mid-infrared range will be performed in both mult-band imaging and low-resolution
spectroscopic modes. The Galactic plane will be looked through by red clump giants and long periodvariables to the other end of the Galactic disk, which allows to examine the stellar mass distribution
in the disk. The distributions of all kinds of objects will be revealed that supply abundant dust
grains into the ISM. Also, dust grain distribution in the Galaxy will be examined. Life cycle of dustin the Galaxy will be depicted based on these results.

焦点面検出カメラ FPC-S
中間赤外線撮像低分散分光装置 MIRACLE 中分散分光装置MIRMESGlobal dust circulation in the Galaxy
Scientific Backgrounds
Global dust grain circulation in the Galaxy not well understood... Need knowledge on the gravitational potential in the Galaxy
The Galaxy is a spiral galaxy with a bar structure in the center... Spiral pattern still not well defined... Bar structure not confirmed yet in the far-side
The central structure may have substructures... The substructure still controversial
Many high mass-loss stars are found near the center of the Galaxy... They dominate mass and dust return rates in the local space
Issues to be solved-- Stellar mass distribution in the Galaxy- Shapes of the bulge, bar, arms, and disk.
-- Distributions of high mass-loss objects in the Galaxy- Dominant contributor to the interstellar dust recycling-- Dust distribution in the Galaxy- Ejected dust grains accumulated over their life cycleGlobal dust circulation in the Galaxy

Spitzer GLIMPSE ( 0.6”/pixel,10” grid ) Galactic Plane near G. C. @3.6um
High resolution (PSF~0.7”) and high sensitivity imaging with FPC-S and MIRACLE isessential for further resolving and measuring faint crowded stars in the Galactic plane.

Global dust circulation in the Galaxy

L and M band imaging with FPC-S and MIRACLE is indispensable for detecting stars withthick circumstellar dust shells as indicated by blue circles.
Low resolution spectroscopic survey with MIRACLE is unique and powerful to characterize
the sources seen in the imaging survey.

Major Objective [3]惑星系形成過程の総合理解-Thorough Understanding ofPlanetary System Formation-

SPICA惑星系形成過程の総合理解-Thorough Understanding of Planetary System Formation-

分子雲

重力収縮による星の誕生

固体成分の沈殿・成長、集積星と原始惑星系円盤

ガス成分の散逸
惑星系

惑星系形成のパラダイム
原始惑星系円盤（ガスと塵の集まり）
太陽系外の惑星系や原始惑星系円盤に、生命の源である水や有機物質はどのように分布するのか？

塵が赤道面に集積(？)
塵の集積がどう起きて惑星へと成長するのか？
ガスの散逸はどうやって起きるのか？

地球型惑星の誕生(？)
太陽系外にどのような惑星系が存在するのか？
われわれの太陽系は普遍的な存在なのか？

ガスをまとって木星型巨大惑星に(？)
惑星系

Open Questions
Protoplanetary disk
with gas and dust

What are the distributions of gas, dust, woter ice andorganic materals: i.e., ingredients of planets & life?
Dust settling (?)

How do the accumulation of dust and planetesimals occur?
What is the role of gas for the formation of planets?
Fomation of cores(?)
Gaseous accretion (?)

What are the poplulation and diversity of exoplanetary systems?
Are planetary systems like our solar system common or unique?
Planetary systems (?)

Planetary Systems：Objective #1•

科学目的 Objective– 惑星系の多様性解明のため、太陽系外惑星の直接検出と惑星大気組成の観測を、最も観測的に有利な波長である赤外線領域において挑戦する。
• To understand the diversity of the planetary systems, we will attempt to directly detectexoplanets and to measure their atmospheric composition in the infrared wavelengths.

•

科学目標 Target– 主星：惑星のコントラスト比１０－６以上の観測を実現することにより、系外木星型惑星を直接に検出すると同時に、分光観測によりその大気の組成を明らかにする。これを我々の太陽系の惑星系と比較することにより、惑星系の多様性を解明する。
• With the planet/star contrast ratio of 10-6 or better, we will directly detect gas exoplanets,
and perform their spectroscopic observations to clarify the composition of the atmosphere.
Comparison with the results on our Solar System planets enables us to reveal thediversity of the planetary systems.

– トランジット法を利用した分光観測により、巨大地球型惑星の大気検出を試みる。木星型惑星については、多数の赤外分子バンドの観測を通し大気組成を詳細に調べる。
• With the spectroscopic observations utilizing the transit method, we will try to detect theatmosphere of giant earth-like planets. We will also apply the same approach to gas giant
planets for detailed studies of their atmosphere.

中間赤外コロナグラフ SCI
中間赤外線中分散分光装置 MIRMES
中間赤外線高分散分光装置 MIRHES

太陽系外惑星を赤外線の目ではっきりと見つける• 太陽系外惑星の直接検出とその大気組成観測– 中間赤外コロナグラフ観測装置（撮像＋分光）

Planetary Systems：Objective #2• 科学目的 Objective– 原始惑星系円盤のガスの散逸過程および散逸時間スケールを観測し、木星型惑星の形成メカニズム、および地球型惑星の生成条件を明らかにする。
• We reveal the formation mechanism of gas giant planets and initialcondition of terrestrial planet formation, by observing the process andtimescale of dispersing gas in protoplanetary disks• 科学目標 Target– 原始惑星系円盤中のガス、特に主成分である水素分子ガスを赤外線高感度観測により検出し、残存ガスの量を求め、主星の質
量や年齢との相関を解明する。
• With sensitive infrared spectroscopic observations, we willmeasure the gas in proto-planetary disks, especially molecularhydrogens, and resolve the relation of gas mass with the age ofprimary stars.

中間赤外線中分散分光装置 MIRMES
中間赤外線高分散分光装置 MIRHES
遠赤外線分光撮像装置 SAFARI

水素分子輝線で見る円盤ガス成分の進化• ガス成分を直接トレース
する水素分子輝線で、ガス円盤の温度・質量・サイズを求める– 中間赤外線分光装置による観測– 地球質量の千分の一までの水素分子質量をトレース– 他の分子ガスは遠赤外線分光でも観測
Sako et al. 06• 円盤ガス成分の進化を解明し、惑星誕生のシナリオを完成させるPlanetary Systems：Objective #3• 科学目的 Objective– われわれの太陽系と同様の空間スケールで、惑星系形
成により原始惑星系円盤がどのように進化していくかを解明する。
• We will reveal the evolution of planet forming regions in
protoplanetary disks at a spatial scale comparable to ourSolar system.

• 科学目標 Target– 原始惑星系円盤の高分散赤外線分光観測により、ガスのさまざまな速度成分の輝線強度比を求め、それに基づき円盤の空間構造、物理状態、化学組成の分布を明らかにする。
• We will elucidate the geometric, physical and chemical
structure of proto-planetary disks by measuring the motion ofgas with high-dispersion infrared spectroscopy.

中間赤外線高分散分光装置 MIRHES

ガスの運動から円盤構造をとらえる
Revealing the Disk Structure through the Gas
Motion• ガスの運動から、円盤の幾何構造や化学組成の分布を探る– 中間赤外高分散分光装置(fundamental)(overtone)

Planetary Systems：Objective #4• 科学目的 Objective– 多数の主系列星周りの塵円盤の観測により、惑星系の普遍性および多様性を理解する。
• We reveal the similarity or diversity of extrasolar systems by observing a
number of debris disks, which are much more easily observable thanexoplanets.

• 科学目標 Target– 「あかり」よりも３倍以上良い空間分解能と１０倍以上すぐれた感度により、太陽系と同程度の塵しかない円盤まで検出し、惑星系と塵円盤と相互関係を解明する。
• With the help of 3 times or more higher spatial resolution and 10 times ormore higher sensitivity than AKARI, we will detect a number of disks
whose amount of dust of even comparable to our solar system, leading us
to understand relationship with planetary systems observed using theother methods.

中間赤外線撮像装置

MIRACLE 中間赤外コロナグラフ SCI
遠赤外線分光撮像装置
SAFARI

主系列星の塵円盤の調査
Dust Disks around the Main-Sequence Stars
・SPICAの高感度赤外線観測で、あかりやスピッツァーが検出したものより、約10倍の距離にある恒星のまわりの塵円盤を多数検出できる。

Planetary Systems：Objective #5• 科学目的 Objective– 惑星系形成過程における氷の役割と、生命の起源につながる固体物
質の供給仮定を解明する。
• We will reveal the role of ice for planet formation, and how the elements fororiginating and sustaining life could be supplied to terrestrial protoplanets.

• 科学目標 Target– コロナグラフを用いて原始惑星系円盤および主系列星の塵円盤の高感度観測を行い、その進化的関係を明らかにする。
• We will apply high-contrast IR corpnagraphy to protoplanetary disks and debris
disks, observe their structures, and understand their relationship for disk
evolution.

– 主系列星の塵円盤を、「あかり」よりも３倍以上良い空間分解能で赤外線分光観測し、固体物質、特に氷および微小惑星帯の分布や物理状態を明らかにする。
• Through infrared spectroscopic observations with 3 times or higher spatial
resolution than AKARI, We will reveal distribution and physical state of solidmaterials, particularly ice, in proto-planetary disks and dust disks in the mainsequence stars.

中間赤外コロナグラフ

SCI

中間赤外線撮像装置 MIRACLE

遠赤外線分光撮像装置 SAFARI

塵円盤の固体物質• 氷（惑星材料＆生命をもたらす水）の分布と物理状態– 中間・遠赤外線撮像分光装置による観測

ISO spectrum of dust and ice features
The CSO SHARCII 350um image of Vega
associated with a young cirurumcstellar(Marsh et al.) with SAFARI pixel scale at 43-62um
disk in HD 141517 (Malfeit et al. 1999)
overlaid. Spatial resolution equivalent to ~23 AU
will be enough for observing the snow-line predicted at 42 AU.

Planetary Systems：Objective #6• 科学目的 Objective– 我々の太陽系の姿を明確にし、探査機による太陽系天体の観測結果と天文学的手法による惑星系観測結果を結ぶ為、太陽系内の始原天体の物理的情報を太陽系外縁部まで調査する。
– In order to reveal the whole picture of the solar system, we willsurvey physical information for primordial objects in the solar system.

• 科学目標 Target– 「あかり」よりも10倍以上すぐれた感度により、太陽系内始原天体のアルベド・サイズ・熱慣性・組成を太陽系外縁部まで調査する。
– With the help of 10 times or more higher sensitivity than AKARI, we
will make an unprecedented survey of albedo, size, thermal inertia,
and surface composition for primitive objects in the solar system.

遠赤外線分光撮像装置 SAFARI
中間赤外線撮像・低分散分光装置 MIRACLE
中間赤外線高分散分光装置 MIRHES

太陽系小天体の探査
Survey of Our Solar System

y near-Earth objects, main-belt asteroids,
Jovian Trojans, Centaurs, TransNeptunian objects, comets (photometry
with MIRACLE & SAFARI)z Systematic search of surface
materaial for SSOs (spectroscopy
with MIRHES & SAFARI)y Determination of size distribution of
NEAs, MBAs (>0.1km in diameter),
Jovian Trojans (>0.3km), and TNOs(>30km)y Study of correlation among the physicaland dynamical properties for SSOs

SAFARI/SPICA will detect most
discovered outer SSOs (and theSSOs which will be discovered in the
future) by photometric-mode and halfof discovered outer SSOs by
spectroscopy.
12µm
20µm
26µm
32µm
42µm

1000

sensor limited detectability(confusion free) of
SSOs in diameter [km]z Establishment of comprehensive
catalogue of albedo, size, andthermal inertia for primitive objects
in the solar system (SSOs);

48µm
85µm
160µm
Outer SSOs
V=24.5mag, pv=0.04

PhotometryObs date: 20200101
pv=0.1, ILM

100

10

1

0.1

Det Num: 815/842 (97%)
Orbit data: MPCORB.DAT in 20080917

1

10

heliocentric distance [AU]100

太陽系始原天体の探査
Survey of Our Solar Systemz

始原天体の熱輻射観測によるアルベド・サ
イズ・熱慣性の決定– 中間・遠赤外線による測光観測– 衛星・近地球型小惑星・メインベルト小惑星・木星トロヤ群・太陽系外縁部天体・短周期彗星・長周期彗星のアルベ
ド・サイズ・熱慣性– 各始原天体をグループ分けし、太陽系形成・進化に関連する物理的情報を統計的に調べる分光観測による組成探査– 中間・遠赤外線による分光観測– 彗星の揮発性成分探査

12µm
20µm
26µm
32µm
42µm

1000

sensor limited detectability(confusion free) of
SSOs in diameter [km]

•

48µm
85µm
160µm
Outer SSOs
V=24.5mag, pv=0.04

PhotometryObs date: 20200101
pv=0.1, ILM

100

10

1

0.1

Det Num: 815/842 (97%)
Orbit data: MPCORB.DAT in 20080917

1

10

heliocentric distance [AU]SPICAは、現在までに発見されている殆ど全ての外縁天体の測光観測と、約半分の天体の分光観測が可能。また将来HSC/SubaruPan-STARRS・LSSTで発見されうる太陽系内小天体についても殆どの測光観測が可能である

100

太陽系外縁部の探査
Survey of Outer Solar System
太陽系外縁天体（TNO）のSED例。TNOのサイズとアルベドを決めるには、遠赤外線観測が重要。SPICAであれば、60AU でも観測可能な天体がある

太陽系外縁天体のサイズ（直径）に対する累積
ヒストグラム（ Davis, Farinella 1997を基に計算）。