DIOS : the Dark Baryon Exploring Mission

DIOS : the Dark Baryon Exploring Mission -‐ Diﬀuse Intergalac=c Oxygen Surveyor -‐
DIOS
PI : Ohashi, T. Purpose : To observe cosmic web. Y. Tawara, I. Mitsuishi (Nagoya U), T. Ohashi, Y. Ishisaki, Y. Ezoe, S. Yamada (TMU), K. Mitsuda, N. Yamasaki, Y. Takei (ISAS/
JAXA) & DIOS working group 1
DIOS collabora=on
• TMU: T. Ohashi, Y. Ishisaki, Y. Ezoe, S. Sasaki, S. Konami • Nagoya: Y. Tawara, I. Mitsuishi, A. Furuzawa, I. Sakurai • U. Tokyo: Y. Suto, H. Kawahara • Tsukuba U: K. Yoshikawa • Tokyo Tech: N. Kawai • Kanazawa U: R. Fujimoto • Toho U: T. Kitayama • ISAS/JAXA: K. Mitsuda, N. Yamasaki, Y. Takei, M. Ishida • Kyoto U: T. Tsuru • Tokyo U Sci: K. Matsushita, K. Sato • Saitama U: M. Tashiro • Aoyama Gakuin U: A. Bamba, M. Sawada • RIKEN: S. Yamada • Nara Wemen's U: N. Ota Support from overseas colleagues •  SRON (NL): J.-‐W. den Herder, H. Akamatsu •  IASF (Italy): L. Piro •  NASA/GSFC (US): R. Kelley, S. Bandler •  MIT (US): E. Figueroa-‐Feliciano •  NASA/MSFC (US): C. Kouveliotou 2
Thermal history of the universe
Warm-‐Hot Intergalac=c Medium “ WHIM” 105K<T<107K. ρ<1000ρB Ursino+2014 3
– 23 –
Science Target of DIOS
! 
More than half of baryons in the local universe remain uniden=ﬁed (Fukugita et al. 98): (dark baryon) Numerical simula=ons indicate much of local baryons are in the form of Warm-‐Hot Intergalac=c Medium (WHIM: ~ 106 K) Spa=al distribu=on, physical state(kT, n, Z) need to be measured to study WHIM !  Search for dark baryon and study of its nature reveal chemical and structure forma=on of the universe. (= DIOS target in n-‐kT diagram) ! 
Shull et al. 2012
Fig. 8.— Compilation of the current observational measurements of the low-redshift baryon
census (Section 3.3). Slices of the pie-chart show baryons in collapsed form (galaxies, groups,
clusters), in the circumgalactic medium (CGM) and intercluster medium (ICM), and in cold
gas (H I and He I). Large reservoirs include di↵use photoionized Ly↵ forest, and WHIM
traced by O VI and broad Ly↵ absorbers. Blended colors (BLAs and O VI) have combined
total of 25 ± 8%, accounting for double-counting of WHIM at 105 106 K with detectable
metal ions. The collapsed phases (galaxies, CGM, ICM, cold neutral gas) total 18 ± 4%.
Formally, 29 ± 13% of the baryons remain unaccounted for. Some could be detected in
hotter, X-ray absorbing WHIM at T
106 K. Large error bars on other IGM phases allow
additional “missing baryons” in photoionized gas and low-column density O VI and Ly↵
absorbers. Deeper spectroscopic UV and X-ray surveys are needed to resolve this issue.
DIOS observable
Temperature
! 
Starforming
Ly α
Density (overdensity)
Branchini et al. 2009
4
Status of WHIM search and DIOS strategy
Chandra ! 
Absorp=on lines can detect low-‐
temperature gas using bright bgd source – but, geometry and thermal structures are diﬃcult to es=mate –  UV abs. line (OVI) probes only about 10% of the WHIM –  X-‐ray abs. line : Signiﬁcance is s=ll poor Blazar H2356 (z = 0.17): LETG
C V line at z = 0.112 (4.2σ) WHIM at z=0.11
0
-5
0
-5
0
-5
44
Zappacosta et al. 2012
2
0
-2
-4
-6
44
! 
DIOS： –  High resolu=on survey of oxygen emission lines from WHIM (ΔE < 5 eV, with 200-‐300 =mes the ASTRO-‐H grasp [SΩ]) –  3-‐dimensional distribu=on of WHIM will be observed Fig. 2.— R
fit continuum
and renorma
panels show
the total co-a
Fig. 1.— Portions of the total co-added spectrum covering the
CV and OVII regions at the z=0.112 of the intervening absorber.
The magenta model is the best-fit continuum. Blue and red lines
refer to the modelling for the intervening and blazar frame systems.
out of the 6 best-fitting continuum residuals, and appears prominent in the best-fitting continuum residuals
to the co-added spectrum. The second absorption feature
is only visible in the best-fitting continuum residuals to 5
the co-added spectrum.
In the following analysis, we focus exclusively on the
Yoshikawa et al. 2001
co-added H
28.0 ˚
A, 31.
chose these
where tran
with CV i
ization, or
produce sig
we used sim
range, we a
the atomic
shift (Figur
Absorp=on line WHIM search
6
DIOS and its grasp (SΩ)
SΩ-(cm2-deg2)
1000
1 m
Orbit: 550 km al=tude, Inclina=on 30°, period 95 min 100
ATHENADIOS -X4IFU
Chandra
10
Suzaku-XIS
1
0.1
0.1
XMM
ASTRO4H-SXS
1
10
100
Energy-ResoluCon-(eV)
4-‐reﬂec=on telescope and TES calorimeter array ΔE < 5 eV, F.O.V. = 50×50 arcmin2 , SΩ > 100 cm2deg
Mechanical coolers are same as ASTRO-‐H
DIOS (Diffuse Intergalactic Oxygen Surveyor)
7 6
6
0.4
5.5
5.5
DIOS: Expected spectrum
0.2
5
-1
Takei et al. 2011
Galactic OVIII
WHIM OVIII
(z=0.033)
10
Galactic OVII
WHIM OVII
(z=0.033)
Counts s-1 keV -1 in 2.6 × 2.6 arcmin2
Astrophysical Journal, 734:91 (18pp), 2011 June 20
0
1
2
3
4
log ( ρgas/< ρgas>)
Mass fraction
4.5
-2
5
0
4.5
-2
-1
0
Detectable frac=on
1
2
log ( ρgas
Takei et al.
0.202<z<0.274 T>105K 0.5
0.4
0.3
0.2
1
0.1
Galac=c + BGD
0
-2
1
2
3
4
log ( ρgas/< ρgas>)
>0.48ph/cm /s/str for OVII & OVIII が全体の20％
10-2
5 Ms (!) with Table 1DIOS
WHIM (z = 0.033)
-3
0
Figure 4. Top left: contours of constant gas mass fraction in phase-space, i.e., the fraction in unit log ρ and log T intervals. The gas
2 slice 0.202 < z < 0.27
mean (X-axis) and its temperature is in units of K (Y-axis). The plots considers only gas particles in the redshift
Color-coded contours are drawn with respect to different values of the gas mass fraction, indicated in the color scale. Top right: sam
to gas elements characterized by O vii + O viii line systems strong enough to be detected with 1 Ms observation with CRIS. Bottom
function of the gas density obtained by merging the gas mass fraction in the ρ–T plane over its temperature. Black curve: all ga
elements in which both O vii and O viii are above 5σ detection threshold of 0.07 photons s−1 cm−2 sr−1 , corresponding to 1 Ms
curve: same as the red dotted curve but referring to a 100 ks exposure with detection threshold of 0.48 photons s−1 cm−2 sr−1 .
10-1
10
-1
0.4
0.45
0.5
Emission Line Detections
0.55
0.6
Model
texp
fline
B2
1.0
0.07
B2 0.65
0.1
0.48
0.7
B1
1.0
0.07
B1 Energy
0.1 (keV)0.48
dN O vii /dz
4.2 (3.1)
2.1 (0.6)
3.3 (1.6)
1.4 (0.03)
dN O viii /dz
2.6 (1.9)
1.5 (0.5)
2.1 (1.0)
1.1 (0.05)
dN O vii+O viii /dz
2.4 (1.6)
1.1 (0.2)
1.8 (0.7)
0.7 (<10−3 )
NO vii+O viii
639 (4
293 (5
479 (1
186 (0
Line-‐free energy ranges of MW emission give us windows in redshi{ space for WHIM detec=on 7: expected
number
O viii
and O viii
!  5 deg × 5 deg survey (1 Ms × 30) plus one Column
deep (5 M
s) ofpsimultaneous
oin=ng can be detections
a per square degree due to ga
z =model
0.5. All fulfills
estimates the
assume
an angular
resolution of 2. 6 × 2. 6. The numbers in parenthesis indic
CRIS angular resolution (goal). For this purpose, we search
To confirm that our B2
current
constraints
contributed by the WHIM.
mission lines in each ofplan
the 128 × 128 × 7 mock spectra uson the soft X-ray diffuse
background, we have compared the
re 1. Emission spectrum! 
in a 2.′ 6 × 2.′ 6 area taken in a 1 Ms observation with Xenia CRIS, assuming an energy resolution ∆E = 1 eV. Black: sum of the Galactic
Notes. Column
1: WHIM model;
Column
2: exposure time (Ms); Column 3: minimum line surface br
round and unresolved extragalactic background. The Galactic O vii triplet and the O viii Kα line at z = 0 are flagged.
Red: contribution
from
the extragalactic
required for a 5σ detection (photons s−1 cm−2 sr−1 ); Column 4: expected number of O vii detections per re
The O vii and O viii lines at z = 0.033 are indicated in the plot.
element and unit redshift; Column 5: expected number of O viii detections per resolution element and unit
lor version of this figure is available in the online journal.)
Column 6: expected number of simultaneous O viii and O viii detections per resolution element and unit
a two-step procedure. (1) We identify the O vii (triplet) and
ii lines by searching for local maxima in the appropriate en-
′
′
total SB predicted by the model in the [0.65, 1] keV band
and the redshift range of 0.202 < z < 0.274. The angular size
gas mass fraction, indicated in th
with that measured by Hickox
& ′ Markevitch (2007a) after
′
Expected 3D map at z = 0.2
Gas distribu=on at z = 0.2 (Takei et al. 2011) OVII and OVIII simultaneous 5σ
1 Ms per 1 deg ﬁeld
0.5 – 1 Ms poin=ng per posi=on. About 30 points mapped. DIOS can pick up ﬁlaments and faint galaxy groups. Overdensity ρ/<ρ> ~ 30 is explored, revealing about 30% of baryons.
9 Payload conﬁgura=on
4-‐reﬂec=on telescope
Focal length = 70 cm: wide ﬁeld with small instrument TES calorimeter Stable against noise, arrays are possible
ADR
Mechanical coolers
Cryogen-‐free cooling system： light weight, leads to IR and X future missions
図 2: DIOS 観測装置 (FXT+XSA) のシステム構成。
10
Payload mechanical design
Vacuum =ght dewar will be supported by truss structure !  Vibra=on characteris=cs sa=sﬁes spacecra{ requirements !  Payload mass is 323 kg , 380 W (Spacecra{ < 700 kg) ! 
TES calorimeter dewar
Ｘ-‐ray telescope
Radiator
1 m
Spacecra{ bus
11
FXT : Four Stage X-‐ray Telescope
搭載望遠鏡の開発
Very short F].L. , Large eﬀec=ve area & FOV " Large GRASP
的
Developed by Nagoya University Parabola
!  Mirrors will be made in-‐house using foil の拡張案に最適な望遠鏡を設計する。また、
hyperbola DIOS 搭載 4 回反射型望遠鏡の複数シェルの製作
replica=on technique (Suzaku, ASTRO-‐H) 、酸素輝線を用いて性能評価を実施し、ミッション要求性能を達成する。
F.L.
θ 700mm !  Angular resolu=on: < 5’ (required) 容及び研究方法
! 
HPD 5.4’ (D=200 mm) sample measurement 高いエネルギーを集光するためには、X 線の反射鏡に対する入射
小さくしなければならない。そこで、申請者は
DIOS
HPD 衛星で実現
6.5’ (D=500 mm) 1 nest, 8.8’ for 10 nest (Conical approxima=on)
最長焦点距離 1.2 m をもつ 4 回反射望遠鏡を提案する。反射鏡
requirement (goal) θmax ~ 2を採用し、結像性能をあげ
0 degree
は SΩ を大きくとれる Spherical-top
ang. resol. < 5’ (3’) • 
Mirror R
adii :
8
0 –
3
00 m
m に部分的に Wolter 型反射鏡を用いる。光線追跡シミュレータを
F.O.V. > 40 x 40 (50x50) •  Mirror length : 40 mm 、反射鏡の厚み、大きさや反射鏡間隔といったパラメータに対す
arcmin2 •  Mirror thickness : 170 µm -‐ : 220 µm •  Nes=ng : 183 遠鏡の性能依存性を明らかにして、最適化を行う。
Vignetting(φ
Curve
シェル (図 3　のイメージを参照
) の性能測定は小口径部
180 付
[email protected]
0.1 keV
口径部 (φ500 付近) 反射鏡をそれぞれ 10 シェルずつ用いて行う
0.5 keV
目標とする。これまでの製作法を用いて反射鏡を大量生産する。
1.0 keV
反射鏡の性能評価を行う上で重要になるのが反射鏡の位置決めで
段間の位置決め誤差をなくすために 4 段一体で反射鏡を保持する
FOV=50’ FWHM
メントプレートを用いる。また、反射鏡保持の溝幅の遊びにより、
の位置がずれので、2 枚重ねたプレートをずらすことにより溝の
図 1: 2 回反射型望遠鏡と 4 回反射
型望遠鏡の比較。
ければならない。以下では本望遠鏡を
TES calorimeter
Japan -‐ US (NASA/GSFC) collabora=on a{er Suzaku and ASTRO-‐H !  US plans Micro-‐X rocket experiment soon !  Pixel size 500-‐640 µm, Requirement 8 x 8 (goal 16 × 16 ) cover 50’ 3 / 13
6 / 13
ements
offorDIOS
ut
SQUID Chip
FDM Mission
!  Energy resolu=on : Requirement 5 eV (goal 2 eV) ith 1 SQUID, 1
!  Key issues in the development : large array of TES & read out and 4 inductances
! 
s
lly attached
iplexing
6ed
Channel
for
2 TES signals
h BBFB
analog
M
mapping
ationontolerant
moto+
Tue)
ted at 1MHz
ut
Shunt R
LC Filter
RS
✓
Input Coil
RF
Formed on chip
Feedback Coil
< 100 mK
300 K
2.5 mm
oster 411
ada+ on Thu)L
d at 1.5MHz
Poster
409
SQUID
aki+ on Thu)
Refrigerator
(ADR)
Mul=-‐pixel TES (Ti-‐Au bilayer) array : TES
16 x 16 array was successfully made Equiv.resolu=on to Astro-H
Energy : 4.8 eV at 6 keV ADR
(without absorber) 20 x nW@50
20 array under ~ 640
mKdeveloping ✓
✓ See Poster 402
Achieved 4on
pixels (Hishi+
Fri)readouts with wide dynamic range ADR inside
(for test pulse) Successfully made low power SQUID in a test chip Goal : mul=plexing 8-‐16 pixels SQUIDs
Possibility of small upgrading
! 
Space science roadmap: Small projects will use Epsilon rocket. One launch per 2 years, and the rocket capacity will be improved " larger and heavier PL ! 
DIOS may accommodate small addi=onal features # 
X-‐ray telescope (longer focal length -‐> larger eﬀec=ve area) #  e.g. (EDGE case) : FL = 1.2 m, Aeﬀ=1800 cm2 ( 3 x original) # 
Fast re-‐poin=ng (X-‐ray a{erglow of gamma-‐ray bursts) Upgraded design of 4-‐stage X-‐ray telescopeUpgraded eﬀ
baseline upgraded
Focal length
70 cm
120 cm Diameter
60 cm
100 cm
Field of View 50’
40’
design Eﬀec=ve area 200 cm2 @ 3 keV
Baseline 50 cm2 @ 6 keV
FOV
Baseline upgraded 15
16
Wide range of targets for DIOS High sensi=vity for diﬀuse so{ X-‐rays: !  3-‐dim structure of dark baryons !  Charge exchange lines from low density atmosphere !  Dynamics of hot interstellar gas (Galac=c fountain and galac=c winds) !  Large-‐scale shocks and par=cle accelera=on !  Beyond the edge of clusters of galaxies
SNR: RX J1713-‐3946
Milky-‐way hot gas
Structure of dark baryons
Cluster: A3667 Earth's magnetosphere
IGM (105-‐107K) 17
Summary
•  Science：Performs dark baryon survey and expands the X-‐ray spectroscopy science which will be started by ASTRO-‐H •  Even with small spacecra{, the large f.o.v. (50 arcmin) and low BGD will enable us to detect faint extended emission from wide range of objects •  New technologies for micro-‐calorimeters and cooling system will be further improved and provides a step leading to future large missions •  Epsilon 4th launch: call will be end of 2015 and launch will be 2022 ( the earliest case) •  (listed in “Masterplan 2014” by Science Council of Japan) 18
END
19
Ｘ線によるWHIMの観測 WHIM emission at z=0は 0.4-‐0.6 keVで観測値としてはDiﬀuse Backgroundの20％以下予測値としては12+/-‐ 4 % (Galeazzi+2009), 17+/-‐ 1% (Ursino+2014) X線では酸素輝線で現れるのでエネルギー分解能をあげれば分離可能ただし，観測値からは密度とアバンダンスの絶対値はわからない。 →　吸収線を用いれば解くことができるはず。 →　AGNまたは最強の背景光源としてGRBを利用? 0.202<z<0.274&T>105K >0.48ph/cm2/s/str for OVII & OVIII が全体の20％ Takei+ 2011 OVII+OVIIIという確実な検出では比較的高温高密度に限られてしまうが， 1st trialとしては仕方のない選択：a few*10ρB<ρ<200ρB 20 目標 z<0.3のバリオンの30(~50)%を輝線の空間分布， z分布として3Dマッピングする GRBの吸収構造としてWHIMを検出することで， WHIMの密度と重元素量に制限を与える要求仕様Ｘ線望遠鏡：視野40分以上，角度分解能5分角以上，SΩ>100cm2deg2 検出器:エネルギー分解能5eV(goal2eV)以下，素子数64以上（goal 256) 衛星システム：イプシロンロケットに搭載可能で，fast-‐repointg 機能をもつ馬場崎さん →小型衛星バスだけでなく，独自バスでの検討を行った。酒井さん DIOSの目標と要求 21 Branchini et DIOS observable
al. 2009
! 
! 
! 
Temperature
Search for Dark Baryons
Numerical simula=ons indicate much of local baryons are in the form of Warm-‐Hot Intergalac=c Medium (WHIM: ~ 106 K) Starforming
Absorp=on lines can detect low-‐
density gas – but, geometry and thermal structures are diﬃcult to Ly α
es=mate Emission lines like H-‐like and He-‐
Density (overdensity)
WHIM at z=0.11
like triplets are simple, and Zappacosta et al. 2012
spa=al structure can be Chandra measured LETG
High-‐resolu=on spectra can separate from Galac=c emission with redshi{s 0
-5
! 
0
-5
0
-5
Branchini et al. 2009 Blazar H2356 (z = 0.17): C V line at z = 0.112 (4.2σ)22
44
2
0
22-2
-4
-6
4
X-‐ray emission All Gas WHIM SZ SZ eﬀect for WHIM ? SZでclusterは暗く（温度が低く）見える。ではWHIMも同様に見えるはず？ Planck, SPTの結果では，ICMが主力でWHIMは一桁下。ただし，Redshi{依存性が小さい →近傍のWHIMはやはりＸ線輝線，遠方をSZでさがしてＸ線で確認など戦略が必要 0.4-‐0.6 keV emission ΔT ΔT 150GHz でのSZΔT Ursino+ 2014 Ursino+ 2014 24

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