Japanese Future Gravitational Wave Projects on & off Earth !
Nobuyuki Kanda (Osaka City Univ.)LCGT collaboration
DECIGO collaboration
26th Nov. 2009IUCAA, Pune
Thanks to DST and IUCAA for our visiting.
Plan of TalkIntroduction
• What is a Gravitational Wave ?• Why are we trying to measure? • GW detection
Ground-based detectors• World wide detectors• TAMA
300m, middle size, since 1995• CLIO
100m, prototype of LCGT, cryogenic test• LCGT
3km, underground, cryogenic, NS-NS range ~ 200Mpc
Space-based detectors• in General• DECIGO
Science, Conceptual design, DECIGO-Pathfinder2
Gravity has some mysterious still now...• very week,• large error for the measurement of coupling constant,
• but dominant interaction of the universe,
• not yet quantized,• intermediate boson (graviton) is not yet discovered,
• not yet confirmed ‘(wave) propagation’
4
http://CPEPweb.org/
by F.Satoarbitrary error (ambiguity)co
stan
ts
Gravity has some mysterious still now...• very week,• large error for the measurement of coupling constant,
• but dominant interaction of the universe,
• not yet quantized,• intermediate boson (graviton) is not yet discovered,
• not yet confirmed ‘(wave) propagation’
4
http://CPEPweb.org/
by F.Satoarbitrary error (ambiguity)co
stan
ts
Metric of the Space-Time
Flat Space-Time
Curved (distorted) Space-Time
5
<- t<- x<- y<- z
<-
t<
- x
<-
y<
- z
t (time)
x,y,z (space)
gµν = ηµν =
−1 0 0 00 1 0 00 0 1 00 0 0 1
ds2 = gµν dxµdxν
gµν �= ηµν
Gravity distorts the space-time.
Curved space-time
Propagation of the distortion• --> Waves !
6
Rµν − 12
gµνR = −κ Tµν
Gravity distorts the space-time.
Curved space-time
Propagation of the distortion• --> Waves !
6
Explosion of
the star ?
Rµν − 12
gµνR = −κ Tµν
Einstein Equation :
In case of small perturbation “h”, a wave equation is derived as;
• strain ‘h’• light speed• transverse• quadrupole
(tidal force)
Gravitational Waves
7
Rµν − 1
2gµνR = −κ Tµν
gµν = ηµν + hµν
�∇2 − 1
c2∂2
∂t2
�hµν = 0
h+ = h
0 0 0 00 1 0 00 0 −1 00 0 0 0
h× = h
0 0 0 00 0 1 00 1 0 00 0 0 0
Force (Displacement) by GW
Tidal force on masses
8
h+ = h
0 0 0 00 1 0 00 0 −1 00 0 0 0
h+ cos(�k · �x− 2πfGW t)
Proof of GW (indirect)Binary Pulsar PSR1913+16 observation (Hulse & Taylor)
• Pulsar is very stable clock.• Change of orbital period according
to a lost of kinetic energy by GW radiation.
Taylor, 1993(ノーベル賞講演より抜粋) 9
Direct measurements of GW, Why?
PhysicsTEST of Einstein’s general relativity in strong field.
Astronomy, Astrophysics• Radiation from compact / massive objects.
Physics of black-hole, neuron star, supernovae, etc...--> Graviational Wave Astronomy
Cosmology• Cosmic background radiation of GW• POP-III stars, star formation, etc...
Physics on early universe.
10
Expected GW sourcesEvent like:
• Coalescence of compact binaries• neutron star (NS)• black-hole (BH)
NS-NS is most promising.• Supernovae• BH ringdown
Continuous waves:• Pulsar rotation• Binaries
Stochastic Background• Early universe (i.e. Inflation)• Cosmic string
Unknown sources...
11
Coalescence of neutron star binary (NS-NS)
12
time
stra
in a
mp
litud
e
inspiral phase merger Blackholequasi-normal mode
distortion of space-time
=h =
δ�
�
Coalescence of neutron star binary (NS-NS)
12
time
stra
in a
mp
litud
e
inspiral phase merger Blackholequasi-normal mode
distortion of space-time
=h =
δ�
�
amplitude ~10-24 for NS-NS at 200Mpc away!(in frequency spectrum, ~10-22~-23 [/√Hz] @10~100Hz)
13
-2
-1
0
1
2
x10-2
4
4.03.83.63.43.23.0s
stra
in a
mp
litud
e
time
1× 10−24
• small amplitude• Waveform can determine masses and absolute amplitude.
--> ‘standard candle’
amplitude ~10-24 for NS-NS at 200Mpc away!(in frequency spectrum, ~10-22~-23 [/√Hz] @10~100Hz)
13
-2
-1
0
1
2
x10-2
4
4.03.83.63.43.23.0s
stra
in a
mp
litud
e
time
-2
-1
0
1
2
x10-2
4
3.993.983.973.963.953.943.93s
‘chirp’ waveform
1× 10−24
f(t) --> mass --> absolute amplitude
• small amplitude• Waveform can determine masses and absolute amplitude.
--> ‘standard candle’
How to detect GW : Free Test Masses & Laser Interferometer
14
Mirror
Mirror
Laser Light
Beam Splitter
Interferencecos( 2 pi 2dL /lambda)
Michelson Interferometer
t
xFree mass = mirror
t
x
light
How to detect GW : Free Test Masses & Laser Interferometer
14
Mirror
Mirror
Laser Light
Beam Splitter
Interferencecos( 2 pi 2dL /lambda)
Michelson Interferometer
t
xFree mass = mirror
t
x
light
How to detect GW : Free Test Masses & Laser Interferometer
14
Mirror
Mirror
Laser Light
Beam Splitter
Interferencecos( 2 pi 2dL /lambda)
Michelson Interferometer
t
xFree mass = mirror
t
x
light
Schematic Figure
Free mass --> suspended mirror
To integrate strain ‘h’ --> long baseline arms.
Limited size --> Folding arms / Storage cavity
Against noises -->• high power laser• Cooling• etc..
15
h =δl
�
GW & detector sensitivities (spectrum)
16
10-27
10-26
10-25
10-24
10-23
10-22
10-21
10-20
10-19
10-18
10-17
10-16
10-15
10-14
10-13
10-12
10-11
strain h [1/sqrt(Hz)]
10-4
10-3
10-2
10-1
100
101
102
103
104
frequency [Hz]
NS-NS (30kpc) NS-NS(200Mpc) Stellarcore collapse at Galactic centre WD confision noise
Stochastic GW from Inflation (! ~10-16
and ~10-15
)
LISA
Ultimate DECIGO
LCGT, adv.LIGODECIGO
LIGO I
DECIGO PathFinder
GW frequency
Str
ain
Sen
sitiv
ity =
Noi
se le
vel
World Wide Network of GW Detectors
AIGO (planned)
eLIGO (current upgarading)adv.LIGO (Start at 2014?)
LIGO (Hanford) 4km & 2km
TAMA 300m
CLIO 100m
LCGT 3km, budgetary request
LIGO (Livingston) 4km
VIRGO 3km
EGO
GEO 600m
18
Focus of Ground-based Detectors
19
10-27
10-26
10-25
10-24
10-23
10-22
10-21
10-20
10-19
10-18
10-17
10-16
10-15
10-14
10-13
10-12
10-11
strain h [1/sqrt(Hz)]
10-4
10-3
10-2
10-1
100
101
102
103
104
frequency [Hz]
NS-NS (30kpc) NS-NS(200Mpc) Stellarcore collapse at Galactic centre WD confision noise
Stochastic GW from Inflation (! ~10-16
and ~10-15
)
LISA
Ultimate DECIGO
LCGT, adv.LIGODECIGO
LIGO I
DECIGO PathFinder
Focus of Ground-based Detectors
19
10-27
10-26
10-25
10-24
10-23
10-22
10-21
10-20
10-19
10-18
10-17
10-16
10-15
10-14
10-13
10-12
10-11
strain h [1/sqrt(Hz)]
10-4
10-3
10-2
10-1
100
101
102
103
104
frequency [Hz]
NS-NS (30kpc) NS-NS(200Mpc) Stellarcore collapse at Galactic centre WD confision noise
Stochastic GW from Inflation (! ~10-16
and ~10-15
)
LISA
Ultimate DECIGO
LCGT, adv.LIGODECIGO
LIGO I
DECIGO PathFinder
10Hz ~ 10 kHz• Compact Binaries• Supernovae (Stellar-core collapse)• BH quasi-normal mode• Pulsars (Continuous wave)• Stochastic
Japanese experiments:TAMA --> CLIO --> LCGT
20
10-25
10-24
10-23
10-22
10-21
10-20
10-19
10-18
10-17
10-16
10-15
10-14Strain equivalent noise spectrum [1/rHz]
10 100 1000 10000
frequency [Hz]
LCGT design : Broadband RSE Detuned RSE
Operated Detectors :
CLIO (current, in normal temperature) TAMA dt9 LIGO_I
Japanese experiments:TAMA --> CLIO --> LCGT
20
10-25
10-24
10-23
10-22
10-21
10-20
10-19
10-18
10-17
10-16
10-15
10-14Strain equivalent noise spectrum [1/rHz]
10 100 1000 10000
frequency [Hz]
LCGT design : Broadband RSE Detuned RSE
Operated Detectors :
CLIO (current, in normal temperature) TAMA dt9 LIGO_I
Japanese experiments:TAMA --> CLIO --> LCGT
20
10-25
10-24
10-23
10-22
10-21
10-20
10-19
10-18
10-17
10-16
10-15
10-14Strain equivalent noise spectrum [1/rHz]
10 100 1000 10000
frequency [Hz]
LCGT design : Broadband RSE Detuned RSE
Operated Detectors :
CLIO (current, in normal temperature) TAMA dt9 LIGO_I
TAMA
CLIO
LCGT
Japanese experiments:TAMA --> CLIO --> LCGT
20
10-25
10-24
10-23
10-22
10-21
10-20
10-19
10-18
10-17
10-16
10-15
10-14Strain equivalent noise spectrum [1/rHz]
10 100 1000 10000
frequency [Hz]
LCGT design : Broadband RSE Detuned RSE
Operated Detectors :
CLIO (current, in normal temperature) TAMA dt9 LIGO_I
TAMA
CLIO
LCGT
since 1995-middle size (300m)establish interferometer technique and data analysis
prototype of LCGTundergroundto confirm a cryogenic technique
3kmundergroundcryogenic
TAMA300
Configuration• Fabry=Perot=Michelson, with Power Recycling• baseline: 300m• laser: Injection-lock Nd:YAG, 10W, 1064nmSite• National Astronomical Observatory,
Mitaka, Tokyo
21
TAMA
300m
300m
(1995- )middle size detector
GW searches in TAMA
24
Source or GW Search Method Results
Inspiral from binary Matched FilteringUpper Limit : ~20 event/yr for MWG
Phys. Rev. D 74, 122002 (2006).
BH Ringdown Matched FilteringTrigger Rate :< 1 event/day for MWG
Phys.Rev. D71 (2005) 103005
Burst from core collapse
Excess PowerUpper Limit: 6 x 103 ev/sec for MWG
Phys. Rev. D 71 (2005) 082002
Burst from core collapseALF
Upper Limit:0.55 ev/day for hrss ~ 10-17
Class. Quantum Grav. 23 (2006) S715Burst from core collapse
TF ClusterUpper Limit (partial data)1.4 x 10-3 ev/sec within 10pc
Class. Quantum Grav. 25 (2008) 184035
Burst from core collapse
Wavelet Success the Extraction of Unstable component
(Burst like noise) veto with AUX ch. Systematic trial was done.Class. Quantum Grav., 24 S405, (2007)
continuous GW from SN1987A remnant pulser integration h ~ 4 x 10-23
Class. Quantum Grav. 20 (2003) 645.
These will be extend/upgrade for LCGT.
TAMA
25
Reduction of noises ! Seismic disturbances --> UndergroundThermal motion --> Cryogenicenhance GW --> km baseline
Recent status : CLIO
Sensitivity reach to the thermal noise at room temperature.
28
10-19
10-18
10-17
10-16
10-15
10-14
10-13
Displacement [m/rtHz]
5 6 7 8 910
2 3 4 5 6 7 8 9100
2 3 4 5 6 7 8 91000
2 3
Frequency [Hz]
Mirror thermal noise (300K) 081105_5 (Current best) 090427_2 (15:30)
Search GW from Vela pulser
Vela pulser (PSR J0835-4510)• might radiate GW at ~ 22Hz• Search : Complex Heterodyne + Matched Filter• Using observation data in 2007
Upper limit : h0 ~ 5.3 x 10-20 (C.L.99.4%)
29
T.Akutsu et al., Class. Quantum Grav. 25 (2008) 184013
Location of LCGTLCGT is planed to be built underground at
Kamioka, where the prototype CLIO
detector is placed.
LCGT
Underground• in Kamioka, Japan• Silent & Stable environment
3km baseline
Cryogenic Mirror• 20K• saffhire substrate
30
Plan2011-2014 : construction2015-2016 : commissioning2017- : observation
LCGT collaboration
31
Man power OrganizationLCGT is hosted by ICRR under MOU with NAOJ and KEK. Its organization consists of 92 domestic researchers belonging to 17 universities or research institutes and 26 oversea membersbelonging to 14 universities or research institutes (118 researchers in total).
LCGT Board consists of representatives of ICRR, NAOJ, and KEK with other senior members
LCGT collaboration
31
Man power OrganizationLCGT is hosted by ICRR under MOU with NAOJ and KEK. Its organization consists of 92 domestic researchers belonging to 17 universities or research institutes and 26 oversea membersbelonging to 14 universities or research institutes (118 researchers in total).
LCGT Board consists of representatives of ICRR, NAOJ, and KEK with other senior members
Optical design
32
Optical design of LCGT
Re-design is under going ;for example---removing the 180 m long mode cleaner cavity---flexibility change of possible adoption of detuned RSE
Broad band RSE installed in a power recycled FP-Michelson interferometer
33
Design of anti-vibration system
A B C
A)SAS(GASF 3stage)+cryo-sus:FM1、FM2、EM1、EM2
B)SAS(GASF 2stage)+non-cryo:BS、PRM、SEM、FM、MC2F、MC2E
C)STACK+2stages: MC1F、MC1E、MMT、PD
34
Design of Quiet refrigerator
Switching box
Pulse tube ref.1st & 2nd stages
To compressor4K cold head
40K cold stage
Soft heat links
Design Sensitivity
35
10-24
10-23
10-22
10-21
10-20
10-19
Strain equivalent noise spectrum [1/rHz]
10 100 1000
frequency [Hz]
Broadband RSE Detuned RSE
Binary inspiral:
1.4-1.4 Msolar, 200Mpc BH ringdown: Kerr param. a=0.95
2.8 Msolar 100 Msolar
Stellar core collapse at Galactic Centre
DFM waveforms
Expected Number of NS-NS events
371.00.5 2.00.2 5.00.10.0
0.2
0.4
0.6
0.8
1.0
Observation time �yr�
Probabilityofdetection
�atleast1enent�
Detection Range (optimal direction, S/N>8)
Expected # of events/yr
LCGT (BRSE) 231 Mpc 3.9 +9.82 -3.11
LCGT (DRSE) 312 Mpc 9.2 +23.1 -7.29
Galactic DNS rate : 83.0+209.1 x10-6 (C.I.95%) -66.1V. Kalogera, ApJ, 601, L179 (2004)cf: Kim, C., AIP Conference Proceedings, vol. 983, pp. 576 (2008)
1 ye
ar o
bser
vatio
n
6 m
onth
s
1 m
onth
90% detection
38
Sensitivity for Continuous Waves
10-28
10-27
10-26
10-25
10-24
10-23
Strain h
1 10 100 1000frequency [Hz]
Broadband RSE, with 1yr integration 10yr integration 2weeks integration
Detuned RSE, with 1yr integration 10yr integration 2weeks integration
known pulsars with maximum allowed amplitude LMXB etc.
Other Possibe Sources
BH quasi-normal mode ringdown• Typical mass range : several 10 Msolar ~ 104 Msolar
Supernovae• up to ~ a few Mpc away• core collapse, core bounce• 3D instability• convection & SASI• PNS core g-mode
StochasticSingle detector can’t do...
• It must be done by international network.39
Network of Detectors
International Network of the GW detectors is important.
LCGT would like to contribute.
AIGO
LIGO (Hanford) 4km & 2km
TAMA 300mCLIO 100mLCGT 3km
LIGO (Livingston) 4km
VIRGO 3kmEGO
GEO 600m
90
0
-90-12 0 12
decl.[deg]
Quadratic Sum : LCGT+LIGO(Hanford)
Sky coverage by detector network
LCGT will make important role in the network,with a complemental sensitivity map.
zenith direction of detectorsLIGO HanfordLIGO LivingstonVIRGOLCGT
-12 0 12
LCGT90
0
-90
LIGO (Hanford)
R.A.[hour]
-12 0 12
90
0
-90
decl.[deg]
41R.A.[hour]
decl.[deg]
R.A.[hour]
R.A.[hour]
90
0
-90-12 0 12
decl.[deg]
Quadratic Sum : LCGT+LIGOx2+VIRGO
Sky coverage by detector network
zenith direction of detectors LIGO HanfordLIGO LivingstonVIRGOLCGT
-12 0 12
LCGT90
0
-90
LIGO x2 + VIRGO
-12 0 12
90
0
-90
42
LCGT will make important role in the network,with a complemental sensitivity map.
R.A.[hour]
decl.[deg]
R.A.[hour]
decl.[deg]
43
We have been developed :TAMA -> CLIO -> LCGT
LCGT is future Japanese ground-based detector.• underground• cryogenic mirror• long (km) baseline• NS-NS detection range will reach as over 200 Mpc.
for the first detection of GW in world-wide network.
Future “Space” Detectors
45
LISA (NASA, ESA)
DECIGO (Japan), BBO(NASA)To escape from seismic noise, to achieve longer base-
line, we will place laser interferometers in space !
figure: LISA
sun
earth
Focus of Space-based Detectors
46
10-27
10-26
10-25
10-24
10-23
10-22
10-21
10-20
10-19
10-18
10-17
10-16
10-15
10-14
10-13
10-12
10-11
strain h [1/sqrt(Hz)]
10-4
10-3
10-2
10-1
100
101
102
103
104
frequency [Hz]
NS-NS (30kpc) NS-NS(200Mpc) Stellarcore collapse at Galactic centre WD confision noise
Stochastic GW from Inflation (! ~10-16
and ~10-15
)
LISA
Ultimate DECIGO
LCGT, adv.LIGODECIGO
LIGO I
DECIGO PathFinder
Focus of Space-based Detectors
46
10-27
10-26
10-25
10-24
10-23
10-22
10-21
10-20
10-19
10-18
10-17
10-16
10-15
10-14
10-13
10-12
10-11
strain h [1/sqrt(Hz)]
10-4
10-3
10-2
10-1
100
101
102
103
104
frequency [Hz]
NS-NS (30kpc) NS-NS(200Mpc) Stellarcore collapse at Galactic centre WD confision noise
Stochastic GW from Inflation (! ~10-16
and ~10-15
)
LISA
Ultimate DECIGO
LCGT, adv.LIGODECIGO
LIGO I
DECIGO PathFinder
mHz - deci-Hz• Stochastic background from eary univerise
• Binaries• BHs
drawn by Sora.K
DECIGO / DECIGO Path Finder
DECIGO collaboration
47
Seiji Kawamura, Takashi Nakamura, Kimio Tsubono, Takahiro Tanaka, Ikkoh Funaki, Naoki Seto, Kenji Numata, Shuichi Sato, Nobuyuki Kanda, Takeshi Takashima, Kunihito Ioka, Kazuhiro Agatsuma,
Tomotada Akutsu, Tomomi Akutsu, Koh-suke Aoyanagi, Koji Arai, Yuta Arase, Akito Araya, Hideki Asada, Yoichi Aso, Takeshi Chiba, Toshikazu Ebisuzaki, Motohiro Enoki, Yoshiharu Eriguchi, Masa-
Katsu Fujimoto, Ryuichi Fujita, Mitsuhiro Fukushima, Toshifumi Futamase, Katsuhiko Ganzu, Tomohiro Harada, Tatsuaki Hashimoto, Kazuhiro Hayama, Wataru Hikida, Yoshiaki Himemoto,
Hisashi Hirabayashi, Takashi Hiramatsu, Feng-Lei Hong, Hideyuki Horisawa, Mizuhiko Hosokawa, Kiyotomo Ichiki, Takeshi Ikegami, Kaiki T. Inoue, Koji Ishidoshiro, Hideki Ishihara, Takehiko Ishikawa,
Hideharu Ishizaki, Hiroyuki Ito, Yousuke Itoh, Shogo Kamagasako, Nobuki Kawashima, Fumiko Kawazoe, Hiroyuki Kirihara, Naoko Kishimoto, Kenta Kiuchi, Shiho Kobayashi, Kazunori Kohri, Hiroyuki Koizumi, Yasufumi Kojima, Keiko Kokeyama, Wataru Kokuyama, Kei Kotake, Yoshihide Kozai, Hideaki Kudoh, Hiroo Kunimori, Hitoshi Kuninaka, Kazuaki Kuroda, Kei-ichi Maeda, Hideo Matsuhara,
Yasushi Mino, Osamu Miyakawa, Shinji Miyoki, Mutsuko Y. Morimoto, Tomoko Morioka , Toshiyuki Morisawa, Shigenori Moriwaki, Shinji Mukohyama, Mitsuru Musha, Shigeo Nagano,
Isao Naito, Noriyasu Nakagawa, Kouji Nakamura, Hiroyuki Nakano, Kenichi Nakao, Shinichi Nakasuka, Yoshinori Nakayama, Erina Nishida, Kazutaka Nishiyama, Atsushi Nishizawa, Yoshito Niwa,
Masatake Ohashi, Naoko Ohishi, Masashi Ohkawa, Akira Okutomi, Kouji Onozato, Kenichi Oohara, Norichika Sago, Motoyuki Saijo, Masaaki Sakagami, Shin-ichiro Sakai, Shihori Sakata, Misao Sasaki,
Takashi Sato, Masaru Shibata, Hisaaki Shinkai, Kentaro Somiya, Hajime Sotani, Naoshi Sugiyama, Yudai Suwa, Hideyuki Tagoshi, Kakeru Takahashi, Keitaro Takahashi, Tadayuki Takahashi,
Hirotaka Takahashi, Ryuichi Takahashi, Ryutaro Takahashi, Takamori Akiteru, Tadashi Takano, Keisuke Taniguchi, Atsushi Taruya, Hiroyuki Tashiro, Mitsuru Tokuda, Masao Tokunari,
Morio Toyoshima, Shinji Tsujikawa, Yoshiki Tsunesada, Ken-ichi Ueda, Masayoshi Utashima, Hiroshi Yamakawa, Kazuhiro Yamamoto, Toshitaka Yamazaki,
Jun'ichi Yokoyama, Chul-Moon Yoo, Shijun Yoshida, Taizoh Yoshino
DECIGO
Science of DECIGO
Stochastic Background GW : Hearing a call of the early universe
Huge number of binary systems :Foreground (cleaning) problem
Probing dark energyNS formation
Black Hole related GWIMBH (intermediate mass blackhole)BH+NS
Others...
50
DECIGO
Science of DECIGO
Stochastic Background GW : Hearing a call of the early universe
Huge number of binary systems :Foreground (cleaning) problem
Probing dark energyNS formation
Black Hole related GWIMBH (intermediate mass blackhole)BH+NS
Others...
50
cosmological interests !
DECIGO
Deci-Hz band has fruitful info. Compact Binaries (NS, stellar mass BH, IMBH)
1 ~ several years before coalescence of NS-NS
Escape from WD-WD confusion noise around mHz51
TGW ∼�
f
0.2[Hz]
�−8/3 �M
1.2M⊙
�−5/3
[yrs]
f ∼�
Gρ ∼�
ρ
106[g/cm3]
�1/2
[Hz]
0.01
0.1
1
10
frequ
ency
[Hz]
3.0x1082.52.01.51.00.50.0time [sec]
1.4-1.4 Msolar 10-10 Msolar
DECIGOStochastic Background GW from early universe
Two (or more) set of DECIGO/BBO make possible to reach the sensitivity of stochastic GW from early universe.
52
Ω
Ω
Ω
DECIGO
Foreground GW from NS-NS binariesMany neutron star binaries are exist.
Roughly ~105 NS-NS binary mergers will appear on DECIGO for year(s) of observation.These signals called as NS-NS ‘foreground’.It appear as ‘confusion noise’ around 0.1Hz.
53
10-24
10-23
10-22
10-21
0.012 3 4 5 6 7 8 9
0.12 3 4 5 6 7 8 9
1Hz
DECIGO instrumental noise spectrum simulated signal : noise + 105 NS-NS binaries*
* 0-10 years before merge
How to remove is a problem.(In another words, we will use
many NS’s GWs !)
DECIGOCleaning requires ...Quite huge number of templates will be needed.
(Culter & Harms, Phys.Rev. D73 042001, for BBO)
Very acculate waveform parameters must be determined. → Δm/m < ~10-7 %
(in our estimation)
54
!"#$%
!"#$&
!"#$'
!"#$$
$ ' & % ( ) * +",!
$ ' & % ( ) * +!
-.
/012345/67896:8/;<8=>9?@/
/;AB;/CB8DA98/=E86FGF:H/;=E86F//<AI89/;<8=>9?@
//!@J@/K/!"#%/L
//!@J@/K/!"#(/L
//!@J@/K/!"#)/L
However, in principle, the
cleaning will be possible !
(total fitting parameters)/(data amount)
~(R x Tobs x n) / (f x Tobs)
DECIGO
NS-NS probe for ...NS formation
DECIGO might see z~5 NS binaries.S/N ~ (1+z)1/6
Good angular resolution~ λ/D ~ 109 m / 1AU ~ 10-2 rad (❨Diffraction limit. It will be slightly better with mode analysis.)❩
Dark energy, or Weak lensinggeometrical test of high-redshift universe
dL-z relation
55
Cutler&Holz, arxiv0906.3752
DECIGOAcceleration of Expansion of the Universe
NS-NS (z~1)GW
DECIGO
Output
Expansion +Acceleration?
Time
Stra
in
Template (No Acceleration)
Real Signal ?Phase Delay~1sec (10 years)
Seto, Kawamura, Nakamura, PRL 87, 221103 (2001)
DECIGO
More Massive Objects
IMBH (Intermidiate Mass Black Hole)Enough high S/N
1000Msolar-1000Msolar @ z=1 --> S/N ~ 103
BH + NSAlso enough S/N, better than NS-NS.
57
DECIGO
DECIGO conceptual design
58
Let’s focus on experimental apparatus.
Laser
Photo-detector
!"""#$%&$ '()*+,-
.&)/01&22'345
%&$ '()*+,-
Mirror
Deci-hertz Interferometer Gravitational Wave ObservatoryConceptual design :
Space-based, drag freeFabry=Perot IF, Finesse:10, 10W 532nm laser,3 interferometers1000 km base linemirror diameter : 1m, weight 100 kg
DECIGO
Why FP cavity?
Frequency
Stra
in
Radiation pressure
noise f -2
Shot noiseShot n
oise f1
Transponder type(e.g. LISA)
Shot noise
Shortenarm length
Shot noise
f1
Radiation pressure
noise f -2
Transponder type(e.g. LISA) Shorten
arm length Implement FP cavity
Implement FP cavity
FP cavity type Better best- sensitivity
DECIGO
Requirements
Acceleration noise should be suppressed below radiation pressure noiseForce noise: DECIGO = LISA/50 (Acceleration noise in terms of h: 1, Distance: 1/5000, Mass:
100)Fluctuation of magnetic field, electric field, gravitational field, temperature, pressure, etc.
Sensor noise should be suppressed below shot noise.Phase noise: DECIGO = LCGT×10 (Sensor noise in terms of h: 1, storage time: 10)
Frequency noise, intensity noise, beam jitter, etc. Thruster system should satisfy range, noise,
bandwidth, and durability.
DECIGO
Cavity and S/C control
Local Sensor
Actuator
Displacement signal between the two Mirrors
Thruster Thruster
Displacement Signal between S/C and Mirror
Mirror
S/C 1
S/C 2
Fig: S. Kawamura
Cavity length change PDH error signal Mirror position (and Laser frequency)
Relative motion between mirror and S/C Local sensor S/C thruster
DECIGO
Orbit and Constellation
Record-disk orbit around the Sun
Relative acc. 4x10-12 m/s2
Halo orbit around L2 (or L1)
Relative acc. 4x10-7 m/s2
(Mirror force ~10-9 N )
(Mirror force ~10-4 N )
Separated unit
Constellation
4 interferometer units
2 overlapped units Cross correlation
2 separated units Angular resolution
overlapped units
Separated unit
Candidate of orbit:
DECIGO
Orbit and Constellation
Record-disk orbit around the Sun
Relative acc. 4x10-12 m/s2
Halo orbit around L2 (or L1)
Relative acc. 4x10-7 m/s2
(Mirror force ~10-9 N )
(Mirror force ~10-4 N )
Separated unit
Constellation
4 interferometer units
2 overlapped units Cross correlation
2 separated units Angular resolution
overlapped units
Separated unit
Candidate of orbit:
DECIGO
DECIGO-PF
DECIGO Pathfinder (DPF)
Single satellite
(Payload ~1m3 , 350kg)
Low-earth orbit (Altitude 500km, sun synchronous)
30cm FP cavity with 2 test masses Stabilized laser source
Drag-free control
Local Sensor
Actuator
Thruster
First milestone mission for DECIGOShrink arm cavity DECIGO 1000km DPF 30cm
DECIGO
DPF satellite
Stabilized. Laser source
Interferometer module
Satellite Bus system
Solar Paddle
MissionThruster head
On-boardComputer
Bus thruster
Mast structure
Satellite Bus (‘Standard bus’ system)
DPF PayloadSize : 950mm cubeWeight : 150kgPower : 130WData Rate: 800kbpsMission thruster x12
Power SupplySpW Comm.
Size : 950x950x1100mmWeight : 200kgSAP : 960W Battery: 50AHDownlink : 2MpbsDR: 1GByte3N Thrusters x 4
DECIGO
DPF mission payload
Fabry-Perot interferometer Finesse : 100
Length : 30cm
Test mass : 1kg
Signal extraction by PDH
Drag-free control Local sensor signal Feedback to thrusters
Mission weight : ~150kgMission space : ~90 x 90 x 90 cm
Laser source Yb:YAG laser (1030nm) Power : 25mW Freq. stab. by Iodine abs. line
DECIGODPF Sensitivity
Satellite mass : 350kg, Area: 2m2
Altitude: 500kmThruster noise: 0.1μN/Hz1/2
Laser source : 1030nm, 25mW IFO length : 30cmFinesse : 100, Mirror mass : 1kgQ-factor : 105, Substrate: TBDTemperature : 293K (Preliminary parameters)
DECIGO
Possible GW target of DPF
Observable range reaches the Galactic center (SNR~5 )
BH QNM
h ~ 10-15 , f ~ 0.3 Hz Distance 1Mpc, m = 105 Msun
IMBH inspiral and merger
Obs. Duration (~1000sec)
h ~ 10-15 , f ~ 4 Hz Distance 10kpc, m = 103 Msun
KAGAYA
Blackholes events in our galaxy
Hard to access by others Original observation
DECIGOPossible GW target of DPF
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For equarl mass binary with S/N>5, a range reach to 100kpc for IMBH.
dete
ctio
n ra
nge
Galactic centre
by K.Yagi(Kyoto Univ.)
DECIGOPossible GW target of DPF
69
IMBH binary in globular cluster in our galaxy would be targets.
velocity deviation
mass distance *Masses are estimated from velocity deviations.
DPF can detect!
not detectabledi
stan
ce
expected rate : 3.3 x10-9 events/yr by K.Yagi(Kyoto Univ.)
DECIGO
Gravity of the EarthMeasure gravity field of the Earth for Satellite Orbits
Determine global gravity field
Density distributionMonitor of change in time Ground water motion
Strains in crusts by
earthquakes and volcanoes
GPS satellite
東京大字地震研・新谷氏、京都大学・福田氏の資料/情報提供
Observation Gap
between GRACE and GRACE-FO (2012-16) DPF contribution
in international network
DECIGO
R&D for DPF (1)
Stabilized Laser BBM development Yb:YAG (NPRO) source Saturated absorption by I2
Stability test, Packaging
By M.Musha
By S.SatoIFO and housing BBM-EM development Test of concepts + Earth gravity sensors
By A.Araya
DECIGO
R&D for DPF (2)
Attitude control and Drag-free Satellite structure (mass distribution) Passive attitude stabilization
by gravity gradient Mission thruster position
Control topology
ByS.Moriwaki
DECIGO
R&D for DPF (2)
Attitude control and Drag-free Satellite structure (mass distribution) Passive attitude stabilization
by gravity gradient Mission thruster position
Control topology
Thruster System design with existing tech. Noise meas. system (thruster stand) Development of Slit FEEP
By I.Funaki
ByS.Moriwaki
DECIGO
Roadmap of DECIGO/DPF
73
2009 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
Mission
Objectives Test of key technologiesTest of key technologiesTest of key technologiesTest of key technologiesTest of key technologiesTest of key technologiesTest of key technologiesTest of key technologiesTest of key technologies
Detection of GW w/ minimum spec.Test FP cavity between S/C
Detection of GW w/ minimum spec.Test FP cavity between S/C
Detection of GW w/ minimum spec.Test FP cavity between S/C
Detection of GW w/ minimum spec.Test FP cavity between S/C
Detection of GW w/ minimum spec.Test FP cavity between S/C
Detection of GW w/ minimum spec.Test FP cavity between S/C
Full GW astronomyFull GW astronomyFull GW astronomyFull GW astronomyFull GW astronomyFull GW astronomy
Scope 1 S/C1 arm1 S/C1 arm1 S/C1 arm1 S/C1 arm1 S/C1 arm1 S/C1 arm1 S/C1 arm1 S/C1 arm1 S/C1 arm
3 S/C1 interferometer
3 S/C1 interferometer
3 S/C1 interferometer
3 S/C1 interferometer
3 S/C1 interferometer
3 S/C1 interferometer
3 S/C,3 interferometer
3 or 4 units
3 S/C,3 interferometer
3 or 4 units
3 S/C,3 interferometer
3 or 4 units
3 S/C,3 interferometer
3 or 4 units
3 S/C,3 interferometer
3 or 4 units
3 S/C,3 interferometer
3 or 4 units
DICIGO Pathfinder (DPF) Pre-DECIGO
DECIGO
R&DFabrication
R&DFabrication
R&DFabrication
3678
DECIGOOrganization
74
PI: Kawamura (NAOJ)Deputy: Ando (Tokyo)
Executive CommitteeKawamura (NAOJ), Ando (Tokyo), Seto (NAOJ), Nakamura (Kyoto), Tsubono
(Tokyo), Tanaka (Kyoto), Funaki (ISAS), Numata (Maryland), Sato (Hosei), Kanda (Osaka city), Takashima (ISAS), Ioka (Kyoto)
Pre-DECIGO
Sato (Hosei)
Satellite
Funaki (ISAS)
Science, Data
Tanaka (Kyoto)Seto (NAOJ)
Kanda (Osaka city)
DECIGO pathfinderLeader: Ando (Tokyo)
Deputy: Takashima (ISAS)
Detector
Ueda (NAOJ)
Housing
Sato (Hosei)
Laser
Ueda (ILS)Musya (ILS)
Drag free
Moriwaki (Tokyo)
Sakai (ISAS)
Thruster
Funaki (ISAS)
Bus
Takashima (ISAS)
Data
Kanda (Osaka city)
Detector
Numata (Maryland)Ando (Tokyo)
Mission phase
Design phase
DECIGO
Collaboration and support・Supports from LISA
Technical advises from LISA/LPF experiences
Support Letter for DECIGO/DPF LISA-DECIGO workshop (2008.11) ・Collab. with Stanford univ. group
Drag-free control of DECIGO/DPF UV LED Charge Management System for DPF
・Collab. with JAXA navigation-control section
formation flight of DECIGO, DPF drag-free control
・Research Center for the Early Universe (RESCEU), Univ. of Tokyo
Support DECIGO as ones of main projects (2009.4-)
・Collab. with UNISEC (University Space Engineering Consortium)
Call for active young engineers
DECIGO
DECIGO is a future space-based GW detector project :
Fabry-Perot IF, 1000km baseline, constellation flight
Deci-Hz band is a focus of DECIGO! (same to BBO)
Fruitful frequency band for not only astronomical sources but also cosmological studies.
DECIGO Path Finder is going now.
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