karsten danzmann- gavitational wave space missions
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Gavitational WaveSpace Missions
Karsten Danzmann
Albert Einstein Institute Hannover
LIGO-G070743-00-Z
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Quantum Fluctuations in the Early Universe
Merging super-massiveblack holes (SMBH) atgalactic cores
Phasetransitionsin theEarly
Universe
Captureof blackholes andcompact
stars bySMBH
Mergingbinaryneutronstars and
blackholes indistantgalaxies
Neutronstarquakesandmagnetars
Gravitational Wave Spectrum
ASTROD DECIGO
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A Collaborative NASA/ESA Mission
Cluster of 3 S/C in heliocentric orbit
Laser interferometer measures distance changesbetween free flying test masses inside the S/C
Equilateral triangle
with 5 million km arms
Trailing the Earth by
20 (50 million km)
Inclined against
ecliptic by 60
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Cosmic backgrounds,superstring bursts?
Massive Black Hole Binary (BHB)
inspiral and merger
Ultra-compact binaries
Extreme Mass RatioInspiral (EMRI)
LISA: A Universe Full ofStrong GW Sources
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Absolute Distances from SMBH Mergers:
Hubble Constant and Dark Energy
100s of events expected to z~3 ~10s to z~20
Cosmological distance requiresredshift via identification of host
Noise from weak lensing Comparable precision to CMB, WL,BAO, CL, SN techniques
Absolute & independentmeasurement
100 BHB, 3000 SNIa (Dalal et al
0601275), includes lensing noise
H0and Dark Energy parameterspotentially measured to
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LISA layout
Laser transponder with 6 links, all transmitted to ground
Diffraction widens the laser beamto many kilometers
1 W sent, still 100 pW receivedby 40 cm Cassegrain
Michelson with 3rd armand Sagnac mode
Can distinguish bothpolarizations of a GW
Can form Null combination!main transponded
laser beams
reference
laser beams
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NRC Beyond
Einstein Review
November 6-8, 2006Washington
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BEPAC Recommendations for LISA
"On purely scientific grounds LISA is the mission that is most promisingand least scientifically risky. Even with pessimistic assumptions aboutevent rates, it should provide unambiguous and clean tests of the theoryof general relativity in the strong field dynamical regime and be able tomake detailed maps of space time near black holes. Thus, the
committee gave LISA its highest scientific ranking."
" LISA is an extraordinarily original and technically bold mission concept.LISA will open up an entirely new way of observing the universe, withimmense potential to enlarge our understanding of physics and astronomyin unforeseen ways. LISA, in the committees view, should be theflagship missionof a long-term program addressing Beyond Einsteingoals."
"NASA should invest additional Beyond Einstein funds in LISAtechnology development and risk reduction, to help ensure that theAgency is in a position to proceed in partnership with ESA to a new startafter the LISA Pathfinder results are understood."
LISA was recommended second in implementation because of moneyand programmatics. But even assuming an unnecessarily pessimisticfinancial contribution from ESA, and being second in Beyond Einstein, the
assumed launch date of LISA as ESA Cosmic Vision Mission L1 in2018 is still feasible and the committee strongly recommends that.
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LISA Status
ESA-NASA collaboration agreement since August 2004
Joint Management Structure working well!
Mission Formulation Study began in January 2005
Technology precursor LISA Pathfinder in Phase C/D
Launch in 2010
LISA technically well on track for launch in 2015!
Launch date is determined by budget
ESA SPC Meeting 22 Feb 2007: LISA L1 launch in 2018!
NASA Beyond Einstein Review: Report released September 6, 2007
LISA is Flagship mission! Schedule compatible with ESA!
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0.1m 10m 1 Hz 100 10k
4x107 4x105 4x103 M 40 0.4frequency
f/ binary black hole mass whose freq at merger=
f
Current detectors
BBO3rd generation
Adv detectors
LISA
10-22
10-23
10-24
10-25
5/(yr Hz) | 1/Hz
ASTROD
Adapted from Sathya
DECIGO
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ASTROD Mission Concept
Sun
Inner Orbit
Earth Orbit
Outer OrbitLaunch Position
.Earth (800 days after launch)
L1 point
Laser Ranging
S/C 2
S/C 1
from W T Ni
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ASTROD technological
requirements Weak-light phase locking to 100 fW.
Heterodyne interferometry and data analysis for unequal-
arm interferometry. Coronagraph design and development: sunlight in the
photodetectors should be less than 1 % of the laser light.
High precision space clock and/or absolute stabilized laserto 10-17.
Drag-free system. Accelerometer noise requirement: (0.3-1)10-15[1+10(/3mHz)2] ms-2Hz-1/2 at 0.1 mHz
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