Download Deci hertz laser interferometer can determine the position of the

Determination of the equation of
state of the universe using 0.1Hz
Gravitational Wave Antenna
Takashi Nakamura and Ryuichi Takahashi
Dept. Phys. Kyoto Univ
Dec.15.GWDAW9
Prog.Theor.Phys in press
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Dark energy is the most important and most difficult
problem in physics in the 21st century so that many
independent observations and experiments are
indispensable.
At first the optical astronomy took part in the game
using the type Ia supernova
Then CMB took part in the game by WMAP
Very recently GRB has taken part in the game.
In future why not gravitational wave!!
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Ghirlanda et al (2004)
Peak energy of the spectra to total jet gamma ray energy relation
?
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GRBs
with known z
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Swift was launched
2004 Nov 20
→more data will be
available
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In 2001 we considered what we
can do using 0.1 hertz laser
interferometer
( Seto, Kawamura and TN : PRL
87 221103)
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Our Point and Strategy
• Consider the ultimate
possible detector in the
sprit of necessity is the
mother of the invention
• We call the detector
DECIGO( DECi hertz laser
Interferometer Gravitational
wave Observatory)
Consider the coalescing
binary neutron stars at z=1 .
Observe them one year
before the final merging
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Time delay of chirp signal due to the acceleration
of the universe can be measured
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Matched Filter Analysis Using
Ultimate DECIGO
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Punch Point of Ultimate DECIGO
a)
100,000 Mass of neutron stars, Black Hole will give us
mass function of NS and BH
b) Direct measurement of Acceleration of the universe;
Independent measurement of the curvature of the
universe, independent information of EOS of the
universe Today we discuss more details.
c) Background gw predicted by inflation model
up to
can be measured.
Completely independent information from MAP and
PLANCK
d) If the fundamental scale is Tev, then the redshifted GW
at T=Tev is just 0.1Hz Band. We may see something.
e) For near source , accurate time(0.01sec) and spatial
position(10arcsec) of the coalescing binary neutron
stars a week before the final merging (Takahashi and
Nakamura at GWDAW8 and ApJ 596 (2003) 231)
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• discovery of new binary
pulsar PSR J0737-3039
• Coalescence rate
180/Myr/Galaxy
although corrected factor
2 in 2004.
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Expected event rate as a function of z
S/N will increase
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Accuracy of determination
of Hubble parameter as a
function of z.
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Dependence of the accuracy on the observing time
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Dependence of the accuracy on the mass of the binary
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Equation of the state of the dark energy
The angular position of the source is determined
within a few arc seconds so that the host galaxy
will be identified. Then the red shift z will be obtained.
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The estimation error of cosmological parameters
for general non-flat universe
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The estimation error of cosmological parameters
for flat universe
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The estimation error of cosmological parameters
for SNAP satellite case
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Conclusion
1) We showed that the ultimate DECIGO can determine
the cosmological parameters comparable or better than
SNAP.
2) This is completely independent determination of
the property of the dark energy.
3) To determine more than 100,000 wave signals is
a challenge for data analysis.
4) What we can do by 1000 times less sensitive
practical DECIGO with ten years observations.
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• After subtracting these binaries and possible other
sources from the row data, we might observe
• the primordial gw background even if
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