Using Gravitational Waves Detectors to detect something else then gravitational waves

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Using Gravitational Waves Detectors to detect
something else then gravitational waves

• Mihai Bondarescu
• California Institute of Technology

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Kips Ph237 Gravitational Waves on the web and
DVD
Tomorrow, 115, this room

• http//elmer.tapir.caltech.edu/ph237
• Very high resolution 2x1.5Gb/lecture
• Normal resolution 2x250Mb/lecture
• Low resolution .. 2x40Mb/lecture
• Homework problems
• Solutions
• Ppt presentations, reading, etc

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Embeddings of black hole horizons in flat space
Thursday, 115, this room

• My diploma work I did here with Ed Seidel and
  Miguel Alcubierre.
• Previous work axysymmetric, slice through the
  Misner initial data, etc
• Our non-axysymmetric embedding code

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Where do the waves come from?
Very Low Frequency Pulsar Timing
Extra Low Frequency CMB Anisotropy
Low Frequency Doppler LISA
High Frequency LIGO
Big Bang, Inflation of The Universe
Physics no one understands in Early Universe such
as Phase transitions, cosmic strings, domain
walls, mesoscopic excitations
Massive BHs (300 to 30 million suns), Binary
stars New Physics Soliton stars, naked
singularities
Small BHs (2 to 1000 suns), Neutron stars,
Supernovae And the unexpected thats always to
be expected - boson stars, naked singularities,
This slide based on a slide Kip Thorne used in
Caltechs Ph237
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International Network of Bar Detectors Now in
Operation 1000 Hz
U. Rome - Nautilus
This slide based on a slide Kip Thorne used in
Caltechs Ph237
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Interferometric Detectors
TAMA300 Tokyo
LIGO Hanford
GEO600 A.E.I
VIRGO Pisa, Italy
LIGO Livingston
This slide based on a slide Kip Thorne used in
Caltechs Ph237
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During S2, LIGO was within a factor of 10 from
design sensitivity. The data is being analyzed
as we speak
Hanford, Washington
Livingston, Louisiana
This slide based on a slide Kip Thorne used in
Caltechs Ph237
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Other places, other people
This slide based on a slide Kip Thorne used in
Caltechs Ph237
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Noise

• Falling trees in Louisiana
• Waves that hit the ocean floor many kilometers
  away
• Planes flying by
• Tiny changes in the Earth curvature due to the
  Sun and the Moon

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LISA
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Dark Matter

• Hot new physics to be explored
• Were certain that dark matter halos surround
  galaxies
• Know little about their macroscopic or
  microscopic structure
• Gravitational lensing by DM
• Velocities of stars orbiting the galactic center
• Is there any way to use gravitational waves
  technology to learn about dark matter?

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What detectors could one use?

• LIGO and LISA operate in frequency bands too high
  to probe any dark matter physics
• Doppler tracking of spacecrafts too close to
  Earth
• Pulsar timing this talk
• CMB anisotropy

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Pulsar Timing
r
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A spiky CDM modelP. Sikivie et al

• The late infall of cold dark matter onto an
  isolated galaxy such as our own produces caustics
  in its halo.

Figure from P Sikivie astro-ph 9902210
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• A generic surface caustic in phase space
• Dark matter density in physical space

Figure from P Sikivie astro-ph 9902210
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Why Pulsar Timing?

• In the presence of a spherical spike in the
  density time flows differently then in a
  Schwarzschild potential. This will alter the
  frequency of the pulsar if it crosses the spike.

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Dark mater halo with spike in the density
Central potential
P
P
r
r
M-dm
M
dm
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Why Pulsar Timing?

• If one could find a pulsar that goes through such
  a spike without perturbing it and without being
  perturbed, one could theoretically measure the
  change in its frequency.
• The frequency change one obtains at the end of a
  Newtonian calculation in close to the pulsar
  timing accuracy for the best timed pulsars.

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Problems

• Pulsars are slow moving objects (300km/s)
• Unlike gravitational waves, dark matter density
  spikes would alter the frequency of the pulsar
  permanently by a small amount that could be
  attributed to other causes
• There are very few pulsars timed well enough to
  measure such a change in frequency
• The experiment would have to be conducted over
  many years to allow the pulsar to cross the spike
  and change its frequency.

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Dark mater accretion to the pulsar
Dark matter orbiting the pulsar

• Close to spike the location of the spike, dark
  matter particles have very low velocity and
  therefore they can be captured by the pulsar and
  slow it down.

r
pulsar
m
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Other alternatives

• Galactic velocity curves (done by Sikivie and
  Kinney)
• Shows the existence of spherical high density
  regions in the dark matter halos