Hunting for Gravitational Waves

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Hunting for Gravitational Waves
Marco Cavaglià
LIGO Scientific Collaboration Department of
Physics and AstronomyUniversity of Mississippi
Background picture from http//cgwp.gravity.psu.ed
u
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Gravitational waves
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Gravity
(Newtons tree)
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A gravitational wave is a propagating disturbance
of the spacetime
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Sources of gravitational waves
? Coalescing binary neutron stars or black
holes
? Spinning neutron stars
? Gravitational bursts (e.g. supernovae)
? Big bang gravitational echo
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Sources of gravitational waves
? Coalescing binary neutron stars or black
holes
? Spinning neutron stars
? Gravitational bursts (e.g. supernovae)
? Big bang gravitational echo
Picture credit NASA/CXC/AIfA NRAO/VLA/NRL
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Sources of gravitational waves
? Coalescing binary neutron stars or black
holes
? Spinning neutron stars
? Gravitational bursts (e.g. supernovae)
? Big bang gravitational echo
Picture credit NASA/HST/STScI
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Sources of gravitational waves
? Coalescing binary neutron stars or black
holes
? Spinning neutron stars
? Gravitational bursts (e.g. supernovae)
? Big bang gravitational echo
Picture credit NASA/HST/STScI
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Sources of gravitational waves
? Coalescing binary neutron stars or black
holes
? Spinning neutron stars
? Gravitational bursts (e.g. supernovae)
? Big bang gravitational echo
Picture credit NASA/WMAP
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How do we know that gravitational waves exist?
Indirect detection slow down of a binary pulsar
John Rowe Animation Australia Telescope National
Facility, CSIRO
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Nobel prize in physics, 1993
R. Hulse
J. Taylor
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Merger of a binary black hole system
(equal-mass, unequal-spin black holes)
(Picture credit L. Rezzolla, Albert-Einstein
Institute, Golm, Germany)
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Merger of a binary black hole system
(equal-mass, zero-spin black holes)
(Courtesy of L. Rezzolla, Albert-Einstein
Institute, Golm, Germany)
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Back of the envelope calculation
For a coalescing compact object into a black hole
Distance Earth-Sun (1.5 x 107 km). stretch
es by a fraction of an atom!
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A typical signal for a coalescing binary system
inspiralmergerringdown
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A typical signal stretch of data
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(but with a smaller needle)
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LIGO
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A way to answer is to use the most incredible
scientific tool of the new millennium
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LIGO
Laser
Interferometer
Gravitational-wave
Observatory
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(No Transcript)
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The LIGO Observatories
Hanford (WA) 4 km 2 km interferometers
Livingston (LA) 4 km interferometer
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LIGO instrument
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Hanford, WA
Livingston, LA
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Vacuum equipment
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Core optics
Fused silica (high-Q, low-absorption, 1 nm
surface rms, 25-cm diameter)
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Core optic suspensions
Suspended by single steel wire Actuation of
alignment/position with magnets and coils
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Seismic suspensions
Multi-stage (mass springs) optical table
support gives 106 suppression Pendulum suspension
gives additional 1/f2 suppression above 1 Hz
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The control room
Vitor Cardoso
(postdoc _at_ Ole Miss)
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LIGO is so sensitive that it feels
? Cars and trucks
? Airplanes
? Sea waves
? Earthquakes
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S5 run
1 yr of triple coincidence data between the
three LIGO interferometers
S5 duty cycles ? 52.8 in triple coincidence ?
57.0 in H1L1 coincidence ? Total for H1 77.7
? Total for H2 78.2 ? Total for L1 65.7
? H1H2L1V1 11.3
K. Riles, LIGO-G070793
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BNS horizon distance
K. Riles, LIGO-G070793
Distance to which an interferometer can detect an
inspiral NS-NS system, averaged over all sky
positions and orientations with snr8
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S5 BNS horizon 30Mpc
S5 BBH horizon
Image R. Powell
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LIGO Phase II and III
Enhanced LIGO ? Factor of 2 improvement in
sensitivity (event rate x 8) ? Install in 2008
- online in 2009 for one yr

Advanced LIGO ? Factor of 10 improvement in
sensitivity (event rate x 1000) ? Install
starting in 2011 - online in 2014
BNS range Initial LIGO - Hundreds of
galaxies ELI - Thousands of galaxies AdL -
Millions of galaxies!
3 hrs of AdL 1 yr of initial LIGO
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Outreach
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LIGO Science Education Center
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Photos by Ana Sousa
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http//www.ligo-la.caltech.edu
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You can also contribute!
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The Einstein_at_home Project
Thu Nov 22 2007 0107 UTC
http//www.einsteinathome.org
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Thank you!
Visit http//www.phy.olemiss.edu/GR/ligoteamfor
the latest news on LIGO research at Ole Miss
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LIGO Hands-on activities
? http//www.einsteinsmessengers.org/ ?
http//www.ligo-la.caltech.edu ?
http//www.ligo-la.caltech.edu/worksheets/SEC/sech
ome.html ? http//ilog.ligo-la.caltech.edu/ ?
http//www12.i2u2.org ? http//www.einstein-onli
ne.info/en ? http//www.lisa-science.org/