Download Image credit: LIGO collaboration

Gravitational waves
BAS ROELENGA & JOSÉ VERSTEEG-VELTKAMP
Image credit: R. Hurt/Caltech-JPL
Outline
Background
LIGO
Detection
Future
Conclusions
Image credit: http://scaleofuniverse.com/what-are-gravitational-waves/
Background: spacetime
Einstein's Theory of Special
Relativity (1905)
Minkowski (1907)
4 dimensional framework
Image credit: ESA–C.Carreau
Background: gravitational waves
Poincaré (1905)
Einstein's Theory of General
Relativity (1915)
Ripples in spacetime
Violent/energetic events
Carry information
Image credit: http://www.newsweek.com/when-black-holes-collide-einstein-right-426078
Background: how hard can it be?
Einstein says no!
Image credit: http://www.nobelprize.org/nobel_prizes/physics/laureates/1921/
Background: how hard can it be?
Einstein says no!
Weber 1969
Image credit: Special Collections and University Archives, University of Maryland Libraries
Background: how hard can it be?
Einstein says no!
Weber 1969
Everyone (early '70s):
◦ IBM
◦ Bell Labs
◦ Moscow
◦ NASA
Image credit: http://www.lpi.usra.edu/lunar/missions/apollo/apollo_17/images/lsg_lg.gif
Gravitational wave observatories
Advanced LIGO detectors
Virgo detector
GEO 600
Image credit: LIGO collaboration/Virgo collaboration/GEO 600
LIGO: the gravitational wave detector
Two detectors:
◦ Livingston observatory (L1)
◦ Hanford observatory (H1)
Image credit: LIGO collaboration
LIGO: gravitational wave propagation
Propagate at speed of light
Quadrupole wave
Image credit: K. Riles. https://arxiv.org/pdf/1209.0667.pdf
LIGO: how does Advanced LIGO detect
gravitational waves?
Modified Michelson interferometer
Gravitational wave strain
Image credit: LIGO collaboration and K. Riles. https://arxiv.org/pdf/1209.0667.pdf
LIGO: Measuring gravitational wave strain
Change of phase in light
LIGO: enhancing gravitational wave effect
Modified Michelson interferometer
Resonant optical cavity
Image credit: LIGO collaboration
LIGO: minimizing background noise
Obtaining the best sensitivity
Several noise factors
Image credit: LIGO collaboration
Detection: first detection
Detection of coincident signal
GW150914 for both searches
Image credit: LIGO collaboration
Detection: first detection
Significance of detection:
◦ > 4.6σ for generic transient search
◦ > 5.1σ for binary coalescence search
Image credit: LIGO collaboration
Detection: what was measured?
Coalescence of two black holes
Comparing to simulations
Image credit: LIGO collaboration
Detection: coalescence of two black holes
Detection: validation
Need to be absolutely sure!!
Instrumental and environmental disturbances
Future
Another LIGO detection (Dec 2015)
◦ BH merger: 14 Msun and 8 Msun
Extending the network:
◦ VIRGO
New detectors:
◦ LISA (space)
◦ INDIGO (ground, India)
◦ Einstein Telescope (ground, Limburg?)
Future: other detection methods
Pulsar timing
Rotating neutron star or white
dwarf
Future: other detection methods
Pulsar timing
Rotating neutron star or white
dwarf
Image credit: coolblue.nl
Future: other detection methods
Pulsar timing
Rotating neutron star or white
dwarf
Regular pulses
Change in period
Image credit: NASA-JPL/Caltech
Future: other detection methods
CMB polarization
Leftover Big Bang radiation
Image credit: ESA and the Planck Collaboration
Future: other detection methods
CMB polarization
Leftover Big Bang radiation
Look for B-mode polarization
Image credit: Sky & Telescope
Future: other detection methods
CMB polarization
Leftover Big Bang radiation
Look for B-mode polarization
Klik om tekst toe te voegen
BICEP2 detection!
Image credit: National Science Foundation
Future: other detection methods
CMB polarization
Leftover Big Bang radiation
Look for B-mode polarization
BICEP2 detection!
Image credit: National Science Foundation
Conclusions
Old idea (1905), exciting new
science
More detections incoming
New era of astronomy?
Image credit: Werner Benger, Zuse-Institut Berlin and Max-Planck-Institut für Gravitationsphysik