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Gravitational Wave Data Analysis GW detectors Signal processing: preparation Noise spectral density Matched filtering Probability and statistics Software implementation
Gravitational Wave Data Analysis
GW detectorsSignal processing: preparationNoise spectral densityMatched filteringProbability and statisticsSoftware implementation
Gravitational Wave Data Analysis
Gravitational Wave Detectors
Junwei Cao (曹军威) and Junwei Li (李俊伟)Tsinghua University
Gravitational Wave Summer School Kunming, China, July 2009
Gravitational Waves
Gravitational waves are prediction of Einstein’s General Theory of Relativity.No direct detection of GWsis successful for nearly 100 years.A new window to observe the universe
Strength of GWs
For the binary system shown in the figure, the strain h=2δl/lbecomes h~R1R2/DdFor neutron stars of 1.4M⊙out at Virgo cluster (15Mpc): h~10-21
Crazy but within current reach!
Binary: a typical GW source
Frequency Ranges
Laser Interferometers
The Michelson interferometer measures phase differences between two returning beams recombined at the beam splitter. (Albert A. Michelson, 1852-1931, Nobel Prize 1907)Modern interferometers use lasers
GW Laser Detectors
LIGO
Simultaneously detect signal (within msec)
GEO VirgoTAMA
AIGO
GW Laser Detectors (Contd.)
LIGO: Laser Interferometer Gravitational wave Observatory (激光干涉引力波天文台)U.S. NSF flagship project with largest single investment; a joint effort of Caltech and MITLSC: the LIGO Scientific Collaboration over 500 scientists from over 60 institutes worldwide
LIGO Hanford Observatory (H1, H2) LIGO Livingston Observatory (L1)
LIGO & LSC
LIGO Experiences
LIGO Status
LIGO deliverable – S5 run with over 1 year triple coincidence, no gold-plated detectionEnhanced LIGO – 2 times sensitivity improvement, S6 starts in July 2009Advanced LIGO – 10 times sensitivity improvement, 103 times signals and frequent GW detections are expected
Struggle Against Noises
LIGO Data
Data are comprised of:Gravitational Wave channel (AS_Q)Physical Environment MonitorsInternal Engineering Monitors
Multiple data products beyond raw data
RDS_R_L1, including both GW and environmental channelsRDS_R_L3, including only AS_Q channel
L-RDS_R_L3-751658016-16.gwf
Site (H,L) Data Type
GPS Start Time
Duration
GW Data Analysis
Burst, Inspiral, Stochastic, ContinuousSignal processing, probability, statistical analysisOnline, offline, real-timeMatlab, DMT(C++), Scripts (Python)Clusters, grids, …
