Status and Prospects for LIGO Crab Pulsar Barry
Status and Prospects for LIGO Crab Pulsar Barry C. Barish Caltech 17 -March-06 St Thomas, Virgin Islands 17 -March-06 Confronting Gravity - St Thomas
LIGO Livingston, Louisiana 4 km 17 -March-06 Confronting Gravity - St Thomas 2
LIGO Hanford Washington 4 km 17 -March-06 2 km Confronting Gravity - St Thomas 3
Interferometer optical layout vacuum suspended, seismically isolated test masses mode cleaner 4 km various optics laser 10 W 6 -7 W 4 -5 W 150 -200 W 9 -12 k. W 200 m. W photodetector GW channel 17 -March-06 Confronting Gravity - St Thomas 4
LIGO Beam Tube • Minimal enclosure • Reinforced concrete • No services • 1. 2 m diameter - 3 mm stainless 50 km of weld • 65 ft spiral welded sections • Girth welded in portable clean room in the field 17 -March-06 Confronting Gravity - St Thomas 5
LIGO vacuum equipment 17 -March-06 Confronting Gravity - St Thomas 6
Core Optics installation and alignment 17 -March-06 Confronting Gravity - St Thomas 7
LIGO Optics fused silica § § § Caltech data 17 -March-06 Surface uniformity < 1 nm rms Scatter < 50 ppm Absorption < 2 ppm ROC matched < 3% Internal mode Q’s > 2 x 106 CSIRO data Confronting Gravity - St Thomas 8
Interferometer Noise Limits Seismic Noise test mass (mirror) Quantum Noise Residual gas scattering "Shot" noise LASER Wavelength & amplitude fluctuations 17 -March-06 Beam splitter photodiode Confronting Gravity - St Thomas Radiation pressure Thermal (Brownian) Noise 9
What Limits LIGO Sensitivity? 17 -March-06 § Seismic noise limits low frequencies § Thermal Noise limits middle frequencies § Quantum nature of light (Shot Noise) limits high frequencies § Technical issues alignment, electronics, acoustics, etc limit us before we reach these design goals Confronting Gravity - St Thomas 10
Commissioning /Running Time Line 1999 2000 2001 2002 2003 2004 2005 2006 3 4 1 2 3 4 1 2 3 4 Inauguration First Lock Full Lock all IFO 4 K strain noise Engineering 10 -17 10 -18 10 -20 10 -21 E 2 E 3 E 5 E 7 E 8 Science Now S 1 E 9 S 2 10 -22 E 10 S 3 4 x 10 -23 at 150 Hz [Hz-1/2] E 11 S 4 S 5 Runs First Science Data 17 -March-06 Confronting Gravity - St Thomas 11
Evolution of LIGO Sensitivity § § § 17 -March-06 S 1: S 2: S 3: S 4: S 5: 23 Aug – 9 Sep ‘ 02 14 Feb – 14 Apr ‘ 03 31 Oct ‘ 03 – 9 Jan ‘ 04 22 Feb – 23 Mar ‘ 05 4 Nov ‘ 05 - Confronting Gravity - St Thomas 12
Initial LIGO - Design Sensitivity 17 -March-06 Confronting Gravity - St Thomas 13
Sensitivity Entering S 5 … Rms strain in 100 Hz BW: 0. 4 x 10 -21 17 -March-06 Confronting Gravity - St Thomas 14
S 5 Run Plan and Outlook Interferometer duty cycles § Goal is to “collect at least a year’s data of coincident operation at the science goal sensitivity” § Expect S 5 to last about 1. 5 yrs § S 5 is not completely ‘hands-off’ 17 -March-06 Run S 2 S 3 S 4 S 5 Targ et L 1 37% 22% 75% 85% 90% H 1 74% 69% 81% 85% 90% H 2 58% 63% 81% 85% 90% 3 way 22% 16% 57% 70% 75% Confronting Gravity - St Thomas SRD goal 15
Sensitivity Entering S 5 … Hydraulic External Pre-Isolator 17 -March-06 Confronting Gravity - St Thomas 16
Locking Problem is Solved 17 -March-06 Confronting Gravity - St Thomas 17
What’s after S 5? 17 -March-06 Confronting Gravity - St Thomas 18
“Modest” Improvements Now – 14 Mpc Then – 30 Mpc 17 -March-06 Confronting Gravity - St Thomas 19
Astrophysical Sources § Compact binary inspiral: “chirps” » NS-NS waveforms are well described » BH-BH need better waveforms » search technique: matched templates § Supernovae / GRBs: “bursts” » burst signals in coincidence with signals in electromagnetic radiation » prompt alarm (~ one hour) with neutrino detectors § Pulsars in our galaxy: “periodic” » search for observed neutron stars (frequency, doppler shift) » all sky search (computing challenge) » r-modes § Cosmological Signal “stochastic background” 17 -March-06 Confronting Gravity - St Thomas 20
Our Searches § Several inspiral searches are performed currently: Mass BBH 10 Inspiral-Burst S 4 3 Spin is important BNS 1 PBH “High mass ratio” Coming soon 0. 1 1 17 -March-06 3 » Primordial black holes binaries (PBHB) » Binary Neutron Stars (BNS) » Binary Black Holes (BBH) § Other searches in progress » » 10 Confronting Gravity - St. Mass Thomas Spinning Black Holes Coincidences with GRB Black Hole Ringdown Inspiral-Burst 21
Template Bank § Covers desired region of mass param space § Calculated based on L 1 noise curve § Templates placed for max mismatch of = 0. 03 17 -March-06 2110 templates Second-order post-Newtonian Confronting Gravity - St Thomas 22
Binary Neutron Star Search Results (S 2) cumulative number of events Physical Review D 17 -March-06 Rate < 47 per year per Milky-Way-like galaxy signal-to-noise ratio squared Confronting Gravity - St Thomas 23
Binary Black Hole Search 17 -March-06 Confronting Gravity - St Thomas 24
From Limit Setting to Detections 17 -March-06 Confronting Gravity - St Thomas 25
Improving Sensitivities Effective distance of L 1 improved – S 3 S 4 8 Mpc to 40 Mpc 17 -March-06 Confronting Gravity - St Thomas 26
Binary Inspiral Search: LIGO Ranges binary neutron star range binary black hole range 17 -March-06 Confronting Gravity - St Thomas Image: R. Powell 27
Astrophysical Sources § Compact binary inspiral: “chirps” » NS-NS waveforms are well described » BH-BH need better waveforms » search technique: matched templates § Supernovae / GRBs: “bursts” » burst signals in coincidence with signals in electromagnetic radiation » prompt alarm (~ one hour) with neutrino detectors § Pulsars in our galaxy: “periodic” » search for observed neutron stars (frequency, doppler shift) » all sky search (computing challenge) » r-modes § Cosmological Signal “stochastic background” 17 -March-06 Confronting Gravity - St Thomas 28
‘Unmodeled’ Bursts GOAL search for waveforms from sources for which we cannot currently make an accurate prediction of the waveform shape. METHODS ‘Raw Data’ Time-domain high pass filter frequency Time-Frequency Plane Search ‘TFCLUSTERS’ Pure Time-Domain Search ‘SLOPE’ 8 Hz 0. 125 s time 17 -March-06 Confronting Gravity - St Thomas 29
Burst Search Results § Blind procedure gives one event candidate » Event immediately found to be correlated with airplane over-flight 17 -March-06 Confronting Gravity - St Thomas 30
Burst Source - Upper Limit 17 -March-06 Confronting Gravity - St Thomas 31
Astrophysical Sources signatures § Compact binary inspiral: “chirps” » NS-NS waveforms are well described » BH-BH need better waveforms » search technique: matched templates § Supernovae / GRBs: “bursts” » burst signals in coincidence with signals in electromagnetic radiation » prompt alarm (~ one hour) with neutrino detectors § Pulsars in our galaxy: “periodic” » search for observed neutron stars (frequency, doppler shift) » all sky search (computing challenge) » r-modes § Cosmological Signal “stochastic background” 17 -March-06 Confronting Gravity - St Thomas 32
Detection of Periodic Sources § Pulsars in our galaxy: “periodic” » search for observed neutron stars » all sky search (computing challenge) » r-modes § Frequency modulation of signal due to Earth’s motion relative to the Solar System Barycenter, intrinsic frequency changes. §Amplitude modulation due to the detector’s antenna pattern. 17 -March-06 Confronting Gravity - St Thomas 33
Directed Pulsar Search 28 Radio Sources 17 -March-06 Confronting Gravity - St Thomas 34
ALL SKY SEARCH enormous computing challenge Einstein@Home LIGO Pulsar Search using home pc’s BRUCE ALLEN Project Leader Univ of Wisconsin Milwaukee LIGO, UWM, AEI, APS http: //einstein. phys. uwm. edu 17 -March-06 Confronting Gravity - St Thomas 35
All Sky Search – Final S 3 Data NO Events Observed 17 -March-06 Confronting Gravity - St Thomas 36
Astrophysical Sources § Compact binary inspiral: “chirps” » NS-NS waveforms are well described » BH-BH need better waveforms » search technique: matched templates § Supernovae / GRBs: “bursts” » burst signals in coincidence with signals in electromagnetic radiation » prompt alarm (~ one hour) with neutrino detectors § Pulsars in our galaxy: “periodic” » search for observed neutron stars (frequency, doppler shift) » all sky search (computing challenge) » r-modes § Cosmological Signal “stochastic background” 17 -March-06 Confronting Gravity - St Thomas 37
Signals from the Early Universe § Strength specified by ratio of energy density in GWs to total energy density needed to close the universe: § Detect by cross-correlating output of two GW detectors: Overlap Reduction Function 17 -March-06 Confronting Gravity - St Thomas 38
Stochastic Background Search (S 3) Fraction of Universe’s energy in gravitational waves: (LIGO band) 17 -March-06 Confronting Gravity - St Thomas 39
Results – Stochastic Backgrounds 17 -March-06 Confronting Gravity - St Thomas 40
Conclusions § LIGO works! § Data Analysis also works for broad range of science goals. Now making transition from limit setting to detection based analysis § Data taking run (S 5) to exploit Initial LIGO is well underway and will be complete within ~ 1. 5 years § Incremental improvements to follow S 5 are being developed. (improve sensitivity ~ x 2) § Advanced LIGO fully approved by NSF and NSB and funding planned to commence in 2008. (design will improve sensitivity ~ x 20) § R&D on third generation detectors is underway 17 -March-06 Confronting Gravity - St Thomas 41
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