LIGO Interferometry CLEOQELS Joint Symposium on Gravitational Wave

LIGO Interferometry CLEO/QELS Joint Symposium on Gravitational Wave Detection, Baltimore, May 24, 2005 Daniel Sigg G 050253 -00 -D LIGO I

Interferometer Configurations G 050253 -00 -D LIGO I 2

Antenna Pattern + polarization G 050253 -00 -D × polarization LIGO I averaged 3

Sensitivity G 050253 -00 -D LIGO I 4

2001 2003 G 050253 -00 -D LIGO I 5

Seismic Isolation G 050253 -00 -D LIGO I 6

Suspensions G 050253 -00 -D LIGO I 7

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Some Requirements q q q q Sensitivity: ~10 -19 m/√Hz at 150 Hz Controller range: ~100 µm (tides) Control of diff. arm length: ≤ 10 -13 m rms Laser intensity noise: ≤ 10 -7 /√Hz at 150 Hz Frequency noise: ≤ 3× 10 -7 Hz/√Hz at 150 Hz Angular Control: ≤ 10 -8 rad rms Input beam jitter: ≤ 4× 10 -9 rad/√Hz at 150 Hz G 050253 -00 -D LIGO I 9

Length Sensing and Control q Separate common and differential mode Ø Ø q Diff. arm Michelson Common arm PR cavity Sensors Ø Anti-symmetric port Ø In reflection Ø PR cavity sample G 050253 -00 -D LIGO I 10

The Auto-Alignment System q q Optical levers for damping suspension & stack modes Wavefront RF sensors for 10 angular dofs Quadrant detectors for beam positions on ends Video analysis of beam splitter image for input beam position G 050253 -00 -D LIGO I 11

Sideband Images as Function of Thermal Heating No Heating 30 m. W 60 m. W 90 m. W Best match 120 G 050253 -00 -D m. W 150 m. W LIGO I 180 m. W Input beam 12

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 at 150 Hz [Hz-1/2] 10 -22 E 10 S 2 S 3 E 11 S 4 S 5 Runs First Science Data G 050253 -00 -D LIGO I 13

The 4 th Science Run q Dates (2005): Ø Start: 22 Feb Ø Stop: 23 Mar q Duty cycle: Ø Ø H 1: 80% L 1: 74% H 2: 81% Triple coincidence: 57% G 050253 -00 -D LIGO I 14

Results from the 1 st/2 nd Science Run q Binary inspirals (S 2): Ø Neutron star binary coalescence: range up to 1. 5 Mpc, rate ≤ 47/y/MW (90% CL) Ø Black hole coalescence (0. 2 -1 M ) in Galactic halo: rate ≤ 63/y/MW (90% CL) q Pulsars (S 2): Ø Limits on 28 pulsars Ø Upper limits on h as low as 2× 10 -24 (95% CL) and as low as 5× 10 -6 on the eccentricity q Stochastic background (S 1): Ø Energy limit as fraction of closure density: h 2100 W 0 ≤ 23 ± 4. 6 (90% CL) Ø PRELIMINARY S 2: h 2100 W 0 ≤ 0. 018 +0. 007 -0. 003 (90% CL) q Burst (S 2): Ø Sensitivity: hrss ~ 10 -20 - 10 -19 /√Hz, rate ≤ 0. 26/day (90% CL) Ø GRB 030329: hrss ≤ 6× 10 -21 /√Hz G 050253 -00 -D LIGO I 15

Summary q q Sophisticated feedback compensation networks are essential in running a modern gravitational-wave interferometer All LIGO interferometers are within a factor of 2 of design sensitivity over a broad range of frequencies For sources like binary neutron star coalescence we can see beyond our own galaxy! Join Einstein@home (einstein. phys. uwm. edu) G 050253 -00 -D LIGO I 16