Seismic isolation of Advanced LIGO: Review of strategy, instrumentation and performance

The new generation of gravitational waves detectors require unprecedented levels of isolation from seismic noise. This article reviews the seismic isolation strategy and instrumentation developed for the Advanced LIGO observatories. It summarizes over a decade of research on active inertial isolation and shows the performance recently achieved at the Advanced LIGO observatories. The paper emphasizes the scientific and technical challenges of this endeavor and how they have been addressed. An overview of the isolation strategy is given. It combines multiple layers of passive and active inertial isolation to provide suitable rejection of seismic noise at all frequencies. A detailed presentation of the three active platforms that have been developed is given. They are the hydraulic pre-isolator, the single-stage internal isolator and the two-stage internal isolator. The architecture, instrumentation, control scheme and isolation results are presented for each of the three systems. Results show that the seismic isolation sub-system meets Advanced LIGO's stringent requirements and robustly supports the operation of the two detectors.Laser Interferometer Gravitational-Wave ObservatoryNational Science Foundation (U.S.

Search for gravitational waves from binary black hole inspiral, merger, and ringdown

We present the first modeled search for gravitational waves using the complete binary black-hole gravitational waveform from inspiral through the merger and ringdown for binaries with negligible component spin. We searched approximately 2 years of LIGO data, taken between November 2005 and September 2007, for systems with component masses of 1–99M⊙ [1-99 M circled dot operator] and total masses of 25–100M⊙ [25-100 M circled dot operator]. We did not detect any plausible gravitational-wave signals but we do place upper limits on the merger rate of binary black holes as a function of the component masses in this range. We constrain the rate of mergers for 19M⊙≤m1 [19 M circled dot operator greater than or equal to m subscript 1], m2≤28M⊙ [m subscript 2 greater than or equal to 28 M circled dot operator] binary black-hole systems with negligible spin to be no more than 2.0  Mpc-3 {Mpc superscript -3] Myr-1 [Myr superscript -1] at 90% confidence.National Science Foundation (U.S.)United States. National Aeronautics and Space AdministrationCarnegie TrustLeverhulme TrustDavid & Lucile Packard FoundationResearch CorporationAlfred P. Sloan Foundatio

Search for gravitational waves associated with the August 2006 timing glitch of the Vela pulsar

The physical mechanisms responsible for pulsar timing glitches are thought to excite quasinormal mode oscillations in their parent neutron star that couple to gravitational-wave emission. In August 2006, a timing glitch was observed in the radio emission of PSR B0833-45, the Vela pulsar. At the time of the glitch, the two colocated Hanford gravitational-wave detectors of the Laser Interferometer Gravitational-wave observatory (LIGO) were operational and taking data as part of the fifth LIGO science run (S5). We present the first direct search for the gravitational-wave emission associated with oscillations of the fundamental quadrupole mode excited by a pulsar timing glitch. No gravitational-wave detection candidate was found. We place Bayesian 90% confidence upper limits of 6.3×10-21 to 1.4×10-20 on the peak intrinsic strain amplitude of gravitational-wave ring-down signals, depending on which spherical harmonic mode is excited. The corresponding range of energy upper limits is 5.0×1044 to 1.3×1045  erg.David & Lucile Packard FoundationUnited States. National Aeronautics and Space AdministrationAlfred P. Sloan FoundationCarnegie TrustNational Science Foundation (U.S.)Research CorporationLeverhulme Trus

Application of a Hough search for continuous gravitational waves on data from the fifth LIGO science run

We report on an all-sky search for periodic gravitational waves in the frequency range 50-1000 Hz with the first derivative of frequency in the range -8.9 × 10⁻¹⁰ Hz s⁻¹ to zero in two years of data collected during LIGO's fifth science run. Our results employ a Hough transform technique, introducing a χ² test and analysis of coincidences between the signal levels in years 1 and 2 of observations that offers a significant improvement in the product of strain sensitivity with compute cycles per data sample compared to previously published searches. Since our search yields no surviving candidates, we present results taking the form of frequency dependent, 95% confidence upper limits on the strain amplitude h₀. The most stringent upper limit from year 1 is 1.0 × 10⁻²⁴ in the 158.00-158.25 Hz band. In year 2, the most stringent upper limit is 8.9 × 10⁻²⁵ in the 146.50-146.75 Hz band. This improved detection pipeline, which is computationally efficient by at least two orders of magnitude better than our flagship Einstein@Home search, will be important for 'quick-look' searches in the Advanced LIGO and Virgo detector era