P. M. Meyers

Detectability of eccentric compact binary coalescences with advanced gravitational-wave detectors

Compact binary coalescences are a promising source of gravitational waves for second-generation interferometric gravitational-wave detectors such as advanced LIGO and advanced Virgo. While most binaries are expected to possess circular orbits, some may be eccentric, for example, if they are formed through dynamical capture. Eccentric orbits can create difficulty for matched filtering searches due to the challenges of creating effective template banks to detect these signals. In previous work, we showed how seedless clustering can be used to detect low-mass (M_total≤10M_⊙) compact binary coalescences for both spinning and eccentric systems, assuming a circular post-Newtonian expansion. Here, we describe a parametrization that is designed to maximize sensitivity to low-eccentricity (0≤e≤0.6) systems, derived from the analytic equations. We show that this parametrization provides a robust and computationally efficient method for detecting eccentric low-mass compact binaries. Based on these results, we conclude that advanced detectors will have a chance of detecting eccentric binaries if optimistic models prove true. However, a null observation is unlikely to firmly rule out models of eccentric binary populations.

Prospects for searches for long-duration gravitational-waves without time slides

The detection of unmodeled gravitational-wave transients by ground-based interferometric gravitational-wave detectors is an important goal for the advanced detector era. These searches are commonly cast as pattern recognition problems, where the goal is to identify statistically significant clusters indicating the presence of gravitational-wave transients in spectrograms of detector strain power when the precise signal morphology is unknown. In previous work, we have introduced a clustering algorithm referred to as seedless clustering, and shown that it is a powerful tool for detecting weak and long-lived (

A 3D Broadband Seismometer Array Experiment at the Homestake Mine

\ensuremath{\sim}10\char21{}1000\text{ }\text{ }\mathrm{s}

Measurement and subtraction of Schumann resonances at gravitational-wave interferometers

) gravitational-wave transients. However, as the algorithm is currently conceived, in order to carry out a search on approximately a year of data, significant computational resources may be required for estimating background events. Currently, the use of the algorithm is limited by the computational resources required for performing background studies to assign significance to events identified by the algorithm. In this paper, we present an analytic method for estimating the background generated by the seedless clustering algorithm and compare the performance to both Monte Carlo Gaussian noise and time-shifted gravitational-wave data from a week of LIGOs 5th Science Run. We demonstrate qualitative agreement between the model and measured distributions and argue that the approximation will be useful to supplement conventional background estimation techniques for advanced detector searches for long-duration gravitational-wave transients.

Validating gravitational-wave detections: The Advanced LIGO hardware injection system

Seismometer deployments are often confined to near the Earth’s surface for practical reasons, despite the clear advantages of deeper seismometer installations related to lower noise levels and more homogeneous conditions. Here, we describe a 3D broadband seismometer array deployed at the inactive Homestake Mine in South Dakota, which takes advantage of infrastructure originally setup for mining and is now used for a range of scientific experiments. The array consists of 24 stations, of which 15 were underground, with depths ranging from 300 ft (91 m) to 4850 ft (1478 m), and with a 3D aperture of ∼1.5 km in each direction, thus spanning a 3D volume of about 3.4 km^3. We describe unique research opportunities and challenges related to the 3D geometry, including the generally low ambient noise levels, the strong coherency between observed event waveforms across the array, and the technical challenges of running the network. This article summarizes preliminary results obtained using data acquired by the Homestake array, illustrating the range of possible studies supported by the data.

Thermal modelling of Advanced LIGO test masses

Correlated magnetic noise from Schumann resonances threatens to contaminate the observation of a stochastic gravitational-wave background in interferometric detectors. In previous work, we reported on the first effort to eliminate global correlated noise from the Schumann resonances using Wiener filtering, demonstrating as much as a factor of two reduction in the coherence between magnetometers on different continents. In this work, we present results from dedicated magnetometer measurements at the Virgo and KAGRA sites, which are the first results for subtraction using data from gravitational-wave detector sites. We compare these measurements to a growing network of permanent magnetometer stations, including at the LIGO sites. We show the effect of mutual magnetometer attraction, arguing that magnetometers should be placed at least one meter from one another. In addition, for the first time, we show how dedicated measurements by magnetometers near to the interferometers can reduce coherence to a level consistent with uncorrelated noise, making a potential detection of a stochastic gravitational-wave background possible.