J. A. Clark
A5010805202- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Astrophysical Phenomena and Observations
- Nuclear physics research studies
- Cosmology and Gravitation Theories
- Astrophysics and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- Nuclear Physics and Applications
- High-pressure geophysics and materials
- Astronomical and nuclear sciences
- Atomic and Molecular Physics
- Neutrino Physics Research
- Geophysics and Sensor Technology
- Seismic Waves and Analysis
- Radio Astronomy Observations and Technology
- Cryospheric studies and observations
- Atomic and Subatomic Physics Research
- Geology and Paleoclimatology Research
- Statistical and numerical algorithms
- Quantum Chromodynamics and Particle Interactions
- Advanced Frequency and Time Standards
- Nuclear reactor physics and engineering
- Seismic Imaging and Inversion Techniques
- Seismology and Earthquake Studies
Georgia Institute of Technology
2016-2024
California Institute of Technology
2011-2024
Argonne National Laboratory
2015-2024
University of Manitoba
2003-2024
National Institute of Environmental Health Sciences
2023
Joint Institute for Nuclear Astrophysics
2022
University of Massachusetts Amherst
2012-2021
Wheaton College - Illinois
2002-2021
University of Glasgow
2007-2020
State Street (United States)
2020
Advanced gravitational wave interferometers, currently under realization, will soon permit the detection of waves from astronomical sources. To open era precision astronomy, a further substantial improvement in sensitivity is required. The future space-based Laser Interferometer Space Antenna and third-generation ground-based observatory Einstein Telescope (ET) promise to achieve required improvements frequency ranges. vastly improved third generation observatories could detailed...
Summary An exact method is presented for calculating the changes in sea level that occur when ice and water masses are rearranged on surface of elastic viscoelastic non-rotating Earth models. The used to calculate instantaneous delayed vi scoelastic following partial melting late Quaternary sheets. We find there can be large errors usual assumption uniform over ocean basins. If a quantity equivalent 100-m rise melts from Laurentide Fennoscandian sheets, then South Pacific as 120m. In North...
Advanced gravitational wave detectors, currently under construction, are expected to directly observe signals of astrophysical origin. The Einstein Telescope (ET), a third-generation detector, has been proposed in order fully open up the emerging field astronomy. In this paper we describe sensitivity models for ET and investigate potential limits imposed by fundamental noise sources. A special focus is set on evaluating frequency band below 10 Hz where complex mixture seismic, gravity...
The sea-level rise due to ice-sheet melting since the last glacial maximum was not uniform everywhere because of deformation Earth's surface and its geoid by changing ice water loads. A numerical model is employed calculate global changes in relative sea level on a spherical viscoelastic Earth as northern hemisphere sheets melt fill ocean basins with meltwater. Predictions for past 16,000 years explain large proportion variance record, particularly during Holocene. Results indicate that...
The goal of the Laser Interferometric Gravitational-Wave Observatory (LIGO) is to detect and study gravitational waves (GWs) astrophysical origin. Direct detection GWs holds promise testing general relativity in strong-field regime, providing a new probe exotic objects such as black holes neutron stars uncovering unanticipated astrophysics. LIGO, joint Caltech–MIT project supported by National Science Foundation, operates three multi-kilometer interferometers at two widely separated sites...
Large gravitational wave interferometric detectors, like Virgo and LIGO, demonstrated the capability to reach their design sensitivity, but transform these machines into an effective observational instrument for astronomy a large improvement in sensitivity is required. Advanced detectors near future third-generation observatories more than one decade will open possibility perform astronomical observations from Earth. An overview of possible science reaches technological progress needed...
ABSTRACT Gravitational waves provide a unique tool for observational astronomy. While the first LIGO–Virgo catalogue of gravitational-wave transients (GWTC-1) contains 11 signals from black hole and neutron star binaries, number observations is increasing rapidly as detector sensitivity improves. To extract information observed signals, it imperative to have fast, flexible, scalable inference techniques. In previous paper, we introduced bilby: modular user-friendly Bayesian library adapted...
We identify an observable imprint of a first-order hadron-quark phase transition at supranuclear densities on the gravitational-wave (GW) emission neutron-star mergers. Specifically, we show that dominant postmerger GW frequency fpeak may exhibit significant deviation from empirical relation between and tidal deformability if strong leads to formation gravitationally stable extended quark matter core in remnant. A comparison signatures large, representative sample microphysical, purely...
The advanced interferometer network will herald a new era in observational astronomy. There is very strong science case to go beyond the detector and build detectors that operate frequency range from 1 Hz-10 kHz, with sensitivity factor ten better amplitude. Such be able probe of topics nuclear physics, astronomy, cosmology fundamental providing insights into many unsolved problems these areas.
We describe updates and improvements to the BayesWave gravitational wave transient analysis pipeline, provide examples of how algorithm is used analyze data from ground-based detectors. models signals in a morphology-independent manner through sum frame functions, such as Morlet-Gabor wavelets or chirplets. instrument noise using combination parametrized Gaussian component non-stationary non-Gaussian transients. Both signal model employ trans-dimensional sampling, with complexity adapting...
Abstract Fracture geometry is an important concern in the design of a massive hydraulic fracture for improved natural gas recovery from low-permeability reservoirs. Determination extent vertical growth and containment layered rock, priori, requires understanding parameters that may control across layer interfaces. We have conducted laboratory experiments elastic finite element studies show at least two distinct geologic conditions can inhibit or contain fractures rock: (1) weak interfacial...
We present direct upper limits on gravitational wave emission from the Crab pulsar using data first 9 months of fifth science run Laser Interferometer Gravitational-wave Observatory (LIGO). These are based two searches. In we assume that follows observed radio timing, giving an limit beats indirect inferred spin-down and braking index energetics nebula. second allow for a small mismatch between signal frequencies interpret our results in context possible mechanisms.
We present upper limits on the gravitational wave emission from 78 radio pulsars based data third and fourth science runs of LIGO GEO 600 detectors. The both have been combined coherently to maximize sensitivity. For first time, within binary (or multiple) systems included in search by taking into account signal modulation due their orbits. Our are therefore measured for 56 these pulsars. remaining 22, our results improve previous up a factor 10. example, tightest limit strain is...
We analyzed the available LIGO data coincident with GRB 070201, a short-duration, hard-spectrum γ-ray burst (GRB) whose electromagnetically determined sky position is spiral arms of Andromeda galaxy (M31). Possible progenitors such short, hard GRBs include mergers neutron stars or star and black hole, soft repeater (SGR) flares. These events can be accompanied by gravitational-wave emission. No plausible candidates were found within 180 s long window around time 070201. This result implies...
We present an effective, low-dimensionality frequency-domain template for the gravitational wave signal from stellar remnants binary neutron star coalescence. A principal component decomposition of a suite numerical simulations mergers is used to construct orthogonal basis functions amplitude and phase spectra waveforms variety equations state mass configurations. review phenomenology late merger / post-merger emission in coalescence demonstrate how understanding dynamics during after leads...
We carry out two searches for periodic gravitational waves using the most sensitive few hours of data from second LIGO science run. The first search is targeted at isolated, previously unknown neutron stars and covers entire sky in frequency band 160-728.8 Hz. targets accreting star low-mass X-ray binary Scorpius X-1, bands 464-484 Hz 604-624 Hz, orbit parameters. Both look coincidences between Livingston Hanford 4-km interferometers. For isolated our 95% confidence upper limits on wave...
We report on a search for gravitational waves from the coalescence of compact binaries during third and fourth LIGO science runs. The focused generated inspiral phase binary evolution. In our analysis, we considered three categories systems, ordered by mass: (i) primordial black hole with masses in range 0.35 M(sun) < m1, m2 1.0 M(sun), (ii) neutron stars 3.0 (iii) holes M(sun)< m_(max) additional constraint m1+ m_(max), where was set to 40.0 80.0 runs, respectively. Although detectors...
We introduce a novel cooling technique capable of approaching the quantum ground state kilogram-scale system—an interferometric gravitational wave detector. The detectors Laser Interferometer Gravitational-wave Observatory (LIGO) operate within factor 10 standard limit (SQL), providing displacement sensitivity 10−18 m in 100 Hz band centered on 150 Hz. With new feedback strategy, we dynamically shift resonant frequency 2.7 kg pendulum mode to lie this optimal band, where its effective...
Predictions of global changes in relative sea level caused by retreat the Antarctic Ice Sheet from its 18,000 yr B.P. maximum to present size are calculated numerically. When combined with predictions sea-level change resulting Northern Hemisphere ice sheets, results may be compared directly observations on continent as well at distant localities. The comparison few Antarctica supports view that was larger years ago than present. contribution total eustatic rise is assumed 25 m (25% rise)....
Abstract Laboratory experiments have been conducted to determine the effect of in-situ stress variations on hydraulic fracture containment. Fractures were initiated in layered rock samples with prescribed variations, and growth characteristics determined as a function levels. Stress contrasts 300 400 psi (2 3 MPa) found sufficient restrict laboratory Nevada tuff Tennessee Nugget sandstones. The required level was not depend mechanical properties. However, permeability resultant pore pressure...
The neutron-rich nucleus $^{144}$Ba ($t_{1/2}$=11.5 s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers $A$ less than 200. Until now, indirect evidence for such strong has been inferred from observations as enhanced $E1$ transitions and interleaving positive- negative-parity levels in ground-state band. In this experiment, strength was measured directly by sub-barrier, multi-step Coulomb excitation a post-accelerated 650-MeV beam on...