ORCID Profile
0000-0002-6540-6824
Current Organisation
Australian National University
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Publisher: SPIE
Date: 21-12-2008
DOI: 10.1117/12.769329
Publisher: American Astronomical Society
Date: 13-12-2017
Publisher: American Physical Society (APS)
Date: 18-10-2019
Publisher: American Astronomical Society
Date: 19-03-2020
Abstract: On 2019 April 25, the LIGO Livingston detector observed a compact binary coalescence with signal-to-noise ratio 12.9. The Virgo detector was also taking data that did not contribute to detection due to a low signal-to-noise ratio, but were used for subsequent parameter estimation. The 90% credible intervals for the component masses range from to ( – if we restrict the dimensionless component spin magnitudes to be smaller than 0.05). These mass parameters are consistent with the in idual binary components being neutron stars. However, both the source-frame chirp mass and the total mass of this system are significantly larger than those of any other known binary neutron star (BNS) system. The possibility that one or both binary components of the system are black holes cannot be ruled out from gravitational-wave data. We discuss possible origins of the system based on its inconsistency with the known Galactic BNS population. Under the assumption that the signal was produced by a BNS coalescence, the local rate of neutron star mergers is updated to 250–2810 .
Publisher: American Physical Society (APS)
Date: 08-10-2024
Publisher: American Astronomical Society
Date: 18-12-2017
Publisher: Springer Science and Business Media LLC
Date: 16-10-2017
DOI: 10.1038/NATURE24471
Abstract: On 17 August 2017, the Advanced LIGO and Virgo detectors observed the gravitational-wave event GW170817-a strong signal from the merger of a binary neutron-star system. Less than two seconds after the merger, a γ-ray burst (GRB 170817A) was detected within a region of the sky consistent with the LIGO-Virgo-derived location of the gravitational-wave source. This sky region was subsequently observed by optical astronomy facilities, resulting in the identification of an optical transient signal within about ten arcseconds of the galaxy NGC 4993. This detection of GW170817 in both gravitational waves and electromagnetic waves represents the first 'multi-messenger' astronomical observation. Such observations enable GW170817 to be used as a 'standard siren' (meaning that the absolute distance to the source can be determined directly from the gravitational-wave measurements) to measure the Hubble constant. This quantity represents the local expansion rate of the Universe, sets the overall scale of the Universe and is of fundamental importance to cosmology. Here we report a measurement of the Hubble constant that combines the distance to the source inferred purely from the gravitational-wave signal with the recession velocity inferred from measurements of the redshift using the electromagnetic data. In contrast to previous measurements, ours does not require the use of a cosmic 'distance ladder': the gravitational-wave analysis can be used to estimate the luminosity distance out to cosmological scales directly, without the use of intermediate astronomical distance measurements. We determine the Hubble constant to be about 70 kilometres per second per megaparsec. This value is consistent with existing measurements, while being completely independent of them. Additional standard siren measurements from future gravitational-wave sources will enable the Hubble constant to be constrained to high precision.
Publisher: American Physical Society (APS)
Date: 04-09-2019
Publisher: The Optical Society
Date: 16-01-2013
DOI: 10.1364/OL.38.000278
Publisher: The Optical Society
Date: 11-2019
DOI: 10.1364/OL.44.005386
Publisher: IOP Publishing
Date: 29-07-2020
Publisher: American Astronomical Society
Date: 16-10-2017
Publisher: American Physical Society (APS)
Date: 30-09-2019
Publisher: AIP Publishing
Date: 09-01-2023
DOI: 10.1063/5.0131984
Abstract: We present a direct measurement of the displacement noise spectrum of a macroscopic silicon flexure at room temperature. A cantilever attached to the 100 μm thick flexure holds a mirror which forms part of an optical cavity to enhance the displacement sensitivity to thermal noise. We predict the displacement noise spectrum using a simple model that assumes the dominant source of frequency-dependent loss is thermo-elastic d ing and find good agreement with the experimental data. The measurement is consistent with a frequency-independent loss of ϕ0,fi=1.6×10−5 combined with frequency-dependent thermo-elastic d ing as the dominant losses. A crossover between the two that occurs well above the flexure resonant frequency allows a broadband measurement of the thermal noise of the silicon flexure. The flexure material, geometry, and measurement band are similar to those of planned future gravitational wave detectors.
Publisher: AIP Publishing
Date: 14-05-2012
DOI: 10.1063/1.4717717
Abstract: A near threshold all-optical backaction lifier is realized. Operating near threshold in an integrated micron scale architecture allows a nearly three orders of magnitude improvement in both gain and optical power requirements over the only previous all-optical implementation, with 37 dB of gain achieved for only 12 μW of input power. Minor parameter adjustment allows narrowband optical filtering.
Publisher: American Astronomical Society
Date: 30-09-2019
Abstract: When formed through dynamical interactions, stellar-mass binary black holes (BBHs) may retain eccentric orbits ( e 0.1 at 10 Hz) detectable by ground-based gravitational-wave detectors. Eccentricity can therefore be used to differentiate dynamically formed binaries from isolated BBH mergers. Current template-based gravitational-wave searches do not use waveform models associated with eccentric orbits, rendering the search less efficient for eccentric binary systems. Here we present the results of a search for BBH mergers that inspiral in eccentric orbits using data from the first and second observing runs (O1 and O2) of Advanced LIGO and Advanced Virgo. We carried out the search with the coherent WaveBurst algorithm, which uses minimal assumptions on the signal morphology and does not rely on binary waveform templates. We show that it is sensitive to binary mergers with a detection range that is weakly dependent on eccentricity for all bound systems. Our search did not identify any new binary merger candidates. We interpret these results in light of eccentric binary formation models. We rule out formation channels with rates ≳100 Gpc −3 yr −1 for e 0.1, assuming a black hole mass spectrum with a power-law index ≲2.
Publisher: Optica Publishing Group
Date: 17-11-2009
DOI: 10.1364/OE.17.021977
Publisher: American Astronomical Society
Date: 11-09-2019
Publisher: American Physical Society (APS)
Date: 09-07-2009
Publisher: OSA
Date: 2012
Publisher: Springer Science and Business Media LLC
Date: 07-2020
Publisher: American Physical Society (APS)
Date: 24-08-2020
Publisher: Wiley
Date: 04-10-2016
Publisher: SPIE
Date: 02-06-2014
DOI: 10.1117/12.2059435
Publisher: The Optical Society
Date: 22-05-2012
DOI: 10.1364/OE.20.012742
Publisher: IOP Publishing
Date: 05-03-2020
Publisher: The Optical Society
Date: 04-05-2016
DOI: 10.1364/OE.24.010486
Publisher: The Optical Society
Date: 18-07-2014
DOI: 10.1364/OE.22.018168
Publisher: American Astronomical Society
Date: 07-04-2017
Publisher: American Physical Society (APS)
Date: 26-03-2010
Publisher: Cambridge University Press (CUP)
Date: 2020
DOI: 10.1017/PASA.2020.39
Abstract: Gravitational waves from coalescing neutron stars encode information about nuclear matter at extreme densities, inaccessible by laboratory experiments. The late inspiral is influenced by the presence of tides, which depend on the neutron star equation of state. Neutron star mergers are expected to often produce rapidly rotating remnant neutron stars that emit gravitational waves. These will provide clues to the extremely hot post-merger environment. This signature of nuclear matter in gravitational waves contains most information in the 2–4 kHz frequency band, which is outside of the most sensitive band of current detectors. We present the design concept and science case for a Neutron Star Extreme Matter Observatory (NEMO): a gravitational-wave interferometer optimised to study nuclear physics with merging neutron stars. The concept uses high-circulating laser power, quantum squeezing, and a detector topology specifically designed to achieve the high-frequency sensitivity necessary to probe nuclear matter using gravitational waves. Above 1 kHz, the proposed strain sensitivity is comparable to full third-generation detectors at a fraction of the cost. Such sensitivity changes expected event rates for detection of post-merger remnants from approximately one per few decades with two A+ detectors to a few per year and potentially allow for the first gravitational-wave observations of supernovae, isolated neutron stars, and other exotica.
Publisher: Springer Science and Business Media LLC
Date: 26-04-2018
DOI: 10.1007/S41114-018-0012-9
Abstract: We present possible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next decade, with the intention of providing information to the astronomy community to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals, and study the capability of the network to determine the sky location of the source. We report our findings for gravitational-wave transients, with particular focus on gravitational-wave signals from the inspiral of binary neutron star systems, which are the most promising targets for multi-messenger astronomy. The ability to localize the sources of the detected signals depends on the geographical distribution of the detectors and their relative sensitivity, and $$90\\%$$ 90 % credible regions can be as large as thousands of square degrees when only two sensitive detectors are operational. Determining the sky position of a significant fraction of detected signals to areas of 5– $$20~\\mathrm {deg}^2$$ 20 deg 2 requires at least three detectors of sensitivity within a factor of $$\\sim 2$$ ∼ 2 of each other and with a broad frequency bandwidth. When all detectors, including KAGRA and the third LIGO detector in India, reach design sensitivity, a significant fraction of gravitational-wave signals will be localized to a few square degrees by gravitational-wave observations alone.
Publisher: American Physical Society (APS)
Date: 02-04-2020
Publisher: American Astronomical Society
Date: 10-2020
Abstract: We present a search for continuous gravitational waves from five radio pulsars, comprising three recycled pulsars (PSR J0437−4715, PSR J0711−6830, and PSR J0737−3039A) and two young pulsars: the Crab pulsar (J0534+2200) and the Vela pulsar (J0835−4510). We use data from the third observing run of Advanced LIGO and Virgo combined with data from their first and second observing runs. For the first time, we are able to match (for PSR J0437−4715) or surpass (for PSR J0711−6830) the indirect limits on gravitational-wave emission from recycled pulsars inferred from their observed spin-downs, and constrain their equatorial ellipticities to be less than 10 −8 . For each of the five pulsars, we perform targeted searches that assume a tight coupling between the gravitational-wave and electromagnetic signal phase evolution. We also present constraints on PSR J0711−6830, the Crab pulsar, and the Vela pulsar from a search that relaxes this assumption, allowing the gravitational-wave signal to vary from the electromagnetic expectation within a narrow band of frequencies and frequency derivatives.
Publisher: IOP Publishing
Date: 12-04-2017
Publisher: IOP Publishing
Date: 16-01-2020
Abstract: GW170817 is the very first observation of gravitational waves originating from the coalescence of two compact objects in the mass range of neutron stars, accompanied by electromagnetic counterparts, and offers an opportunity to directly probe the internal structure of neutron stars. We perform Bayesian model selection on a wide range of theoretical predictions for the neutron star equation of state. For the binary neutron star hypothesis, we find that we cannot rule out the majority of theoretical models considered. In addition, the gravitational-wave data alone does not rule out the possibility that one or both objects were low-mass black holes. We discuss the possible outcomes in the case of a binary neutron star merger, finding that all scenarios from prompt collapse to long-lived or even stable remnants are possible. For long-lived remnants, we place an upper limit of 1.9 kHz on the rotation rate. If a black hole was formed any time after merger and the coalescing stars were slowly rotating, then the maximum baryonic mass of non-rotating neutron stars is at most , and three equations of state considered here can be ruled out. We obtain a tighter limit of for the case that the merger results in a hypermassive neutron star.
Publisher: American Physical Society (APS)
Date: 02-09-2020
Publisher: Springer Science and Business Media LLC
Date: 10-02-2020
Publisher: AIP Publishing
Date: 06-2016
DOI: 10.1063/1.4953326
Abstract: With the recent detection of gravitational waves, non-classical light sources are likely to become an essential element of future detectors engaged in gravitational wave astronomy and cosmology. Operating a squeezed light source under high vacuum has the advantages of reducing optical losses and phase noise compared to techniques where the squeezed light is introduced from outside the vacuum. This will ultimately provide enhanced sensitivity for modern interferometric gravitational wave detectors that will soon become limited by quantum noise across much of the detection bandwidth. Here we describe the optomechanical design choices and construction techniques of a near monolithic glass optical parametric oscillator that has been operated under a vacuum of 10−6 mbar. The optical parametric oscillator described here has been shown to produce 8.6 dB of quadrature squeezed light in the audio frequency band down to 10 Hz. This performance has been maintained for periods of around an hour and the system has been under vacuum continuously for several months without a degradation of this performance.
Publisher: IOP Publishing
Date: 20-08-2020
Publisher: American Physical Society (APS)
Date: 11-07-2019
Publisher: American Physical Society (APS)
Date: 04-09-2019
Publisher: AIP Publishing
Date: 20-09-2010
DOI: 10.1063/1.3494530
Abstract: Sensors based on whispering gallery mode resonators can detect single nanoparticles and even single molecules. Particles attaching to the resonator induce a doublet in the transmission spectrum which provides a self-referenced detection signal. However, in practice this spectral feature is often obscured by the width of the resonance line which hides the doublet structure. This happens particularly in liquid environments that reduce the effective Q factor of the resonator. In this paper we demonstrate an interferometric setup that allows the direct detection of the hidden doublet and thus provides a pathway for developing practical sensor applications.
Publisher: American Physical Society (APS)
Date: 05-12-2019
Publisher: Springer Science and Business Media LLC
Date: 07-10-2020
Publisher: American Physical Society (APS)
Date: 11-09-2020
Publisher: SAGE Publications
Date: 18-06-0015
Abstract: Pain can elevate stress in people with dementia. Although salivary cortisol is used as a biomarker of stress in people with dementia, few studies have reported the feasibility of collection methods to assess salivary cortisol in nursing home residents with both dementia and chronic pain. To explore the feasibility of collecting cortisol via salivary swab as an indicator of stress in people with dementia and chronic pain. Participants ( N = 43) aged ≥ 65 years and living with dementia and chronic pain were randomly assigned to the PARO (in idual, nonfacilitated, 30-min sessions with the robotic seal PARO, 5 days per week for 6 weeks) or usual-care group using computer-generated random numbers. Salivary cortisol was collected in the early morning before the intervention (Week 0) and at the completion of the intervention (Week 6) for comparison. There were multiple challenges associated with saliva collection and analysis, including cognitive impairment of participants, ability to obtain repeated s les with saliva volume adequate for assay, and overall cost. Ultimately, adequate saliva was collected from only 8 participants (both pre- and post-intervention) for assay and quantitative analysis. Considering the multiple challenges involved in obtaining valid saliva s les in this population, salivary cortisol may not be a feasible biomarker of physiological stress in people with dementia and chronic pain.
Publisher: The Optical Society
Date: 19-03-2014
DOI: 10.1364/OL.39.001752
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-2010
Publisher: American Physical Society (APS)
Date: 30-08-2010
Publisher: Optica Publishing Group
Date: 17-03-2020
DOI: 10.1364/OE.390250
Abstract: We report the infrasonic performance of a fiber optic laser frequency reference with potential application to space-based gravitational wave detectors, such as the Laser Interferometer Space Antenna. We determine the optimum cross-over frequency between an optical frequency comb stabilized to a Rubidium atomic reference and two passive, all-fiber interferometers interrogated using digitally enhanced homodyne interferometery. By measuring the relative stability between the three independent optical frequency references, we find the optimum cross-over frequency to occur at 1.5 mHz, indicating that our passive fiber frequency reference is superior to the optical frequency comb at all higher frequencies. In addition, we find our fiber interferometers achieve a stability of 20 kHz/ Hz at 1.5 mHz, improving to a stability of 4 Hz/ Hz above 3 Hz. These results represent an independent characterization of digitally enhanced fiber references over long time scales and provide an estimate of thermal effects on these passively isolated systems, informing future reference architectures.
Publisher: American Physical Society (APS)
Date: 04-12-2019
Publisher: American Physical Society (APS)
Date: 20-02-2019
Publisher: American Physical Society (APS)
Date: 20-11-2019
Publisher: The Optical Society
Date: 18-06-2012
DOI: 10.1364/OL.37.002448
Publisher: The Optical Society
Date: 18-12-2016
DOI: 10.1364/OL.41.000084
Publisher: American Astronomical Society
Date: 26-06-2019
Publisher: American Physical Society (APS)
Date: 17-05-2018
Publisher: American Astronomical Society
Date: 20-04-2020
No related grants have been discovered for Terry McRae.