3,174 research outputs found

    Prospects for observing ultra-compact binaries with space-based gravitational wave interferometers and optical telescopes

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    Space-based gravitational wave interferometers are sensitive to the galactic population of ultra-compact binaries. An important subset of the ultra-compact binary population are those stars that can be individually resolved by both gravitational wave interferometers and electromagnetic telescopes. The aim of this paper is to quantify the multi-messenger potential of space-based interferometers with arm-lengths between 1 and 5 Gm. The Fisher Information Matrix is used to estimate the number of binaries from a model of the Milky Way which are localized on the sky by the gravitational wave detector to within 1 and 10 square degrees and bright enough to be detected by a magnitude limited survey. We find, depending on the choice of GW detector characteristics, limiting magnitude, and observing strategy, that up to several hundred gravitational wave sources could be detected in electromagnetic follow-up observations.Comment: 6 pages, 3 figures Updated to include new results. Submitted to MNRA

    Gravity Waves, Chaos, and Spinning Compact Binaries

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    Spinning compact binaries are shown to be chaotic in the Post-Newtonian expansion of the two body system. Chaos by definition is the extreme sensitivity to initial conditions and a consequent inability to predict the outcome of the evolution. As a result, the spinning pair will have unpredictable gravitational waveforms during coalescence. This poses a challenge to future gravity wave observatories which rely on a match between the data and a theoretical template.Comment: Final version published in PR

    Forward Modeling of Space-borne Gravitational Wave Detectors

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    Planning is underway for several space-borne gravitational wave observatories to be built in the next ten to twenty years. Realistic and efficient forward modeling will play a key role in the design and operation of these observatories. Space-borne interferometric gravitational wave detectors operate very differently from their ground based counterparts. Complex orbital motion, virtual interferometry, and finite size effects complicate the description of space-based systems, while nonlinear control systems complicate the description of ground based systems. Here we explore the forward modeling of space-based gravitational wave detectors and introduce an adiabatic approximation to the detector response that significantly extends the range of the standard low frequency approximation. The adiabatic approximation will aid in the development of data analysis techniques, and improve the modeling of astrophysical parameter extraction.Comment: 14 Pages, 14 Figures, RevTex

    Comment on "Gravity Waves, Chaos, and Spinning Compact Binaries"

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    In this comment, I argue that chaotic effects in binary black hole inspiral will not strongly impact the detection of gravitational waves from such systems.Comment: 1 page, comment on gr-qc/991004

    Copper cable theft: revisiting the price–theft hypothesis

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    Objectives: To test the commonly espoused but little examined hypothesis that fluctuations in the price of metal are associated with changes in the volume of metal theft. Specifically, we analyze the relationship between the price of copper and the number of police recorded 'live’ copper cable thefts from the British railway network (2006 to 2012)

    Magic conditions for multiple rotational states of bialkali molecules in optical lattices

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    We investigate magic-wavelength trapping of ultracold bialkali molecules in the vicinity of weak optical transitions from the vibrational ground state of the X 1 Σ + potential to low-lying rovibrational states of the b 3 Π 0 potential, focusing our discussion on the 87 Rb 133 Cs molecule in a magnetic field of B = 181 G. We show that a frequency window exists between two nearest-neighbor vibrational poles in the dynamic polarizability where the trapping potential is “near magic” for multiple rotational states simultaneously. We show that the addition of a modest DC electric field of E = 0.13 kV/cm leads to an exact magic-wavelength trap for the lowest three rotational states at a angular-frequency detuning of Δ v ′ = 0 = 2 π × 218.22 GHz from the X 1 Σ + ( v = 0 , J = 0 ) → b 3 Π 0 ( v ′ = 0 , J = 1 ) transition. We derive a set of analytical criteria that must be fulfilled to ensure the existence of such magic frequency windows and present an analytic expression for the position of the frequency window in terms of a set of experimentally measurable parameters. These results should inform future experiments requiring long coherence times on multiple rotational transitions in ultracold polar molecules

    Detection Strategies for Extreme Mass Ratio Inspirals

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    The capture of compact stellar remnants by galactic black holes provides a unique laboratory for exploring the near horizon geometry of the Kerr spacetime, or possible departures from general relativity if the central cores prove not to be black holes. The gravitational radiation produced by these Extreme Mass Ratio Inspirals (EMRIs) encodes a detailed map of the black hole geometry, and the detection and characterization of these signals is a major scientific goal for the LISA mission. The waveforms produced are very complex, and the signals need to be coherently tracked for hundreds to thousands of cycles to produce a detection, making EMRI signals one of the most challenging data analysis problems in all of gravitational wave astronomy. Estimates for the number of templates required to perform an exhaustive grid-based matched-filter search for these signals are astronomically large, and far out of reach of current computational resources. Here I describe an alternative approach that employs a hybrid between Genetic Algorithms and Markov Chain Monte Carlo techniques, along with several time saving techniques for computing the likelihood function. This approach has proven effective at the blind extraction of relatively weak EMRI signals from simulated LISA data sets.Comment: 10 pages, 4 figures, Updated for LISA 8 Symposium Proceeding
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