1,525 research outputs found

    Who Loses: An examination of losses in housing net worth, non-housing assets, and total savings from 2007 to 2008 among American families

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    This study models the loss in non-housing assets, increase in non-housing liabilities, and net change in housing value across people by education, ethnic, and occupational categories in the 2007-2008 collapse of Wall Street financial markets. Hypotheses of plausible loci of loss include the usual social categories. Findings do not confirm all of the common presuppositions—managerial class workers have among the largest losses, retirees somewhat limited losses, and losses by educational group decline with advancing education, with the possible exception of Ph.D. holders. The group which had the most severe losses in all asset categories was the armed forces. The magnitude of the suggested effects would indicate that additional policy attention should be targeted on military family outcomes under economic stress.housing net worth; non-household liabilities; non-household assets; occupational group; education level;

    PyCBC Live: Rapid Detection of Gravitational Waves from Compact Binary Mergers

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    We introduce an efficient and straightforward technique for rapidly detecting gravitational waves from compact binary mergers. We show that this method achieves the low latencies required to alert electromagnetic partners of candidate binary mergers, aids in data monitoring, and makes use of multidetector networks for sky localization. This approach was instrumental to the analysis of gravitational-wave candidates during the second observing run of Advanced LIGO, including the period of coincident operation with Advanced Virgo, and in particular the analysis of the first observed binary neutron star merger GW170817, where it led to the first tightly localized sky map (31 deg231~\mathrm{deg}^2) used to identify AT 2017gfo. Operation of this analysis also enabled the initial discovery of GW170104 and GW170608 despite non-nominal observing of the instrument.Comment: 10 pages, 5 figures, submitted to Physical Review

    Investigating the noise residuals around the gravitational wave event GW150914

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    We use the Pearson cross-correlation statistic proposed by Liu and Jackson, and employed by Creswell et al., to look for statistically significant correlations between the LIGO Hanford and Livingston detectors at the time of the binary black hole merger GW150914. We compute this statistic for the calibrated strain data released by LIGO, using both the residuals provided by LIGO and using our own subtraction of a maximum-likelihood waveform that is constructed to model binary black hole mergers in general relativity. To assign a significance to the values obtained, we calculate the cross-correlation of both simulated Gaussian noise and data from the LIGO detectors at times during which no detection of gravitational waves has been claimed. We find that after subtracting the maximum likelihood waveform there are no statistically significant correlations between the residuals of the two detectors at the time of GW150914.Comment: 14 pages, 7 figures. Minor text and figure changes in final v3. Notebooks for generating the results are available at https://github.com/gwastro/gw150914_investigatio

    The Effect of Mandatory Employer-Sponsored Insurance (ESI) on Health Insurance Coverage and Labor Force Utilization in Hawaii: Evidence from the Current Population Survey (CPS) 1994-2004

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    Using data from the Current Population Surveys, we examine the impact of Hawaii’s mandatory employer-sponsored insurance on health insurance coverage and employment structure in Hawaii. We find empirical evidence of three phenomena. First, private employer-sponsored insurance coverage for full-time workers (more than 20 hours per week) is more prevalent in Hawaii, other things held constant, than in other states and the U.S. as a whole. Second, there is avoidance of the employer-mandate in Hawaii by skirting the 20 hour rule, which changes the both the distribution of employment and the distribution of employment-based insurance coverage by hours worked. Third, Hawaii workers who match with part-time jobs without employer-sponsored health insurance obtain publicly provided health insurance or military coverage with higher probability than their counterparts elsewhere in the U.S. These results suggest that employer mandates induce both higher rates of coverage and labor market sorting.health insurance, employee sponsored insurance, Hawaii's labor market

    A mock data study for 3G ground-based detectors: the performance loss of matched filtering due to correlated confusion noise

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    The next-generation (3G/XG) ground-based gravitational-wave (GW) detectors such as Einstein Telescope (ET) and Cosmic Explorer (CE) will begin observing in the next decade. Due to the extremely high sensitivity of these detectors, the majority of stellar-mass compact-binary mergers in the entire Universe will be observed. It is also expected that 3G detectors will have significant sensitivity down to 2-7 Hz; the observed duration of binary neutron star signals could increase to several hours or days. The abundance and duration of signals will cause them to overlap in time, which may form a confusion noise that could affect the detection of individual GW sources when using naive matched filtering; Matched filtering is only optimal for stationary Gaussian noise. We create mock data for CE and ET using the latest population models informed by the GWTC-3 catalog and investigate the performance loss of matched filtering due to overlapping signals. We find the performance loss mainly comes from a deviation in the noise's measured amplitude spectral density. The redshift reach of CE (ET) can be reduced by 15-38 (8-21) % depending on the merger rate estimate. The direct contribution of confusion noise to the total SNR is generally negligible compared to the contribution from instrumental noise. We also find that correlated confusion noise has a negligible effect on the quadrature summation rule of network SNR for ET, but might reduce the network SNR of high detector-frame mass signals for detector networks including CE if no mitigation is applied. For ET, the null stream can mitigate the astrophysical foreground. For CE, we demonstrate that a computationally efficient, straightforward single-detector signal subtraction method suppresses the total noise to almost the instrument noise level; this will allow for near-optimal searches.Comment: 22 pages, 10 figures, comments are welcome, public code: https://github.com/gwastro/confusion-noise-3

    Mock data study for next-generation ground-based detectors: The performance loss of matched filtering due to correlated confusion noise

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    The next-generation (3G/XG) ground-based gravitational-wave (GW) detectors such as Einstein Telescope (ET) and Cosmic Explorer (CE) will begin observing in the next decade. Due to the extremely high sensitivity of these detectors, the majority of stellar-mass compact-binary mergers in the entire Universe will be observed. It is also expected that 3G detectors will have significant sensitivity down to 2-7 Hz; the observed duration of binary neutron star signals could increase to several hours or days. The abundance and duration of signals will cause them to overlap in time, which may form a confusion noise that could affect the detection of individual GW sources when using naive matched filtering; matched filtering is only optimal for stationary Gaussian noise. We create mock data for CE and ET using the latest population models informed by the GWTC-3 catalog and investigate the performance loss of matched filtering due to overlapping signals. We find the performance loss mainly comes from a deviation in the noise's measured amplitude spectral density. The redshift reach of CE (ET) can be reduced by 15%-38% (8%-21%) depending on the merger rate estimate. The direct contribution of confusion noise to the total signal-to-noise ratio (SNR) is generally negligible compared to the contribution from instrumental noise. We also find that correlated confusion noise has a negligible effect on the quadrature summation rule of network SNR for ET, but might reduce the network SNR of high detector-frame mass signals for detector networks including CE if no mitigation is applied. For ET, the null stream can mitigate the astrophysical foreground. For CE, we demonstrate that a computationally efficient, straightforward single-detector signal subtraction method suppresses the total noise to almost the instrument noise level; this will allow for near-optimal searches

    Detecting binary compact-object mergers with gravitational waves: Understanding and Improving the sensitivity of the PyCBC search

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    We present an improved search for binary compact-object mergers using a network of ground-based gravitational-wave detectors. We model a volumetric, isotropic source population and incorporate the resulting distribution over signal amplitude, time delay, and coalescence phase into the ranking of candidate events. We describe an improved modeling of the background distribution, and demonstrate incorporating a prior model of the binary mass distribution in the ranking of candidate events. We find a 10%\sim 10\% and 20%\sim 20\% increase in detection volume for simulated binary neutron star and neutron star--binary black hole systems, respectively, corresponding to a reduction of the false alarm rates assigned to signals by between one and two orders of magnitude.Comment: 7 pages, 3 figures, as accepted by Ap

    Hierarchical approach to matched filtering using a reduced basis

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    Searching for gravitational waves from compact binary coalescences (CBC) is performed by matched filtering the observed strain data from gravitational-wave observatories against a discrete set of waveform templates designed to accurately approximate the expected gravitational-wave signal, and are chosen to efficiently cover a target search region. The computational cost of matched filtering scales with both the number of templates required to cover a parameter space and the in-band duration of the waveform. Both of these factors increase in difficulty as the current observatories improve in sensitivity, especially at low frequencies, and may pose challenges for third-generation observatories. Reducing the cost of matched filtering would make searches of future detector's data more tractable. In addition, it would be easier to conduct searches that incorporate the effects of eccentricity, precession or target light sources (e.g. subsolar). We present a hierarchical scheme based on a reduced bases method to decrease the computational cost of conducting a matched-filter based search. Compared to the current methods, we estimate without any loss in sensitivity, a speedup by a factor of \sim 18 for sources with signal-to-noise ratio (SNR) of at least =6.0= 6.0, and a factor of 88 for SNR of at least 5. Our method is dominated by linear operations which are highly parallelizable. Therefore, we implement our algorithm using graphical processing units (GPUs) and evaluate commercially motivated metrics to demonstrate the efficiency of GPUs in CBC searches. Our scheme can be extended to generic CBC searches and allows for efficient matched filtering using GPUs
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