50 research outputs found

    Observation of gravitational waves from the coalescence of a 2.5–4.5 M ⊙ compact object and a neutron star

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    We report the observation of a coalescing compact binary with component masses 2.5–4.5 M ⊙ and 1.2–2.0 M ⊙ (all measurements quoted at the 90% credible level). The gravitational-wave signal GW230529_181500 was observed during the fourth observing run of the LIGO–Virgo–KAGRA detector network on 2023 May 29 by the LIGO Livingston observatory. The primary component of the source has a mass less than 5 M ⊙ at 99% credibility. We cannot definitively determine from gravitational-wave data alone whether either component of the source is a neutron star or a black hole. However, given existing estimates of the maximum neutron star mass, we find the most probable interpretation of the source to be the coalescence of a neutron star with a black hole that has a mass between the most massive neutron stars and the least massive black holes observed in the Galaxy. We provisionally estimate a merger rate density of 55−47+127Gpc−3yr−1 for compact binary coalescences with properties similar to the source of GW230529_181500; assuming that the source is a neutron star–black hole merger, GW230529_181500-like sources may make up the majority of neutron star–black hole coalescences. The discovery of this system implies an increase in the expected rate of neutron star–black hole mergers with electromagnetic counterparts and provides further evidence for compact objects existing within the purported lower mass gap

    Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

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    Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

    Observation of gravitational waves from the coalescence of a 2.5−4.5 M⊙ compact object and a neutron star

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    Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

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    Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

    Ultralight vector dark matter search using data from the KAGRA O3GK run

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    Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

    Responsiveness to the Portuguese version of the international consultation on incontinence questionnaire - short form (ICIQ-SF) after stress urinary incontinence surgery

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    OBJECTIVE: To evaluate the reliability and responsiveness (internal and external) of the Portuguese version of the ICIQ-SF. We assessed the responsiveness of the ICIQ-SF after surgical procedures for the treatment of stress urinary incontinence. MATERIALS AND METHODS: Prospective open label study in 2 tertiary referral centers. Sixty-one patients of both genders (54 female and 7 male) were enrolled. Patients were treated using surgical procedures, mostly with synthetic sling (82%). Patients were assessed before surgery and at least 1 month postoperatively using the ICIQ-SF in its translated and validated Portuguese version. Patients also underwent pre-operative urodynamic tests, Stamey incontinence grading and pad usage assessments. After surgery, patients underwent stress tests, Stamey incontinence grading and pad usage assessments. RESULTS: The mean age was 57.2 (&plusmn; 11.6) years and the mean duration of follow-up was 7.2 months (&plusmn; 4.5). Objective parameters such as urodynamic tests (by means of VLPP) and pad usage had significant correlation with changes in post-treatment scores on the ICIQ-SF (p = 0.0062 and p < 0.0001 respectively). The responsiveness expressed in terms of standardized effect sizes (SES) and standardized response means (SRM) was large for both questionnaires (p < 0.0001). CONCLUSION: The results showed high responsiveness (large effect sizes I and II) for the Portuguese version of the ICIQ-SF, indicating that this instrument is suitable for measuring outcomes in clinical trials for Brazilian patients with stress urinary incontinence

    Concurrent validity, internal consistency and responsiveness of the portuguese version of the king's health questionnaire (KHQ) in women after stress urinary incontinence surgery

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    OBJECTIVE: To evaluate the concurrent validity, internal consistency and responsiveness of King's Health Questionnaire (KHQ) in patients who underwent sling procedures for the treatment of stress urinary incontinence. MATERIALS AND METHODS: We performed a prospective open label multicenter study in 4 tertiary referral centers. Sixty-eight female patients were enrolled with urodynamically diagnosed urinary stress incontinence. Patients were treated using surgical procedures, mostly (73%) with the synthetic sling procedure, which has been considered one of the gold standard methods for the treatment of urinary incontinence. The patients were assessed before and after one month of postoperative follow up, using the KHQ in its validated Portuguese version. Patients also underwent preoperative urodynamic test, Stamey incontinence grading, pad usage and the assessment of number of pads used per day. After surgery, patients underwent stress test, Stamey incontinence grading pad usage and the assessment of number of pads used per day. RESULTS: The concurrent validity showed good correlations in some domains of KHQ to clinical parameters. The internal consistency was higher after treatment compared to preoperative values. Objective parameters, such as pad usage and the assessment of number of pads used per day, had significant correlation with changes in post-treatment scores on KHQ. The responsiveness expressed in terms of standardized effect size (SES) and standardized response mean (SRM) was large. CONCLUSION: The results showed moderate concurrent validity, strong internal consistency and high responsiveness for KHQ, indicating that it is suitable for measuring outcomes in clinical trials among female patients with stress urinary incontinence
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