33 research outputs found

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

    Get PDF

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

    Get PDF
    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

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

    Get PDF
    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

    Get PDF
    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

    Wiener klinische Wochenschrift / Postoperative management of patients undergoing cardiac surgery in Austria : A national survey on current clinical practice in hemodynamic monitoring and postoperative management

    No full text
    Background No data are currently available regarding the current clinical practice in postoperative care of cardiac surgical patients in Austria. Objective The study investigated the current intensive care management concerning hemodynamic monitoring and strategies to treat common perioperative disorders of patients after cardiac surgery in Austria. Methods A survey consisting of 31 questions was sent to intensivists at all 9 hospitals offering cardiac surgery in Austria. Results The response rate was 100%. The mean number of procedures on cardiopulmonary bypass per centre was 722223. In the majority of cases postoperative critical care is performed by anesthesiologists. Blood gas analysis, pulse oximetry, electrocardiogram, temperature, central venous pressure, arterial pressure and hourly urine output are de facto standard monitoring in all centers. Transesophageal echocardiography is available in all centers and is frequently used. Crystalloids are the first choice for volume replacement, whereas levosimendan and adrenaline are employed for the treatment of low cardiac output syndrome. Conclusions This study provides insights into the current state of postoperative management of cardiac surgical patients in Austria. Standard monitoring as proposed by international guidelines is well established in Austrian intensive care units. Echocardiography is widely seen as a very important tool in the postoperative care of cardiac surgical patients. Knowledge about the status quo of postoperative intensive care management of cardiac surgical patients enables further development of patient care.(VLID)362004

    Injection Site Erythema in a Patient on Therapeutic Anticoagulation with Low Molecular Weight Heparin after Mechanical Aortic Valve Replacement: A Rare Presentation of Heparin- and Protamine-Induced Thrombocytopenia

    No full text
    Previous exposition to heparin and protamine in patients undergoing cardiopulmonary bypass and postoperative therapeutic anticoagulation with LMWH may lead to the development of heparin-induced thrombocytopenia (HIT) and/or protamine-induced thrombocytopenia (PIT). This case deals with a rare clinical presentation of circulating IgG antibodies against heparin/platelet factor 4 complexes and heparin/protamine complexes after cardiac surgery. Ensuing purpura and skin necrosis (blisters) at the injection sites of LMWH and clinical symptoms improved rapidly after replacement of LMWH by an alternative anticoagulant. The aim of this report is to draw attention to the several different clinical manifestations of heparin- and/or protamine-induced thrombocytopenia and shows a possible course of treatment and recovery

    Pseudothrombocytopenia Inducing Nonindicated Platelet Transfusion after Cardiac Surgery

    No full text
    Pseudothrombocytopenia (PTCP) is an in vitro phenomenon of low platelet count caused by the agglutination of platelets, leading to false low platelet counts in automated cell counting. Typically, ethylenediaminetetraacetic acid (EDTA) mediates this platelet clumping. PTCP has little clinical significance, but misdiagnosis may lead to unnecessary diagnostic tests and treatment. In this case report, we present a 65-year-old Caucasian female suffering from multiple complications during and after cardiac surgery. During her postoperative stay at the ICU, she was diagnosed with thrombocytopenia and an inadequate response to platelet supplementation
    corecore