The Advanced LIGO detectors are sophisticated opto-mechanical devices. At the core of their operation is feedback control. The Advanced LIGO project developed a custom digital control and data ...acquisition system to handle the unique needs of this new breed of astronomical detector. The advligortsis the software component of this system. This highly modular and extensible system has enabled the unprecedented performance of the LIGO instruments, and has been a vital component in the direct detection of gravitational waves.
The most common cardiovascular manifestation of Systemic Lupus Erythematosus is pericardial disease. Tamponade in SLE is rarely described. The patient discussed in this case report presented with ...symptoms of heart failure. Physical exam, laboratory testing, echocardiography, and right heart catheterization revealed multiple morbid conditions including tamponade. The diagnoses satisfied four criteria for the classification of SLE. This case emphasizes the importance of a thorough physical exam in guiding diagnostic and therapeutic measures.
LIGO's mission critical timing system has enabled gravitational wave and multi-messenger astrophysical discoveries as well as the rich science extracted. Achieving optimal detector sensitivity, ...detecting transient gravitational waves, and especially localizing gravitational wave sources, the underpinning of multi-messenger astrophysics, all require proper gravitational wave data time-stamping. Measurements of the relative arrival times of gravitational waves between different detectors allow for coherent gravitational wave detections, localization of gravitational wave sources, and the creation of skymaps. The carefully designed timing system achieves these goals by mitigating phase noise to avoid signal up-conversion and maximize gravitational wave detector sensitivity. The timing system also redundantly performs self-calibration and self-diagnostics in order to ensure reliable, extendable, and traceable time stamping. In this paper, we describe and quantify the performance of these core systems during the latest O3 scientific run of LIGO, Virgo, and KAGRA. We present results of the diagnostic checks done to verify the time-stamping for individual gravitational wave events observed during O3 as well as the timing system performance for all of O3 in LIGO Livingston and LIGO Hanford. We find that, after 3 observing runs, the LIGO timing system continues to reliably meet mission requirements of timing precision below 1 \(\mu\)s with a significant safety margin.
The Advanced LIGO detectors are sophisticated opto-mechanical devices. At the core of their operation is feedback control. The Advanced LIGO project developed a custom digital control and data ...acquisition system to handle the unique needs of this new breed of astronomical detector. The advligorts is the software component of this system. This highly modular and extensible system has enabled the unprecedented performance of the LIGO instruments, and has been a vital component in the direct detection of gravitational waves.
Precision measurements of space and time, like those made by the detectors of the Laser Interferometer Gravitational-wave Observatory (LIGO), are often confronted with fundamental limitations imposed ...by quantum mechanics. The Heisenberg uncertainty principle dictates that the position and momentum of an object cannot both be precisely measured, giving rise to an apparent limitation called the Standard Quantum Limit (SQL). Reducing quantum noise below the SQL in gravitational-wave detectors, where photons are used to continuously measure the positions of freely falling mirrors, has been an active area of research for decades. Here we show how the LIGO A+ upgrade reduced the detectors' quantum noise below the SQL by up to 3 dB while achieving a broadband sensitivity improvement, more than two decades after this possibility was first presented.
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