Publications by authors named "A Ubhi"
Advanced Laser Interferometer Gravitational-wave Observatory (LIGO A+) is a major upgrade to LIGO-the Laser Interferometer Gravitational-wave Observatory. For the A+ project, we have developed, produced, and characterized sensors and electronics to interrogate new optical suspensions designed to isolate optics from vibrations. The central element is a displacement sensor with an integrated electromagnetic actuator known as a BOSEM (Birmingham Optical Sensor and ElectroMagnetic actuator) and its readout and drive electronics required to integrate them into LIGO's control and data system.
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- The study investigates compact binary coalescences with at least one component mass between 0.2 and 1.0 solar masses using data from Advanced LIGO and Advanced Virgo detectors over six months in 2019, but they found no significant gravitational wave candidates.
- The analysis leads to an upper limit on the merger rate of subsolar binaries ranging from 220 to 24,200 Gpc⁻³ yr⁻¹, based on the detected signals’ false alarm rate.
- The researchers use these limits to set new constraints on two models for subsolar-mass compact objects: primordial black holes (suggesting they make up less than 6% of dark matter) and
We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection.
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- On May 21, 2019, Advanced LIGO and Virgo detected a significant gravitational-wave signal known as GW190521, indicating a high probability event with a low chance of false alarms.
- The signal suggests it resulted from the merger of two black holes, one around 85 solar masses and the other about 66 solar masses, with the primary black hole likely being an intermediate mass black hole.
- The source of the merger is estimated to be about 5.3 billion light-years away, and the rate of similar black hole mergers is estimated to be about 0.13 mergers per billion cubic parsecs per year.