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Analysis of 91 confident gravitational wave signals from compact binary coalescences, including data from LIGO Virgo KAGRA's O4a run, continues to validate General Relativity (GR). The study examined parameterized deviations across eight tests, finding no evidence for physics beyond GR. These results improve previous bounds on GR deviations and constrain the graviton mass.
Analysis of 42 gravitational wave events from GWTC-4.0, combined with previous observations, consistently supports General Relativity (GR). Seven tests on binary merger remnants, including ringdown consistency and post-merger echo searches, reveal no strong evidence of GR deviation. The hierarchical analysis shows GR predictions fall within a high credible region, despite minor fluctuations attributed to catalog size.
This paper details the calibration, systematic uncertainties, and triggering efficiency of scintillation light in the MicroBooNE LArTPC detector over five years. It presents a comprehensive analysis of the light simulation, triggering schemes, PMT gain calibration, and stability. Crucially, the study identifies a significant decline in light yield and a high rate of single photoelectron noise, impacting low-energy event detection. These findings are critical for long-term LArTPC operations and future neutrino experiments.
The LIGO-Virgo-KAGRA Collaboration performed directed searches for continuous gravitational waves from 15 supernova remnants. Utilizing five distinct analysis pipelines, the study analyzed data from the first eight months of the fourth observing run (O4). No gravitational wave signals were detected, leading to the most stringent upper limits on intrinsic strain amplitude, neutron star ellipticity, and r-mode amplitudes for these sources to date.
The LIGO-Virgo-KAGRA Collaboration performed narrowband searches for continuous gravitational waves (CWs) from 34 known pulsars using data from the first two parts of their fourth observing run. This search, utilizing a 5n-vector narrowband pipeline with expanded parameter space coverage to include \"ddot{f}\" and binary systems, found no evidence of CWs. The study set new upper limits on CW strain amplitudes, with 20 pulsars showing limits below their theoretical spin-down limits. This research advances our understanding of neutron star internal structure by constraining the energy radiated as CWs.