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  1. ; ; ; ; ; ; ; ; ; ; et al ( , The Astrophysical Journal)
    Abstract

    We present Fermi Gamma-ray Burst Monitor (Fermi-GBM) and Swift Burst Alert Telescope (Swift-BAT) searches for gamma-ray/X-ray counterparts to gravitational-wave (GW) candidate events identified during the third observing run of the Advanced LIGO and Advanced Virgo detectors. Using Fermi-GBM onboard triggers and subthreshold gamma-ray burst (GRB) candidates found in the Fermi-GBM ground analyses, the Targeted Search and the Untargeted Search, we investigate whether there are any coincident GRBs associated with the GWs. We also search the Swift-BAT rate data around the GW times to determine whether a GRB counterpart is present. No counterparts are found. Using both the Fermi-GBM Targeted Search and the Swift-BAT search, we calculate flux upper limits and present joint upper limits on the gamma-ray luminosity of each GW. Given these limits, we constrain theoretical models for the emission of gamma rays from binary black hole mergers.

     
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  2. ; ; ; ; ; ; ; ; ; ; et al ( , Progress of Theoretical and Experimental Physics)
    Abstract KAGRA, the underground and cryogenic gravitational-wave detector, was operated for its solo observation from February 25 to March 10, 2020, and its first joint observation with the GEO 600 detector from April 7 to April 21, 2020 (O3GK). This study presents an overview of the input optics systems of the KAGRA detector, which consist of various optical systems, such as a laser source, its intensity and frequency stabilization systems, modulators, a Faraday isolator, mode-matching telescopes, and a high-power beam dump. These optics were successfully delivered to the KAGRA interferometer and operated stably during the observations. The laser frequency noise was observed to limit the detector sensitivity above a few kilohertz, whereas the laser intensity did not significantly limit the detector sensitivity. 
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  3. ; ; ; ; ; ; ; ; ; ; et al ( , Physics Letters B)
    Free, publicly-accessible full text available November 1, 2024
  4. ; ; ; ; ; ; ; ; ; ; et al ( , Physics Letters B)
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  5. ; ; ; ; ; ; ; ; ; ; et al ( , Physics Letters B)
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  6. ; ; ; ; ; ; ; ; ; ; et al ( , Physics Letters B)
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  7. ; ; ; ; ; ; ; ; ; ; et al ( , Physics Letters B)
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  8. ; ; ; ; ; ; ; ; ; ; et al ( , Physics Letters B)
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  9. ; ; ; ; ; ; ; ; ; ; et al ( , Physics Letters B)
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  10. ; ; ; ; ; ; ; ; ; ; et al ( , Physics Letters B)
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