First joint observation by the underground gravitational-wave detector KAGRA with GEO 600

Abstract

We report the results of the first joint observation of the KAGRA detector with GEO600. KAGRA is a cryogenic and underground gravitational-wave detector consisting of a laser interferometer with three-kilometer arms, and located in Kamioka, Gifu, Japan. GEO600 is a British–German laser interferometer with 600m arms, and located near Hannover, Germany. GEO600 and KAGRA performed a joint observing run from April 7 to 20, 2020. We present the results of the joint analysis of the GEO–KAGRA data for transient gravitational-wave signals, including the coalescence of neutron-star binaries and generic unmodeled transients. We also perform dedicated searches for binary coalescence signals and generic transients associated with gamma-ray burst events observed during the joint run. No gravitational-wave events were identified. We evaluate the minimum detectable amplitude for various types of transient signals and the spacetime volume for which the network is sensitive to binary neutron-star coalescences. We also place lower limits on the distances to the gamma-ray bursts analysed based on the non-detection of an associated gravitational-wave signal for several signal models, including binary coalescences. These analyses demonstrate the feasibility and utility of KAGRA as a member of the global gravitational-wave detector network.

Open Data from the Third Observing Run of LIGO, Virgo, KAGRA, and GEO

“…These factors measure the fraction of time spent as a function of the number of detectors in operation. The same plots (with the caveat of a difference in the color code) can be found on the GWOSC web summary pages for O3a (see footnote 311) and O3b (see footnote 312) and have been produced from Abbott et al (2022) for O3GK. of observing time spent with one, two, or three instruments in operation.…”

“…During the O3GK run, the duty factors of KAGRA (K1) and GEO 600 (G1) are 53% and 80%, respectively, leading to a coincident observing factor of 47% (Abbott et al 2022). The lower duty cycle of KAGRA is due to the fact that alignment sensing and control with wave front sensors was not yet implemented at the time of the run, leading to a higher susceptibility to microseismic ground vibrations.…”

“…KAGRA was expected to join O3, but this initial plan changed due to the outbreak of COVID-19. Instead, KAGRA and GEO 600 307 operated during an extended observing phase, O3GK, from 2020 April 7 to April 21 (Abbott et al 2022).…”

“…Acernese et al (2022a),Abbott et al (2022), andAbe et al (2022).CBC analyses(Sachdev et al 2019;Davies et al 2020;Aubin et al 2021) seek signals from merging neutron stars and black holes by filtering the data with waveform templates. BURST analyses(Klimenko et al 2016;Cornish et al 2021) search for generic GW transients with minimal assumptions on the source or signal morphology by identifying excess power in the time-frequency representation of the GW strain data.…”

Radial Oscillations in Neutron Stars with Delta Baryons

“…The f -mode oscillations of NSs are very significant as they are most likely to be detectable with a thirdgeneration detector like the Einstein Telescope and the Cosmic Explorer [26][27][28] or even in the best case by the current generation LIGO/Virgo/KAGRA detectors [29,30] because it depends on the EoS of compact stars. It is also anticipated to be excited in many astrophysical scenarios and hence result in efficient GW emission.…”