The coalescence of binary neutron star (BNS) in the event GW170817, leading to the generation of gravitational waves (GW) and accompanied by kilonova (KNe), the electromagnetic (EM) counterpart, has been a prime topic of interest for the Astronomy community in recent times as it provided much insight into multi-messenger astronomy. Since its discovery in 2017, several research teams have put...
The circular polarized astrophysical gravitational wave backgrounds may exist with detectable SNR for a finite observation time and the sensitivity of detectors, and may become the foreground radiation for observing the circular polarized cosmological gravitational wave background.
In this work, we developed a new analysis method introducing Stokes parameters into the gravitational wave...
GW observations can probe the central engine of core-collapse supernovae by distinct emission from neutron stars (NS) and black holes (BH). While high-frequency GWs are expected from a NS, relatively low-frequency GWs are expected from a BH-torus system. Scaling of the emission during spin-down of the Kerr BH of mass $M\simeq 2.5M_\odot c^2$ powering GW170817B/GRB170817A predicts an energy...
This presentation covers the current development of quantum noise enhancement for future observations of KAGRA. In particular I talk about the implementation of the squeezed light source in the confines of the Kamioka mine. The equipment of the KAGRA detector creates some differences in squeezer design compared to above-ground detectors.
Core-collapse supernovae (CCSNe) are one of the new astrophysical events to be detected by the LVK observatory. Also, it is an interesting candidate for multi-messenger analysis due to their EM and neutrino emission. However, GW signals from CCSNe cannot be exactly modeled due to the stochasticity involved in the collapse dynamics and the dependency on many parameters such as the progenitor...
DeepClean is a machine learning-based noise subtraction method that cleans GW strain data by subtracting noise from PEM channels monitoring environmental noises. We compiled the PEM channels to reduce AC power noises from KAGRA’s main power supplies. These channels were used to address AC power noises in KAGRA O4 strain data during offline analysis. In this study, we use DeepClean to remove AC...
On January 1st, 2024, a 7.6 magnitude earthquake struck near the KAGRA site, marking the most significant seismic tremor in the area of the KAGRA site in the past century. We confirmed no serious damage in the tunnel structure, infrastructure, vacuum system, and cryogenic system according to the almost full inspection for KAGRA. On the other hand, we confirmed that nine of twenty mirror...
It is predicted by a class of inflationary models that the Universe could have a stochastic gravitational waves background (SGWB) with a circular polarization. The possibility of detecting and characterizing the circular polarization of the SGWB, which is a collection of gravitational waves (GWs) consisting of signals too faint to be resolved individually, and investigating the dipole...
Many gravitational waves from black hole mergers have been observed, and their science has attracted attention.
We have developed a filter using the Laplace transform to analyze gravitational waves from black hole quasinormal mode oscillations, which are predicted to be properties of spacetime around black holes.
The Laplace transform has an algebraically clear solution for a damped sine...
One of the most exciting discoveries of this century was the direct detection of the gravitational waves (GWs) with the Advanced LIGO and Advanced Virgo experiments. The frontier of gravitational wave science is gradually transitioning from the first detection phase to precision verification phase with statistics of gravitational wave events. Taiwan-LIGO instrumentation group have joined LIGO...
