arXiv subjects

Chao-Wan-Zhen Wang

Publications and source records attributed to Chao-Wan-Zhen Wang.

2 recordsLinked to original sources

arXiv2025

Wavelets for power spectral density estimation of gravitational wave data

Power spectral density (PSD) estimation is a critical step in gravitational wave (GW) detectors data analysis. The Welch method is a typical non-parametric spectral estimation approach that estimates the PSD of stationary noise by averaging periodograms of several time segments, or by taking the median of periodograms to adapt to non-stationary noise. In this work, we propose a wavelet-based approach for fast PSD estimation of both stationary and non-stationary noise. For stationary noise, we apply wavelet smoothing to the periodogram, avoiding the segmentation step in the Welch method, and enabling PSD estimates with high frequency resolution and low variance. The wavelet smoothing PSD outperforms Welch PSD in matched filtering and parameter estimation. For non-stationary noise, we estimate the PSD by taking the median of wavelet packet coefficients in each frequency bin, which offers greater robustness than the traditional median periodogram method. This work introduces a new PSD estimation approach for GW data analysis and expands the application of wavelet methods in this field.

gr-qc↗

arXiv2024

Testing the first law of black hole mechanics with gravitational waves

The successful observation of gravitational waves has provided humanity with an additional method to explore the universe, particularly black holes. In this study, we utilize data from LIGO and Virgo gravitational wave observations to test the first law of black hole mechanics, employing two different approaches. We consider the secondary compact object as a perturbation to the primary black hole before the merger, and the remnant black hole as a stationary black hole after the merger. In the pre-merger and post-merger analysis, our results demonstrate consistency with the first law, with an error level of approximate 25% at a 68% credibility level for GW190403 051519. In the full inspiral-merger-ringdown analysis, our results show consistency with the first law of black hole mechanics, with an error level of about 6% at a 68% credibility level and 10% at a 95% credibility level for GW191219 163120. Additionally, we observe that the higher the mass ratio of the gravitational wave source, the more consistent our results are with the first law of black hole mechanics. Overall, our study sheds light on the nature of compact binary coalescence and their implications for black hole mechanics.

gr-qc↗