Application of the Hilbert-Huang transform for analyzing standing-accretion-shock-instability induced gravitational waves in a core-collapse supernova

M. Takeda; Y. Hiranuma; N. Kanda; K. Kotake; T. Kuroda; R. Negishi; K. Oohara; K. Sakai; Y. Sakai; T. Sawada; H. Takahashi; S. Tsuchida; Y. Watanabe; T. Yokozawa

doi:10.1103/physrevd.104.084063

arXiv · 2107.05213

Application of the Hilbert-Huang transform for analyzing standing-accretion-shock-instability induced gravitational waves in a core-collapse supernova

M. Takeda·Y. Hiranuma·N. Kanda·K. Kotake·T. Kuroda·R. Negishi·K. Oohara·K. Sakai·Y. Sakai·T. Sawada·H. Takahashi·S. Tsuchida·Y. Watanabe·T. Yokozawa

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Abstract

Through numerical simulations, it is predicted that the gravitational waves (GWs) reflect the characteristics of the core-collapse supernova (CCSN) explosion mechanism. There are multiple GW excitation processes that occur inside a star before its explosion, and it is suggested that the GWs originating from the CCSN have a mode for each excitation process in terms of time-frequency representation. Therefore, we propose an application of the Hilbert-Huang Transform (HHT), which is a high-resolution time-frequency analysis method, to analyze these GW modes for theoretically probing and increasing our understanding of the explosion mechanism. The HHT defines frequency as a function of time, and is not bound by the trade-off between time and frequency resolutions. In this study, we analyze a gravitational waveform obtained from a three-dimensional general-relativistic CCSN model that showed a vigorous activity of the standing-accretion-shock-instability (SASI). We succeed in extracting the SASI induced GWs with high resolution on a time-frequency representation using the HHT and we examine their instantaneous frequencies.

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M. Takeda, Y. Hiranuma, N. Kanda, K. Kotake, T. Kuroda, R. Negishi, K. Oohara, K. Sakai, Y. Sakai, T. Sawada, H. Takahashi, S. Tsuchida, Y. Watanabe, T. Yokozawa. 2021-10-19. Application of the Hilbert-Huang transform for analyzing standing-accretion-shock-instability induced gravitational waves in a core-collapse supernova. https://doi.org/10.1103/physrevd.104.084063

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