Decadal upgrade strategy for KAGRA toward post-O5 gravitational-wave astronomy
Abstract
The KAGRA Collaboration has investigated a ten-year upgrade strategy for the KAGRA gravitational wave detector, considering a total of 14 upgrade options that vary in mirror mass, quantum noise reduction techniques, and the quality of cryogenic suspensions. We evaluated the scientific potential of these configurations with a focus on key targets such as parameter estimation of compact binary coalescences, binary neutron star post-merger signals, and continuous gravitational waves. Rather than aiming to improve all science cases uniformly, we prioritized those most sensitive to the detector configuration. Technical feasibility was assessed based on required hardware developments, associated R\&D efforts, cost, and risk. Our study finds that a high-frequency upgrade plan that enhances sensitivity over a broad frequency range above ~200 Hz offers the best balance between scientific return and technical feasibility. Such an upgrade would enable sky localization of binary neutron star mergers at 100 Mpc to better than 0.5 deg in a LIGO-Virgo-KAGRA network, and improve the measurement precision of tidal deformability parameter by approximately 10% at median, compared to a network without KAGRA.
Cite
@article{arxiv.2508.03392,
title = {Decadal upgrade strategy for KAGRA toward post-O5 gravitational-wave astronomy},
author = {KAGRA Collaboration and T. Akutsu and M. Ando and M. Aoumi and A. Araya and Y. Aso and L. Baiotti and R. Bajpai and K. Cannon and A. H. -Y. Chen and D. Chen and H. Chen and A. Chiba and C. Chou and M. Eisenmann and K. Endo and T. Fujimori and S. Garg and D. Haba and S. Haino and R. Harada and H. Hayakawa and K. Hayama and S. Fujii and Y. Himemoto and N. Hirata and C. Hirose and H. -F. Hsieh and H. -Y. Hsieh and C. Hsiung and S. -H. Hsu and K. Ide and R. Iden and S. Ikeda and H. Imafuku and R. Ishikawa and Y. Itoh and M. Iwaya and H-B. Jin and K. Jung and T. Kajita and I. Kaku and M. Kamiizumi and N. Kanda and H. Kato and T. Kato and R. Kawamoto and S. Kim and C. Kim and K. Kobayashi and K. Kohri and K. Kokeyama and K. Komori and A. K. H. Kong and T. Koyama and J. Kume and S. Kuroyanagi and S. Kuwahara and K. Kwak and S. Kwon and H. W. Lee and R. Lee and S. Lee and K. L. Li and L. C. -C. Lin and E. -T. -Lin and Y. -C. Lin and G. C. Liu and K. Maeda and M. Meyer-Conde and Y. Michimura and K. Mitsuhashi and O. Miyakawa and S. Miyoki and S. Morisaki and Y. Moriwaki and M. Murakoshi and K. Nakagaki and K. Nakamura and H. Nakano and T. Narikawa and L. Naticchioni and L. Nguyen Quynh and Y. Nishino and A. Nishizawa and K. Obayashi and M. Ohashi and M. Onishi and K. Oohara and S. Oshino and R. Ozaki and M. A. Page and K. -C. Pan and B. -J. Park and J. Park and F. E. Pena Arellano and N. Ruhama and S. Saha and K. Sakai and Y. Sakai and R. Sato and S. Sato and Y. Sato and Y. Sato and T. Sawada and Y. Sekiguchi and N. Sembo and L. Shao and Z. -H. Shi and R. Shimomura and H. Shinkai and S. Singh and K. Somiya and I. Song and H. Sotani and Y. Sudo and K. Suzuki and M. Suzuki and H. Tagoshi and K. Takada and H. Takahashi and R. Takahashi and A. Takamori and S. Takano and H. Takeda and K. Takeshita and M. Tamaki and K. Tanaka and S. J. Tanaka and A. Taruya and T. Tomaru and T. Tomura and S. Tsuchida and N. Uchikata and T. Uchiyama and T. Uehara and K. Ueno and T. Ushiba and H. Wang and T. Washimi and C. Wu and H. Wu and K. Yamamoto and T. Yamamoto and T. S. Yamamoto and R. Yamazaki and Y. Yang and S. -W. Yeh and J. Yokoyama and T. Yokozawa and H. Yuzurihara and Z. -C. Zhao and X. Zhu and Z. -H. Zhu},
journal= {arXiv preprint arXiv:2508.03392},
year = {2025}
}