The Current Status and Future Prospects of KAGRA, the Large-Scale Cryogenic Gravitational Wave Telescope Built in the Kamioka Underground
Authors: Abe Homare , Akutsu Tomotada , Ando Masaki , Araya Akito , Aritomi Naoki , Asada Hideki , Aso Yoichi , Bae Sangwook , Bajpai Rishabh , Cannon Kipp , Cao Zhoujian , Capocasa Eleonora , Chan Man , Chen Dan , Chen Yi-Ru , Eisenmann Marc , Flaminio Raffaele , Fong Heather , Fujikawa Yuta , Fujimoto Yuya , Hadiputrawan I. , Haino Sadakazu , Han Wenbiao , Hayama Kazuhiro , Himemoto Yoshiaki , Hirata Naoatsu , Hirose Chiaki , Ho Tsung-Chieh , Hsieh Bin-Hua , Hsieh He-Feng , Hsiung Chia-Hsuan , Huang Hsiang-Yu , Huang Panwei , Huang Yao-Chin , Huang Yun-Jing , Hui David , Inayoshi Kohei , Inoue Yuki , Itoh Yousuke , Jung Pil-Jong , Kajita Takaaki , Kamiizumi Masahiro , Kanda Nobuyuki , Kato Takashi , Kim Chunglee , Kim Jaewan , Kim Young-Min , Kobayashi Yuichiro , Kohri Kazunori , Kokeyama Keiko , Kong Albert , Koyama Naoki , Kozakai Chihiro , Kume Jun’ya , Kuroyanagi Sachiko , Kwak Kyujin , Lee Eunsub , Lee Hyung , Lee Ray-Kuang , Leonardi Matteo , Li Kwan-Lok , Li Pengbo , Lin Lupin , Lin Chun-Yu , Lin En-Tzu , Lin Hong-Lin , Liu Guo-Chin , Luo Ling-Wei , Ma’arif Miftahul , Michimura Yuta , Mio Norikatsu , Miyakawa Osamu , Miyo Kouseki , Miyoki Shinji , Morisue Nozomi , Nakamura Kouji , Nakano Hiroyuki , Nakano Masayuki , Narikawa Tatsuya , Quynh Lan , Nishimoto Takumi , Nishizawa Atsushi , Obayashi Yoshihisa , Oh Kwangmin , Ohashi Masatake , Ohashi Tomoya , Ohkawa Masashi , Okutani Yoshihiro , Oohara Ken-ichi , Oshino Shoichi , Pan Kuo-Chuan , Parisi Alessandro , Park June , Arellano Fabián , Saha Surojit , Sakai Kazuki , Sawada Takahiro , Sekiguchi Yuichiro , Shao Lijing , Shikano Yutaka , Shimizu Hirotaka , Shimode Katsuhiko , Shinkai Hisaaki , Shoda Ayaka , Somiya Kentaro , Song Inhyeok , Sugimoto Ryosuke , Suresh Jishnu , Suzuki Takamasa , Suzuki Takanori , Suzuki Toshikazu , Tagoshi Hideyuki , Takahashi Hirotaka , Takahashi Ryutaro , Takeda Hiroki , Takeda Mei , Taruya Atsushi , Tomaru Takayuki , Tomura Tomonobu , Trozzo Lucia , Tsang Terrence , Tsuchida Satoshi , Tsutsui Takuya , Tuyenbayev Darkhan , Uchikata Nami , Uchiyama Takashi , Uehara Tomoyuki , Ueno Koh , Ushiba Takafumi , Putten Maurice , Washimi Tatsuki , Wu Chien-Ming , Wu Hsun-Chung , Yamada Tomohiro , Yamamoto Kazuhiro , Yamamoto Takahiro , Yamazaki Ryo , Yeh Shu-Wei , Yokoyama Jun’ichi , Yokozawa Takaaki , Yuzurihara Hirotaka , Zeidler Simon , Zhao Yuhang 
Published: April 2022

KAGRA is a gravitational-wave (GW) detector constructed in Japan with two unique key features: It was constructed underground, and the test-mass mirrors are cooled to cryogenic temperatures. These features are not included in other kilometer-scale detectors but will be adopted in future detectors such as the Einstein Telescope. KAGRA performed its first joint observation run with GEO600 in 2020. In this observation, the sensitivity of KAGRA to GWs was inferior to that of other kilometer-scale detectors such as LIGO and Virgo. However, further upgrades to the detector are ongoing to reach the sensitivity for detecting GWs in the next observation run, which is scheduled for 2022. In this article, the current situation, sensitivity, and future perspectives are reviewed.