Overview of KAGRA: KAGRA science
Authors: Akutsu T , Ando M , Arai K , Arai Y , Araki S , Araya A , Aritomi N , Asada H , Aso Y , Bae S , Bae Y , Baiotti L , Bajpai R , Barton M A , Cannon K , Cao Z , Capocasa E , Chan M , Chen C , Chen K , Chen Y , Chiang C -Y , Chu H , Chu Y -K , Eguchi S , Enomoto Y , Flaminio R , Fujii Y , Fujikawa F , Fukunaga M , Fukushima M , Gao D , Ge G , Ha S , Hagiwara A , Haino S , Han W -B , Hasegawa K , Hattori K , Hayakawa H , Hayama K , Himemoto Y , Hiranuma Y , Hirata N , Hirose E , Hong Z , Hsieh B H , Huang C -Z , Huang H -Y , Huang P , Huang Y , Huang Y -C , Hui D C Y , Ide S , Ikenoue B , Imam S , Inayoshi K , Inoue Y , Ioka K , Ito K , Itoh Y , Izumi K , Jeon C , Jin H -B , Jung K , Jung P , Kaihotsu K , Kajita T , Kakizaki M , Kamiizumi M , Kanda N , Kang G , Kashiyama K , Kawaguchi K , Kawai N , Kawasaki T , Kim C , Kim J , Kim J C , Kim W S , Kim Y -M , Kimura N , Kita N , Kitazawa H , Kojima Y , Kokeyama K , Komori K , Kong A K H , Kotake K , Kozakai C , Kozu R , Kumar R , Kume J , Kuo C , Kuo H -S , Kuromiya Y , Kuroyanagi S , Kusayanagi K , Kwak K , Lee H K , Lee H W , Lee R , Leonardi M , Li K L , Li T G F , Lin C -Y , Lin F -K , Lin F -L , Lin H L , Lin L C -C , Liu G C , Luo L -W , Majorana E , Marchio M , Michimura Y , Mio N , Miyakawa O , Miyamoto A , Miyazaki Y , Miyo K , Miyoki S , Mori Y , Morisaki S , Moriwaki Y , Nagano K , Nagano S , Nakamura K , Nakano H , Nakano M , Nakashima R , Nakayama Y , Narikawa T , Naticchioni L , Negishi R , Nguyen Quynh L , Ni W -T , Nishizawa A , Nozaki S , Obuchi Y , Ogaki W , Oh J J , Oh K , Oh S H , Ohashi M , Ohishi N , Ohkawa M , Ohta H , Okutani Y , Okutomi K , Oohara K , Ooi C P , Oshino S , Otabe S , Pan K , Pang H , Parisi A , Park J , Pe na Arellano F E , Pinto I , Sago N , Saito S , Saito Y , Sakai K , Sakai Y , Sakuno Y , Sato S , Sato T , Sawada T , Sekiguchi T , Sekiguchi Y , Shao L , Shibagaki S , Shimizu R , Shimoda T , Shimode K , Shinkai H , Shishido T , Shoda A , Somiya K , Son E J , Sotani H , Sugimoto R , Suresh J , Suzuki T , Suzuki T , Tagoshi H , Takahashi H , Takahashi R , Takamori A , Takano S , Takeda H , Takeda M , Tanaka H , Tanaka K , Tanaka K , Tanaka T , Tanaka T , Tanioka S , Tapia San Martin E N , Telada S , Tomaru T , Tomigami Y , Tomura T , Travasso F , Trozzo L , Tsang T , Tsao J -S , Tsubono K , Tsuchida S , Tsuna D , Tsutsui T , Tsuzuki T , Tuyenbayev D , Uchikata N , Uchiyama T , Ueda A , Uehara T , Ueno K , Ueshima G , Uraguchi F , Ushiba T , van Putten M H P M , Vocca H , Wang J , Washimi T , Wu C , Wu H , Wu S , Xu W -R , Yamada T , Yamamoto K , Yamamoto K , Yamamoto T , Yamashita K , Yamazaki R , Yang Y , Yokogawa K , Yokoyama J , Yokozawa T , Yoshioka T , Yuzurihara H , Zeidler S , Zhan M , Zhang H , Zhao Y , Zhu Z -H 
Published: August 2020

KAGRA is a newly build gravitational wave observatory, a laser interferometer with 3 km arm length, located in Kamioka, Gifu, Japan. In this paper, one of a series of articles featuring KAGRA, we discuss the science targets of KAGRA projects, considering not only the baseline KAGRA (current design) but also its future upgrade candidates (KAGRA+) for the near to middle term ($\sim$5 years).