1. Prototype system of the Japanese Virtual Observatory The Japanese Virtual Observatory (JVO) aims at providing easy access to federated astronomical databases (especially SUBARU, Nobeyama and ALMA) and data analysis environment using the Grid technology. JVOQL (JVO Query Language) is defined in order to write request conditions for federated databases. The JVO prototype system is developed for the purpose of technical feasibility study, including functionality of JVOQL, remote operations using Globus toolkit, and automatic search for services. The prototype consists of several components: JVO portal where users can look up astronomical catalogs and build a query request easily, distributed data servers containing data of Subaru Suprime-Cam and 2MASS, and JVO controller to decompose a request written in JVOQL into individual queries for data servers. We confirm that this prototype actually works as federated databases and that the Grid service of the Globus toolkit version 3 has adequate performance for the federation of distributed databases. Masahiro Tanaka, Yuji Shirasaki, Satoshi Honda, Masatoshi Ohishi, Yoshihiko Mizumoto (NAOJ), Naoki Yasuda (U. Tokyo), Yoshifumi Masunaga (Ochanomizu U.) JVO Prototype Introduction Development of JVO To be used by general education, amateur astronomers and families as well as researchers. Nobeyama ： ～１ TB/yr Subaru ： ～ 20TB/yr ALMA ： ～？ PB/yr etc. Increasing amount of Astronomical Data Conventional methods are inadequate. Cumbersome task for every instrument: Data retrieval, transfer, analysis, etc... Enables observation regardless of time and place. Internal data analysis reduces data transfer. Make multi-wavelength research easy due to unified data manipulation regardless of observational instruments. VO is a system to observe “the Universe in computers”, which is constructed by employing these information technologies. The main purpose of the development of JVO prototype is to test functionality of employed technologies. JVO prototype version 2 has currently been developed. http://jvo.nao.ac.jp/ As an example of research using JVO, here exhibits a series of processes for searching gravitational lens object in data obtained with Subaru telescope. １． Retrieve Subaru catalog data in a specified region. ↓ ２． Calculate brightness ↓ ３． Define condition to select quasars. ↓ ４． Make a list of pair quasar objects. ↓ ５． Retrieve image data of the pair objects ↓ ６． Narrow candidates by analyzing the image data. Work flow for Gravitational lens search Several-hour task in conventional ways. Five-minute task with JVO ! Benefit of VO... After authentication, choose catalogs and specify retrieval condition using JVOQL editor. Retrieval condition is reflected in JVOQL Editor. User Operation Windows Result Display Windows Registry is used to find available data in JVO and to construct work flow of remote procedure calls. JVOQL parser decomposes JVOQL, Scheduler generates work flow, and Executer performs remote procedure calls. It is easy to add new analysis tools for conducting particular science. Search result is obtained in the form of VOTable, which is international standard to express table data in the XML form, and displayed on WWW browser. Combination of Information technologies and Astronomy Web service Grid technology Data Mining Database technology Visualization etc… Information science takes important roles in Astronomy. ↑ Retrieve SDSS QSO and display spectra ← ↑ Retrieve and display SXDS data JVO features １． Grid environment using Globus Toolkit Globus Toolkit ver.3 is employed for JVO Prototype ver.2. “Grid Service” of GTK3 is used for remote operation. RFT (Reliable File Transfer) and SFS is used for file transfer between portal and remote servers. ２． JVOQL (JVO Query Language) for database federation We defined JVOQL to write search condition to federate distributed database. JVOQL is based on SQL, widely used as a language for a relational database, and provides functionalities of cross match and retrieval of image and spectrum. ３． Multi-user and multi-task JVO includes authentication system. It certifies users, permits access to JVO system, and manages users’ processes and storage areas. ４． Metadata management Metadata is information on remote servers, services and observational data. We defined XML expressions of metadata and stored them into Registry, which is constructed using XML DB. That enables automated federation of distributed database and analysis servers, and contents of available observational data in JVO.