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 Developmentof JVO

To be used by general education, amateur astronomers and families as well as researchers.

Nobeyama 　 ：　～１ TB/yrSubaru 　 ： ～ 20TB/yrALMA 　 ：　～？ 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/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 forGravitational 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 displaySXDS data

User DBUser DB

Grid Service

OA

I-PM

HO

AI-

PMH

MetaDBMetaDB

•JCOQL Editor•DB Search with Resource finder•UCD finder•Name Revolver•Status Monitor

•JCOQL Editor•DB Search with Resource finder•UCD finder•Name Revolver•Status Monitor

•User Register•User Authentication•User Register•User Authentication

User In

terfaceJV

O System

Registry(XMLDB)

Query interfaceQuery interfaceUser ManagementUser Management•Simple Analysis•Source Extraction（Sextractor）

•Hyper- Z•Image Operation•Photometry

•Specific Analysis•Gravitational Lens•Dust Distribution•Chemical Evolution

•Simple Analysis•Source Extraction（Sextractor）

•Hyper- Z•Image Operation•Photometry

•Specific Analysis•Gravitational Lens•Dust Distribution•Chemical Evolution

Analysis InterfaceAnalysis Interface

JVOQL ParserJVOQL Parser

SchedulerScheduler

ExecuterExecuter

Controller

•VOTable Viewer •Plotter Image •Viewer•Spectrum Viewer•Multi- catalog Superpose Plot•Multi- wavelength Image Plot

•VOTable Viewer •Plotter Image •Viewer•Spectrum Viewer•Multi- catalog Superpose Plot•Multi- wavelength Image Plot

• DB Search with Resource finder

• DB Search with Resource finder

DB NavigatorDB Navigator

Data DisplayData Display

Servlet

JSP

JSPJSP

JSPJSP

MetadataQuery

(XPath)Result (XML)

Grid Service

Query Command(JVOQL)

Status Monitor

JobStatus

JVOQL Parsed Query

Job Elem

ent

Data tran

sfer with

SFS

Astro DBAstro DB

Grid Service

OA

I-PM

HO

AI-

PMH

MetaDBMetaDB

OAI- PMHOAI- PMH

Astro DBAstro DB

Grid Service

OA

I-PM

HO

AI-

PMH

MetaDBMetaDB

Grid Service

ControllerController

SchedulerScheduler

ExecuterExecuter

OA

I-PMH

OA

I-PMH

Statusmonotor

Job StatusAnalysisCommand

RFT RFT

Remote Executionwith Grid Service

Status

ServerInfo

Data tran

sfer with

SFS

Remote Executionwith Grid Service

Data Analysis

ServerInfo

JVO features

１． Grid environment using Globus ToolkitGlobus 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 federationWe 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-taskJVO includes authentication system. It certifies users, permits access to JVO system, and manages users’ processes and storage areas.

４． Metadata managementMetadata 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.