Transcript ppt (demo)
Japanese Virtual Observatory (JVO) National Astronomical Observatory of Japan (NAOJ) Contact Address: [email protected] We present two demos which show the current status on construction of Virtual Observatory in NAOJ. The first program demonstrates a system which federates the distributed database system using the GRID technology. The second one demonstrates a scientific case of searching for gravitationally lensed system using the Subaru-XMM Deep Survey (SXDS) data. Demo 1: GRID-based database federation Main Control Window Column attributes are shown by pushing the “column_info” button, where you can also control the column layout. Open JVO QL Editor Write JVO SQL here The query result is shown up in a result page, which is a kind of VOTable viewer and provides an easy access to both the table and image data. For graphical viewing of the table data, plotting tool is available. You can specify any column or expression for X/Y axis. Demo 2: Scientific Scenario Gravitational Lens Search The current JVO prototype can communicates with four distributed database, “Subaru Deep Field i’-band” (SDF-i’), SDF-z’, “Subaru XMM Deep Survey” (SXDS), and 2MASS. A main control window provides you to specify a query in JVO Query Language. You can save/load the QL in a file with the Export/Import button. A QL editor is opened by pushing the editor button and provides an easy way to specify search conditions. This program demonstrates a scientific use-case of an Japanese Virtual Observatory. In this demo Gravitation Lens systems are searched by selecting a pair of two objects which are closely located and have similar colors. The corresponding images are also retrieved, so you can check the morphology of the objects. Color map is constructed from the images taken at three bands (B, R, z’) to visualize the color type of surrounding objects, which helps to find a multiple lens system . A Color-Color and a SED plot are also drawn, which help to reject a possible stellar binary which locates at “stellar locus” in the Color-Color plot. The JVO system splits the user input query into pieces of queries for each database, then issues search commands to appropriate servers through a “globus-job-submit” command of Globus Toolkit. This example shows a demo doing a cross-matching search between the two databases SDF-i’ and SDF-z’. At first a search command is issued to the SDF-i’ database server, mizu-g, then the result is transferred to the SDF-z’ database server, minazuki-g, where cross-matching search is executed. Image requests are issued at the last two steps.The query results are transferred through GridFTP in a VOTable format for table data and in FITS for image data. On “JVO Query Language Editor” (shown at left button of this poster), you can specify criteria such as separation angle of two objects, brightness similarity, color similarity, and parameter range. On “Query Result” page, you can check the selected images and colors visually. You can also download the FITS image for more precise examination. The order of the record can be sorted with values of any column. Pushing the “Catalog All” button opens a new window “Table Selection” which shows a list of database accessible from the editor. Sort with a separation angle Checking a catalog and pushing the “selected_table” button, a list of tables included in the database are shown in the same window. SXDS database consist of 20 object-list tables and image meta data tables. Pushing the “column_save” button, the editor is updated such that you can set restriction parameters for the selected columns. This field sets a restriction for a color of R-B 0.0 0.3 In this example, to search for a distant and point-like object, restrictions on the ellipticity and star parameter calculated by Sextractor is set to 0.0~0.3 and 0.7~1.0, respectively . A list of columns of the selected table are shown in the column-list window as below, where you can chose the columns you want to use for a search. You can enlarge the image appearance by changing image size here. The above three pictures shows images around the selected objects at B, R and z’-bands from left to right, respectively. The left picture is a color image which is a compound of the three bands images. Below are the color-color and SED plot.