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Hello!. Virtual Observatories. Ajit Kembhavi IUCAA Pune, India. Data Storage and Retrieval. The Astronomer Vermeer 1632-1675. The Library of Alexandria 3 rd Century BC. The Data Avalanche. Immense amounts of data are being produced by large telescopes using large area detectors.

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slide2

Virtual Observatories

Ajit Kembhavi

IUCAA

Pune, India

slide3

Data Storage and Retrieval

The Astronomer

Vermeer 1632-1675

The Library of Alexandria

3rd Century BC

the data avalanche
The Data Avalanche

Immense amounts of data are being produced by large telescopes using large area detectors.

Terabytesof data are now available, andPetabyteswill soon be available from frequent all sky imaging.

Vast databases are also being produced throughsimulations.

astronomical data explosion
Astronomical Data Explosion

~ 100 Gb/night

P. Quinn

data explosion
Data Explosion

Peter Quinn

wavelength coverage
Wavelength Coverage

The data spans the electromagnetic spectrum from the radio to the gamma-ray region.

Obtaining, analysing and interpreting the data in different wavebands involves highly specialised instruments and techniques.

The astronomer needs new tools for using this wealth of data in multiwavelength studies.

the alliance
The Alliance

Members of the IVOA

virtual observatories
Virtual Observatories
  • Provide tools for data analysis, visualization and mining.
  • Develop interoperability concepts to make different databases seamless.
  • Manage vast data resources and provide these on-line to astronomers and other users.

Empower astronomers by providing sophisticated query and computational tools, and computing grids for producing new science.

ivoa technology initiatives
IVOA Technology Initiatives

The IVOA has identified six major technical initiatives to fulfill the scientific goal of the VO concept.

IVOA-LISTS

slide16
REGISTRIES: These collect metadata about data resources and information services into a queryable database. The registry is distributed. A variety of industry standards are being investigated.

DATA MODELS: This initiative aims to define the common elements of astronomical data structures and to provide a framework to describe their relationships.

UNIFORM CONTENT DESCRIPTORS: These will provide the common language for for metadata definitions for the VO.

slide17
DATA ACCESS LAYER:This provides a standardized access mechanisms to distributed data objects. Initial prototypes are a Cone Search Protocol and a simple Image Access Protocol.

VO QUERY LANGUAGE:This will provide a standard query language which will go beyond the limitations of SQL.

VOTable: This is an XML mark-up standard for astronomical tables.

science initiatives
Science Initiatives
  • Many IVOA projects have active Science Working Groups consisting of astronomers from a broad cross-section of the community representing all wavelengths.
  • The focus here is to develop a clear perception of the scientific requirements of a VO.
  • Projects within the working groups will develop new capabilities for VO based analysis.
  • This will enable the community to create new research programs and to publish their data and research in a more pervasive and scientifically useful manner.
slide19

Virtual Observatory -India

A collaboration between IUCAA and PSPL,

with a grant from the Ministry of Communications and Information Technology

data archives and mirrors at vo i
Data Archives and Mirrors at VO-I

SDSS

2Mass

2DFGRS

2QZ

FIRST

NVSS

Chandra

Vizier, Aladin, ADS

fast computing
Fast Computing
  • Four alpha server ES-45 nodes, each
  • with 4 processors, each node with 8
  • GB RAM
    • Fast, Low latency interconnect Memory Channel Architecture
    • Trucluster clustering environment (Tru64 Unix, DecMPI, openMP)
vo india software projects
VO-India Software Projects

VOPlot Visualizer for catalogue data

VOTable C++ Parser

VOTable Streaming writer

Data Converters

Fits Browser

User interfaces and query tools

Applications beyond astronomy

All tools have web-based and stand alone versions

the voplot collaboration
The VOPlot Collaboration

Visualization and simple statistics of catalogue data. Integration with sky atlases.

the voplot tool
The VOPlot Tool

A VO-I + CDS collaboration

First conceived as a web-based tool for Vizier

Then integrated with Aladin

VOPlot is now also a stand alone system

It has been integrated with many data bases

Sonali Kale, K.D. Balaji et. Al.

VOPlot

catalog data interface tool

Catalog Data Interface Tool

A tool to query catalog data.

Simple, customizable, graphic interface.

Not specific to type of data or catalogue.

SQL queries for expert users.

VO tools available for analysis:

VOPlot, Aladin,VOStat, SIMBAD, NED...

slide51

SDSS J125637-022452

High proper motion L-subdwarf

Optical spectra of mixed late M and mid L type

Only the third L subdwarf known

slide52

Positions 1986-2000

Proper motion

0.617 arcsec / yr

slide54

AVO Prototype Demo

Astrogrid:

Astronomy Catalogue Extractor

AVO: Aladin+SED

VO-India:VOPlot

fits manager
FITS Manager

View, create and add to FITS files

Convert to other formats

Pallavi Kulkarni

Fits-manager

votable java streaming writer
VOTable Java Streaming Writer

Acts on a data array in memory

to convert it to the VOTable form,

which is streamed row by row

to an output file. Very large

VOTables can be written without

excessive memory.

Pallavi Kulkarni

VOTable-Java

votable
VOTable
  • This is a new data exchange standard produced through efforts led by Francois Ochsenbien of CDS, Strasbourg and Roy Williams of Caltech.
  • VOTable is in XML format. Physical quantities come with sophisticated semantic information.
votable1
VOTable
  • The format enables computers to easily parse the information and communicate it to other computers.
  • Federation and joining of information become possible and Grid computing is easier.
  • VOTable parsers have been developed in Perl, Java and C++.
  • Enhancements and extensions are being considered.

Streaming Parser

Non-streaming Parser

votable data
VOTable Data

The data part in a VOTable may be represented using one of three different formats:

  • FITS : VOTable can be used either to encapsulate FITS files, or to re-encode the metadata.
  • BINARY : Supported for efficiency and ease of programming, no FITS library is required, and the streaming paradigm is supported.
  • TABLEDATA : Pure XML format for small tables.
c votable parser
C++ VOTable Parser

Motivation:

  • Provide a library for API based access to VOTable files.
  • APIs can be directly used to develop VOTable applications without having to do raw VOTable processing.
  • Streamingand Non-streaming versions are available.

Sonali Kale, Sudip Khanna

c votable parser1
C++ VOTable Parser

Salient Features:

  • Implemented as a wrapper over XALAN-C++.
  • XALAN-C++ is a robust implementation of the W3C recommendations for

XSL Transformations (XSLT) and the

XML Path language (XPath).

  • XPath queries can be used to access the VOTable data.
slide62

Project Design

VTable

Metadata

Link Collection

Link

Field Collection

Field

LinkCollection

Link

TableData

Values

minimum

RowCollection

maximum

Row

OptionCollection

ColumnCollection

Options

slide63

IUCAA HPC Facility Hercules

HPC Team :

Sarah Ponthratnam

Sunu Engineer

Rajesh Nayak

Anand Sengupta

Co-proposed by :

Ajit Kembhavi

T. Padmnabhan

Tarun Souradeep

  • Four Alpha Server ES-45 machines
  • Each with 4 processors Alpha (21264C)
    • 1.25 GHz clock speed
    • Cache on chip: 64 Kb –I, 64 Kb-D
    • Cache :16 Mb ECC DDR
    • RAM 3 x 8 Gb + 12 Gb
  • Fast, Low latency interconnect
    • Memory channel Architecture (MCA)
  • High volume Storage
      • 1 Tera-byte SCSCI
  • Trucluster clustering environment (Tru64 Unix, DecMPI, openMP)

> 30 G flops

Preliminary HPL benchmark

ES-45

Specfp2000: 1327

Linpack 1000x1000: 6847

virtual observatory india1
Virtual Observatory - India

Persistent Systems

IUCAA

slide65

Caltech, Fermilab, JHU, NASA/HEARC, Microsoft, NCSA/UIUC, NOAO, NRAO, Raytheon ITS, SDSC/UCSD, SAO/CXC, STScI, UPenn, UPitts/CMU, UWis, USC, USNO, USRA, CVO

NVO-People

virtual observatory india2
Virtual Observatory - India

Ajit Kembhavi

Inter-University Centre for Astronomy and Astrophysics

Pune, India

virtual observatories1
Virtual Observatories
  • Provide tools for data analysis, visualization and mining.
  • Develop interoperability concepts to make different databases seamless.
  • Manage vast data resources and provide these on-line to astronomers and other users.
  • Empower astronomers by providing sophisticated query and computational tools, and computing grids for producing new science.
slide68

Terapix

Jodrell Bank

high volume storage
High Volume Storage

Raid 5, 4 Terabyte

cvo collaborations
CVO Collaborations
  • There are three major projects at the CVO involving collaborations with other VO.
  • CVO is collaborating with the German Astrophysical VO to incorporate ROSAT X-ray data and catalogues into the CVO system.
  • CVO is collaborating with the Australian VO.to incorporate 2Qz and 2DF galaxy spectra into the CVO database.
  • CVO is an associate member of NVO and is have put in place some components of the NVO galaxy morphology demo.
science initiatives1
Science Initiatives
  • Many IVOA projects have active Science Working Groups consisting of astronomers from a broad cross-section of the community representing all wavelengths.
  • The focus here is to develop a clear perception of the scientific requirements of a VO.
  • Projects within the working groups will develop new capabilities for VO based analysis.
  • This will enable the community to create new research programs and to publish their data and research in a more pervasive and scientifically useful manner.
australian vo collaborations
Australian –VO Collaborations
  • The distributed volume renderer (dvr) software, is a tool for rendering large volumetric data sets using the combined memory and processing resources of Beowulf like clusters.
  • A collaboration between the Melbourne site of Aus-VO and AstroGrid aims to develop the existing dvr software into a grid-based volume rendering service.
  • Users will be able to select FITS-format cubes from a number of "Data Centres",have the data transferred to a chosen rendering cluster, and then proceed to visualise the volume of data remotely (See Demo).
c votable parser2
C++ VOTable Parser
  • Initial version

- Released on May 31st , 2002.

- Support only for reading of tables.

- Support only for pure-XML TABLEDATA and not for BINARY or FITS data streams.

- Runs on Windows NT 4.0, Windows 2000 and

RedHat Linux 7.1.

  • Future enhancements

- Can be incorporated quickly and efficiently.

parser design
Parser Design

Class Details

  • VTable: In memory representation of a single <TABLE>

from the <RESOURCE> element in VOTable

  • TableMetaData: Contains MetaData (Fields, Links and Description)
  • Resource:Represents the <RESOURCE> element in the VOTable.
  • TableData: Contains Rows
  • Field: Representation of <FIELD> from VOTable
  • Row: Representation of <TR> from VOTable
  • Column: Representation of <TD> from VOTable
parser design1
Parser Design

API – Typical Operations

  • File Level I/O Routines
    • Open VOTable file
    • Close VOTable file
  • Table I/O Operations
    • Get number of rows
    • Get number of columns
    • Get column(field) information (column name, column number, etc.)
    • Accessing table data
parser implementation
Parser Implementation
  • Development on Windows NT 4.0 platform using VC++. Ported to RedHat Linux 7.1/gcc-2.96 with zero effort.
  • 18 C++ classes representing various elements of the VOTable format.
  • 8500 lines of C++ code written for V1.1 release
  • Project start date: April 7th 2002
  • V1.1 Release: May 31st 2002
  • Current status: V1.2 design in progress
slide78

What is in Release V1.1

  • Parser to serve as a building block for developing VOTable based applications.
  • Can be easily used by users of CFITSIO library.
  • Supports powerful XPath queries against VOTable files.
  • The first version of the VO Table parser can now be downloaded:

http://vo.iucaa.ernet.in/~voi/html/infopage.html

slide79

VOTable Parser Demo

  • Serves as a tutorial to help understand the basic APIs provided by the VOTable parser.
  • Demonstrates how to access the data and metadata elements of a VOTable file.
future work
Future Work
  • Develop APIs for writing data in VOTable format.
  • Develop APIs for supporting IMAGE data and FITS files in VOTable.
  • Enhance existing API set to allow more elaborate and flexible operations on VOTable files.
  • Support future VOTable versions.
  • Develop applications for conversion between FITS and VOTable formats.
references
References
  • The first version of the C++ parser can now be downloaded from the VO-India website

http://vo.iucaa.ernet.in/~voi

  • VOTable Details:

http://vizier.u-strasbg.fr/doc/VOTable/

  • XALAN

http://xml.apache.org/xalan-c/index.html

  • XPATH

http://www.w3.org/TR/xpath

slide88
REGISTRIES: These collect metadata about data resources and information services into a queryable database. The registry is distributed. A variety of industry standards are being investigated.
  • DATA MODELS: This initiative aims to define the common elements of astronomical data structures and to provide a framework to describe their relationships.
  • UNIFORM CONTENT DESCRIPTORS: These will provide the common language for for metadata definitions for the VO.