VOScript | ESA-VO Team | INTEROP 2010, Nara | Pag. 1 VOScript: VO Spectral analysis scripting tool...

VOScript | ESA-VO Team | INTEROP 2010, Nara | Pag. 1

VOScript: VO Spectral analysis scripting tool ESA-VO TeamJuan González

Deborah Baines

Isa Barbarisi

Andrea Laruelo

Science Arcives and VO Team (SAT)

Computer Support Engineering Unit (SRE-OE)

ESAC, Madrid

VOScript


Motivation

Project scope

Architectural design

Example science case

Roadmap

Presentation Overview


VOSCRIPT: Motivation

VOScript is being developed as a direct response to the feedback from the astronomy community to VOSpec:

• ‘How do I do … for 10^9 sources?’ - EURO-VO School, January 2010. (Multitargetting)

• ‘Want to have the automatic retrieval of spectra from a list of objects’ – requested by a number of AIDA Research Initiative proposals. (Batch processing)

• ‘Is there the ability of performing a fit (e.g. Gaussian) to a large number of spectra in one go?’ - EURO-VO School, April 2009. (Automated analysis)

• ‘Can I broadcast a spectral list to Topcat?’ – EURO-VO School, April 2009. (Tables interaction)


VOSCRIPT: Scope

To cover the use science cases reported, a wider approach was followed, taking more design considerations into account:

• Run everywhere: provide multi-platform, multi-language access interfacing.

• User access through several abstraction layers: From simple top-level usage to low-level data model tuning

• Fully extensible: Based on a very comprehensive data model for which capabilities can be extended directly by the user


Motivation

Project scope



Roadmap



VOSCRIPT: Architecture

Run everywhere: Multi-platform, multi-language access interfacing: JVM language based scripting

• Data Access modules within VOSpec fully re-engineered to bring to the user a comprehensive object structure, that may be distributed as a single jar file accessed by object-based JVM scripting.

• Existing code in many general purpose programming languages may be reused in JVM-based equivalent languages, including Java, C, Python, Tcl, JavaScript, Pascal, PHP, Ruby, Ada, AWK, Cobol, ColdFusion, Common Lisp, Component Pascal, Erlang, Forth, LOGO, Lua, Oberon-2, Objective Caml, Rexx, Scheme…

• http://en.wikipedia.org/wiki/List_of_JVM_languages



Run everywhere: Multi-platform, multi-language access interfacing: Shell access

• Shell access module comes bundled, based on org.apache.commons.cli

• Provides access from any shell command interpreter in any OS that may run Java: bash, csh, tcsh, etc.

• Flexibility and customization capabilities quite reduced compared to JVM languages access. Only recommended for fast access to basic functionality.

• http://en.wikipedia.org/wiki/Shell_%28computing%29



Abstraction levels: documentation to be provided covering different layers of the application

• Simple high-level access described module by module, by UML diagrams and simple use cases

• Well documented Java API for further low-level access, including for instance a new Spectral DM parser (Legacy formats to custom SDM with few lines of code)


Motivation

Project scope



Roadmap



VOSCRIPT SCIENCE CASE

AIM: Search the VO for specific IR lines for a large list of young stars, calculate the equivalent widths of the lines, save the results as a table and produce plots.

Using VOScript:

• Searched the VO for ISO spectra for a list of ~320 Herbig Ae/Be stars.

• Calculated the Equivalent Widths of some strong spectroscopic lines in the IR, e.g. [OI] 63um, [CII] 158µm, PAH lines….

• Output is a table which can be loaded into TOPCAT.

Using TOPCAT (or STILTS):

• Cross matched the VOScript results table with catalogues in the VO for photometry, stellar parameters, etc - e.g. Garcia Lopez et al 2006: accretion luminosities, mass luminosities and Bracket gamma EWs for Herbig Ae/Be stars.

• Produced histograms and scatter plots to compare spectroscopic lines and look for any trends.



Import libraries

Load list of targets

Set the logging information

Add more sources to target list

Create output table and list of spectra

Define SSA services to be queried



Download each spectrum and save locally

EW calculation

Query SSA services with target list and search radius = 0.05 degrees

Cut each spectrum centered on line of interest

Save results into a table, as CSV, VOTABLE etc

Add metadata and fitting to output table


VOSCRIPT INITIAL RESULTS: IR LINES

Only observe [OI] 63µm emission from sources with large flared disks (blue), as identified by their SED in the IR. (Red = all sources).



[CII]158µm appears stronger in sources with self-shadowed disks (green) than with flared disks (blue). (Red = all sources).

Surprise result. Although Pinte et. al. (2010) disk models do show that the line originates from larger radii and lower density regions than the [OI] IR lines, and it is very sensitive to the amount of UV radiation.



PAH 6.2µm stronger in sources with flared disks (blue) than self-shadowed disks (green) - agrees with Acke and van den Ancker, 2004, A&A, 426, 151. (Red = all sources).


Motivation

Project scope



Roadmap



VOSCRIPT: Roadmap

Call for BETA testers:

• VOScript still in internal stage.

• Willing to provide early test releases for interested parties, along with script examples and documentation adapted to the case.

• Send us your science case to [email protected]

VOScript | ESA-VO Team | INTEROP 2010, Nara | Pag. 1 VOScript: VO Spectral analysis scripting tool...

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