ESAVO/European Space Astronomy Centre (ESAC)Villafranca del Castillo, MADRID (SPAIN)Pedro OsunaASVOWS 21-23 Mar 2007 ESAC

Astronomical Spectroscopy in the VO era: VOSpec

Pedro OsunaIsa Barbarisi, Jesus Salgado, Andrea Laruelo

European Space Astronomy Centre (ESAC)Science Archives and VO Team

ESAVO/European Space Astronomy Centre (ESAC)Villafranca del Castillo, MADRID (SPAIN)Pedro OsunaASVOWS 21-23 Mar 2007 ESAC

Making data available in the Internet

Create document

WEB SERVER

robots

ESAVO/European Space Astronomy Centre (ESAC)Villafranca del Castillo, MADRID (SPAIN)Pedro OsunaASVOWS 21-23 Mar 2007 ESAC

Making data available in the VO

Create service

SSA SERVER

ESAVO/European Space Astronomy Centre (ESAC)Villafranca del Castillo, MADRID (SPAIN)Pedro OsunaASVOWS 21-23 Mar 2007 ESAC

Making data available in VO: DAL Toolkit

Config Files

SpectraFITS Files

Ingestor

DB

ServerDAL Request

VOTable

File Sys

ESAVO/European Space Astronomy Centre (ESAC)Villafranca del Castillo, MADRID (SPAIN)Pedro OsunaASVOWS 21-23 Mar 2007 ESAC

VOSpec Main Features• Handle SSAP spectra• Open local Spectra (Fits or VOTable)• Create a SED of spectra coming from a

wide range of different providers registered in the VO Registry (http://esavo.esa.int/registry) and also coming from local data

• Create SSAP Wrapper with your own set of local spectra and immediately display it

• Graphic options like color modification, zoom, unzoom, change spectra visualization, change units etc..

• Save results as Image/VOTable• Math operations like Polynomial,

BlackBody fitting, Gaussian, Nomalization, DeReddening, Red-shift, Luminosity Differences etc.

• Access to Theoretical Spectra through TSAP and Spectral Atomic Lines through SLAP

• Interoperability with other vo-aware tools through Plastic Technology

ESAVO/European Space Astronomy Centre (ESAC)Villafranca del Castillo, MADRID (SPAIN)Pedro OsunaASVOWS 21-23 Mar 2007 ESAC

De-Reddening

• Interstellar reddening is a phenomenon associated with interstellar extinction where the spectrum of electromagnetic radiation from a radiation source changes characteristics from that which was emitted.

• Reddening occurs due to the light scattering off dust and other matter in the interstellar medium. It preferentially removes shorter wavelength photons from a radiated spectrum while leaving behind the longer wavelength photons (in the optical, light that is redder), leaving the spectroscopic lines unchanged

• VOSpec povides support to this phenomenon allowing to apply the Calzetti, Cardelli O’Donnel or LMC formula, depending by the case.

• Please visit the VOSpec User Manual to see the video of the De-Reddening functionality.

ESAVO/European Space Astronomy Centre (ESAC)Villafranca del Castillo, MADRID (SPAIN)Pedro OsunaASVOWS 21-23 Mar 2007 ESAC

De-Reddening – IRAS 10178-5958 case

ESAVO/European Space Astronomy Centre (ESAC)Villafranca del Castillo, MADRID (SPAIN)Pedro OsunaASVOWS 21-23 Mar 2007 ESAC

Theoretical Spectra Access in VOSpec

• VOSpec allows the user to rescale theoretical spectra using real spectral data for the object to be studied.

• Even if there are many differences between theoretical and real spectra, it’s been studied a solution to unify them in a common access protocol in order to visualize them in the same plot

• Main differences between both kind of spectra are the following:

- Models have specific input parameters- Theoretical Spectra are not normalized

ESAVO/European Space Astronomy Centre (ESAC)Villafranca del Castillo, MADRID (SPAIN)Pedro OsunaASVOWS 21-23 Mar 2007 ESAC

Simple Line Access through VOSpec

• There is a scientific need to have access to spectral line databases in the VO. Many science cases could make use of this kind of access

• VOSpec provides access to Atomic Line Databases through the Simple Line Access Protocol (SLAP)

• Please visit the VOSpec User Manual to see the video of the SLAP functionality.

ESAVO/European Space Astronomy Centre (ESAC)Villafranca del Castillo, MADRID (SPAIN)Pedro OsunaASVOWS 21-23 Mar 2007 ESAC

Best Fit fitting toolMOTIVATION MOTIVATION

Currently, to find the model that best fits a given SED:•Choose parameters manually•Inspect result visually (“Chi-by-eye”)•Modify parameters manually•Reinspect visually•Loop… GOAL

Best Fit finds thebest fit modelautomatically

METHOD

Levenberg-Marquardt Chi-squareminimization algorithm

ESAVO/European Space Astronomy Centre (ESAC)Villafranca del Castillo, MADRID (SPAIN)Pedro OsunaASVOWS 21-23 Mar 2007 ESAC

Best Fit step by step

Selecting TSA server

Initial model

Best fit model

minimizationproccess

Select TSA server

Select initial parameters

ESAVO/European Space Astronomy Centre (ESAC)Villafranca del Castillo, MADRID (SPAIN)Pedro OsunaASVOWS 21-23 Mar 2007 ESAC

Plastic Technology and Applications

• PLASTIC is a protocol for communication between client-side astronomy applications. Through PLASTIC applications can do tasks such as instruct each other to load Spectra, VOTables, highlight a subset of rows or load an image of a particular area of sky. Although such operations are quite simple, they enable powerful collaborations between tools. The philosophy is that the astronomer should have a suite of interoperating tools at his disposal, each of which does one thing well and which can be composed according to his particular needs.

• VOSpec allows registration to the Plastic Hub and it can interoperate with other VO-aware tools like Aladin, Astroscope, VOQuest etc

• Please visit http://plastic.sourceforge.net for more details about the project

Sending spectra from Astroscope to VOSpec through Plastic

Sending spectra from Aladin to VOSpec through Plastic

ESAVO/European Space Astronomy Centre (ESAC)Villafranca del Castillo, MADRID (SPAIN)Pedro OsunaASVOWS 21-23 Mar 2007 ESAC

Future implementations on VOSpec

You name it, we implement it.

See VOSpec at work: http://esavo.esac.esa.int/vospec/

And the User Manual at: http://esavo.esac.esa.int/VOSpecManual/