GHOST, Brussels, Feb.14th 2006

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The GHOST in CU8

Coralie NeinerParis-Meudon Observatory

Coralie.Neiner@obspm.fr

GHOST website: http://www.ster.kuleuven.be/~coralie/gaiahot.html

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GAIA lexicon…CU = Coordination Unit For CU8: manager=CBJ, deputy=Frederic Thevenin, scientific coordinator=CBJ, technical coordinator=Michel Nonon

DU = Development Unit = a group of people contributing to a CU or a sub-part of a CU (with a DU coordinator) GHOST = Gaia Hot Stars Team = a DU

(G)WP = (Gaia) Work Package = a group of tasks to be performed in a CU (with a WP manager and sub-WP managers)

SSU = Specific Stars Unit

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The CUs of GAIA CU1: System architecture (O’Mullan)

CU2: Data simulations (Luri)

CU3: Core processing (Bastian)

CU4: Object processing (Pourbaix, Tanga)

CU5: Photometric processing (van Leeuwen)

CU6: Spectroscopic processing (Katz) D. Katz this morning

CU7: Variability processing (Eyer) C. Aerts this morning

CU8: Astrophysical parameters (Bailer-Jones) now!

(CU9: Catalogue access)

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CU8 Astrophysical parametersWork Beakdown Structure

Top level WPs:

Common packages GWP-C-81xx

Support packages GWP-S-82xx

Algorithmic units GWP-S-83xx (all objects)

GWP-S-84xx (SSU)

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Common WPs:

GWP-C-8110 Coordination and management

GWP-C-8120 Definition of system architecture

GWP-C-8130 Simulations

GWP-C-8140 Configuration management

GWP-C-8150 Hardware/System administration

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Support WPs:

GWP-S-8210 Stellar models/spectra (Korn/Thevenin)

Provide synthetic spectra for single stars across the full AP space expected, at sufficient wavelength resolution and coverage to ensure accurate simulation in BBP, MBP and RVS.

GHOST contribution:

models for hot stars and emission line stars (contributors: Y.Frémat, R. Blomme, C. Martayan, J. Zorec, J.-C. Bouret, F. Martins,…) Y. Frémat this afternoon

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GWP-S-8220 Calibrations and auxiliary data (Soubiran)

Provide the real data and parameters required to calibrate the classification and AP estimation methods. Perform new observations if necessary.

GHOST contribution:

- provide a list of object types than need new observations (contributors: the whole GHOST)

- provide a list of typical targets for this object types (contributors: the whole GHOST)

- help with the observations (contributors: I. Kolka with the Tartu Observatory, A.-M. Hubert, M. Floquet, C. Neiner with the Pic du Midi/TBL,…)

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GWP-S-8230 Interstellar extinction (Straizys)

Establish an optimal method for determining the line-of-sight interstellar extinction to individual stars, based on BBP, MBP and RVS.

GHOST contribution:

make sure the interstellar extinction is treated properly in emission line stars…

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Algorithmic units:

GWP-S-8310 Discrete Source Classifier (DSC) (Bailer-Jones)

Use photometry of unresolved ‘slow’ sources to determine the broad class of the object (single star, binary, QSO, …)

GHOST contribution:

provide typical criteria for hot stars and emission line stars?

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GWP-S-8320 Generalized Stellar Parametrizer – Photometry (GSP-phot) (Bailer-

Jones)

Estimate APs for the full range of type of single stars based on photometry (and parallaxes in late-mission)

GHOST contribution:

provide typical photometric criteria for hot stars and emission line stars?

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GWP-S-8330 Initial Spectral Analyser (ISA) (Manteiga)

For single stars, from RVS spectra, find evidence for binarity, search for emission lines, estimate Av from the DIB

GHOST contribution:

provide typical spectral criteria for hot stars and emission line stars?

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GWP-S-8340 Generalized Stellar Parametrizer – Spectroscopy (GSP-spec) (Recio-Blanco)

Estimate APs for the full range of type of single stars based on RVS and GSP-Phot

GHOST contribution:

provide spectral criteria for hot stars and emission line stars?

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GWP-S-8350 Object Clustering Analysis (OCA) (Sarro)

Identify natural or intrinsic classes of objects (unsupervised classification)

GHOST contribution:

provide algorithms for unsupervised classification for hot stars and emission line stars?

Would the algorithm developed in Leuven be useful here?

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GWP-S-8360 Luminosity, Age and Mass Estimator (LAME) (Lebreton)

Estimate the luminosity, age and mass of single stars based on their APs, parallax and apparent G-band magnitude

GHOST contribution:

help to determine the G-band magnitude and luminosity, which are crucial for the age and mass determination, for hot stars and emission line stars

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GWP-S-8410 SSU: QSOs (Claeskens)

GWP-S-8420 SSU: Unresolved galaxies (Kontizas)

GWP-S-8430 SSU: Solar system objects (Lagerkvist)

GWP-S-8440 SSU: Non-single stars (?)

GWP-S-8450 Extended stellar parametrizer (Frémat)

51 SSU: Hot stars (Neiner)

52 SSU: Cool stars (Lanzafame)

53 SSU: Ultra cool dwarfs (Barrado)

54 SSU: Abundance anomalous stars (Straizys)

55 SSU: Emission line stars (Neiner)

GWP-S-8460 Outlier analysis (Manteiga)

Study, develop and test algorithms which provide extended parameter estimates for the considered stars.

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GWP-S-8451 (hot stars) & GWP-S-8455 (emission line stars)

Study, develop and test algorithms which provide extended parameter estimates

GHOST contribution: everything in these 2 WPs!

Tasks:

1. Develop, implement and test classification algorithms

2. Obtain synthetic data to operate and test algorithms

3. Obtain auxiliary data (via GWP-S-8210!)

4. Analyse test data and GAIA data

5. Participate in final catalogue

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Deliverables:

1. Project plan (March 2006)

2. Reports on performance of various algorithms (2006- 2008)

3. Final version of algorithms (2010)

4. Documentation (2010)

5. Improved version from real GAIA data (2012-2016)

6. Progress reports

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Observations:

- To converge on a list of objects types for which we need new observations, via the GHOST mailing list and website in the coming months

- To converge on a list of targets for these object types, via the GHOST mailing list and website in the coming months

- To organize, obtain and reduce observations, in collaboration with GWP-S-8210, in particular in Tartu and in France (and with belgian telecopes?) for the semesters 2007A and 2007B

What needs to be done(before launch in 2011)

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Models:

- Develop RVS synthetic spectra for OB stars (Frémat et al.) 2006-2007

- Develop RVS synthetic spectra with emission (Zorec et al.) 2006-2008

- Develop photometric models for OB stars with and without emission (Frémat et al.) 2006-2008

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Criteria:

- Find suitable criteria to classify hot stars from RVS spectra (Fremat et al.) 2006

- Find suitable criteria to classify emission line stars from RVS spectra (Martayan et al.) 2006

- Find suitable criteria to classify hot stars from GAIA photometry (Fabregat et al.?) 2006-2007

- Find suitable criteria to classify emission line stars from GAIA photometry (Kolka et al.) 2006-2007

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Criteria in practice:

The ‘hot stars’ and ‘emission lines stars’ include:

- O stars - Wolf-Rayet

- B stars - Luminous Blue Variable (LBV)

- Be stars - β Cep stars

- B[e] stars - Slowly Pulsating B (SPB) stars

- shell Be stars - T Tauri

- Herbig Ae/Be stars - …

2 millions hot stars in photometry + 400 000 RVS spectra!

400 000 emission line stars + 80 000 RVS spectra!

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Algorithms:

- Study, develop and test algorithms to classify hot stars and provide stellar parameters (Frémat et al.) 2006-2010

- Study, develop and test algorithms to classify emission line stars and provide stellar parameters (Martayan et al.) 2006-2010

- Help with study, development and test of algorithms to provide luminosity, mass and age estimates (GWP-S-8360) (Frémat et al.?) 2006-2010

- Help with study, development and test of algorithms for interstellar extinction (GWP-S-8230) (Who?) 2006-2010

Final versions in Java, with documentation

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Algorithms in practice:

- We can study and test algorithms in any language

- We then select the best algorithm for a certain task (efficiency is an important issue!)

- We write it in Java, with the help of the data center (CNES) if needed

- We test it thoroughly

- We provide it to the data center at the latest in 2010 for integration in the GAIA algorithm

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Where/How can the belgian members of the GHOST contribute:

- Y. Frémat in Brussels is already involved in many tasks. Needs help!?

- Expertise of members from Liege for WR stars would be welcome (for example)

- Will the members from Leuven concentrate on CU7?

- Contributions to observations?

Discussion open!...