1. GHOST, Brussels, Feb.14th 2006 1 The GHOST in CU8 Coralie Neiner Paris-Meudon Observatory Coralie.Neiner@obspm.fr GHOST website: http://www.ster.kuleuven.be/~coralie/gaiahot.html

2. GHOST, Brussels, Feb.14th 2006 2 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

3. GHOST, Brussels, Feb.14th 2006 3 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)

4. GHOST, Brussels, Feb.14th 2006 4 CU8 Astrophysical parameters Work Beakdown Structure Top level WPs:  Common packagesGWP-C-81xx  Support packagesGWP-S-82xx  Algorithmic unitsGWP-S-83xx (all objects) GWP-S-84xx (SSU)

5. GHOST, Brussels, Feb.14th 2006 5 Common WPs: GWP-C-8110Coordination and management GWP-C-8120Definition of system architecture GWP-C-8130Simulations GWP-C-8140Configuration management GWP-C-8150Hardware/System administration

6. GHOST, Brussels, Feb.14th 2006 6 Support WPs: GWP-S-8210Stellar 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

7. GHOST, Brussels, Feb.14th 2006 7 GWP-S-8220Calibrations 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,…)

8. GHOST, Brussels, Feb.14th 2006 8 GWP-S-8230Interstellar 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…

9. GHOST, Brussels, Feb.14th 2006 9 Algorithmic units: GWP-S-8310Discrete 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?

10. GHOST, Brussels, Feb.14th 2006 10 GWP-S-8320Generalized 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?

11. GHOST, Brussels, Feb.14th 2006 11 GWP-S-8330Initial 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?

12. GHOST, Brussels, Feb.14th 2006 12 GWP-S-8340Generalized 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?

13. GHOST, Brussels, Feb.14th 2006 13 GWP-S-8350Object 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?

14. GHOST, Brussels, Feb.14th 2006 14 GWP-S-8360Luminosity, 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

15. GHOST, Brussels, Feb.14th 2006 15 GWP-S-8410SSU: QSOs (Claeskens) GWP-S-8420SSU: Unresolved galaxies (Kontizas) GWP-S-8430SSU: Solar system objects (Lagerkvist) GWP-S-8440SSU: Non-single stars (?) GWP-S-8450Extended 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-8460Outlier analysis (Manteiga)  Study, develop and test algorithms which provide extended parameter estimates for the considered stars.

16. GHOST, Brussels, Feb.14th 2006 16 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

17. GHOST, Brussels, Feb.14th 2006 17 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

18. GHOST, Brussels, Feb.14th 2006 18 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)

19. GHOST, Brussels, Feb.14th 2006 19 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

20. GHOST, Brussels, Feb.14th 2006 20 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

21. GHOST, Brussels, Feb.14th 2006 21 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!

22. GHOST, Brussels, Feb.14th 2006 22 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

23. GHOST, Brussels, Feb.14th 2006 23 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

24. GHOST, Brussels, Feb.14th 2006 24 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!...