A-Stars and the Virtual Observatory Paolo Padovani, ST-ECF/ESO AVO Science Manager

1. A-Stars and the Virtual Observatory Paolo Padovani, ST-ECF/ESO AVO Science Manager The Virtual Observatory and A-Stars • The Virtual Observatory (VO) • Europe and the VO: the Astrophysical Virtual Observatory • A-Stars and the (A)VO: concrete applications • Disclaimer n. 1: Big topic, good for a whole workshop • Disclaimer n. 2: Extragalactic astronomer! P. Padovani, The A-Star Puzzle

2. Astronomy in the XXI century Radical changes are needed! • Huge surveys: 100Msources at <3k spectra/night  >100 yr! • Ever fainter sources: surpassed the identification limits of 8 - 10m telescopes (Rmag≈25) • Huge data collections: downloading Sloan Digital Sky Survey (SDSS) DR2 (~ 1/3 of total) images (5 Tb)  ~ 1 yr at 200 kb/s (ESO’s speed); catalogs (1.4 Tb)  ~ 3 months. On DVDs  ~ 1,000 of them. And analysis?? (similar size for MACHO, 2MASS etc …) • Ever increasing amount of data P. Padovani, The A-Star Puzzle

3. R ~ 25.5, VLT/FORS2, texp ~ 2.5 hrs (Szokoly et al. 2004) P. Padovani, The A-Star Puzzle

4. Astronomical Data Explosion ~ 100 Gb/night P. Quinn P. Padovani, The A-Star Puzzle

5. ESO/ST-ECF Science Archive Facility holdings  P. Padovani, The A-Star Puzzle

6. The solution? • Data mining to increase observing efficiency  intelligent pre-selection • Statistical identification to diminish need for a spectrum  multi-wavelength, multi-parameter analysis • In-situanalysis to avoid download • Easy and smart access to all archives and data providers P. Padovani, The A-Star Puzzle

7. The name: Virtual Observatory • An innovative, evolving system, which takes advantage of astronomical data explosion • It will allow users to interrogate multiple data centres in a seamless and transparent way and to utilize at best astronomical data • Data analysis tools and models will be made more accessible • It will allow new science by moving Astronomy beyond era of “classical” identification by combining all available information • Good communication  common language! Adoption and definition of VO standards and protocols within the International Virtual Observatory Alliance (IVOA: http://ivoa.net) • And it’s all happening now … P. Padovani, The A-Star Puzzle

8. International Virtual Observatory Alliance Mission To facilitate the international coordination and collaboration necessary for the development and deployment of the tools, systems and organizational structures necessary to enable the international utilization of astronomical archives as an integrated and interoperating virtual observatory SVO P. Padovani, The A-Star Puzzle

9. So what …? • The VO will make life much easier for all astronomers, even those not involved with colossal surveys, huge teams, and Tb of data! • Web: all documents of the world inside your computer • VO: all astronomical databases in the world inside your computer • Concrete example: • Find all the high-resolution spectra of A-type stars available in all astronomical archives in a given wavelength range • Tell me which ones are in raw or processed form • Allow me to retrieve them • If raw, give me access to the tools to reduce them on-the-fly Very time consuming, if at all possible, at present P. Padovani, The A-Star Puzzle

10. Virtual Observatory in Europe • AVO Project started November 2001 • Three-year, 5 M€, Phase A project, funded by the European Commission (FP5) and six organizations: ESO, ESA, AstroGrid, CNRS (CDS, TERAPIX), University Louis Pasteur, JBO • Manpower: ~ 17 FTEs/yr total, 50/50 EC and partners • Next step: EURO-VO, implementation phase (some EC funding secured, need more) • Visit us at http://www.euro-vo.org • Science Working Group established two years ago to provide scientific advice to AVO Project; implementation of selected science cases through demonstrations P. Padovani, The A-Star Puzzle

11. The AVO Prototype • Evolution of Aladin (Centre de Donnés astronomiques de Strasbourg [CDS]) • Downloadable Java application (http://www.euro-vo.org/twiki/bin/view/Avo/SwgDownload) • Extensible toolset with plug-ins which allows easy access to images, spectra, catalogues, with overlays, plotting facilities, and a cross-correlation utility • Still prototype but also research tool: first refereed, VO-based scientific paper “Discovery of optically faint obscured quasars with Virtual Observatory tools”, P. Padovani et al., A&A, in press (astro-ph/0406056) ST-ECF/ESO Press release May 28 P. Padovani, The A-Star Puzzle

12. A-star VO Cases • Establishing open cluster membership • Are chemically peculiar A-type stars more likely to be X-ray emitters than normal A-type stars? (Damiani et al., 2003) P. Padovani, The A-Star Puzzle

13. Open Cluster Membership Pleiades: POSS II image P. Padovani, The A-Star Puzzle

14. Loading catalogues parallax P. Padovani, The A-Star Puzzle

15. Plotting Data: Parallax Histogram cluster parallax = 8.46±0.22 mas P. Padovani, The A-Star Puzzle

16. Colour-magnitude diagram ZAMS can correct for reddening by adding a new column P. Padovani, The A-Star Puzzle

17. Colour-magnitude diagram parallax P. Padovani, The A-Star Puzzle

18. Open Cluster Membership Can be done now with existing tool, will be easier to do in the near future P. Padovani, The A-Star Puzzle

19. Available archive data 2 clicks away from journal articles! P. Padovani, The A-Star Puzzle

20. MAST data in detail • Cross-correlation of Sky2000 star catalogue with Multi-mission Archive at STScI (MAST; Optical/UV) • Out of 22,400 A-type stars: • 754 have International Ultraviolet Explorer (IUE) data, for a total of ~ 10,000 observations • 128 have non-IUE (FOS, GHRS, STIS, FUSE, EUVE, Copernicus, HUT, WUPPE, BEFS) data, for a total of 1,700 observations, ~ 60% of which are spectra • How much else is available? P. Padovani, The A-Star Puzzle

21. Peculiar A Stars in the X-rays Renson et al. (1991) catalog of 6684chemically peculiar stars, 4736 of which A-type (equatorial projection) P. Padovani, The A-Star Puzzle

22. Peculiar A Stars in the X-rays: Comparison Sample HD catalog (blue; 272,150 sources) with A-type stars (yellow; 72,154) selected (equatorial projection) P. Padovani, The A-Star Puzzle

23. Peculiar A Stars in the X-rays WGACAT of ROSAT PSPC observations, 88486 sources (equatorial projection) P. Padovani, The A-Star Puzzle

24. Chemically peculiar A-type stars in the X-rays • Cross-correlation of Renson et al. CP catalogue (A-type only) with WGACAT: 79/4736 matches = 1.7±0.6% (3; spurious matches subtracted). Magnetic only: 22/1433 = 1.5±0.7% • Cross-correlation of HD A-type stars with WGACAT: 392/72154 = 0.54±0.03%; correcting for CP star contamination (=10%; e.g., Monin et al. 2002)  ~ 0.4% • Cross-correlation of SAO A-type stars with WGACAT: 351/47230 = 0.7±0.1%; correcting for CP stars one gets ~ 0.6% • Chemically peculiar A-type stars are ~ 3 - 4 times more likely to be X-ray sources than normal A-type stars. Magnetic field appears not to play a role. P. Padovani, The A-Star Puzzle

25. Chemically peculiar A-type stars in the radio band? • Cross-correlation of Renson et al. CP catalogue (A-type only) with (almost) all-sky radio catalogues down to ~ 1 mJy gives null results • Expected, given fluxes of few detected sources so far ( 1 - 2 mJy, e.g., Drake et al. 1987) P. Padovani, The A-Star Puzzle

26. Summary • The Virtual Observatory is happening, because it has to! • Handling and manipulating astronomical data and tools residing at various locations around the world will be made much easier than it is now • Everybody will benefit, including A-type star researchers! • Tools are available now to help you with your work P. Padovani, The A-Star Puzzle

27. AVO prototype downloadable at http://www.euro-vo.org/twiki/bin/view/Avo/SwgDownload AVO Web Page P. Padovani, The A-Star Puzzle

28. Astronomical Data on the Web P. Padovani, The A-Star Puzzle