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Microlensing search for extra-solar planets from Dome C

Microlensing search for extra-solar planets from Dome C. Arnaud Cassan Astronomisches Rechen-Institut (ARI), Zentrum für Astronomie der Universität Heidelberg (ZAH) J.-P. Beaulieu, P. Fouqué, J.-B. Marquette, C. Coutures. Outline. 1/ The microlensing method 2/ The current observing setup

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Microlensing search for extra-solar planets from Dome C

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  1. Microlensing search for extra-solar planets from Dome C Arnaud Cassan Astronomisches Rechen-Institut (ARI),Zentrum für Astronomie der Universität Heidelberg (ZAH) J.-P. Beaulieu, P. Fouqué, J.-B. Marquette, C. Coutures Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  2. Outline • 1/ The microlensing method • 2/ The current observing setup • 3/ Results and capabilities of the method • 4/ Why observing from Dome C ? • 5/ Summary & conclusion Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  3. The Gravitational microlensing effect Probing the Galactic Halo (MACHO, EROS) Galactic structure (OGLE, MACHO, EROS) Search for extra-solar planets (PLANET, MOA, MicroFun) ► Magnification of the source star flux Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  4. Observations toward the Bulge Probability of a microlensing event : 10-6 observations toward the Bulge OGLE fields Dome C is definitely the best site to observe the Bulge from Earth Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  5. Image separation : • Einstein radius crossing time : • Maximum amplification : • unresolved images ! • Flux magnification monitoring 3 - 4 weeks continuous observations from Dome C Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  6. The « standard » multi-site setup: a network of telescopes Ongoing microlensing events alerted byOGLE, MOA (EROS, MACHO) Follow-up network : PLANET collaboration Days Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  7. Observational strategy Observatories Raw data Data reduction pipeline BUT requires many “manual” operations…  One site allow much more automated procedures, from data reduction to data analysis and modeling ( on-line reduction ) ”Homebase” :- light curves modeling- observational strategy- public alerts- anomaly predictions Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  8. MOA 2003-BLG-53Lb : a Jupiter-like planet Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  9. OGLE-2005-BLG-071Lb : another Jupiter-like planet Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  10. OGLE-2005-BLG-390Lb a 5.5 Earth-mass planet Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  11. OGLE-2005-BLG-169Lb : a weak Neptune plant signal Gaps in the coverage  difficulties in modeling and finding a unique model Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  12. Detection efficiencies  [1] Modeling of individual events, e.g. : Cassan et al., 2006, en préparation  [2] Statistical combination of the individual efficiencies Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  13. Microlensing detection efficiencies 1995 - 2006 These planets of few Earth masses and few AU orbits may be very common A continuous monitoring from Dome C would push the detection efficiency limits toward low-mass stars Cassan et al., 2006, en préparation Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  14. Limits on abundance of exoplanets Ultimately, microlensing can provide a good estimation of Galactic planet abundance Gaudi et al. 2000 No strong selection with star brightness(only the lens mass is involved) The « whole » range of star mass is probed(prop. to their abundance) Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  15. Multiple planetary systems Ex. Constraints on additional Jupiter-like planets on OGLE-2005-BLG-390 Kubas, Cassan et al. (in preparation) Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  16. Complementary to other methods Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  17. Main goals of microlensing • Detection of Neptune to Earth-mass planets • Abundance of extra-solar planets in the Galaxy • From space simulations (MPF satellite, Bennett et al. 2005) : • 66 terrestrial planets • 100 icy giants • 3300 gas giants •  Order of magnitude of what may be expected from Dome C Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  18. Why Dome C ? • With he current setup : • Gaps in the light curve • Multi-site photometry= difficulties with combining data sets from different telescopes (mean seeing/air mass, weather conditions, CCDs…) • Australia do not provide stable weather conditions to operate a deep round-the-clock monitoring •  Only 1 terrestrial planet so far Given that : - the theoretical efficiency is higher than is achievable now - the main difficulties come from • the non-continuous monitorin • The weather conditions - the statistical point of view is the most relevant for microlensing search for exoplanets ► The ground base detection capabilities have been reached ► Dome C is the most relevant site to achieve the ultimate goal of microlensing searches for exoplanets = statistical aspect Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  19. What would Dome C provide for microlensing towards the Bulge ? • Continuous monitoring of the Bulge • Stable weather condition  eliminate false alerts • Stable and good seeing, low background • One telescope with one instrument  high improvement of photometry precision + known systematic errors Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  20. A possible setup • A 2m-class telescope • 28k x 28k camera • 0.09”/pixel -> 0.5deg2 FOV • FWHM 0.25’’ • 2 deg2 monitored in the Bulge • Time Sampling : every 20 min • During Antarctica winter season: in 2005 (sun < -18 deg) -> 81 days • 3 – 4 weeks continuous observations (time scale < 30 d) • A OGLE-like alert + following setup Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  21. Summary & Conclusion • 4 extra-solar planets discovered : • 2 Jupiter-like + 1 Neptune planets (2003-2006) • A 5.5 Earth-mass planet (2006) • Abundance of exoplanets around M-dwarfs • will ultimately extend to “all” stars • Sensitivity/limits on multi-planetary systems • Complementary to other techniques (ex. RV) • Dome C is the only site on Earth that allows a continuous monitoring of the Galactic Bulge • A realistic project : • Experience from an ongoing project (10 years with PLANET) • Expertise of data reduction/image subtraction technique • Expertise in modeling, statistical analysis Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  22. Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  23. u Magnification: The single lens case Magnification curves Einstein ring radius: (t-t0)/tE Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  24. Cassan & kubas (in preparation) Ida & Lin, 2005, ApJ 246, 1045 Model predictions vs. microlensing observation OGLE 2005-BLG-390Lb Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  25. Crowded fields Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  26. Galactic microlensing Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  27. Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  28. OGLE 2005-BLG-390Lb : a cool 5.5 Earth-mass planet 10.8.05 31.7.05 Beaulieu et al., 2006, Nature 439, 437 Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  29. Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  30. What we know from the unique modeling • Planet/star mass ratio : q = mp / M*= (7.6 ± 0.7) x 10-5 • Instantaneous separation/Re : d = rphys / RE= 1.61 ± 0.01 • Source star distance : DS= 8.5 kpc • Einstein ring crossing time : tE= 11.0 ± 0.1 days • RE = vttE = 1/c [ 4GM*DL(1-DL/DS) ]1/2 Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  31. The mass of OGLE 2005-BLG-390Lb Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  32. Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  33. Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  34. Deriving physical parameters • Planet mass & orbit : mp = 5.5 +5.5-2.7 Earth-mass • ap = 2.6+1.5-0.6 AU • Host star :M* = 0.2 +0.2-0.1 Msol • Lens distance : DL = 6.6 ± 1 kpc Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  35. Détection des exoplanètes Juillet 2003 (Planète jovienne) Mai 2005 (Planète jovienne) Udalski et al., 2005, ApJ 628 Bond et al., 2004, ApJ 606 Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  36. intermédiaireSéparation :grandefaible Microlentilles doubles : caustiques et courbes critiques Courbes critiques (plan-lentille) Caustiques (plan-source) Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  37. The microlensing effect lens plane source plane Image < mas Source Observer Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

  38. The PLANET collaboration(Probing Lensing Anomalies NETwork) M. D. Albrow, J.P. Beaulieu, D. Bennett, S. Brillant, J. A. R. Caldwell, H. Calitz, A. Cassan, K. Cook, C. Coutures, M. Dominik, J. Donatowicz, D. Dominis, P. Fouqué, J. Greenhill, K. Hill, M. Hoffman, K. Horne, U. Jorgensen, S. Kane, D. Kubas, R. Martin, J. Menzies, P. Meintjes, K. R. Pollard, K. C. Sahu, J. Wambsganss, A. Williams ARI Heidelberg (Germany), IAP Paris (France), Univ. of Notre Dame (USA), Univ. of Canterbury (New Zealand), SAAO (South Africa), Boyden Observatory (South Africa), Canopus Observatory (Tasmania), Niels Bohr Institute (Denmark), Univ. of Potsdam (Germany), STSI (USA), Perth Observatory (Australia), ESO (Chile), OMP (France) Arnaud Cassan Optical and Infrared Wide-Field Astronomy in Antarctica ARI / ZAH Heidelberg IAP, 14 – 16 June 2006

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