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Unravelling the Origins of the Milky Way with Gaia

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Unravelling the Origins of the Milky Way with Gaia Unravelling the origins of the Milky Way with Gaia Anthony Brown Sterrewacht Leiden, Leiden University [email protected] l The formation of the Milky Way l Galactic archaeology with Gaia l Complementary ground based spectroscopic surveys l The data processing consortium l Broader impact of Gaia Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.1/34 The Milky Way Image credit: Lund Observatory Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.2/34 The Milky Way Image credit: NASA/JPL-Caltech/R. Hurt (SSC) Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.3/34 The Milky Way Image credit: Lund Observatory Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.4/34 The Milky Way Image credit: Infrared Processing and Analysis Center/Caltech & University of Massachusetts Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.5/34 How was it formed? Movie credit: Amina Helmi, University of Groningen Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.6/34 How was it formed? Movie credit: Amina Helmi, University of Groningen Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.7/34 How was it formed? Image credit: R. Jay GaBany Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.8/34 How was it formed? Image credit: Davide de Martin, www.skyfactory.org Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.9/34 How was it formed? Image credit: A. McConnachie et al. Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.10/34 Galactic Archaeology Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.11/34 Galactic Archaeology Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.12/34 Galactic Archaeology Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.13/34 Galactic Archaeology Hypothesis: Milky Way built up through hierarchical merging process u Where are the building blocks of our Galaxy? u When did they merge with the Milk Way? u What was the chemical make-up of the building blocks? The formation history of the Milky Way can be unravelled by measuring the location, motions and astrophysical characteristics of its stars Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.14/34 What Gaia offers Photometry sample sample 40 30 20 10 0 60 50 40 30 20 10 0 3.0 3.0 2.5 2.5 photons) photons) 3 3 2.0 2.0 1.5 1.5 1.0 1.0 BP counts (10 RP counts (10 0.5 0.5 0.0 0.0 Spectroscopy Astrometry 400 500 680 900 640 700 800 9001000 λ (nm) λ (nm) Gaia LSF: AF S6R7T1 (V-I)=+2.0 0.5 0.4 0.3 Data 0.2 Relative intensity processing 0.1 0.0 -10 -5 0 5 10 AL position [pixel] Stellar types, 3D positions 3D motions ages, compositions Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.15/34 Unravelling the formation history of the Milky Way Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.16/34 Unravelling the formation history of the Milky Way 60 60 50 50 ] ] −1 −1 40 40 [Gyr [Gyr φ φ Ω Ω 3 30 30 − − r r Ω Ω 2 20 20 1 10 10 5 10 15 20 25 30 35 40 −3000 −2000 −1000 0 1000 2000 3000 Ω −1 L [kpc km s−1] φ [Gyr ] z Gomez´ et al, 2010, MNRAS Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.17/34 Unravelling the formation history of the Milky Way 60 60 50 50 ] ] −1 −1 40 40 [Gyr [Gyr φ φ Ω Ω 30 30 − − r r Ω Ω 20 20 10 10 5 10 15 20 25 30 35 40 −3000 −2000 −1000 0 1000 2000 3000 Ω −1 L [kpc km s−1] φ [Gyr ] z Gomez´ et al, 2010, MNRAS Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.18/34 Unravelling the formation history of the Milky Way 0 0 0 10 10 10 −1 10 −1 ) 10 φ −1 10 P( k −2 10 −2 10 −2 −3 10 10 −1 0 −1 0 −1 0 10 10 10 10 10 10 wavenumber [Gyr] wavenumber [Gyr] wavenumber [Gyr] Gomez´ et al, 2010, MNRAS Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.19/34 Unravelling the formation history of the Milky Way 0 0 0 10 10 10 −1 10 −1 ) 10 φ −1 10 P( k −2 10 Gaia only! Astrometric and radial velocity performance are crucial −2 10 −2 −3 10 10 −1 0 −1 0 −1 0 10 10 10 10 10 10 wavenumber [Gyr] wavenumber [Gyr] wavenumber [Gyr] Gomez´ et al, 2010, MNRAS Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.20/34 Chemical tagging [α=Fe] [Fe=H] Nissen & Schuster, 2010, A&A 511, L10 Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.21/34 Chemical tagging Font et al, 2006, ApJ 646, 886 Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.22/34 Chemical tagging Gaia photometry: cool star, [Fe=H] variation sample sample 40 30 20 10 0 40 30 20 10 0 1.4 3.0 1.2 2.5 1.0 photons) photons) 3 2.0 3 0.8 1.5 0.6 1.0 0.4 BP counts (10 RP counts (10 0.2 0.5 0.0 0.0 400 500 680 900 640 700 800 900 1000 λ (nm) λ (nm) Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.23/34 Chemical tagging Gaia photometry: cool star, [α=Fe] variation sample sample 40 30 20 10 0 40 30 20 10 0 8 3 6 photons) photons) 3 2 2 4 1 2 BP counts (10 RP counts (10 0 0 400 500 680 900 640 700 800 900 1000 λ (nm) λ (nm) Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.24/34 Chemical tagging Gaia spectroscopy: [Fe=H] and [α=Fe] variation 160 140 ] − 120 100 Flux [e 80 [Fe=H] = 0, [α/Fe] = 0 60 [Fe=H] = 0, [α/Fe] = +0:4 40 850 855 860 865 870 λ [nm] 160 140 ] − 120 RVS spectra simulated 100 by P. Sartoretti Flux [e 80 [Fe=H] = 1:5, [α/Fe] = 0 − 60 [Fe=H] = 1:5, [α/Fe] = +0:4 − 40 850 855 860 865 870 λ [nm] Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.25/34 Large spectroscopic surveys l ∼ Ten million star survey l Five years on 8-m and 4-m telescopes l R ∼ 5000 for radial velocities at V > 17 l R ∼ 20 000–40 000 for chemical tagging Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.26/34 4 DPAC membership January 2013 432 total 1 10 BR: 5 4 CA: 1 CL: 1 50 5 30 ESA: 28 23 IL: 1 5 US: 2 2 99 4 24 4 66 12 42 9 DPAC Data Processing Centres NL contributions sample sample 40 30 20 10 0 60 50 40 30 20 10 0 3.0 3.0 2.5 2.5 photons) photons) 3 3 2.0 2.0 1.5 1.5 1.0 1.0 BP counts (10 RP counts (10 0.5 0.5 0.0 0.0 400 500 680 900 640 700 800 9001000 λ (nm) λ (nm) Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.29/34 Stellar physics Accurate distances across the HR diagram u luminosity calibration I calibration photometric and spectroscopic distance indicators u astrometric detection of stellar, sub-stellar and planetary companions I 10 000 stars with masses to 1% u fundamental parameters for rare stellar types u precision tests of stellar interior models and stellar evolution Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.30/34 Solar system science Solar system around the time of Gaia launch (courtesy F. Mignard) Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.31/34 Solar system science l Accuracies: ground-based 0:1–1 arcsec, Gaia single measurement 0:1–1 mas l Systematic survey down to 20 mag ∼ 3 × 105 objects I ∼ 50 000 new objects expected ◦ I Observations at high ecliptic latitudes and to within 45 from Sun ! exotic orbits l Orbits: for virtually all objects observed — ×30 better than now l Masses from close encounters ∼ 100 masses expected l Diameters for over 1000 asteroids: shape, density l Photometric data in several bands: albedo, taxonomic classification l Light curves over 5 years: rotation, pole, shape l Space distribution vs. physical properties l Perihelion precession for 300 planets: GR testing, solar J2 Milky Way Galactic archaeology Spectroscopic surveys DPAC Bonus science NVR Leiden 30.01.2013 - p.32/34 Exoplanets with Gaia u Astrometric survey 5 I monitoring of several 10 FGK stars to ∼ 200 pc I detection limits ∼ 1 MJ and P < 10 yr I complete census of all stellar types over P = 2–9 yr I masses rather than lower limit (m sin i) I multiple systems measurable u Results expected I orbits for ∼ 5000 systems u Photometric transits I ∼ 1000 to 10 000 with a .
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