Modelling the Milky Way: Modelling the Milky Way: challenges in scientific computing and data analysis Matthias Steinmetz
16 Dec The Future of Astrocomputing 2010 Can we form disk galaxies? 3
Not really … � Formation of disks has been notoriously difficult � Feedback? � Resolution? � Numerical Methods? Agertz et al, 2010 • AMR vs SPH The Future of Astrocomputing � Remember: on galactic scales, hydrodynamics is an approximation (probably) ! � What is the mass of MW-type DM halo � Abundance M~2.5×10 12 M ⊙ 16 Dec � Stellar dynamics M~10 12 M ⊙ 2010 4
V circ and V esc from SDSS + = + = 0 . 40 0 . 21 1 . 21 M M 0 . 82 − − 0 . 30 AC no AC 0 . 18 × 12 × M ⊙ 10 12 M ⊙ 10 The Future of Astrocomputing RAVE 16 Dec 2010 Xue et al 2008 5
Compare SDSS stellar mass function with DM halo mass function = × 12 M ⊙ M 2 . 5 10 MW The Future of Astrocomputing Forero et al 2009 Guo et al 2009 16 Dec 2010 6
We still do not really understand how to form disk galaxies Agertz et al, 2010 The Future of Astrocomputing 16 Dec 2010 7 Guo et al 2009
Most of the angular momentum comes in late and thus at low density The Future of Astrocomputing 16 Dec Navarro & MS 2010 1997 8
The local universe is not a representative part of the universe. The Future of Astrocomputing The MW is situated in a region of relatively low density and with large nearby mass concentrations like Virgo, the local supercluster, Perseus Pisces and Coma 16 Dec 2010 9
Local Group alikes are pretty rare! � analysis of 90 Mpc box, constrained simulation � WMAP5 normalization � one excellent candidate � Virgo: The Future of Astrocomputing • Mass: 1.2×10 14 M ⊙ (more massive) ← • distance: 14.9 Mpc (19.0 Mpc NED) � Fornax: ← • mass: 4.2 ×10 13 M ⊙ (7.0×10 13 M ⊙ ApJ 548, L139) ← • distance: 19.2 Mpc (17.6 Mpc NED) � Local group • mass: 3.0×10 13 M ⊙ (lower mass end) • MW/Andromeda distance: 690kpc (700kpc) 16 Dec 2010 11
16 Dec The Future of Astrocomputing 2010 12
16 Dec The Future of Astrocomputing 2010 CLUES 13
16 Dec The Future of Astrocomputing 2010 Metz, Kroupa & Jerjen complete! 2009 14
6 DM only simulations, populated with galaxies semi- analytically. The Future of Astrocomputing 16 Dec Libeskind et al 2005 2010 15
Preferential infall of satellites The Future of Astrocomputing 16 Dec MW 2010 M31 Libeskind et al, 2011 16
Preferential infall of satellites The Future of Astrocomputing Quadrupole: infall along a filament Pointing towards Virgo 16 Dec MW 2010 M31 17
The MW is not a typical galaxy … The Future of Astrocomputing Forero et al, 2011 16 Dec 2010 18
16 Dec The Future of Astrocomputing 2010 Doumler et al, 2011 19
16 Dec The Future of Astrocomputing 2010 Doumler et al, 2011 20
16 Dec The Future of Astrocomputing 2010 How about observations? 21
16 Dec The Future of Astrocomputing 2010 The Milky Way is all around us! 22
How about observations? � The substructure crisis � Systematic searches using large imaging surveys (SDSS) reveal a considerable (sufficient?) number of new satellites � Substructure in phase space → tracing the The Future of Astrocomputing formation history of the Milky Way � Lot of activities following the discovery of Sagittarius dwarf � Imaging � SDSS, PanStarrs, Euclid, LSST � Spectroscopy � SDSS, RAVE, GAIA, HERMES, 4MOST � Astrometry 16 Dec 2010 � Hipparcos & GAIA 23
Velocity Substructure in RAVE The Future of Astrocomputing 16 Dec 2010 Williams et al, 2010 24
Velocity Substructure in RAVE The Future of Astrocomputing 16 Dec Williams et al, 2010 2010 25
Illustrative simulations The Future of Astrocomputing 16 Dec Williams et al, 2010 2010 26
Recent disruption event The Future of Astrocomputing 16 Dec Williams et al, 2010 2010 27
The Future of Astrocomputing 16 Dec 2010 28 Mary Williams http://www.rave-survey.aip.de/rave/
16 Dec The Future of Astrocomputing 2010 Outlook: The GAIA epoch 29
The Future: GAIA � Cornerstone mission of ESA � Scheduled for launch in late 2012 � Main objective: To create the largest and The Future of Astrocomputing most precise three dimensional chart of our Galaxy by providing unprecedented positional and radial velocity measurements for about one billion stars in our Galaxy and throughout the Local Group. 16 Dec 2010 30
Schedule 1993 1997 2001 2017 1994 1995 1996 1998 1999 2000 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2018 2019 2020 2021 Proposal Concept & Technology Study Mission Selection Re-Assessment Study Phase B1 The Future of Astrocomputing Definition Selection of Prime Contractor (EADS Astrium) Phase B2 Phase C/D Implementation Launch late 2012 Scientific operation Operation Studies Software Development Data Processing Mission Data Processing Intermediate Final Mission Products 16 Dec 2010 Now Figure courtesy Michael Perryman and François Mignard 31
Light Bending in Solar System The Future of Astrocomputing 16 Dec 2010 32 Light bending in microarcsec, after subtraction of the much larger effect by the Sun
16 Dec The Future of Astrocomputing 2010 The Future: GAIA RAVE RAVE 33
16 Dec The Future of Astrocomputing 2010 GAIA 34
One Billion Stars in 3-D will Provide � in our Galaxy … � the distance and velocity distributions of all stellar populations � the spatial and dynamic structure of the disk and halo � its formation history � a detailed mapping of the galactic dark-matter distribution � a rigorous framework for stellar structure and evolution theories � a large-scale survey of extra-solar planets (~15,000) The Future of Astrocomputing � a large-scale survey of Solar System bodies (~250,000) � … and beyond � definitive distance standards out to the LMC/SMC � rapid reaction alerts for supernovae and burst sources (~20,000) � QSO detection, redshifts, microlensing structure (~500,000) � fundamental quantities to unprecedented accuracy: γ to 2×10-6 (2×10-5 present) � Fundamental physics - reference frame - solar system - extrasolar planets - 16 Dec � stellar systems - stellar physics - Galactic astronomy - quasars and 2010 galaxies. 35
16 Dec The Future of Astrocomputing 2010 36
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