challenges in scientific computing and data analysis Matthias - - PowerPoint PPT Presentation

challenges in scientific computing and data analysis Matthias Steinmetz

Modelling the Milky Way: Modelling the Milky Way:

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16 Dec 2010 The Future of Astrocomputing

Can we form disk galaxies?

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16 Dec 2010 The Future of Astrocomputing

Not really …

Formation of disks has been notoriously difficult

Feedback? Resolution? Numerical Methods?

• AMR vs

SPH

Remember: on galactic

scales, hydrodynamics is an approximation (probably) !

What is the mass of MW-type

DM halo

Abundance M~2.5×1012 M⊙ Stellar dynamics M~1012 M⊙

Agertz et al, 2010

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16 Dec 2010 The Future of Astrocomputing

Vcirc and Vesc from SDSS

Xue et al 2008

RAVE

12 21 . 18 .

10 82 . × =

+ − AC no

M

M⊙

12 40 . 30 .

10 21 . 1 × =

+ − AC

M

M⊙

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Compare SDSS stellar mass function with DM halo mass function

M⊙

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10 5 . 2 × =

MW

M

Forero et al 2009 Guo et al 2009

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We still do not really understand how to form disk galaxies

Guo et al 2009

Agertz et al, 2010

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Most of the angular momentum comes in late and thus at low density

Navarro & MS 1997

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The local universe is not a representative part

• f the universe.

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

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16 Dec 2010 The Future of Astrocomputing

Local Group alikes are pretty rare!

analysis of 90 Mpc box, constrained simulation WMAP5 normalization

• ne excellent candidate

Virgo:

• Mass: 1.2×1014 M⊙

(more massive)

• distance: 14.9 Mpc

(19.0 Mpc ← NED)

Fornax:

• mass: 4.2 ×1013 M⊙

(7.0×1013 M⊙ ← ApJ 548, L139)

• distance: 19.2 Mpc

(17.6 Mpc ← NED)

Local group

• mass: 3.0×1013M⊙

(lower mass end)

• MW/Andromeda distance: 690kpc (700kpc)

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CLUES

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Metz, Kroupa & Jerjen 2009 complete!

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Libeskind et al 2005 6 DM only simulations, populated with galaxies semi- analytically.

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16 Dec 2010 The Future of Astrocomputing

MW M31

Preferential infall

• f satellites

Libeskind et al, 2011

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MW M31

Preferential infall

• f satellites

Quadrupole: infall along a filament Pointing towards Virgo

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The MW is not a typical galaxy …

Forero et al, 2011

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Doumler et al, 2011

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Doumler et al, 2011

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How about observations?

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The Milky Way is all around us!

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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

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

Hipparcos & GAIA

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Velocity Substructure in RAVE

Williams et al, 2010

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Velocity Substructure in RAVE

Williams et al, 2010

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Illustrative simulations

Williams et al, 2010

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Recent disruption event

Williams et al, 2010

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Mary Williams http://www.rave-survey.aip.de/rave/

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Outlook: The GAIA epoch

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The Future: GAIA

Cornerstone mission of ESA Scheduled for launch in late 2012 Main objective: To create the largest and

most precise three dimensional chart of

• ur Galaxy by providing unprecedented

positional and radial velocity measurements for about one billion stars in our Galaxy and throughout the Local Group.

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Schedule

Proposal Concept & Technology Study Mission Selection Re-Assessment Study Phase B1 Scientific

• peration

Launch late 2012 Final Studies Mission Data Processing Implementation Data Processing Definition Operation Mission Products Intermediate Selection of Prime Contractor (EADS Astrium) Phase B2 Phase C/D Software Development 1995 2000 2005 2010 2015 2020 1994 1993 1997 1998 1999 2019 2018 2017 2016 2014 2013 2012 2011 2009 2008 2007 2006 2004 2003 2002 2001 1996 2021

Now

Figure courtesy Michael Perryman and François Mignard

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Light Bending in Solar System

Light bending in microarcsec, after subtraction of the much larger effect by the Sun

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The Future: GAIA

RAVE RAVE

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GAIA

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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) 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 -

stellar systems - stellar physics - Galactic astronomy - quasars and

galaxies.

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