Galaxy formation is the
central subject of my research. Here the physics involved is an
incredibly complicated blend of gravity, hydrodynamics, nuclear and
atomic physics, as well as magnetohydrodynamics and radiation physics.
The fundamental equations governing the forces between particles and
fields in this low-energy regime are all well established, yet we are
far from understanding how they produce the bewildering complexity of
cosmic objects we see around us, like galaxies, globular star clusters,
compact objects, or damped Lyman-alpha absorbers in the intergalactic
medium, to name just a few. It is the goal of my research to make
progress in untangling these physical processes, to separate the
important from the unimportant, and to find some answers to the many
questions that astrophysicists face in contemporary extragalactic
astronomy.
I make extensive use of
simulation techniques to study cosmic structure formation, both based
on collisionless and hydrodynamic simulations. In order to allow use of
the full power of modern supercomputers, I develop massive parallel simulation algorithms for distributed
memory computers, and study new methods for discretizing the
Euler and Navier-Stokes equations, for example on a moving mesh. One of
my goals is to develop new calculational tools that allow
multi-physics, multi-scale simulations on peta-scale
supercomputers.
| Dark matter and dark energy |
Through numerical N-body
simulations I seek clues to the nature of the dark matter and aim
at advancing strategies for exploring the formation of our Galaxy,
for searching for signals from dark matter annihilation, and for
designing experiments for direct detection of dark matter. Dark
energy has emerged as one of the most important challenges for modern
field theory and cosmology. The evidence for an accelerated expansion
history of the universe is by now quite compelling, but the magnitude
of the implied dark energy component cannot be naturally explained as a vacuum energy, in addition
to raising a new coincidence problem: Why is the dark energy dominating
just now? I work on carrying out high-resolution cosmological
simulations of different dark energy cosmologies, including also
non-standard theories of gravity and coupled dark matter-dark energy
cosmologies, and to compare them to the standard ΛCDM model. The
goal is to explore the viability of these theories and to inform
strategies for successfully constraining dark energy through
observations.
The Millennium Run used more than 10 billion particles to trace the
evolution of the matter distribution in a cubic region of the Universe
over 2 billion light-years on a side. It kept busy the principal
supercomputer at the Max Planck Society's Supercomputing Centre in
Garching, Germany for more than a month. By applying sophisticated
modelling techniques to the 25 Tbytes of stored output, we have been able to recreate evolutionary histories both for
the 20 million or so galaxies which populate this enormous volume and
for the supermassive black holes which occasionally power quasars at
their hearts. By comparing such simulated data to large observational
surveys, one can clarify the physical processes underlying the buildup
of real galaxies and black holes.
Turn to the Millennium data release site for download of the publicly released
data and for a list of papers that have used the simulation. Pictures and movies of the simulation are available as well. Meanwhile, we have also carried a further Millennium-II simulation,
which features the same particle number but a 125 times better mass
resolution.
The Aquarius Project is a large-scale collaborative programme of the
Virgo Consortium (of which I am a member), similar in scope and scale to the Millennium
Simulation project. At present, the principal set of Aquarius
simulations contains six examples of an isolated halo similar in mass
to that of the Milky Way. These are simulated in their full
cosmological context (assuming the concordance ΛCDM cosmology) and at
various resolutions up to about 200 million particles (counted within
the radius where the enclosed density is 200 times the cosmic mean).
One halo is also simulated at even higher resolution, resulting in
almost 1.5 billion particles within this radius. These simulations are
being used to understand the fine-scale structure predicted around the
Milky Way by the standard structure formation model, and as the basis
for simulation by various techniques of the growth of the stellar
components of our Galaxy. |
|
| A selection of 10 of my most significant papers |
-
E pur si
muove: Galiliean-invariant cosmological hydrodynamical simulations on a moving mesh
Springel V., 2009, Mon. Not. of the R. Astron. Soc.,
in press [preprint]
- The
Aquarius Project: the subhalos of galactic halos
Springel
V., Wang J., Vogelsberger M., Ludlow A., Jenkins A., Helmi A., Fenk
C. S., White S. D. M., 2008, Mon. Not. of the R. Astron. Soc.,
391, 1685 [preprint]
- Prospects for detecting
supersymmetric dark matter in the Galactic halo
Springel
V., White S. D. M., Fenk C. S., Navarro J. F., Jenkins A.,
Vogelsberger M., Wang J., Ludlow A., Helmi A., 2008, Nature, 456, 73 [preprint]
- Modelling feedback from stars
and black holes in galaxy mergers
Springel V., Di Matteo
T., Hernquist L., 2005, Mon. Not. of the R. Astron. Soc., 361, 776 [preprint]
- The cosmological simulation
code GADGET-2
Springel
V., 2005, Mon. Not. of the R. Astron. Soc., 364, 1105 [preprint]
- Simulations of the formation,
evolution and clustering of galaxies and quasars
Springel
V., White S. D. M., Jenkins A., Frenk C. S., Yoshida N., Gao L.,
Navarro J., Thacker R., Croton D., Helly J., Peacock J. A.,
Cole S., Thomas P., Couchman H., Evrard A., Colberg J., Pearce F.,
2005, Nature, 435, 629 [preprint]
- The
history of star formation in a ΛCDM
universe
Springel V., Hernquist L., 2003, Mon. Not. of
the R. Astron. Soc., 339, 312 [preprint]
- Cosmological
SPH simulations: A hybrid multi-phase model for star
formation
Springel V., Hernquist L., 2003, Mon. Not. of
the R. Astron. Soc., 339, 289 [preprint]
- Cosmological
SPH simulations: The entropy equation
Springel V.,
Hernquist L., 2002, Mon. Not. of the R. Astron. Soc., 333, 649 [preprint]
- Populating
a cluster of galaxies - I. Results at z=0
Springel V.,
White S. D. M., Tormen G., Kauffmann G., 2001, Mon. Not. of the R.
Astron. Soc., 328, 726 [preprint]
| Refereed and submitted publications |
-
Superrechner in der Kosmologie
Springel V., 2009, Informatik Spektrum, in press
-
Die
Millennium Simulation – Mit einem Superrechner auf den Spuren der
Galaxies
Springel V., 2006, Sterne und Weltraum, 11, 30
-
Die
Entstehung der Galaxien
Springel V., 2003, Physik
Journal, 6, 31
- Fitting the universe on a supercomputer
White S. D. M., Springel V., 1999, Computing in Science & Engineering, 1, 36
- On the Formation and Evolution of Galaxies postscript
(9.1 MB) Volker Springel, Ludwig-Maximilians-Universität München,
July 1999
- Topology and Luminosity Function of the PSCz Redshift
Survey postscript (974
KB) Volker Springel, University of Tübingen, October 1996. There
are also gzip-compressed versions of three colour plates: figure C.1 (467 KB), figure
C.2 & C.3 (222 KB) and figure
C.4 (687 KB)
-
I have written the parallel cosmological Tree/SPH code GADGET, which is publicly available.
- I have also written a number of other codes as well, but they are
only available to close collaborators. Among them are codes for
parallel initial conditions generation of cosmological simulation and
for the construction of equilibrium compound galaxy models. I have also
authored the SUBFIND algorithm, both in serial and parallel versions. I
have written various parallel FOF group finders, codes for
constructing merger history trees, and for calculating semi-analytic galaxy
formation models.
- Recently, I have written the new finite-volume
hydrodynamics code AREPO that
is based on a moving unstructured grid
that is defined as the Voronoi tessellation of a set of mesh-generating
points. This allows Galilean-invariant simulations of Lagrangian
nature, but at the same time retains the accurcay of traditional
Eulerian approaches.
  
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