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Introduction
Current Members
Previous Members
Projects
Quality of CFC
Core Collapse with
Microphysics (Extended Model Set)
Magnetorotational Stellar Core Collapse
Core Collapse with
Microphysics
Black Hole Formation
Neutron Star Merger
Rotating Neutron Stars
Effective
Relativistic
Potential
Mariage des Maillages
Core Collapse in CFC+
Blazar Light Curves
Axisymmetric Core Collapse
Waveform Catalog
Gravitational waves
from stellar core
collapse
Literature Catalog
Gravitational waves
from stellar core
collapse


Introduction:
Many astrophysical phenomena can be simulated on computers using
methods known as computational hydrodynamics. If typical velocities
in the system are small and gravity is weak, it is sufficient to use
the Newtonian approximation of the laws of motion and gravity.
However, in many astrophysical environments, these approximations
do not hold. Supermassive black holes in quasars and solarmasssized
black holes with accretion discs power jets made of particles
which move at velocities close to the light speed. Here, special
relativistic hydrodynamics is needed for numerical simulations.
Our group has developed and successfully applied computer codes for
such simulations of jets with various sizes and morphologies for many
years.
To describe large amounts of matter compressed on small scales,
one must resort to general relativity, a generalization of
Newton's theory of gravity. Such a situation is encountered near black
holes (the prospective driving engines of astrophysical jets), as well
as in core collapse supernovae, in collapsars (one possible source of
gammaray bursts), or in neutron stars.
Some of these scenarios are emitting gravitational radiation. While
light or sound waves propagate through spacetime,
gravitational waves are ripples of spacetime itself. Such
spacetime distortions have been predicted by Einstein in his general
theory of relativity over 80 years ago, and are planned to be measured
by laser interferometers or resonant bar detectors. Such experiments
(like GEO 600,
LIGO,
VIRGO,
LISA, or
IGEC)
have recently started very sensitive
measurements, and the first successful direct detection of
gravitational waves can be envisaged within the next 5 years.
In order to accomplish a successful detection of gravitational waves,
very efficient electronic filters have to be employed to extract a
possible signal from the data measured by a detector. It is
therefore of great importance to predict as precise as possible the
signals from theoretical models of various astrophysical sources of
gravitational radiation. As part of the German research network
SFB Transregio 7 "Gravitational Wave Astronomy",
our group takes part in this international interdisciplinary
scientific effort.
Additionally, in the development of numerical codes for simulations of both
special and general relativistic
hydrodynamics, our group is closely collaborating with scientists from
the Departamento de Astronomía y Astrofísica at the
Universidad de Valencia in Spain, from the Laboratoire de l'Univers et de ses Théories at the Observatoire de Paris in
France, and from the
Numerical Relativity Group
at the
Max Planck Institute for Gravitational Physics in Potsdam, Germany.
Current Members:
Previous Members:

Miguel A. Aloy


(Departamento de Astronomía y Astrofísica,
Universidad de Valencia, Spain)


Harald Dimmelmeier


(Section of Astrophysics, Astronomy & Mechanics,
Aristotle University of Thessaloniki, Greece)


José A. Font


(Departamento de Astronomía y Astrofísica,
Universidad de Valencia, Spain)


Volker Heesen


(Astronomisches Institut,
RuhrUniversität Bochum, Germany)


Tobias Leismann



Petar Mimica


(Departamento de Astronomía y Astrofísica,
Universidad de Valencia, Spain)


Leonhard Scheck


Florian Siebel


(Institut für Geographie,
LudwigMaximiliansUniversität München, Germany)


Burkhard Zink


(Institute for Theoretical Physics,
Louisiana State University, U.S.A.)

Projects:
Note that the order of the projects is roughly in the order of the
time of completion (oldest projects at the bottom).

A Solution for the Nonuniqueness Problem of the Spacetime Constraint Equations
I. CorderoCarrión,
P. CerdáDurán,
H. Dimmelmeier,
J.L. Jaramillo,
J. Novak,
E. Gourgoulhon
The otherwise very successful CFC scheme for approximating the
Einstein equations in simulations of compact astrophysical objects
fail at very high densities. We have found a reformulation which
solves this problem and extends the applicability of CFC to e.g. black
hole formation.

Gravitational Waves from Black Hole Formation
B. Zink, N. Stergioulas, I. Hawke, C.D. Ott,
E. Schnetter, E. Müller
Modeling the formation of ultracompact objects like neutron stars,
quark stars, or black holes, and the gravitational radiation emitted
by these catastrophic events is an intrinsically general relativistic
problem. Simulating the birth of black holes requires
advanced methods to solve the Einstein equations, relativistic
hydrodynamics, and horizon analysis.

Nonlinear Axisymmetric Pulsations of Rotating Relativistic Stars
H. Dimmelmeier, N. Stergioulas, J.A. Font
With the axisymmetric version of the "Mariage des Maillage" code
we have for the first time simulated pulsations in uniformly and differentially rotating
neutron star models in general relativistic gravity and identified important
nonlinear effects. We have also investigated the issue of
detectability of gravitational wave emitted by such oscillations.

Synthetic Light Curves of BL Lac Objects
P. Mimica, M.A. Aloy, E. Müller, W. Brinkmann
For the first time we have performed a twodimensional simulation of
the internal shocks in a blazar jet under realistic conditions and
have computed the light curve resulting from the collision of two
dense shells moving with different velocities within a jet.

Gravitational Radiation from Relativistic Rotational Core Collapse
H. Dimmelmeier, J.A. Font, E. Müller
We have succeeded for the first time to simulate the
collapse of a rotating stellar core to a neutron star including
the effects of general relativity, making a major step forward
towards realistic predictions of gravitational wave signals.
Comments to: Harald Dimmelmeier
harrydee _at_ mpagarching.mpg.de
 