Relativistic Hydrodynamics

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-Current Members
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-Quality of CFC
-Core Collapse with
  Microphysics (Extended Model Set)

-Magnetorotational Stellar Core Collapse
-Core Collapse with

-Black Hole Formation
-Neutron Star Merger
-Rotating Neutron Stars
-Effective Relativistic

-Mariage des Maillages
-Core Collapse in CFC+
-Blazar Light Curves
-Axisymmetric Core Collapse

Waveform Catalog
linkPfeilExtern.gif Gravitational waves
    from stellar core

Literature Catalog
linkPfeilExtern.gif Gravitational waves
    from stellar core


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 solar-mass-sized 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 gamma-ray 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 linkPfeilExtern.gifGEO 600, linkPfeilExtern.gifLIGO, linkPfeilExtern.gifVIRGO, linkPfeilExtern.gifLISA, or linkPfeilExtern.gifIGEC) 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 linkPfeilExtern.gifSFB 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 linkPfeilExtern.gifDepartamento de Astronomía y Astrofísica at the linkPfeilExtern.gifUniversidad de Valencia in Spain, from the linkPfeilExtern.gifLaboratoire de l'Univers et de ses Théories at the linkPfeilExtern.gifObservatoire de Paris in France, and from the linkPfeilExtern.gifNumerical Relativity Group at the linkPfeilExtern.gifMax Planck Institute for Gravitational Physics in Potsdam, Germany.

top Current Members:


Ewald Müller

(Research group leader)

link Reiner Birkl      (PhD student)
webpage Nicolay J. Hammer (PhD student)
Thomas Mädler (PhD student)
webpage Bernhard Müller 
(PhD student)
link Martin Obergaulinger      (PhD student)

top Previous Members:

webpage Miguel A. Aloy
   (linkPfeilExtern.gifDepartamento de Astronomía y Astrofísica, linkPfeilExtern.gifUniversidad de Valencia, Spain)
webpage Harald Dimmelmeier
   (linkPfeilExtern.gifSection of Astrophysics, Astronomy & Mechanics, linkPfeilExtern.gifAristotle University of Thessaloniki, Greece)
linkPfeilExtern.gif José A. Font
   (linkPfeilExtern.gifDepartamento de Astronomía y Astrofísica, linkPfeilExtern.gifUniversidad de Valencia, Spain)
Volker Heesen
   (linkPfeilExtern.gifAstronomisches Institut, linkPfeilExtern.gifRuhr-Universität Bochum, Germany)
Tobias Leismann
linkPfeilExtern.gif Petar Mimica
   (linkPfeilExtern.gifDepartamento de Astronomía y Astrofísica, linkPfeilExtern.gifUniversidad de Valencia, Spain)
Leonhard Scheck   
Florian Siebel
   (linkPfeilExtern.gifInstitut für Geographie, linkPfeilExtern.gifLudwig-Maximilians-Universität München, Germany)
Burkhard Zink
   (linkPfeilExtern.gifInstitute for Theoretical Physics, linkPfeilExtern.gifLouisiana State University, U.S.A.)

top Projects:

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

  • linkPfeilExtern.gifA Solution for the Nonuniqueness Problem of the Spacetime Constraint Equations

    I. Cordero-Carrión, P. Cerdá-Durán, 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.

  • linkPfeilExtern.gifSimulations of Rotational Stellar Core Collapse in General Relativity with Microphysics

    H. Dimmelmeier, C.D. Ott, H.-T. Janka, A. Marek, I. Hawke, B. Zink, E. Schnetter, E. Müller

    We have performed the first 2D and 3D simulations of rotating stellar core collapse to a neutron star in general relativity with microphysics. We have found that the resulting gravitational wave signals are much more generic than previously anticipated.

  • 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.

  • linkPfeilExtern.gifNonlinear Axisymmetric Pulsations of Rotating Relativistic Stars

    H. Dimmelmeier, N. Stergioulas, J.A. Font

    With the axisymmetric version of the linkPfeil.gif"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.

  • linkPfeilExtern.gifSynthetic Light Curves of BL Lac Objects

    P. Mimica, M.A. Aloy, E. Müller, W. Brinkmann

    For the first time we have performed a two-dimensional 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.

  • linkPfeilExtern.gifGravitational 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.

topComments to: Harald Dimmelmeier emailharrydee _at_