Measuring dark matter by modeling interacting galaxies (2009)
Petsch, H. P., Ruzicka, A., Theis, Ch
The dark matter content of galaxies is usually determined from galaxies in dynamical equilibrium, mainly from rotationally supported galactic components. Such determinations restrict measurements to...
A study of major mergers using a multi-phase ISM code (2009)
Weniger, J., Theis, Ch., Harfst, S.
Galaxy interactions are a common phenomenon in clusters of galaxies. Especially major mergers are of particular importance, because they can change the morphological type of galaxies. They have an...
Substructures formation induced by gravitational tides? (2009)
Renaud, F., Theis, Ch., Naab, T., Boily, C. M.
Physics lectures always refer to the tides as a disruptive effect. However, tides can also be compressive. When the potential of two galaxies overlap, as happens during a merger, fully compressive...
Star cluster survival and compressive tides in Antennae-like mergers (2008)
Renaud, F., Boily, C. M., Fleck, J. -J., Naab, T., Theis, Ch.
Gravitational tides are widely understood to strip and destroy galactic substructures. In the course of a galaxy merger, however, transient totally compressive tides may develop and prevent star...
Shape and orientation of stellar velocity ellipsoids in spiral galaxies (2007)
We present a numerical study of the properties of the stellar velocity distribution in stellar discs which have developed a saturated, two-armed spiral structure. We follow the growth of the spiral...
The early evolution of tidal dwarf galaxies (2007)
Recchi, S., Theis, Ch., Kroupa, P., Hensler, G.
Context: Dwarf galaxies can arise from self-gravitating structures emerging from tidal tails. What fraction of the known dwarf galaxies in the Local Universe can have this origin is still a matter of...
Early evolution of Tidal Dwarf Galaxies (2006)
Recchi, S., Kroupa, P., Theis, Ch., Hensler, G.
Our aim is to study the evolution of tidal dwarf galaxies. The first step is to understand whether a model galaxy without Dark Matter can sustain the feedback of the ongoing star formation. We...
Boltzmann moment equation approach for the numerical study of anisotropic stellar disks (2006)
We present the Boltzmann moment equation approach for the dynamics of stars (BEADS-2D), which is a finite-difference Eulerian numerical code designed for the modelling of anisotropic and...
Is the dark matter halo of the Milky Way flattened? (2006)
Ruzicka, A., Palous, J., Theis, Ch.
We performed an extended analysis of the parameter space for the interaction of the Magellanic System with the Milky Way (MW). The varied parameters cover the phase space parameters, the masses, the...
On stability and spiral patterns in polar disks (2005)
Theis, Ch., Sparke, L., Gallagher, J.
To investigate the stability properties of polar disks we performed two-dimensional hydrodynamical simulations for flat polytropic gaseous self-gravitating disks which were perturbed by a central...
Are galactic disks dynamically influenced by dust? (2004)
Dynamically cold components are well known to destabilize hotter, even much more massive components. In this paper we studied the dynamical influence of a cold dust component on the gaseous phase in...
G. Hensler, Ch. Theis, J. S. Gallagher
Abstract. Here we present as an extension to already published models of massive spherical galaxies one-dimensional chemodynamical models of dwarf elliptical galaxies in the mass range between 10 9...
Physical Processes in Star-Gas Systems (2003)
Spurzem, R., Berczik, P., Hensler, G., Theis, Ch., Amaro-Seoane, P., Freitag, M., ...
First we present a recently developed 3D chemodynamical code for galaxy evolution from the K**2 collaboration. It follows the evolution of all components of a galaxy such as dark matter, stars,...
M51 revisited: a genetic algorithm approach of its interaction history (2003)
Detailed models of observed interacting galaxies suffer from the extended parameter space. Here, we present results from our code MINGA which couples an evolutionary optimization strategy (a genetic...
Star Formation in a Multi-Phase ISM (2003)
Harfst, S., Theis, Ch., Hensler, G.
We present a 3d code for the dynamical evolution of a multi-phase interstellar medium (ISM) coupled to stars via star formation (SF) and feedback processes. The multi-phase ISM consists of clouds...
Chemo-dynamical Evolution of the ISM in Galaxies (2003)
Harfst, S., Hensler, G., Theis, Ch.
Chemo-dynamical models have been introduced in the late eighties and are a generally accepted tool for understanding galaxy evolution. They have been successfully applied to one-dimensional problems,...
A Multi-Phase Chemo-Dynamical SPH Code for Galaxy Evolution (2003)
Berczik, P., Hensler, G., Theis, Ch., Spurzem, R.
In this paper we present some test results of our newly developed Multi-Phase Chemo-Dynamical Smoothed Particle Hydrodynamics (MP- CD-SPH) code for galaxy evolution. At first, we present a test of...
Chemodynamical Modeling of Dwarf Galaxy Evolution (2002)
Berczik, P., Hensler, G., Theis, Ch., Spurzem, R.
We present our recently developed 3-dimensional chemodynamical code for galaxy evolution. It follows the evolution of all components of a galaxy such as dark matter, stars, molecular clouds and...
Chemodynamical Modelling of Galaxy Formation and Evolution (2001)
Berczik, P., Hensler, G., Theis, Ch., Spurzem, R.
We present our recently developed 3-dimensional chemodynamical code for galaxy evolution. This code follows the evolution of different galactic components like stars, dark matter and different...
The merger stage of the ultra-luminous infrared galaxy IRAS 03158+4227 (2001)
Meusinger, H., Stecklum, B., Theis, Ch., Brunzendorf, J.
We examine the merger stage of IRAS 03158+4227, one of the most luminous ULIRGs from the IRAS 2 Jy sample. Deep optical images are presented along with high-resolution NIR images and optical...
Galaxies and Genes: Towards an Automatic Modeling of Interacting Galaxies (2001)
Theis, Ch., Gerds, Ch., Spinneker, Ch.
The main problems in modeling interacting galaxies are the extended parameter space and the fairly high CPU costs of self-consistent N-body simulations. Therefore, traditional modeling techniques...
On the evolution of shape in N-body simulations (1998)
A database on shape evolution of direct N-body models formed out of cold, dissipationless collapse is generated using GRAPE and HARP special purpose computers. Such models are important to understand...
On the puzzling origin of the rare In and Sn isotopes. (1998)
Theis, Ch., Käppeler, F., Wisshak, K., Voss, F.
The Astrophysical Journal, 500(1998) S.1039-48
Condensation and Evaporation of Interstellar Clouds in Chemodynamical Models of Galaxies (1997)
K"oppen, J., Theis, Ch., Hensler, G.
The network of interactions between hot gas, cool clouds, massive stars, and stellar remnants used in the chemodynamical modeling of the interstellar medium is investigated for the types of its...
Fragmentation of Expanding Shells in Spiral and Irregular Galaxies (1997)
Ehlerova, S., Palous, J., Theis, Ch., Hensler, G.
Conditions for the fragmentation of expanding shells due to gravitational instability are discussed. The self-similar analytical solution is compared with the results of 3-dimensional computer...
Stellar neutron capture cross sections of the tin isotopes. (1997)
Wisshak, K., Voss, F., Theis, Ch., Käppeler, F., Guber, K., Kazakov, L., ...
Quaim, S.M. [Hrsg.]
Stellar neutron capture cross sections of the tin isotopes. (1996)
Wisshak, K., Voss, F., Theis, Ch., Käppeler, F., Guber, K., Kazakov, L., ...
Physical Review C, 54(1996) S.1451-62
Stellar neutron capture cross sections of the tin isotopes. (1995)
Wisshak, K., Voss, F., Theis, Ch., Käppeler, F., Guber, K., Kazakov, L., ...
Wissenschaftliche Berichte, FZKA-5603 (August 95)
The s-abundances of the tin isotopes. (1994)
Wisshak, K., Theis, Ch., Guber, K., Voss, F., Käppeler, F., Kazakov, L., ...
Somorjai, E. [Hrsg.]
Nucleosynthesis in the Cd-In-Sn region. (1993)
Nemeth, Zs., Belgya, T., Yates, S.W., Theis, Ch., Kaeppeler, F.
Kaeppeler, F.; Wisshak, K. [Hrsg.]
Stellar(n,#g)cross sections of the tin isotopes. (1993)
Wisshak, K., Kaeppeler, F., Kazakov, L., Kornilov, N., Theis, Ch., Voss, F.
In: Quaim, S.M. [Hrsg.]