399 citations
Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.
- Observatoire astronomique de StrasbourgFR20 papers
- Christian-Albrechts-Universität zu KielDE14 papers
- Centre National de la Recherche ScientifiqueFR7 papers
- Infrared Processing and Analysis CenterUS7 papers
- Leiden UniversityNL7 papers
- Max Planck Institute for AstronomyDE7 papers
- Université de StrasbourgFR7 papers
- University of BonnDE7 papers
- University of HertfordshireGB7 papers
- Agenzia Spaziale ItalianaIT6 papers
- Aix-Marseille UniversitéFR6 papers
- Astronomical Observatory of CapodimonteIT6 papers
9 papers · 1 filter
Gas stripping in galaxy clusters: a new SPH simulation approach
P. Jachym, J. Palous, J. Koppen +1
The influence of a time-varying ram pressure on spiral galaxies in clusters is explored with a new simulation method based on the N-body SPH/tree code GADGET. We have adapted the c…
A Possible Origin of the Mass-Metallicity Relation of Galaxies
J. Koeppen, C. Weidner, P. Kroupa
Observations show that galaxies follow a mass-metallicity relation over a wide range of masses. One currently favoured explanation is that less massive galaxies are less able to re…
Chemical compositions and plasma parameters of planetary nebulae with Wolf-Rayet and wels type central stars
P. Girard, J. Koppen, A. Acker
Aims: Chemical compositions and other properties of planetary nebulae around central stars of spectral types [WC], [WO], and wels are compared with those of `normal' central stars,…
Effects of episodic gas infall on the chemical abundances in galaxies
J. Köppen, G. Hensler
The chemical evolution of galaxies that undergo an episode of massive and rapid accretion of metal-poor gas is investigated with models using both simplified and detailed nucleosyn…
PFP 1: A Large Annular Planetary Nebula Caught in the First Stages of ISM Interaction
M. J. Pierce, D. J. Frew, Q. A. Parker
This paper presents (H-alpha + [NII]) imaging and spectroscopy of a previously unknown, highly evolved planetary nebula of low excitation. It was discovered serendipitously from AA…
An inverse method to interpret colour-magnitude diagrams
Jean-Luc Vergely, Joachim Koeppen, Daniel Egret +1
An inverse method is developed to determine the star formation history, the age-metallicity relation, and the IMF slope from a colour-magnitude diagram. The method is applied to th…
On The Cosmic Origins Of Carbon And Nitrogen
R. B. C. Henry, M. G. Edmunds, J. Koeppen
We analyze the behavior of N/O and C/O abundance ratios as a function of metallicity as gauged by O/H in large, extant Galactic and extragalactic H II region abundance samples. Num…
Keck Spectra of Brown Dwarf Candidates and a Precise Determination of the Lithium Depletion Boundary in the Alpha Persei Open Cluster
J. R. Stauffer, D. Barrado y Navascués, J. Bouvier +8
We have identified twenty-seven candidate very low mass members of the relatively young Alpha Persei open cluster from a six square degree CCD imaging survey. Based on their I magn…
Chemical Evolution of Dwarf Irregular Galaxies - chemodynamical models and the effect of gas infall
Gerhard Hensler, Andreas Rieschick, Joachim K"oppen
Because of their low gravitational energies dwarf galaxies are greatly exposed to energetical influences by the interstellar medium, like e.g. stellar radiation, winds or explosion…