Stefanie Walch

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We present optical lightcurves and spectra of the afterglow of the gamma-ray burst (GRB) of February 18, 2006. GRB 060218 is a nearby long GRB which is clearly associated with a supernova – dubbed SN 2006aj. Our optical lightcurves define the rise times, the lightcurve shapes and the absolute magnitudes in the U , V and R bands, and we compare these data(More)
We present a three-dimensional, fully parallelized, efficient implementation of ionizing UV radiation for smoothed particle hydrodynamics (SPH) including self-gravity. Our method is based on the SPH/tree code VINE. We therefore call it iVINE (for Ioniza-tion + VINE). This approach allows detailed high-resolution studies of the effects of ionizing radiation(More)
We investigate the collapse and fragmentation of low-mass, trans-sonically turbulent prestellar cores, using SPH simulations. The initial conditions are slightly supercritical Bonnor-Ebert spheres, all with the same density profile, the same mass (M O = 6.1 M ⊙) and the same radius (R O = 17, 000 AU), but having different initial turbulent velocity fields.(More)
We present high resolution simulations on the impact of ionizing radiation of massive O-stars on the surrounding turbulent interstellar medium (ISM). The simulations are performed with the newly developed software iVINE which combines ionization with smoothed particle hydrodynamics (SPH) and gravitational forces. We show that radiation from hot stars(More)
We discuss spectral energy distributions of a sample of Herbig Ae/Be stars in the context of a passive irradiated disk model. The data have been presented earlier by Meeus et al. (2001), and preliminary interpretations of these data were given in that paper. While the spectra of Herbig Ae stars all show similarities, there is significant variation between(More)
The spatial segregation between dwarf spheroidal (dSph) and dwarf irregular galaxies in the Local Group has long been regarded as evidence of an interaction with their host galaxies. In this paper, we assume that ram-pressure stripping is the dominant mechanism that removed gas from the dSphs and we use this to derive a lower bound on the density of the(More)
  • D. A. Hubber, S. Walch, A. P. Whitworth
  • 2012
Numerical simulations of star formation frequently rely on the implementation of sink particles, (a) to avoid expending computational resource on the detailed internal physics of individual collapsing protostars, (b) to derive mass functions, binary statistics and clustering kinematics (and hence to make comparisons with observation), and (c) to model(More)