Context. Early B-type stars are invaluable indicators of elemental abundances of their birth environments. In contrast to the surrounding neutral interstellar matter (ISM) and H ii regions, their chemical composition is unaffected by depletion onto dust grains and the derivation of different abundances from recombination and collisional lines. In

We present stellar population models for starbursts in a sample of eleven Wolf-Rayet galaxies. Taking into account the observational data available, we try to reconstruct the number of Wolf-Rayet stars observed and estimate the number of type II supernovae that have exploded in the ionizing cluster. Using the stellar yields of the most recent

Observational and theoretical evidence suggest that long gamma-ray bursts (GRBs) originate from the collapse of massive stars, while short bursts are caused by the coalescence of stellar compact objects. Finding direct evidence for both scenarios is challenging. Intriguingly, the afterglow evolution depends on the density profile of the circumburst

This article presents narrow-band Hα and [OIII] images of the interacting pair of galaxies NGC 5953 (with a Seyfert type 2 nucleus) and NGC 5954 (with a LINER). Long-slit spectroscopy, from [NeV] lambda3425A to [SIII] lambda9532A, at intermediate resolution along position angles 44 deg and 182 deg through the nucleus of NGC 5953, is also presented

We present results from near-infrared integral-field spectroscopy of the circumnuclear starburst in M83, using the CIRPASS instrument on Gemini South. The combination of Paβ, CO (6,3), and [Fe II] equivalent width measurements over large contiguous regions allows us to track the spatial propagation of star formation across the ringlet, which is too

Using deep NIR VLT ISAAC and optical HST WFPC2 imaging in the HDF-S and MS 1054-03, we study the rest-frame UV-to-optical colors and magnitudes of galaxies to z~3. Unlike the present day, there is no evidence for a red sequence at z~3, but there does appear to be a well-defined CMR for blue galaxies at all redshifts, with more luminous galaxies