Spectroscopic observations obtained with the VLT of one planetary nebula (PN) in Sextans A and of five PNe in Sextans A and of several H ii regions in these two dwarf irregular galaxies are presented. The extended spectral coverage, from 320.0 to 1000.0 nm, and the large telescope aperture allowed us to detect a number of emission lines, covering

Context. Main-sequence massive stars embedded in an H ii region should have the same chemical abundances as the surrounding nebular gas+dust. The Cocoon nebula (IC 5146), a close-by Galactic H ii region ionized by a narrow line B0.5 V single star (BD+46 3474), is an ideal target to compare nebular and stellar abundances in detail in the same

New narrow-band images of NGC 4151, taken in excellent seeing conditions with the 4.2-m William Herschel Telescope are presented. These reveal a wealth of detail that can be used to test models for the anisotropy of the narrow-line region. From forbidden O III (4959, 5007)/H-alpha line ratio map, three important features are identified: (1) a jet

Hierarchical models predict that massive early-type galaxies (mETGs) derive from the most massive and violent merging sequences occurred in the Universe. However, the role of wet, mixed, and dry major mergers in the assembly of mETGs is questioned by some recent observations. We have developed a semi-analytical model to test the feasibility of the

Aims:We present multiwavelength (X-ray/optical/near-infrared/millimetre) observations of GRB 051022 between 2.5 h and 1.15 yr after the event. It is the most intense gamma-ray burst ( 10-4 erg cm-2) detected by HETE-2, with the exception of the nearby GRB 030329. Methods: Optical and near infrared observations did not detect the afterglow despite a

Aims.As part of the DART project we have used the ESO/2.2m Wide Field Imager in conjunction with the VLT/FLAMES GIRAFFE spectrograph to study the detailed properties of the resolved stellar population of the Fornax dwarf spheroidal galaxy out to and beyond its tidal radius. Fornax dwarf spheroidal galaxy has had a complicated evolution and contains