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

The Spectral and Photometric Imaging Receiver on-board Herschel has been carrying out deep extragalactic surveys, one of the aims of which is to establish spectral energy distributions of individual galaxies spanning the infrared/submillimetre (IR/SMM) wavelength region. We report observations of the IR/SMM emission from the Lockman North field and

We have observed the planetary nebula NGC 2440 in the transitions [O II] λ3727, He II λ4686, [O III] λλ(4363+5007), H I λλ(4861+6563), He I λ5876, [N II] λ6584, [S II] λλ(6717+6731), and [S III] λ9061, as well as in various continuum filters. As a result, we are able to evaluate the excitation structure of the source and determine the projected