We present new broadband optical and near-infrared CCD imaging together with deep optical intermediate-resolution spectroscopy of the Hickson Compact Group 31. We analyze the morphology and colors of the stellar populations of the galaxies, as well as the kinematics, physical conditions, and chemical composition of the ionized gas in order to get a

We present the results of optical and infrared photometry of the quiescent X-ray transient V404 Cyg during the period 1992-2003.

Modern kinematic diagnostics from high-S/N spectroscopy provide useful tests on the collisionless merger hypothesis for the formation of elliptical galaxies. Bender, Saglia & Gerhard (1994) show that the skewness of the line-of-sight velocity distributions (LOSVD) has opposite sign to the rotation velocity and follows a distinct pattern. Previous N

We present observations and 3D gasdynamic simulations of the jet and knots of the K 4-47 planetary nebula (PN) with the purpose of comparing the observed and predicted physical parameters. From the observations we obtain physical properties of different regions of the K 4-47 PN. We conclude that knots (K1 and K2) are produced by shocks while the

As part of a detailed study of the gas content in a sample of early-type galaxies, we present 21 cm H I line maps of the S0 galaxy NGC 404 at a spatial resolution of 15.2"'×14.4" (α×δ) and a velocity resolution of 2.6 km s-1. The H I has been traced out to a radius R~8R25 or 48 disk scale lengths, making it one of the largest H I extents reported

We have obtained deep near-infrared Ks-band William Herschel Telescope observations of a sample of 15 nearby spiral galaxies having a range of Hubble types and apparent bar strengths. The near-infrared light distributions are converted into gravitational potentials, and the maximum relative gravitational torques due to the bars and the spirals are