Non-axisymmetric features such as bars drive the dynamical and secular evolution of disk galaxies by exerting gravitational torques which redistribute mass and angular momentum. While most (> 70 %) spirals are barred in the local Universe, early studies of the Hubble Deep Field (HDF) suggest a remarkably low bar fraction ( 20 %) at intermediate

We have compiled and studied photometric and spectroscopic data published in the literature of several star-forming regions and young open clusters (Orion, Taurus, IC 348, Sco-Cen complex, Chamaeleon I, TW Hydrae association, σ Orionis cluster, IC 2391, α Persei cluster, and the Pleiades). Our goal was to seek the definition of a simple empirical

We report the detection with the BeppoSAX Wide Field Cameras of a superburst from 4U 1254-69. The superburst is preceded by a normal type-I X-ray burst, has a decay time that is the longest of all eight superbursts detected so far and a peak luminosity that is the lowest. Like for the other seven superbursts, the origin is a well-known type-I X-ray

Recent star count surveys of areas around globular star clusters have shown strong evidence of tidal tails stretching out many degrees beyond the cluster tidal radius. These tails are believed to be cluster stars which have escaped due to tidal shocking after passages through the disk of the Galaxy. Although the statistical star counts indicate and

The structure and evolution of the Milky Way is imprinted on the kinematics, chemical abundances, and spatial distribution of its constituent stars. In the past, samples of stars in the halo and thick disk have primarily been selected either on the basis of their kinematics (e.g., proper-motion selection), their distinct abundances (e.g., objective

We present a detailed morphological, photometric, and kinematic analysis of two barred S0 galaxies with large, luminous inner disks inside their bars. We show that these structures, in addition to being geometrically disklike, have exponential profiles (scale lengths ~300-500 pc) distinct from the central, nonexponential bulges. We also find them