We report the results of an HST survey of 17 AGN, selected solely for having a well developed radio jet bright enough to be detectable with HST for a normal radio-to-optical spectral index. It is found that optical jets are much more common then expected, been detected in ˜30% of the cases. The data are then combined with Chandra X-ray and VLA

Not Available

We consider the Orion Nebula (M 42) within a project aimed at studying the interaction between massive stars and their surrounding ISM. This is an HII region ionized by θ1 Ori C, one of the four massive stars in the Trapezium Cluster. θ1 Ori C has the earliest spectral type (O7Vp) among them, emitting an ionizing flux several orders of magnitude

It is often stated that there is no point in obtaining mid-infrared data with S/N>20, even in the best of cases, because it is impossible to obtain a calibration to better than 5%, although in many cases 10% or greater is a more accurate reflection of the true quality of calibration. Mid-infrared calibration is difficult because of the lack of

Not Available

In a recent paper (Crivellari et al., 2003) we summarized the principles of the algorithmic representation of the structure of a stellar atmosphere. We mentioned there our recent progresses in the numerical treatment of both the global method and the basic components of the corresponding models. As the natural sequel to that paper, we wish to