and – 2 – ABSTRACT Observations of ultraluminous infrared galaxies (ULIRGs) with an achieved resolution approaching the diffraction limit in the mid-infrared from 8-25 µm using the Keck Telescopes are reported. We find extremely compact structures, with spatial scales of < 0.3 ′′ (diameter) in six of the seven ULIRGs observed. These compact sources emit between 30% and 100% of the mid-infrared ...

Context. IGR J09026−4812 was discovered by INTEGRAL in 2006 as a new hard X-ray source. Thereafter, an observation with Chandra pinpointed a single X-ray source within the ISGRI error circle, showing a hard spectrum, and improving its high-energy localisation to a subarcsecond accuracy. Thus, the X-ray source was associated to the infrared counterpart 2MASS J09023731−4813339 whose JHKS photomet...

We present high-resolution infrared imaging of the massive star-forming region around the O-star Herschel 36. Special emphasis is given to a compact infrared source at 0. 25 southeast of the star. The infrared source, hereafter Her 36 SE, is extended in the broad–band images, but features spatially unresolved Br γ line emission. The line-emission source coincides in position with the previous H...

The mid-infrared emission at the center of IRAS 21026+4104 is not that of a simple compact source, as one would expect from an isolated high mass protostellar object. Furthermore the central thermal infrared emission does not appear to be coming directly from a circumstellar disk as has been recently hypothesized from near-infrared observations. The mid-infrared structure is complex, but with t...