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We present 10−15 µm spectra of a sample of H ii regions, YSOs and evolved stars that show strong unidentified infrared emission features, obtained with the ISO/SWS spectrograph on-board ISO. These spectra reveal a plethora of emission features with bands at 11.0, 11.2, 12.0, 12.7, 13.5 and 14.2 µm. These features are observed to vary considerably in(More)
The Infrared Space Observatory (ISO) has provided the first complete mid-IR spectra for a wide range of objects. Almost all of these spectra are dominated by the well-known infrared emission features at 3.3, 6.2, 7.7, and 11.2 µm, the so-called Unidentified Infra-Red (UIR) features. Besides the major features, there is an array of minor features and broad(More)
Sulphur is depleted in cold dense molecular clouds with embedded young stellar objects, indicating that most of it probably resides in solid grains. Iron sulphide grains are the main sulphur species in cometary dust particles, but there has been no direct evidence for FeS in astronomical sources, which poses a considerable problem, because sulphur is a(More)
We report far-infrared and submillimeter observations of supernova 1987A, the star whose explosion was observed on 23 February 1987 in the Large Magellanic Cloud, a galaxy located 160,000 light years away. The observations reveal the presence of a population of cold dust grains radiating with a temperature of about 17 to 23 kelvin at a rate of about 220(More)
With appropriate spatial resolution, images of spiral galaxies in thermal infrared (∼10 μm and beyond) often reveal a bright central component, distinct from the stellar bulge, superimposed on a disk with prominent spiral arms. ISO and Spitzer studies have shown that much of the scatter in the mid-infrared colors of spiral galaxies is related to changes in(More)
Aims. We present clumps of dust emission from Herschel observations of the Large Magellanic Cloud (LMC) and their physical and statistical properties. We catalog cloud features seen in the dust emission from Herschel observations of the LMC, the Magellanic type irregular galaxy closest to the Milky Way, and compare these features with H i catalogs from the(More)
We have obtained 2.5–45 µm spectra of a sample of compact H ii regions, YSOs and evolved stars in order to study the origin and evolution of interstellar Polycyclic Aromatic Hydrocarbon molecules (PAHs). Besides the well–known, strong PAH bands at 3.3, 6.2, 7.7, 8.6, and 11.2 µm, these spectra reveal for the first time, a ubiquitous emission plateau from 15(More)
The carrier of the " 30 " µm emission feature in evolved stars ⋆ Abstract. We present 2−45 µm spectra of a large sample of carbon-rich evolved stars in order to study the " 30 " µm feature. We find the " 30 " µm feature in sources in a wide range of sources: low mass loss carbon stars, extreme carbon-stars, post-AGB objects and planetary nebulae. We extract(More)
We report the discovery of a double ring structure in the waist of the nebula surrounding η Carinae. The rings are detected in the mid-IR dust continuum at wavelengths of 7.9, 11.9, 12.9 and 20 µm. The dust in the rings has a temperature of about 300 K. The orientation of the rings is inclined with respect to the axis of the homunculus by either 37 or 58(More)
The profiles of the 3 to 12 µm PAH features 1. ABSTRACT We present spectra of the 3.3 µm and 11.2 µm PAH features of a large number of stellar sources, planetary nebulae, reflection nebulae, H II regions and galaxies, obtained with ISO-SWS. Clear variations are present in the profiles of these features. Most of the sources show a symmetric 3.3 µm feature(More)