J. Lequeux

An atlas of mid-infrared dust emission in spiral galaxies

We present maps of dust emission at 7 ma nd 15m/7m intensity ratios of selected regions in 43 spiral galaxies observed with ISOCAM. This atlas is a complement to studies based on these observations, dealing with star formation in centers of barred galaxies and in spiral disks. It is accompanied by a detailed description of data reduction and an inventory of generic morphological properties in groups dened according to bar strength and HI gas content.

Results of the ESO-SEST Key Programme on CO in the Magellanic Clouds X. CO emission from star formation regions in LMC and SMC

We present J = 1 0a ndJ = 2 1 12 CO maps of several star-forming regions in both the Large and the Small Magellanic Cloud, and briefly discuss their structure. Many of the detected molecular clouds are relatively isolated and quite small with dimensions of typically 20 pc. Some larger complexes have been detected, but in all cases the extent of the molecular clouds sampled by CO emission is significantly less than the extent of the ionized gas of the star-formation region. Very little diuse extended CO emission was seen; diuse CO in between or surrounding the detected discrete clouds is either very weak or absent. The majority of all LMC lines of sight detected in 13 CO has an isotopic emission ratio I( 12 CO)=I( 13 CO) of about 10, i.e. twice higher than found in Galactic star-forming complexes. At the lowest 12 CO intensities, the spread of isotopic emission ratios rapidly increases, low ratios representing relatively dense and cold molecular gas and high ratios marking CO photo- dissociation at cloud edges.

Mid-IR emission of galaxies in the Virgo cluster and in the Coma supercluster IV. The nature of the dust heating sources

We study the relationship between the mid-IR (5-18

NO DIFFUSE H2 IN THE METAL-DEFICIENT GALAXY I Zw 18

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The CO to H-2 conversion factor in normal late-type galaxies

m) emission of late-type galaxies and various other star formation tracers in order to investigate the nature of the dust heating sources in this spectral domain. The analysis is carried out using a sample of 123 normal, late-type, nearby galaxies with available data at several frequencies. The mid-IR luminosity (normalized to the H-band luminosity) correlates better with the far-IR luminosity than with more direct tracers of the young stellar population such as the H

Abundance differences between the neutral and the ionized gas of the dwarf galaxy IZw 36

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Detection of CO emission from massive molecular clouds in the inner disk of M31

and the UV luminosity. The comparison of resolved images reveals a remarkable similarity in the H

Results of the ESO-SEST Key Programme on CO in the Magellanic Clouds. IX. The giant LMC HII region complex N 11

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Implications of the presence of deuterium in the galactic center

and mid-IR morphologies, with prominent HII regions at both frequencies. The mid-IR images, however, show in addition a diffuse emission not associated with HII regions nor with the diffuse H

A Search for the CO-H2 Dimer in the Galaxy

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