Pascal Gallais

MegaCam: the new Canada-France-Hawaii Telescope wide-field imaging camera

MegaCam is an imaging camera with a 1 square degree field of view for the new prime focus of the 3.6 meter Canada-France-Hawaii Telescope. This instrument will mainly be used for large deep surveys ranging from a few to several thousands of square degrees in sky coverage and from 24 to 28.5 in magnitude. The camera is built around a CCD mosaic approximately 30 cm square, made of 40 large thinned CCD devices for a total of 20 K x 18 K pixels. It uses a custom CCD controller, a closed cycle cryocooler based on a pulse tube, a 1 m diameter half-disk as a shutter, a juke-box for the selection of the filters, and programmable logic controllers and fieldbus network to control the different subsystems. The instrument was delivered to the observatory on June 10, 2002 and first light is scheduled in early October 2002.

Mid-Infrared observations of NGC 1068 with the Infrared Space Observatory

We report on Mid-Infrared (MIR) observations of the Seyfert 2 galaxy NGC 1068, obtained with ISOCAM in low-resolution spectro-imaging mode. The spatial resolution (around 5 arcsec) allows us to disentangle the circumnuclear starburst regions from the emission of the active galactic nucleus (AGN). The global spatial distribution of the Unidentified Infrared Bands (UIBs) is similar to the cold dust component, traced by the 450 microns emission and the gaseous component obtained from the CO(1-0) map. However, a shift between the maximum of the UIB and 450 microns emission is clearly seen in our maps. The UIBs in the MIR (5-16 microns) originate almost exclusively from the starburst regions in the galactic disk with an emission peaking at the extremity of the stellar/ gaseous bar at a distance of 1 kpc from the AGN. The spectrum of the nucleus is characterized over the whole 5-16 microns range by a strong continuum which can be fitted with a power law of index -1.7. Moreover, the high [NeIII]/[NeII] ratio (>2.5) in the nuclear region argues for a hard radiation field from the AGN. Observations indicate that the AGN in NGC 1068 contributes less than 5% to the total integrated UIB emission even though its hot dust continuum contributes as much as 75% to the total MIR flux. On the contrary, the nuclear contribution to the cold dust emission decreases considerably at submillimeter wavelengths and does not represent more than 25% of the total integrated emission at 450 microns.We report on Mid-Infrared (MIR) observations of the Seyfert 2 galaxy NGC 1068, obtained with ISOCAM in low-resolution spectro-imaging mode. The spatial resolution (∼5′′) allows us to disentangle the circumnuclear starburst regions from the emission of the active galactic nucleus (AGN). The global spatial distribution of the Unidentified Infrared Bands (UIBs) is similar to the cold dust component, traced by the 450μm emission and the gaseous component obtained from the CO(1–0) map. However, a shift between the maximum of the UIB and 450μm emission is clearly seen in our maps. The UIBs in the MIR (5–16 μm) originate almost exclusively from the starburst regions in the galactic disk with an emission peaking at the extremity of the stellar/gaseous bar at a distance of 1 kpc from the AGN. The spectrum of the nucleus is characterized over the whole 5–16μm range by a strong continuum which can be fitted with a power law of index α = −1.7. Moreover, the high [NeIII]/[NeII] ratio (> ∼ 2.5) in the nuclear region argues for a hard radiation field from the AGN. Observations indicate that the AGN in NGC 1068 contributes less than ∼5% to the total integrated UIB emission even though its hot dust continuum contributes as much as 75% to the total MIR flux. On the contrary, the nuclear contribution to the cold dust emission decreases considerably at submillimeter wavelengths and does not represent more than 25% of the total integrated emission at 450μm.

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.

ISOCAM view of the starburst galaxies M 82, NGC 253 and NGC 1808

We present results of mid-infrared

Dust Temperatures in the Infrared Space Observatory Atlas of Bright Spiral Galaxies

\lambda = 5.0

Mid-infrared observations of the ultraluminous galaxies IRAS 14348-1447, IRAS 19254-7245, and IRAS 23128-5919

–

The impact of bars on the mid-infrared dust emission of spiral galaxies: global and circumnuclear properties ?

16.5~\mathrm{\mu m}

An Infrared Space Observatory Atlas of Bright Spiral Galaxies

spectrophotometric imaging of the starburst galaxies M 82, NGC 253, and NGC 1808 from the ISOCAM instrument on board the Infrared Space Observatory . The mid-infrared spectra of the three galaxies are very similar in terms of features present. The

Extended mid-infrared emission from VV 114: Probing the birth of a ULIRG

\lambda \ga 11~\mathrm{\mu m}

The Mid-IR view of interacting galaxies

continuum attributed to very small dust grains (VSGs) exhibits a large spread in intensity relative to the short-wavelength emission. We find that the 15