Didier Tiphene

DENIS: A DEEP NEAR-INFRARED SURVEY OF THE SOUTHERN SKY

The DENIS project is the first attempt to carry out a complete digitized survey of the southern sky in the range 1–2.5µm. The main objectives of the programme and the main specifications of the camera and of the data processing stream are briefly outlined

First DENIS I-band extragalactic catalog

This paper presents the rst I-band photomet- ric catalog of the brightest galaxies extracted from the Deep Near Infrared Survey of the Southern Sky (DENIS) An automatic galaxy recognition program has been de- veloped to build this provisional catalog. The method is based on a discriminating analysis. The most discrimi- nant parameter to separate galaxies from stars is proved to be the peak intensity of an object divided by its ar- ray. Its eciency is better than 99%. The nominal ac- curacy for galaxy coordinates calculated with the Guide Star Catalog is about 6 arcsec. The cross-identication with galaxies available in the Lyon-Meudon Extragalactic DAtabase (LEDA) allows a calibraton of the I-band pho- tometry with the sample of Mathewson et Al. Thus, the catalog contains total I-band magnitude, isophotal di- ameter, axis ratio, position angle and a rough estimate of the morphological type code for 20260 galaxies. The internal completeness of this catalog reaches magnitude Ilim =1 4 :5, with a photometric accuracy of 0:18 m. 25% of the Southern sky has been processed in this study. This quick look analysis allows us to start a radio and spectrographic follow-up long before the end of the survey.

VIRTIS-H: a high-spectral-resolution channel for the Rosetta infrared imaging spectrometer

VIRTIS, the infrared imaging spectrometer of the ESA/ROSETTA mission, to be launched in January 2003, is devoted to the in-orbit remote sensing study of comet P/46 Wirtanen. Within the infrared imaging spectrometer VIRTIS, the high spectral resolution channel, VIRTIS-H, has for main scientific objectives to study the fine spectral details of the coma and cometary nucleus, with their composition and physical parameters, in parallel with the imaging spectrometer channel VIRTIS-M. The instrument is a cross-dispersor spectrometer, working in the range 2 - 5 micrometers , at about approximately 1200 spectral resolving power. Its design consists of a telescope, an entrance slit, followed by a collimator, and a prism separating 8 orders of a grating

Virtis-H: an infrared spectrometer for the Rosetta mission -- calibration results

Virtis-H is the high spectral resolution channel of the visible and infrared imaging spectrometer VIRTIS, an instrument of the ESA/ROSETTA mission devoted to the in-orbit remote sensing study of the comet P/46 Wirtanen. After successful tests and calibration, the flight model has been delivered to the European Space Agency for integration on the satellite before the launch foreseen in January 2003. The Virtis-H channel is a cross-dispersion spectrometer in the spectral range 2-5um with a resolution between 1200 and 3000. Its design consists in an afocal telescope-collimator off-axis parabola mirrors, a prism-grating system performing the cross-dispersion, and a three-lens objective imaging the entrance slit on a 436x270 HgCdTe array from Raytheon/IRCOE. At each recorded image, a full spectrum of the observed scene is reconstructed allowing the study of the fine spectral details of the coma and the cometary nucleus. The calibration have shown the fully compliance of the instrument performances with the simulations in terms of spectral resolution, radiometric accuracy and sensibility. For example, spectra of gas, water ice and mineral powders have been measured with Virtis-H showing either its ability to resolve fine spectral lines but also its sensitivity to low fluxes; furthermore, measurements on a 250K blackbody shows its sensibility to relative temperature variation lower than 0.5oC..

Camera of the Infrared Space Observatory

The Infrared Space Observatory (ISO) camera (ISOCAM) is designed to map selected regions of the sky in the spectral region from 2.5 to 17 μm at various spatial and spectral resolutions and at high sensitivity (at >4 μm, <1 mJy/10 s in 200 5). It will make images, within the 3-arcmin field of view of the ISO telescope, with two 32 x 32 IR array detectors: an InSb charge injection device (CID) for the 2.5- to 5.5-μm range and a Si:Ga direct voltage readout for the 4- to 17-μm range. Four different pixel fields of view are available on each channel: 1.5, 3, 6, and 12 arcsec. The spectral range can be selected in each channel by a set of about 10 fixed bandpass filters (resolution from 2 to 100) and continuous variable filters (resolution ≈45); polarization measurements are possible as well. A very wide range of astrophysical problems can be tackled with ISOCAM. We present a brief description of the program planned by the ISOCAM team.

Development of ISOCAM: the camera of the Infrared Space Observatory

ISOCAM, the camera of the Infrared Space Observatory, will image the sky at various angular and spectral resolutions in the wavelength range 2.5 to 17 microns. We recall the main steps of the development, leading to the delivery of the flight model to ESA, and we outline some of the scientific programs to which it will be applied.

French SWIR technology used for astronomy

During the last 30 years, the Space Research Department (DESPA) of Paris Observatory has developed infrared instrumentation for space and ground-based telescopes. First, we present the PbS linear detector of the ISM IR imaging spectrometer of the Phobos mission. Then the CID InSb focal plane of ISOCAM-SW is described. The studies of this CID InSb focal plane allowed us to develop an IR camera for the first astronomical observations using adaptive optics. We also describe the linear array built for the OMEGA imaging spectrometer of the Mars 96 mission. The last chapter is dedicated to the IR spectrometer of the Huygens probe. To conclude, the needs and challenges in the area of mid-band infrared astronomy are discussed.

Searching for Low-Mass Stars with DENIS. Preliminary Results on a Star Forming Region: Orion

DENIS is aimed at mapping for the first time the entire southern sky at near-infrared wavelengths (1 to 2. 5μm). The usefulness of this survey in the search for low mass stars is discussed, and we present some preliminary results for the Orion Nebula, from the initial DENIS images at J and K S bands, obtained during the commissioning of the camera.

First Results Obtained with Denis

We briefly report on the first astronomical results obtained with the DENIS camera at the ESO 1 meter telescope.