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We present observations done with the OASIS instrument and the PUEO adaptive optics system at the Canada-France-Hawaii Telescope. By combining the measurements of Z Canis Majoris photocenter versus wavelength with a model for the system, the spectra of each component was recovered. Its microjet is driven by the embedded Herbig Ae/Be star and found compatible with the 1987 outburst. The kinematics and excitation of RW Aurigae micro-jet are presented, terminal velocities are smaller than those predicted by disk winds, excitation is found compatible with shocks. Two micro-jets (N-S and E-W) are detected in R Monocerotis, they are associated with R Mon A and B respectively. The east-west jet is redshifted. The blueshifted lobe is assumed hidden behind the nebula. We speculate that this lobe is the cause of the nebula variability. The scattered H line profiles is found to vary across the nebula, due to alt-azimuthally dependent line emission (or absorption by orbiting material). Finally,ablueshifted Herbig-Haro object withaelectron density of ~ 2000 cm3 is discovered near FU Orionis, its dynamical scale being compatible with the 1937-39 outburst.

The James Webb Space Telescope (JWST) is a passively cooled, 6.5m aperture class telescope, optimized for diffraction-limited performance in the near-infrared wavelength region (1 - 5 μm). JWST will be capable of high-resolution imaging and spectroscopy and will carry a scientific payload consisting of three scientific instruments. One of the instruments - NIRSpec - is a near-infrared, multi-object, dispersive spectrograph, which will be provided by ESA. EADS Astrium and its subcontractors have been involved in all ESA instrument studies for JWST. The actual NIRSpec design has evolved during three years of studying of different spectrometer design and performance options. Basic feature of the current design is the all ceramic material concept for the instrument structure and mirror optics; both were successfully tested on component level. This paper presents our NIRSpec design concept and its predicted performance.

We propose to implement an Integral-Field Unit (IFU) mode in the near-infrared spectrograph NIRSpec of the future James Webb Space Telescope (JWST), instrument under the responsibility of the European Space Agency (ESA). The IFU mode will provide unique additional scientific capabilities, complementary to those of the main multi-object mode of NIRSpec. It would cover a 3"x3" field of view with a 0.075" sampling and make use of the R=3000 spectral configurations of NIRSpec, covering the complete 1.0-5.0 microns range in three shots. First performance simulations yield a limiting AB magnitude of 24 for a point-like source. On the technical side, the IFU is based on the advanced image slicer concept and would include a stack of forty 900 μm thick, slicing mirrors. We are currently conducting a prototyping work funded by ESA, aiming at demonstrating a TRL6 readiness level for this technology (see presentation by F. Laurent). We present the optical design of the IFU, the strategy used during its definition (minimum impact on NIRSpec), as well as the proposed implementation within the NIRSpec instrument. We will stress that, this currently optional mode is a unique opportunity to provide JWST with a powerful integral field mode at marginal costs.

In the frame of an European Space Agency (ESA) contract, a consortium of three European research institutes (Laboratoire d'Astrophysiqu de Marseille, Centre de Recherche Astronomique de Lyon and the University of Durham) and the Cybernetix company have designed, manufactured and tested a prototype of an Integral Field Unit (IFU) for the NIRSpec instrument of the future James Webb Space Telescope (JWST). After a brief presentation of the optical design of this prototype, which is based on the advanced slicer concept, we will focus on the optical tests of this prototype. We will first present the tests peformed at LAM on the individual optical elements prior to their integration in the mechanical structure, as well as the alignment tests conducted as part of the integration procedure. We will then describe the tests and their results in the visible of the complete IFU system both at room temperature (tests performed at CRAL) and at operating temperature (30 K, tests peformed at the University of Durham). Briefly, these tests included: measurements of the characteristics (position, shape, size ...) of the pseudo-slit of the IFU prototype; measurement of the point-spread-function at different locations within its field of view; and measurement of the position, shape and size of the exit pupils. Last, we will conclude on the TRL6 readiness of the advanced image slicer technique and we will provide a glimpse of how wide-spread this technique is becoming both for ground- and space-based applications.

A group of European Research Institutes (Centre de Recherche Astronomique de Lyon (CRAL), Laboratoire d'Astrophysique de Marseille (LAM), University of Durham) and company (CYBERNETIX) have proposed to implement an Integral Field Unit (IFU) in NIRSpec instrument for the James Webb Space Telescope (JWST). After a brief presentation of the optical design of NIRSpec IFU, we will focus on the prototype of this module built by CRAL. This prototype is composed of two optical elements: a stack of eleven spherical tilted slices associated with a row of ten spherical tilted pupil mirrors. All the optical elements were manufactured by CYBERNETIX. We will introduce the fabrication procedures and an original method of assembling by molecular adhesion in order to comply with environment specifications. Afterwards, the image slicer is tested on the optical bench at CRAL. In fact, the first measure consists in placing a CCD camera in the pupil mirrors plane and determining the characteristics of the eleven images of the telescope pupil such as sizes, positions, photometric quality, diffraction effects and angular errors on slices and comparing these results with specifications. Then, the row of pupil mirrors is installed on the optical bench. In the slit mirrors plane, we observe a pseudo slit (ten images of the slices). We establish the same characteristics as in the first measure. Moreover, in the same plane, some Point Spread Function (PSF) measurements are made and we analyse the PSF in comparison with the simulation. The main results of the tests of the first image slicer prototype are presented. With the exploitation of the results, we validate and improve the image slicer systems for others instruments such as Multi Unit Spectroscopic Explorer (MUSE, study of a second generation instrument for the European Very Large Telescope (VLT)) and the European Space Agency (ESA) Integral Field Spectrograph (IFS) prototype.

We present a summary of high-spatial resolution follow-up observations of the elliptical (E) and lenticular (S0) galaxies in the SAURON survey using the OASIS integral field spectrograph. The OASIS observations explore the central 8x10" regions of these galaxies using a spatial sampling four times higher than SAURON, often revealing previously undiscovered features. Around 75% (31/48) of the SAURON E/S0s with central velocity dispersion >= 120 km/s were observed with OASIS, covering well the original SAURON representative sample. We present here an overview of this follow-up survey, and some preliminary results on individual objects, including a previously unreported counter-rotating core in NGC 4382; the decoupled stellar and gas velocity fields of NGC 2768; and the strong age gradient towards the centre of NGC 3489., 4 pages, 5 figures. Accepted for publication in Astron. Nachr. as refereed proceedings of Euro3D Science Workshop, IoA Cambridge, May 2003

The Multi Unit Spectroscopic Explorer (MUSE) is a second generation VLT panoramic integral-field spectrograph operating in the visible wavelength range. MUSE has a field of 1x1 arcmin(2) sampled at 0.20.2 arcsec(2) and is assisted by a ground layer adaptive optics system using four laser guide stars. The simultaneous spectral range is 0.465-0.93 mum, at a resolution of Rsimilar to3000. MUSE couples the discovery potential of a large imaging device to the measuring capabilities of a high-quality spectrograph, while taking advantage of the increased spatial resolution provided by adaptive optics. This makes MUSE a unique and tremendously powerful instrument for discovering and characterizing objects that lie beyond the reach of even the deepest imaging surveys. MUSE has also a high spatial resolution mode with 7.5x7.5 arcsec(2) field of view sampled at 25 milli-arcsec. In this mode MUSE should be able to get diffraction limited data-cube in the 0.6-1 mum wavelength range. Although MUSE design has been optimized for the study of galaxy formation and evolution, it has a wide range of possible applications; e.g. monitoring of outer planets atmosphere, young stellar objects environment, supermassive black holes and active nuclei in nearby galaxies or massive spectroscopic survey of stellar fields.

The Multi Unit Spectroscopic Explorer (MUSE) is a second-generation instrument in development for the Very Large Telescope (VLT) of the European Southern Observatory (ESO), due to begin operation in 2011/12. MUSE will be an extremely powerful integral-field spectrograph fed by a new multiple-laser adaptive optics system on the VLT. In its usual operating mode, MUSE will, in a single observation, produce a 3-dimensional data cube consisting of 90,000 R 3000 spectra, each covering a full spectral octave (480-930 nm), and fully sampling a contiguous 1×1 arcmin2 field with 0.2×0.2 arcsec2 apertures. A high-resolution mode will increase the spatial sampling to 0.025 arcsec per pixel. MUSE is built around a novel arrangement of 24 identical spectrographs (each comparable to a 1st generation VLT instrument), which are fed by a set of 24 precision image slicers. MUSE is designed for stability, with only 2 modes, and virtually no moving parts, allowing very long exposures to be accumulated. Together with high throughput, this ensures that MUSE will have extreme sensitivity for observing faint objects. We overview the technical and scientific aspects of MUSE, highlighting the key challenges for dealing with the unprecedented quantity and complexity of the data, and the integration with the VLT adaptive optics facility (AOF) - a key development on the path to extremely large telescopes (ELTs). © 2008 Springer-Verlag Berlin Heidelberg.

We are proposing to implement an integral field unit in NIRSPEC the Near Infra-Red Spectrograph for the NGST. This unique IFU will cover a 2x2 arcsec^2 field of view sampled at 0.05" (or 3"x3" @0.07"). The spectral resolution will go up to 3000. We will present the optical design of this unit and its implementation inside the NIRSPEC instrument. We will also show the results from an analysis of the effects of diffraction and stray-light inside the module, as well as the original method of integration we are using.. This module will be built using the image slicer technology, including 40 slices, each 900μm thick. We are also developing an innovative mechanical structure for this unit including the magnifying optics and the slicer itself, providing a very compact unit. The implementation will have a small impact on the NIRSPEC instrument, with only one to three additional gratings to be implemented in the grating wheel. The limiting magnitude of this mode should reach AB=24-26 for a point source. This unit would provide, for a marginal cost, a unique opportunity to offer a very powerful 3D spectrograph on NGST. The NIRSPEC instrument is under the ESA responsibility, and this work is being conducted in the context of the Astrium-ESA phase A study to which we are participating.

A research and development activity on an Image Slicer System for Integral Field Spectroscopy is conducted with possible applications on future instrumentation for major ground-based (VLT second-generation instruments) and space (NGST, SNAP) observatories. These instruments need high-photometric accuracy, compactness and will possibly work under cryogenic environment, while multi-integral field units may require mass production. Several prototypes have been manufactured since March 2000. This paper provides an overview of the difficulties and limits of the design for different applications, and will describe technology developments and performance evaluation. In particular, the assembly of Zerodur micro-optical elements required an original method of assembly using high precision molecular adhesion, in order to comply with optical tolerances. Following the exact characteristics of the optical elements, diffraction and straylight analyses have been performed in the NIR range. It was found that diffraction effects due to the image slicer induce energy losses less than a few percents and do not induce any crosstalk between pseudo-slits. With a good baffling, scatter can be controlled to minimize the background increase to less than 10-4 times the incident flux.

The Near-Infrared Spectrograph (NIRSpec) is one of the four science instruments of the James Webb Space Telescope. Its focal plane consists of two HAWAII-2RG sensors operating in the wavelength range of 0.6 to 5.0 μm and, as part of characterizing NIRSpec, the noise properties of these detectors under dark and illuminated conditions were studied. Under dark conditions, and as already known, 1∕f noise in the detector system causes somewhat higher noise levels than can be accounted for by a simple model that includes white read noise and shot noise on integrated charge. More surprisingly, for high levels of accumulated charge, significantly lower total noise than expected was observed. This effect is shown to be due to pixel-to-pixel correlations intro- duced by signal-dependent interpixel crosstalk, with an interpixel coupling factor, α, that ranges from ∼0.01 for zero signal to ∼0.03 close to satura- tion. © 2013 Society of Photo-Optical Instrumentation Engineers (SPIE) (DOI: 10.1117/1.OE .52.3.034001)

International audience; The transneptunian region has proven to be a valuable probe to test models of the formation and evolution of the solar system. To further advance our current knowledge of these early stages requires an increased knowledge of the physical properties of Transneptunian Objects (TNOs). Colors and albedos have been the best way so far to classify and study the surface properties of a large number TNOs. However, they only provide a limited fraction of the compositional information, required for understanding the physical and chemical processes to which these objects have been exposed since their formation. This can be better achieved by near-infrared (NIR) spectroscopy, since water ice, hydrocarbons, and nitrile compounds display diagnostic absorption bands in this wavelength range. Visible and NIR spectra taken from ground-based facilities have been observed for ∼80 objects so far, covering the full range of spectral types: from neutral to extremely red with respect to the Sun, featureless to volatile-bearing and volatile-dominated (Barkume et al., 2008; Guilbert et al., 2009; Barucci et al., 2011; Brown, 2012). The largest TNOs are bright and thus allow for detailed and reliable spectroscopy: they exhibit complex surface compositions, including water ice, methane, ammonia, and nitrogen. Smaller objects are more difficult to observe even from the largest telescopes in the world. In order to further constrain the inventory of volatiles and organics in the solar system, and understand the physical and chemical evolution of these bodies, high-quality NIR spectra of a larger sample of TNOs need to be observed. JWST/NIRSpec is expected to provide a substantial improvement in this regard, by increasing both the quality of observed spectra and the number of observed objects. In this paper, we review the current knowledge of TNO properties and provide diagnostics for using NIRSpec to constrain TNO surface compositions.

2007-12-07; The near-infrared multi-object spectrograph NIRSpec is one of the three science instruments onboard the future James Webb Space Telescope. It is developed by EADS/Astrium for the European Space Agency (ESA). NIRSpec will cover the 0.6 to 5.0 µm wavelength range and will be able to obtain simultaneous spectra of more than 100 objects in a 9 square arcminute field of view, thanks to an array of micro-shutters.An accurate modeling of the instrument has been performed to obtain realistic estimates of NIRSpec expected performances and to check that the science goals could be achieved. Such a model has also been used to define and validate the operation and calibration scenarios and,on the long run, to develop and test the data reduction software. This model is based on an end-to-end (from the sky to the detectors) Fourier-optics model of the instrument taking into account both geometrical aberrations and diffraction. In this manuscript, we discuss both the hypothesis and the limitations of such a Fourier Optics model. Our study is then focused on NIRSpec image quality, distortion and overall efficiency.In the last sections, we describe the algorithms designed and implemented to compute realistic fake exposures. These exposures are currently used to test NIRSpec exposures data processing software.; Le futur télescope spatial JWST (James Webb Space Telescope) sera lancé en 2013. Conçu pour observer dans l'infrarouge de 0.6 à 27 µm, ce télescope sera équipé, entre autres instruments, du spectrographe multi-objets NIRSpec (Near Infrared Spectrograph). Dans cette thèse, nous modélisons et analysons les performances optiques de cet instrument développé par EADS/Astrium pour l'Agence Spatiale Européenne (ESA).Notre étude se concentre sur la qualité d'image, la distorsion et l'efficacité totale de NIRSpec.Ces calculs de performances reposent sur un code d'optique de Fourier développé durant cette thèse. Dans ce manuscrit, nous discutons les hypothèses et les limites de notre approche et nous présentons les résultats obtenus par l'étude de la distorsion et des effets de la diffraction. Ces résultats ont été utilisés pour vérifier des points clefs de la conception de NIRSpec. La complexité de NIRSpec nous a également amenés à développer un simulateur complet de l'optique et des détecteurs. Nous décrivons les algorithmes mis au point pour ces simulations ainsi que les éléments importants de leur implémentation (optimisation des temps de calculs). Les poses ainsi crées sont actuellement utilisées pour tester les futurs logiciels de traitement des données NIRSpec.