G. Adam

Cancer Research Center of Lyon, Lyons, Rhône-Alpes, France

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Publications (27)24.01 Total impact

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    ABSTRACT: The Nearby Supernova Factory is an international project dedicated to the study of the nearby thermonuclear (type Ia) supernovæ. Based upon the NEAT search for the target discovery and the dedicated integral field spectrograph SNIFS for the follow-up, the goal is to study, on a continuous period of 4 years, the spectro-photometric evolution of ~ 300\sim 300 SNe Ia at z < 0.08 from -15 to +50 days on the extended optical range (320-1000 nm). This will allow to probe in detail the local Hubble diagram, the SNe Ia physics, the SNe-host galaxy correlations, and will serve as an unprecedented nearby benchmark for the high-z cosmological studies to come.
    02/2006: pages 404-407;
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    ABSTRACT: By incorporating spatial coverage with the spectral dimension, integral-field spectroscopy is uniquely suited for exploiting the capabilities of adaptive optics (AO) systems. OASIS is a lenslet-based integral-field spectrograph designed to perform high-resolution observations on AO-corrected sources, operating at visible wavelengths. This instrument was commissioned at the William Herschel Telescope, La Palma, in July 2003 to work with the ING's AO system, NAOMI. Here we present an overview of the capabilities of the OASIS+NAOMI system, and show results obtained using this technique. The science presented here is a small preview of what will be possible for a large number of objects when the GLAS laser guide system is operational.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
    09/2004;
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    ABSTRACT: Early-type galaxies are thought to be among the oldest known stellar systems, and as such have experienced the full diversity of evolutionary mechanisms at work in the universe. They are crucial laboratories for understanding how galaxies form and evolve from early epochs until the present day. A key aspect of unlocking their fossil evidence is by studying the dynamics of stars and gas, and characterising the stellar populations. To this end, the SAURON survey has undertaken a study of 72 representative nearby early-type galaxies and spiral bulges using the SAURON integral field spectrograph at the WHT. Follow-up survey is being continued with OASIS at the WHT, with the aim of completing all E/S0s of the SAURON survey by spring 2005. Here we give an overview of this follow-up survey, and future prospects for using OASIS in this field.
    The Newsletter of the Isaac Newton Group of Telescopes. 09/2004;
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    ABSTRACT: By incorporating spatial coverage with the spectral dimension, integral-field spectroscopy is uniquely suited for exploiting the capabilities of adaptive optics (AO) systems. OASIS is a lenslet-based integral-field spectrograph designed to perform high-resolution observations on AO-corrected sources, operating at visible wavelengths. This instrument was commissioned at the William Herschel Telescope, La Palma, in July 2003 to work with the ING's AO system, NAOMI. Here we present an overview of the capabilities of the OASIS+NAOMI system, and show results obtained using this technique. The science presented here is a small preview of what will be possible for a large number of objects when the GLAS laser guide system is operational.
    Proc SPIE 09/2004;
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    ABSTRACT: The Nearby Supernova Factory (SNfactory) is an ambitious project to find and study in detail approximately 300 nearby Type Ia supernovae (SNe Ia) at redshifts 0.03<z<0.08. This program will provide an exceptional data set of well-studied SNe in the nearby smooth Hubble flow that can be used as calibration for the current and future programs designed to use SNe to measure the cosmological parameters. The first key ingredient for this program is a reliable supply of Hubble-flow SNe systematically discovered in unprecedented numbers using the same techniques as those used in distant SNe searches. In 2002, 35 SNe were found using our test-bed pipeline for automated SN search and discovery. The pipeline uses images from the asteroid search conducted by the Near Earth Asteroid Tracking group at JPL. Improvements in our subtraction techniques and analysis have allowed us to increase our effective SN discovery rate to ∼12 SNe/month in 2003.
    New Astronomy Reviews 01/2004; · 1.82 Impact Factor
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    ABSTRACT: The Nearby Supernova Factory (SNfactory) is an ambitious project to find and study in detail approximately 300 nearby Type Ia supernova at redshifts 0.03 < z < 0.08. This program will provide an exceptional data set of well-studied supernovae in the nearby smooth Hubble flow which can be used as calibration for the current and future programs designed to use supernovae to measure the cosmological parameters. A key ingredient for this program is a reliable supply of Hubble-flow supernovae systematically discovered in numbers greater than ever before using the same techniques as used in distant supernovae searches. In 2002, 35 SNe were found using our testbed pipeline for automated supernova search and discovery. The pipeline uses data from the asteroid search conducted by the Near Earth Asteroid Tracking group at JPL. We present here further results from our efforts in 2003. Improvements in our subtraction techniques and analysis, combined with an improved main searching camera have allowed us to increase our SN discovery rate and we anticipate discovering 100 SNe in 2003.
    04/2003; 35:719.
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    ABSTRACT: The Nearby Supernova Factory (Snfactory) is an international experiment designed to lay the foundation for the next generation of cosmology experiments (such as CFHTLS, wP, SNAP and LSST) which will measure the expansion history of the Universe using Type Ia supernovae. The Snfactory will discover and obtain frequent lightcurve spectrophotometry covering 3200-10000Å for roughly 300 Type Ia supernovae at the low-redshift end of the smooth Hubble flow. The quantity, quality, breadth of galactic environments, and homogeneous nature of the Snfactory dataset will make it the premier source of calibration for the Type Ia supernova width-brightness relation and the intrinsic supernova colors used for K-correction and correction for extinction by host-galaxy dust. This dataset will also allow an extensive investigation of additional parameters which possibly influence the quality of Type Ia supernovae as cosmological probes. The Snfactory search capabilities and follow-up instrumentation include wide-field CCD imagers on two 1.2-m telescopes (via collaboration with the Near Earth Asteroid Tracking team at JPL and the QUEST team at Yale), and a two-channel integral-field-unit optical spectrograph/imager being fabricated for the University of Hawaii 2.2-m telescope. In addition to ground-based follow-up, UV spectra for a subsample of these supernovae will be obtained with HST. The pipeline to obtain, transfer via wireless and standard internet, and automatically process the search images is in operation. Software and hardware development is now underway to enable the execution of follow-up spectroscopy of supernova candidates at the Hawaii 2.2-m telescope via automated remote control of the telescope and the IFU spectrograph/imager.
    Proc SPIE 01/2002;
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    ABSTRACT: We describe MIFS, a second generation integral-field spectrograph for the VLT, operating in the visible wavelength range. It combines a 1'x1' field of view with the improved spatial resolution provided by multi-conjugate adaptive optics and covers a large simultaneous spectral range (0.6-1.0 microns). A separate mode exploits the highest spatial resolution provided by adaptive optics. With this unique combination of capabilities, MIFS has a wide domain of application and a large discovery potential. The MIFS low-spatial resolution mode (sampled at 0.2") combined with the initial MCAO capabilities planned for the VLT will provide ultra-deep fields with a limiting magnitude for spectroscopy of R~28. MIFS will improve the present day detection limit of Lyman alpha emitters by a factor of 100, and will detect low-mass star-forming galaxies to z~7. The MIFS high-spatial resolution mode (3"x3" field sampled at 0.01") is optimized for the next step in (MC)AO. It will probe, e.g., the relationship between supermassive central black holes and their host galaxy and the physics of winds from accretion disks in young stellar objects at unprecedented spatial resolution. MIFS will extend Europe's lead in integral-field spectroscopy. It capitalizes on new developments in adaptive optics, and is a key step towards instrumentation for OWL.
    10/2001;
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    01/2000; 195:341.
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    ABSTRACT: This paper presents OASIS, the new integral field spectrograph built by the Observatoire de Lyon for CFHT. OASIS is designed to be coupled with the AOB system and offers high-spatial imaging spectroscopy capabilities using an array of about 1200 microlenses. A special data reduction software has been extensively developed by Lyon and is available to the general community. Preliminary results from two observing runs in early 1998 are presented. 1. Introduction For most of the astronomical targets which present small scale structures embedded in high diffuse background or crowded environment, the spatial resolution is essential. Understanding the physical processes related to theses structures relies generally on getting spectrographic information at high spatial resolution. This goal is now reachable thanks to the success of the adaptive optics. Today, the main problem is not to get the maximum of light into a long slit, but to get all the valuable information into a 2D area. Giv...
    12/1998;
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    ABSTRACT: This paper presents the Lyα1215Å image, the velocity and velocity dispersion maps of the radiogalaxy 4C 41.17 (z=3.8), obtained with the integral field spectrograph TIGER at CFHT. In a relatively short exposure time (1.86h), the Lyα image reveals a bended elongated component surrounding a narrow bright peak and a West fainter component distributed along the radio axis. Roughly perpendicular to that main axis, a South-East to North-West faint extension to the central region is visible. A high density of smaller ionised clouds shows up in the vicinity of the radiogalaxy. The radial velocity and the velocity dispersion are mapped with a 0.61" spatial sampling. Radial velocities, from 0 to 700km/s, are essentially negative relative to the narrow peak, while velocity dispersions vary from 800km/s in the inner part up to 2000km/s at possible bow shock locations as well as in the South extension. Such data are essential to disentangle the various components of these distant sources. The kinematics, roughly similar to that of nearby galaxies, is interpreted by luminous clouds and a dusty disk structure. Measured negative velocities could be used as expansion rate constraints for hydrodynamics models of the radio jet propagation. They may also be due to an overestimate of the systemic velocity, in the hypothesis of a collapsing bright knot at the central bright peak. Information on star formation triggering along the radiojet will be derived from deeper observations.
    Astronomy and Astrophysics 09/1997; 326:501-504. · 5.08 Impact Factor
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    ABSTRACT: Using the integral field spectrograph Tiger, we obtained low to intermediate spectral resolution 3D data cubes of the cD galaxy NGC 1275. This set up allowed us to disentangle the various astrophysical components by individually mapping the galaxy continuum and the low and high velocity emission line systems with a yet unchallenged 0.8″ spatial resolution.The low velocity system, which is elongated in an east-west direction similar to that of the molecular gas, exhibits trends in spectral characteristics which are consistent on the west side of the nucleus with photoionization by a varying mixture of nuclear radiation and local emission from hot young stars.The high velocity system is only seen north of the nucleus. We report the first detection of gas with velocities intermediate between the LV and HV systems, which we interpret as the first direct evidence of an interaction between the two velocity systems.
    New Astronomy 01/1997; 2(4):345-363. · 1.85 Impact Factor
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  • 01/1997;
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    ABSTRACT: The instrument TIGER is the first prototype of an integral field spectrograph using a microlenses array to perform bidimensional high spatial resolution spectrographic observations. It has been in operation at CFHT for a few years and has been successfully used on a large variety of astrophysical objects, ranging from the planet Mars to distant radio-galaxies and quasars. We discuss the fundamentals of the TIGER design and show that it is superior to long-slit spectrography for high spatial resolution purposes. The main characteristics of the instrument are given and some of the astrophysical results are briefly reviewed.
    Astronomy and Astrophysics Supplement Series 09/1995; 113:347.
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    01/1995; 71:250.
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    ABSTRACT: Bidimensional spectroscopy of the distant (z = 0.471) radio-galaxy 3C 435A has been performed with the integral field spectrograph TIGER at the Canada-France-Hawaii Telescope (CFHT). The (O II) 3727 A and (O III) 4959, 5007 A maps are remarkably superimposed with the 1.4 GHz radio lobe isophotes, showing the narrow relationship between the radio plasma and the ionized component, while the 4.8 GHz radio emission traces a shock region. The (O II)/(O III) ratio map follows the external part of the radio lobe rather than the central jet, and is strongly distorted by multiple components. This high number density is confirmed by the velocity field. The maximum ratio value (approximately equal to 8) indicates a low level of ionization. For the first time, stellar and nebular components are separated at a large redshift, indicating that the alignment effect is mainly due to nebular (O II) and (O III) emission. With the help of our spectrophotometric model, the stellar continuum of the central component A is well fitted with an old (more than 15 Gyrs at z = 0) elliptical galaxy model, while nebular lines witness a faint star formation process. Two companions B and D, located near the radio-axis, fit evolved (greater than or equal to 10 Gyrs) models, ruling out a current star formation activity induced by the radio-jet. Another companion, C, located in a direction roughly perpendicular to the radio-axis, has a blue color of irregular type, a few Gyr age, detectable emission lines and high velocity. Component E, roughly aligned with A and C, is essentially emitting in the (O II) line.
    Astronomy and Astrophysics 11/1994; 292:20-26. · 5.08 Impact Factor
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    ABSTRACT: The galaxy NGC 5728 has been observed with the integral field spectrograph TIGER. This galaxy is known as a Seyfert 2, and its nuclear regions exhibit a complex structure. The decomposition into Gaussian profiles of the spectra arising from the very central region was achieved, and maps associated with the different components found were then obtained. The data show the existence of a central broad line region unresolved in the seeing conditions of the observations, which qualifies NGC 5728 as a (weak) Seyfert 1.
    Astronomy and Astrophysics 05/1990; 232:331-336. · 5.08 Impact Factor
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    ABSTRACT: Observations of the Einstein Cross 2237+030 with the TIGER Integral Field Spectrograph (IFS) strongly confirm the gravitational lens hypothesis. C III semiforbidden emission-line and Mg I absorption-line mappings are used to discriminate the quasar images and the galactic nucleus.
    Astronomy and Astrophysics 12/1988; 208:L15-L18. · 5.08 Impact Factor
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    ABSTRACT: TIGER is a new device designed for true bidimensional spectrography and imagery. Its main advantage is to obtain simultaneously spatial and spectrographic informations on the object. Observations of M51 nucleus with the 3.6 m CFHT telescope demonstrate its ability to perform bidimensional spectgrography with seeing-limited spatial resolution.
    01/1988;