A5090470639- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Adaptive optics and wavefront sensing
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- Calibration and Measurement Techniques
- Advanced Measurement and Metrology Techniques
- Geophysics and Gravity Measurements
- History and Developments in Astronomy
- Optical Systems and Laser Technology
- Optical Polarization and Ellipsometry
- Planetary Science and Exploration
- Radio Astronomy Observations and Technology
- Optical measurement and interference techniques
- Inertial Sensor and Navigation
- Advanced Optical Sensing Technologies
- CCD and CMOS Imaging Sensors
- Solar and Space Plasma Dynamics
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Optical Coherence Tomography Applications
- Advanced optical system design
- Spectroscopy and Laser Applications
- Superconducting and THz Device Technology
Observatoire de la Côte d’Azur
2015-2024
Centre National de la Recherche Scientifique
2015-2024
Lagrange Laboratory
2007-2024
Université Côte d'Azur
2009-2022
Shahid Beheshti University
2020-2021
Institut de Biologie Valrose
2009
Osservatorio Astronomico di Padova
2009
European Southern Observatory
2007
Centre Hospitalier Universitaire de Nice
2003-2006
University of California, San Diego
1998
Direct detection and spectral characterization of extra-solar planets is one the most exciting but also challenging areas in modern astronomy. The challenge consists very large contrast between host star planet, larger than 12.5 magnitudes at small angular separations, typically inside seeing halo. whole design a "Planet Finder" instrument therefore optimized towards reaching highest limited field view short distances from central star. Both evolved young planetary systems can be detected,...
Context.Optical long-baseline interferometry is moving a crucial step forward with the advent of general-user scientific instruments that equip large aperture and hectometric baseline facilities, such as Very Large Telescope Interferometer (VLTI).
The SHINE program is a large high-contrast near-infrared survey of 600 young, nearby stars. It aimed at searching for and characterizing new planetary systems using VLT/SPHERE's unprecedented high-angular resolution imaging capabilities. also intends placing statistical constraints on the occurrence orbital properties giant planet population orbits as function stellar host mass age to test formation theories. We use IRDIS dual-band imager IFS integral field spectrograph SPHERE acquire...
Aims.In this paper, we present an innovative data reduction method for single-mode interferometry. It has been specifically developed the AMBER instrument, three-beam combiner of Very Large Telescope Interferometer, but it can be derived any interferometer.
The planetary system discovered around the young A-type HR8799 provides a unique laboratory to: a) test planet formation theories, b) probe diversity of architectures at these separations, and c) perform comparative (exo)planetology. We present exploit new near-infrared images integral-field spectra four gas giants surrounding obtained with SPHERE, finder instrument Very Large Telescope, during commissioning science verification phase (July-December 2014). With data, we contribute to...
<i>Context. <i/>Among optical stellar interferometers, the CHARA Array located at Mt Wilson in California offers potential of very long baselines (up to 330 m) and prospect coupling multiple beam combiners. This paper presents principle measured performance VEGA, Visible spEctroGraph polArimeter installed September 2007 coherent focus array.<i>Aims. <i/>With 0.3 ms arc spatial resolution up spectral resolution, VEGA intends measure fundamental parameters stars, study activities image analyze...
We present the performance of Integral Field Spectrograph (IFS) SPHERE, high-contrast imager for ESO VLT telescope designed to perform imaging and spectroscopy extrasolar planets, obtained from tests performed at Institute de Plan\'etologie et d'Astrophysique Grenoble facility during integration phase instrument.} {The were using instrument software purposely prepared SPHERE. The output data reduced applying SPHERE reduction handling software, adding an improved spectral deconvolution...
The system of four planets around HR8799 offers a unique opportunity to probe the physics and chemistry at play in atmospheres self-luminous young (~30 Myr) planets. We recently obtained new photometry low-resolution (R~30) spectra d e with SPHERE instrument (paper III). In this paper IV), we compare available known objects atmospheric models (BT-SETTL14, Cloud-AE60, Exo-REM) characterize properties find that HR8799d are well reproduced by those L6-L8 dusty dwarfs discovered field, among...
[Abridged] Context. The young systems PZ Tel and HD 1160, hosting known low-mass companions, were observed during the commissioning of new planet finder SPHERE with several imaging spectroscopic modes. Aims. We aim to refine physical properties architecture both systems. Methods. use data REM observations, as well literature unpublished from VLT/SINFONI, VLT/NaCo, Gemini/NICI, Keck/NIRC2. Results. derive photometry confirm nearly daily photometric variability A. Using spanning 38 yr, we show...
GJ758 B is a brown dwarf companion to nearby (15.76 pc) solar-type, metal-rich (M/H = +0.2 dex) main-sequence star (G9V) that was discovered with Subaru/HiCIAO in 2009. From previous studies, it has drawn attention as being the coldest (~600K) ever directly imaged around neighboring star. We present new high-contrast data obtained during commissioning of SPHERE instrument at VLT. The Y-, J-, H-, and Ks-bands dual-band imaging (DBI) mode IRDIS, providing broad coverage full near-infrared...
Context. The new planet finder for the Very Large Telescope (VLT), Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE), just had its first light in Paranal. A dedicated instrument direct detection of planets, SPHERE, is composed a polametric camera visible light, Zurich IMager POLarimeter (ZIMPOL), and two near-infrared sub-systems: Infra-Red Dual-beam Imager Spectrograph (IRDIS), multi-purpose imaging, polarimetry, long-slit spectroscopy, integral field spectrograph (IFS), an...
We report the first intensity correlation measured with star light since Hanbury Brown and Twiss' historical experiments. The photon bunching $g^{(2)}(\tau, r=0)$, obtained in counting regime, was for 3 bright stars, $\alpha$ Boo, CMi, $\beta$ Gem. collected at focal plane of a 1~m optical telescope, transported by multi-mode fiber, split into two avalanche photodiodes digitally correlated real-time. For total exposure times few hours, we contrast values around $2\times10^{-3}$, agreement...
Aims. We present the first NIR spectro-interferometry of LBV η Carinae. The observations were performed with AMBER instrument ESO Very Large Telescope Interferometer (VLTI) using baselines from 42 to 89 m. aim this work is study wavelength dependence Car's optically thick wind region a high spatial resolution 5 mas (11 AU) and spectral resolution.
We present spatially resolved high-spectral resolution K-band observations of the red supergiant Betelgeuse (alpha Ori) using AMBER at Very Large Telescope Interferometer (VLTI). was observed between 2.28 and 2.31 micron baselines 16, 32, 48m with spectral resolutions 4800 -- 12000. Spectrally dispersed interferograms have been obtained in 2nd, 3rd, 5th lobes, which represents highest spatial (9 mas) achieved for Betelgeuse, corresponding to 5 elements over its stellar disk. The data...
Context. Rotation significantly impacts on the structure and life of stars. In phases high rotation velocity (close to critical), photospheric can be highly modified, present in particular geometrical deformation (rotation flattening) latitudinal-dependent flux (gravity darkening). The fastest known rotators among nondegenerate stars close main sequence, Be stars, are key targets for studying effects fast stellar photospheres.
<i>Context. <i/>The star HD 87643, exhibiting the "B[e] phenomenon", has one of most extreme infrared excesses for this object class. It harbours a large amount both hot and cold dust, is surrounded by an extended reflection nebula.<i>Aims. <i/>One our major goals was to investigate presence companion in HD87643. In addition, close dusty material tested through combination multi-wavelength high spatial resolution observations.<i>Methods. <i/>We observed 87643 with techniques, using near-IR...