VAKILI , Farrokh

We outline a concept for OWL-Moon, a 50-100 m aperture telescope located on the surface of the Moon, to address three major areas in astronomy, namely the detection of biosignatures on habitable exoplanets, the geophysics of exoplanets, and cosmology. Such a large lunar telescope, when coupled with large Earth-based telescopes, would allow...

We address three major questions in astronomy, namely the detection of biosignatures on habitable exoplanets, the geophysics of exoplanets and cosmology. To achieve this goal, two requirements are needed: (i) a very large aperture to detect spectro-polarimetric and spatial features of faint objects such as exoplanets, (ii) continuous monitoring...

For the detection and direct imaging of exoplanets, when the intensity ratio between a star and its orbiting planet can largely exceed 106, coronagraphic methods are mandatory. In 1996, a concept of achromatic interferocoronagraph (AIC) was presented by J. Gay and Y. Rabbia for the detection of very faint stellar companions, such as exoplanets....

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We propose a new approach, based on the Hanbury Brown and Twiss intensity interferometry, to transform a Cherenkov telescope to its equivalent optical telescope. We show that, based on the use of photonics components borrowed from quantum-optical applications, we can recover spatial details of the observed source down to the diffraction limit...

% Context {Direct measurements of fundamental parameters and photospheric structures of post-main-sequence intermediate-mass stars are required for a deeper understanding of their evolution. } % Aims {Based on near-IR long-baseline interferometry we aim to resolve the stellar surface of the F0 supergiant star Canopus, and to precisely measure...

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We present the new speckle camera PISCO2 made in 2010-2012, for the 76-cm refractor of C6te d'Azur Observatory. It is a focal instrument dedicated to the observation of visual binary stars using high-angular-resolution speckle-interferometry techniques to partly overcome the degradation caused by atmospheric turbulence. Fitted with an EMCCD...

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We report on the first daytime on-sky results of a Phase Knife stellar Coronagraph operated in the visible from the French-Italian Concordia station at Dome C of Antarctica. This site has proven in the last few years to offer excellent atmospheric seeing conditions for high spatial resolution observations. The coronagraphic performances...

CONTEXT: The four-quadrant phase mask stellar coronagraph, introduced by D.~Rouan et al., is capable of achieving very high dynamical range imaging and was studied in the context of the direct detection of extra-solar planets. Achromatic four-quadrant phase mask is currently being developed for broadband IR applications. AIMS: We report on...

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Interferometric observations have revealed that the rapid rotator Altair is a flattened star with a non-centrally symmetric intensity distribution. In this work we perform for the first time a physically consistent analysis of all interferometric data available so far, corresponding to three different interferometers operating in several...

We perform a physically consistent analysis of all interferometric data available for Altair in order to estimate two important parameters for this rapid rotator : (1) a gravity-darkening compatible with the expected value for hot stars (Teff∝ g 0.25; von Zeipel effect) and (2) an intermediate inclination for the rotation axis (i=55°±8° for our...

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