References of "Sohy, Sandrine"      in Complete repository Arts & humanities   Archaeology   Art & art history   Classical & oriental studies   History   Languages & linguistics   Literature   Performing arts   Philosophy & ethics   Religion & theology   Multidisciplinary, general & others Business & economic sciences   Accounting & auditing   Production, distribution & supply chain management   Finance   General management & organizational theory   Human resources management   Management information systems   Marketing   Strategy & innovation   Quantitative methods in economics & management   General economics & history of economic thought   International economics   Macroeconomics & monetary economics   Microeconomics   Economic systems & public economics   Social economics   Special economic topics (health, labor, transportation…)   Multidisciplinary, general & others Engineering, computing & technology   Aerospace & aeronautics engineering   Architecture   Chemical engineering   Civil engineering   Computer science   Electrical & electronics engineering   Energy   Geological, petroleum & mining engineering   Materials science & engineering   Mechanical engineering   Multidisciplinary, general & others Human health sciences   Alternative medicine   Anesthesia & intensive care   Cardiovascular & respiratory systems   Dentistry & oral medicine   Dermatology   Endocrinology, metabolism & nutrition   Forensic medicine   Gastroenterology & hepatology   General & internal medicine   Geriatrics   Hematology   Immunology & infectious disease   Laboratory medicine & medical technology   Neurology   Oncology   Ophthalmology   Orthopedics, rehabilitation & sports medicine   Otolaryngology   Pediatrics   Pharmacy, pharmacology & toxicology   Psychiatry   Public health, health care sciences & services   Radiology, nuclear medicine & imaging   Reproductive medicine (gynecology, andrology, obstetrics)   Rheumatology   Surgery   Urology & nephrology   Multidisciplinary, general & others Law, criminology & political science   Civil law   Criminal law & procedure   Criminology   Economic & commercial law   European & international law   Judicial law   Metalaw, Roman law, history of law & comparative law   Political science, public administration & international relations   Public law   Social law   Tax law   Multidisciplinary, general & others Life sciences   Agriculture & agronomy   Anatomy (cytology, histology, embryology...) & physiology   Animal production & animal husbandry   Aquatic sciences & oceanology   Biochemistry, biophysics & molecular biology   Biotechnology   Entomology & pest control   Environmental sciences & ecology   Food science   Genetics & genetic processes   Microbiology   Phytobiology (plant sciences, forestry, mycology...)   Veterinary medicine & animal health   Zoology   Multidisciplinary, general & others Physical, chemical, mathematical & earth Sciences   Chemistry   Earth sciences & physical geography   Mathematics   Physics   Space science, astronomy & astrophysics   Multidisciplinary, general & others Social & behavioral sciences, psychology   Animal psychology, ethology & psychobiology   Anthropology   Communication & mass media   Education & instruction   Human geography & demography   Library & information sciences   Neurosciences & behavior   Regional & inter-regional studies   Social work & social policy   Sociology & social sciences   Social, industrial & organizational psychology   Theoretical & cognitive psychology   Treatment & clinical psychology   Multidisciplinary, general & others     Showing results 1 to 17 of 17 1 The SPECULOOS Southern Observatory Begins its Hunt for Rocky PlanetsJehin, Emmanuel ; Gillon, Michaël ; Queloz, D. et alin Messenger (2018), 174The SPECULOOS Southern Observatory (SSO), a new facility of four 1- metre robotic telescopes, began scientific operations at Cerro Paranal on 1 January 2019. The main goal of the SPECULOOS project is to ... [more ▼]The SPECULOOS Southern Observatory (SSO), a new facility of four 1- metre robotic telescopes, began scientific operations at Cerro Paranal on 1 January 2019. The main goal of the SPECULOOS project is to explore approximately 1000 of the smallest (≤ 0.15 R[SUB]⊙[/SUB]), brightest (K[SUB]mag[/SUB] ≤ 12.5), and nearest (d ≤ 40 pc) very low mass stars and brown dwarfs. It aims to discover transiting temperate terrestrial planets well-suited for detailed atmospheric characterisation with future giant telescopes like ESO’s Extremely Large Telescope (ELT) and the NASA James Webb Telescope (JWST). The SSO is the core facility of SPECULOOS. The exquisite astronomical conditions at Cerro Paranal will enable SPECULOOS to detect exoplanets as small as Mars. Here, we briefly describe SPECULOOS, and present the features and performance of the SSO facility. [less ▲]Detailed reference viewed: 13 (1 ULiège) Discovery of WASP-174b: Doppler tomography of a near-grazing transitTemple, L. Y.; Hellier, C.; Almleaky, Y. et alin Monthly Notices of the Royal Astronomical Society (2018), 480We report the discovery and tomographic detection of WASP-174b, a planet with a near-grazing transit on a 4.23-d orbit around a V= 11.9, F6V star with [Fe/H] = 0.09 ± 0.09. The planet is in a moderately ... [more ▼]We report the discovery and tomographic detection of WASP-174b, a planet with a near-grazing transit on a 4.23-d orbit around a V= 11.9, F6V star with [Fe/H] = 0.09 ± 0.09. The planet is in a moderately misaligned orbit with a sky-projected spin-orbit angle of λ = 31° ± 1°. This is in agreement with the known tendency for orbits around hotter stars to be misaligned. Owing to the grazing transit, the planet's radius is uncertain with a possible range of 0.8-1.8 R[SUB]Jup[/SUB]. The planet's mass has an upper limit of 1.3 M[SUB]Jup[/SUB]. WASP-174 is the faintest hot-Jupiter system so far confirmed by tomographic means. [less ▲]Detailed reference viewed: 27 (3 ULiège) NGTS-4b: A sub-Neptune Transiting in the DesertWest, Richard G.; Gillen, Edward; Bayliss, Daniel et alE-print/Working paper (2018)We report the discovery of NGTS-4b, a sub-Neptune-sized planet transiting a 13th magnitude K-dwarf in a 1.34d orbit. NGTS-4b has a mass M=$20.6\pm3.0$M_E and radius R=$3.18\pm0.26$R_E, which places it ... [more ▼]We report the discovery of NGTS-4b, a sub-Neptune-sized planet transiting a 13th magnitude K-dwarf in a 1.34d orbit. NGTS-4b has a mass M=$20.6\pm3.0$M_E and radius R=$3.18\pm0.26$R_E, which places it well within the so-called "Neptunian Desert". The mean density of the planet ($3.45\pm0.95$g/cm^3) is consistent with a composition of 100% H$_2$O or a rocky core with a volatile envelope. NGTS-4b is likely to suffer significant mass loss due to relatively strong EUV/X-ray irradiation. Its survival in the Neptunian desert may be due to an unusually high core mass, or it may have avoided the most intense X-ray irradiation by migrating after the initial activity of its host star had subsided. With a transit depth of $0.13\pm0.02$%, NGTS-4b represents the shallowest transiting system ever discovered from the ground, and is the smallest planet discovered in a wide-field ground-based photometric survey. [less ▲]Detailed reference viewed: 23 (4 ULiège) Unmasking the hidden NGTS-3Ab: A hot Jupiter in an unresolved binary systemGünther, M. N.; Queloz, D.; Gillen, E. et alin Monthly Notices of the Royal Astronomical Society (2018), 478(4), 4720-4737We present the discovery of NGTS-3Ab, a hot Jupiter found transiting the primary star of an unresolved binary system. We develop a joint analysis of multicolour photometry, centroids, radial velocity (RV ... [more ▼]We present the discovery of NGTS-3Ab, a hot Jupiter found transiting the primary star of an unresolved binary system. We develop a joint analysis of multicolour photometry, centroids, radial velocity (RV) cross-correlation function (CCF) profiles, and their bisector inverse slopes (BIS) to disentangle this three-body system. Data from the Next Generation Transit Survey (NGTS), SPECULOOS and HARPS are analysed and modelled with our new BLENDFITTER software. We find that the binary consists of NGTS-3A (G6V-dwarf) and NGTS-3B (K1Vdwarf) at < 1 arcsec separation. NGTS-3Ab orbits every 1.675 d. The planet radius and mass are Rplanet = 1.48 ± 0.37 RJ and Mplanet = 2.38 ± 0.26MJ, suggesting it is potentially inflated. We emphasize that only combining all the information frommulticolour photometry, centroids and RV CCF profiles can resolve systems like NGTS-3. Such systems cannot be disentangled from single-colour photometry and RV measurements alone. Importantly, the presence of a BIS correlation indicates a blend scenario, but is not sufficient to determine which star is orbited by the third body. Moreover, even if no BIS correlation is detected, a blend scenario cannot be ruled out without further information. The choice of methodology for calculating the BIS can influence the measured significance of its correlation. The presented findings are crucial to consider for wide-field transit surveys, which require wide CCD pixels (> 5 arcsec) and are prone to contamination by blended objects. With TESS on the horizon, it is pivotal for the candidate vetting to incorporate all available follow-up information from multicolour photometry and RV CCF profiles. © 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. [less ▲]Detailed reference viewed: 25 (3 ULiège) SPECULOOS: A network of robotic telescopes to hunt for terrestrial planets around the nearest ultracool dwarfsDelrez, L.; Gillon, Michaël ; Queloz, D. et alin Proceedings of SPIE: The International Society for Optical Engineering (2018), 10700We present here SPECULOOS, a new exoplanet transit search based on a network of 1m-class robotic telescopes targeting the ∼1200 ultracool (spectral type M7 and later) dwarfs bright enough in the infrared ... [more ▼]We present here SPECULOOS, a new exoplanet transit search based on a network of 1m-class robotic telescopes targeting the ∼1200 ultracool (spectral type M7 and later) dwarfs bright enough in the infrared (K-mag ≤ 12.5) to possibly enable the atmospheric characterization of temperate terrestrial planets with next-generation facilities like the James Webb Space Telescope. The ultimate goals of the project are to reveal the frequency of temperate terrestrial planets around the lowest-mass stars and brown dwarfs, to probe the diversity of their bulk compositions, atmospheres and surface conditions, and to assess their potential habitability. © 2018 SPIE. [less ▲]Detailed reference viewed: 36 (0 ULiège) SPECULOOS: Search for habitable Planets EClipsing ULtra-cOOl StarsGillon, Michaël ; Jehin, Emmanuel ; Delrez, Laetitia et alPoster (2013, July 01)The 1000 nearest ultra-cool stars (spectral type M6 and latter) represent a unique opportunity for the search for life outside our solar system. Due to their small luminosity, their habitable zone is 30 ... [more ▼]The 1000 nearest ultra-cool stars (spectral type M6 and latter) represent a unique opportunity for the search for life outside our solar system. Due to their small luminosity, their habitable zone is 30-100 times closer than for the Sun, the corresponding orbital periods ranging from one to a few days. Thanks to this proximity, the transits of a habitable planet are much more probable and frequent than for an Earth-Sun analog, while their tiny size (about 1 Jupiter radius) leads to transits deep enough for a ground-based detection, even for sub-Earth size planets. Furthermore, a habitable planet transiting one of these nearby ultra-cool stars would be amenable for a thorough atmospheric characterization, including the detection of possible biosignatures, notably with the near-to-come JWST. Motivated by these reasons, we have set up the concept of a ground-based survey optimized for detecting planets of Earth-size and below transiting the nearest Southern ultra-cool stars. We present here this concept and its status. [less ▲]Detailed reference viewed: 70 (9 ULiège) Time Delays in Gravitationally Lensed QuasarsEulaers, Eva ; Magain, Pierre ; Sohy, Sandrine Poster (2013, June 25)Detailed reference viewed: 14 (1 ULiège) Measuring Time Delays in Gravitational LensesEulaers, Eva ; Magain, Pierre ; Sohy, Sandrine et alPoster (2008, September)Detailed reference viewed: 16 (1 ULiège) DECPHOT: An Optimal Deconvolution-based Photometric Reduction MethodGillon, Michaël ; Magain, Pierre ; Chantry, Virginie et alin Transiting Extrapolar Planets Workshop (2007, July 01)A high accuracy photometric reduction method is needed to take full advantage of the potential of the transit method for the detection and characterization of exoplanets, especially in deep crowded fields ... [more ▼]A high accuracy photometric reduction method is needed to take full advantage of the potential of the transit method for the detection and characterization of exoplanets, especially in deep crowded fields. In this context, we present DECPHOT, a new deconvolution-based photometry algorithm able to deal with a very high level of crowding and large variations of seeing. It also increases the resolution of astronomical images, an important advantage for the discrimination of false positives in transit photometry. [less ▲]Detailed reference viewed: 71 (18 ULiège) A deconvolution-based algorithm for crowded field photometry with unknown point spread functionMagain, Pierre ; Courbin, F.; Gillon, Michaël et alin Astronomy and Astrophysics (2007), 461A new method is presented for determining the point spread function (PSF) of images that lack bright and isolated stars. It is based on the same principles as the MCS image deconvolution algorithm. It ... [more ▼]A new method is presented for determining the point spread function (PSF) of images that lack bright and isolated stars. It is based on the same principles as the MCS image deconvolution algorithm. It uses the information contained in all stellar images to achieve the double task of reconstructing the PSFs for single or multiple exposures of the same field and to extract the photometry of all point sources in the field of view. The use of the full information available allows us to construct an accurate PSF. The possibility to simultaneously consider several exposures makes it well suited to the measurement of the light curves of blended point sources from data that would be very difficult or even impossible to analyse with traditional PSF fitting techniques. The potential of the method for the analysis of ground-based and space-based data is tested on artificial images and illustrated by several examples, including HST/NICMOS images of a lensed quasar and VLT/ISAAC images of a faint blended Mira star in the halo of the giant elliptical galaxy NGC 5128 (Cen A). [less ▲]Detailed reference viewed: 32 (4 ULiège) High accuracy transit photometry of the planet OGLE-TR-113b with a new deconvolution-based methodGillon, Michaël ; Pont, F.; Moutou, C. et alin Astronomy and Astrophysics (2006), 459A high accuracy photometry algorithm is needed to take full advantage of the potential of the transit method for the characterization of exoplanets, especially in deep crowded fields. It has to reduce to ... [more ▼]A high accuracy photometry algorithm is needed to take full advantage of the potential of the transit method for the characterization of exoplanets, especially in deep crowded fields. It has to reduce to the lowest possible level the negative influence of systematic effects on the photometric accuracy. It should also be able to cope with a high level of crowding and with large-scale variations of the spatial resolution from one image to another. A recent deconvolution-based photometry algorithm fulfills all these requirements, and it also increases the resolution of astronomical images, which is an important advantage for the detection of blends and the discrimination of false positives in transit photometry. We made some changes to this algorithm to optimize it for transit photometry and used it to reduce NTT/SUSI2 observations of two transits of OGLE-TR-113b. This reduction has led to two very high precision transit light curves with a low level of systematic residuals, used together with former photometric and spectroscopic measurements to derive new stellar and planetary parameters in excellent agreement with previous ones, but significantly more precise. [less ▲]Detailed reference viewed: 52 (1 ULiège) High precision photometry in crowded stellar fieldsMagain, Pierre ; Courbin, Frédéric; Gillon, Michaël et alin SPIE Newsroom (2006)A deconvolution-based method which allows to derive high-precision photometry of stars in crowded fields, proves very useful for a variety of astronomical projects, including transit searches for ... [more ▼]A deconvolution-based method which allows to derive high-precision photometry of stars in crowded fields, proves very useful for a variety of astronomical projects, including transit searches for extrasolar planets. [less ▲]Detailed reference viewed: 39 (3 ULiège) A novel approach for extracting time-delays from lightcurves of lensed quasar imagesBurud, I.; Magain, Pierre ; Sohy, Sandrine et alin Astronomy and Astrophysics (2001), 380We present a new method to estimate time delays from light curves of lensed quasars. The method is based on chi [SUP]2[/SUP] minimization between the data and a numerical model light curve. A linear ... [more ▼]We present a new method to estimate time delays from light curves of lensed quasars. The method is based on chi [SUP]2[/SUP] minimization between the data and a numerical model light curve. A linear variation can be included in order to correct for slow long-term microlensing effects in one of the lensed images. An iterative version of the method can be applied in order to correct for higher-order microlensing effects. The method is tested on simulated light curves. When higher-order microlensing effects are present, the time delay is best constrained with the iterative method. Analysis of a published data set for the lensed double Q 0957+561 yields results in agreement with other published estimates. [less ▲]Detailed reference viewed: 21 (1 ULiège) A Method for Spatial Deconvolution of SpectraCourbin, F.; Magain, Pierre ; Kirkove, Murielle et alin Astrophysical Journal (2000), 529A method for spatial deconvolution of spectra is presented. It follows the same fundamental principles as the MCS image deconvolution algorithm'' recently developed by Magain, Courbin, & Sohy and uses ... [more ▼]A method for spatial deconvolution of spectra is presented. It follows the same fundamental principles as the MCS image deconvolution algorithm'' recently developed by Magain, Courbin, & Sohy and uses information contained in the spectrum of a reference point-spread function to spatially deconvolve spectra of very blended sources. An improved resolution rather than an infinite one is aimed at, overcoming the well-known problem of deconvolution artifacts.'' As in the MCS algorithm, the data are decomposed into a sum of analytical point sources and a numerically deconvolved background so that the spectrum of extended sources in the immediate vicinity of bright point sources may be accurately extracted and sharpened. The algorithm has been tested on simulated data including seeing variation as a function of wavelength and atmospheric refraction. It is shown that the spectra of severely blended point sources can be resolved while fully preserving the spectrophotometric properties of the data. Extended objects hidden'' by bright point sources (up to 4-5 mag brighter) can be accurately recovered as well, provided the data have a sufficiently high total signal-to-noise ratio (200-300 per spectral resolution element). Such spectra are relatively easy to obtain, even down to faint magnitudes, within a few hours of integration time with 10 m class telescopes. [less ▲]Detailed reference viewed: 25 (7 ULiège) Deconvolving spectra of lensing galaxies, QSO hosts, and more ...Courbin, F.; Magain, Pierre ; Sohy, Sandrine et alin Messenger (1999), 97Detailed reference viewed: 6 (0 ULiège) Deconvolution with Correct SamplingMagain, Pierre ; Courbin, F.; Sohy, Sandrine in Astrophysical Journal (1998), 494A new method for improving the resolution of astronomical images is presented. It is based on the principle that sampled data cannot be fully deconvolved without violating the sampling theorem. Thus, the ... [more ▼]A new method for improving the resolution of astronomical images is presented. It is based on the principle that sampled data cannot be fully deconvolved without violating the sampling theorem. Thus, the sampled image should be deconvolved not by the total point-spread function but by a narrower function chosen so that the resolution of the deconvolved image is compatible with the adopted sampling. Our deconvolution method gives results that are, in at least some cases, superior to those of other commonly used techniques: in particular, it does not produce ringing around point sources superposed on a smooth background. Moreover, it allows researchers to perform accurate astrometry and photometry of crowded fields. These improvements are a consequence of both the correct treatment of sampling and the recognition that the most probable astronomical image is not a flat one. The method is also well adapted to the optimal combination of different images of the same object, as can be obtained, e.g., from infrared observations or via adaptive optics techniques. [less ▲]Detailed reference viewed: 25 (4 ULiège) Deconvolution with correct sampling.Magain, Pierre ; Courbin, F.; Sohy, Sandrine in The Messenger (1997), 88The authors briefly describe the basic ideas behind a new deconvolution technique which overcomes some of the drawbacks of the traditional methods and which gives results of high photometric and ... [more ▼]The authors briefly describe the basic ideas behind a new deconvolution technique which overcomes some of the drawbacks of the traditional methods and which gives results of high photometric and astrometric accuracy. The authors also show how it can be combined with other techniques (e.g. adaptive optics) to give even better results. [less ▲]Detailed reference viewed: 25 (1 ULiège) 1