Closing the gap between Earth-based and interplanetary mission observations: Vesta seen by VLT/SPHERE

Fétick, Romain; Jordá, L.; Vernazza, Pierre; Marsset, M.; Drouard, A.; Fusco, Thierry; Carry, B.; Marchis, Franck; Hanuš, Josef; Viikinkoski, Matti; Birlan, Mirel; Bartczak, P.; Berthier, J.; Castillo‐Rogez, Julie; Cipriani, F.; Colas, F.; Dudziński, G.; Dumas, Christophe; Ferrais, Marin; Jehin, Emmanuël; Kaasalainen, M.; Kryszczyńska, A.; Lamy, P.; Coroller, H. Le; Marciniak, A.; Michałowski, Tadeusz; Michel, Patrick; Mugnier, Laurent M.; Neichel, Benoît; Pajuelo, M.; Podlewska-Gaca, E.; Santana-Ros, T.; Tanga, P.; Vachier, F.; Vigan, A.; Witasse, Olivier; Yang, Bin

doi:10.1051/0004-6361/201834749

Cited by 30 publications

(42 citation statements)

References 32 publications

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“…Finally, the small number of parameters makes this model suited for image post-processing techniques such as deconvolution of long-exposure images. Deconvolution using parametric PSFs has already been demonstrated by Drummond (1998) and Fétick et al (2019). We plan to develop a myopic deconvolution algorithm estimating both the observed object and the PSF parameters in a marginal approach similar to Blanco & Mugnier (2011).…”

Section: Discussionmentioning

confidence: 82%

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Physics-based model of the adaptive-optics-corrected point spread function

Fétick

Fusco

Neichel

et al. 2019

A&A

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Context. Adaptive optics (AO) systems greatly increase the resolution of large telescopes, but produce complex point spread function (PSF) shapes, varying in time and across the field of view. The PSF must be accurately known since it provides crucial information about optical systems for design, characterization, diagnostics, and image post-processing. Aims. We develop here a model of the AO long-exposure PSF, adapted to various seeing conditions and any AO system. This model is made to match accurately both the core of the PSF and its turbulent halo.Methods. The PSF model we develop is based on a parsimonious parameterization of the phase power spectral density, with only five parameters to describe circularly symmetric PSFs and seven parameters for asymmetrical ones. Moreover, one of the parameters is the Fried parameter r 0 of the turbulence's strength. This physical parameter is an asset in the PSF model since it can be correlated with external measurements of the r 0 , such as phase slopes from the AO real time computer (RTC) or site seeing monitoring. Results. We fit our model against end-to-end simulated PSFs using the OOMAO tool, and against on-sky PSFs from the SPHERE/ZIMPOL imager and the MUSE integral field spectrometer working in AO narrow-field mode. Our model matches the shape of the AO PSF both in the core and the halo, with a relative error smaller than 1% for simulated and experimental data. We also show that we retrieve the r 0 parameter with sub-centimeter precision on simulated data. For ZIMPOL data, we show a correlation of 97% between our r 0 estimation and the RTC estimation. Finally, MUSE allows us to test the spectral dependency of the fitted r 0 parameter. It follows the theoretical λ 6/5 evolution with a standard deviation of 0.3 cm. Evolution of other PSF parameters, such as residual phase variance or aliasing, is also discussed.

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Section: Discussionmentioning

confidence: 82%

“…Image post-processing, such as deconvolution (Mugnier et al 2004), also requires knowledge of the PSF. Deconvolution of long-exposure images using parametric PSFs has already been demonstrated in Drummond (1998) and Fétick et al (2019). A fine model of the PSF is necessary.…”

Section: Introductionmentioning

confidence: 95%

Physics-based model of the adaptive-optics-corrected point spread function

Fétick

Fusco

Neichel

et al. 2019

A&A

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“…We note that, for further development, a more complex PSF model could be investigated. For example, R. Fetick (Fétick et al 2019) recently proposed a new PSF model for AO-corrected applications. This latter model relies on nine parameters and allows the user to fit an AO-corrected PSF both in its corrected area and its wings extremely accurately.…”

Section: Choice Of Psf Modelmentioning

confidence: 99%

“…An obvious example is the comparison with higher spatial resolution space observations, like those obtained with the Hubble Space Telescope, which achieve a ten times higher resolution than classical ground-based observations in median seeing conditions. Source optimal extraction, source deblending, and image deconvolution are other examples where accurate knowledge of the point spread function (PSF) is needed (Beltramo-Martin et al 2019;Fétick, R. JL. et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Reconstruction of the ground-layer adaptive-optics point spread function for MUSE wide field mode observations

Fusco

Bacon

Kamann

et al. 2020

A&A

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Context. Here we describe a simple, efficient, and most importantly fully operational point-spread-function(PSF)-reconstruction approach for laser-assisted ground layer adaptive optics (GLAO) in the frame of the Multi Unit Spectroscopic Explorer (MUSE) Wide Field Mode. Aims. Based on clear astrophysical requirements derived by the MUSE team and using the functionality of the current ESO Adaptive Optics Facility we aim to develop an operational PSF-reconstruction (PSFR) algorithm and test it both in simulations and using on-sky data.Methods. The PSFR approach is based on a Fourier description of the GLAO correction to which the specific instrumental effects of MUSE Wide Field Mode (pixel size, internal aberrations, etc.) have been added. It was first thoroughly validated with full end-to-end simulations. Sensitivity to the main atmospheric and AO system parameters was analysed and the code was re-optimised to account for the sensitivity found. Finally, the optimised algorithm was tested and commissioned using more than one year of on-sky MUSE data. Results. We demonstrate with an on-sky data analysis that our algorithm meets all the requirements imposed by the MUSE scientists, namely an accuracy better than a few percent on the critical PSF parameters including full width at half maximum and global PSF shape through the kurtosis parameter of a Moffat function. Conclusions. The PSFR algorithm is publicly available and is used routinely to assess the MUSE image quality for each observation. It can be included in any post-processing activity which requires knowledge of the PSF.

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“…The breakups of asteroids have been recorded in the form of asteroid families (Nesvorný et al 2015;Vinogradova 2019), we can also see impact features, such as craters or boulders, on surfaces of asteroids. These features can be observed directly during a satellite flyby or even with ground-based instruments (Vernazza et al 2018;Fétick et al 2019).…”

Section: Asteroid Collisions In the Main Beltmentioning

confidence: 99%

Impacts into rotating targets: angular momentum draining and efficient formation of synthetic families

Ševeček

Brož

Jutzi

2019

A&A

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About 10% of the observed asteroids have rotational periods lower than P = 3 h and they seem to be relatively close to the spin barrier. Yet, the rotation has often been neglected in simulations of asteroid collisions. To determine the effect of rotation, we perform a large number of SPH/N-body impact simulations with rotating targets. We developed a new unified SPH/N-body code with self-gravity, suitable for simulations of both fragmentation phase and gravitational reaccumulation. The code has been verified against previous ones (Benz and Asphaug 1994), but we also tested new features, e.g. rotational stability, tensile stability, etc. Using the new code, we ran simulations with D pb = 10 km and 100 km monolithic targets and compared synthetic asteroid families created by these impacts with families corresponding to non-rotating targets. The rotation affects mostly cratering events at oblique impact angles. The total mass ejected by these collision can be up to five times larger for rotating targets. We further compute the transfer of the angular momentum and determine conditions under which impacts accelerate or decelerate the target. While individual cratering collisions can cause both acceleration and deceleration, the deceleration prevails on average, collisions thus cause a systematic spin-down of asteroid population.

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Closing the gap between Earth-based and interplanetary mission observations: Vesta seen by VLT/SPHERE

Cited by 30 publications

References 32 publications

Physics-based model of the adaptive-optics-corrected point spread function

Physics-based model of the adaptive-optics-corrected point spread function

Reconstruction of the ground-layer adaptive-optics point spread function for MUSE wide field mode observations

Impacts into rotating targets: angular momentum draining and efficient formation of synthetic families

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