scholarly journals Simulations of scattered light control algorithms for coronagraphic high contrast imaging

2003 ◽  
Author(s):  
Scott A. Basinger ◽  
Joseph J. Green ◽  
Stuart B. Shaklan ◽  
David C. Redding
Keyword(s):  
Scattered Light ◽  
Control Algorithms ◽  
High Contrast ◽  
Light Control ◽  
Contrast Imaging ◽  
High Contrast Imaging

scholarly journals Origin of the asymmetry of the wind driven halo observed in high-contrast images

2018 ◽  
Vol 620 ◽  
pp. L10 ◽  
Author(s):  
F. Cantalloube ◽  
E. H. Por ◽  
K. Dohlen ◽  
J.-F. Sauvage ◽  
A. Vigan ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Predictive Control ◽  
Near Infrared ◽  
Control Algorithms ◽  
Circumstellar Disk ◽  
High Contrast ◽  
Contrast Imaging ◽  
High Contrast Imaging ◽  
The Asymmetry ◽  
Processing Techniques

The latest generation of high-contrast instruments dedicated to exoplanets and circumstellar disk imaging are equipped with extreme adaptive optics and coronagraphs to reach contrasts of up to 10−4 at a few tenths of arcseconds in the near-infrared. The resulting image shows faint features, only revealed with this combination, such as the wind driven halo. The wind driven halo is due to the lag between the adaptive optics correction and the turbulence speed over the telescope pupil. However, we observe an asymmetry of this wind driven halo that was not expected when the instrument was designed. In this letter, we describe and demonstrate the physical origin of this asymmetry and support our explanation by simulating the asymmetry with an end-to-end approach. From this work, we find that the observed asymmetry is explained by the interference between the AO-lag error and scintillation effects, mainly originating from the fast jet stream layer located at about 12 km in altitude. Now identified and interpreted, this effect can be taken into account for further design of high-contrast imaging simulators, next generation or upgrade of high-contrast instruments, predictive control algorithms for adaptive optics, or image post-processing techniques.

scholarly journals Two cold belts in the debris disk around the G-type star NZ Lupi

2019 ◽  
Vol 625 ◽  
pp. A21 ◽  
Author(s):  
A. Boccaletti ◽  
P. Thébault ◽  
N. Pawellek ◽  
A.-M. Lagrange ◽  
R. Galicher ◽  
...  
Keyword(s):  
Scattered Light ◽  
Planetary Systems ◽  
High Angular Resolution ◽  
High Contrast ◽  
Contrast Imaging ◽  
Nearby Star ◽  
Imaging Device ◽  
High Contrast Imaging ◽  
Debris Disk ◽  
Dust Distribution

Context. Planetary systems hold the imprint of the formation and of the evolution of planets especially at young ages, and in particular at the stage when the gas has dissipated leaving mostly secondary dust grains. The dynamical perturbation of planets in the dust distribution can be revealed with high-contrast imaging in a variety of structures. Aims. SPHERE, the high-contrast imaging device installed at the VLT, was designed to search for young giant planets in long period, but is also able to resolve fine details of planetary systems at the scale of astronomical units in the scattered-light regime. As a young and nearby star, NZ Lup was observed in the course of the SPHERE survey. A debris disk had been formerly identified with HST/NICMOS. Methods. We observed this system in the near-infrared with the camera in narrow and broad band filters and with the integral field spectrograph. High contrasts are achieved by the mean of pupil tracking combined with angular differential imaging algorithms. Results. The high angular resolution provided by SPHERE allows us to reveal a new feature in the disk which is interpreted as a superimposition of two belts of planetesimals located at stellocentric distances of ~85 and ~115 au, and with a mutual inclination of about 5°. Despite the very high inclination of the disk with respect to the line of sight, we conclude that the presence of a gap, that is, a void in the dust distribution between the belts, is likely. Conclusions. We discuss the implication of the existence of two belts and their relative inclination with respect to the presence of planets.

scholarly journals High-contrast study of the candidate planets and protoplanetary disk around HD 100546

2018 ◽  
Vol 619 ◽  
pp. A160 ◽  
Author(s):  
E. Sissa ◽  
R. Gratton ◽  
A. Garufi ◽  
E. Rigliaco ◽  
A. Zurlo ◽  
...  
Keyword(s):  
Scattered Light ◽  
Dust Cloud ◽  
Outer Edge ◽  
Dual Band ◽  
Data Sets ◽  
Contrast Study ◽  
High Contrast ◽  
Contrast Imaging ◽  
High Contrast Imaging ◽  
Disk Plane

The nearby Herbig Be star HD 100546 is known to be a laboratory for the study of protoplanets and their relation with the circumstellar disk, which is carved by at least two gaps. We observed the HD 100546 environment with high-contrast imaging exploiting several different observing modes of SPHERE, including data sets with and without coronagraphs, dual band imaging, integral field spectroscopy and polarimetry. The picture emerging from these different data sets is complex. Flux-conservative algorithm images clearly show the disk up to 200 au. More aggressive algorithms reveal several rings and warped arms that are seen overlapping the main disk. Some of these structures are found to lie at considerable height over the disk mid-plane at about 30 au. Our images demonstrate that the brightest wings close to the star in the near side of the disk are a unique structure, corresponding to the outer edge of the intermediate disk at ~ 40 au. Modeling of the scattered light from the disk with a geometrical algorithm reveals that a moderately thin structure (H∕r = 0.18 at 40 au) can well reproduce the light distribution in the flux-conservative images. We suggest that the gap between 44 and 113 au spans between the 1:2 and 3:2 resonance orbits of a massive body located at ~ 70 au, which mightcoincide with the candidate planet HD 100546b detected with previous thermal infrared (IR) observations. In this picture, the two wings can be the near side of a ring formed by disk material brought out of the disk at the 1:2 resonance with the same massive object. While we find no clear evidence confirming detection of the planet candidate HD 100546c in our data, we find a diffuse emission close to the expected position of HD 100546b. This source can be described as an extremely reddened substellar object surrounded by a dust cloud or its circumplanetary disk. Its astrometry is broadly consistent with a circular orbital motion on the disk plane, a result that could be confirmed with new observations. Further observations at various wavelengths are required to fully understand the complex phenomenology of HD 100546.

The CM120 Biotwin: a high-contrast objective lens, optimum cryo-vacuum and improved EDX performance

1995 ◽  
Vol 53 ◽  
pp. 584-585
Author(s):  
Uwe Lücken ◽  
Michael Felsmann ◽  
Wim M. Busing ◽  
Frank de Jong
Keyword(s):  
Life Science ◽  
Focal Length ◽  
Objective Lens ◽  
High Contrast ◽  
Contrast Imaging ◽  
X Ray ◽  
Forming Mechanism ◽  
Similar Image ◽  
High Contrast Imaging ◽  
Low Concentrations

A new microscope for the study of life science specimen has been developed. Special attention has been given to the problems of unstained samples, cryo-specimens and x-ray analysis at low concentrations.A new objective lens with a Cs of 6.2 mm and a focal length of 5.9 mm for high-contrast imaging has been developed. The contrast of a TWIN lens (f = 2.8 mm, Cs = 2 mm) and the BioTWTN are compared at the level of mean and SD of slow scan CCD images. Figure 1a shows 500 +/- 150 and Fig. 1b only 500 +/- 40 counts/pixel. The contrast-forming mechanism for amplitude contrast is dependent on the wavelength, the objective aperture and the focal length. For similar image conditions (same voltage, same objective aperture) the BioTWIN shows more than double the contrast of the TWIN lens. For phasecontrast specimens (like thin frozen-hydrated films) the contrast at Scherzer focus is approximately proportional to the √ Cs.

scholarly journals Anti-quenching NIR-II molecular fluorophores for in vivo high-contrast imaging and pH sensing

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Shangfeng Wang ◽  
Yong Fan ◽  
Dandan Li ◽  
Caixia Sun ◽  
Zuhai Lei ◽  
...  
Keyword(s):  
Ph Sensing ◽  
High Contrast ◽  
Contrast Imaging ◽  
High Contrast Imaging

Simulations of exoplanets detection obtained with a high-contrast imaging instrument: CHEOPS

2004 ◽  
Author(s):  
Alessandro Berton ◽  
Raffaele G. Gratton ◽  
Markus Feldt ◽  
Silvano Desidera ◽  
Elena Masciadri ◽  
...  
Keyword(s):  
High Contrast ◽  
Contrast Imaging ◽  
High Contrast Imaging ◽  
Imaging Instrument

Laboratory test of a polarimetry imaging subtraction system for the high-contrast imaging

2012 ◽  
Author(s):  
Jiangpei Dou ◽  
Deqing Ren ◽  
Yongtian Zhu ◽  
Xi Zhang ◽  
Rong Li
Keyword(s):  
Laboratory Test ◽  
High Contrast ◽  
Contrast Imaging ◽  
High Contrast Imaging
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