scholarly journals High-resolution imaging follow-up of doubly imaged quasars

2021 ◽  
Vol 503 (2) ◽  
pp. 1557-1567
Author(s):  
Anowar J Shajib ◽  
Eden Molina ◽  
Adriano Agnello ◽  
Peter R Williams ◽  
Simon Birrer ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Time Delays ◽  
Near Infrared ◽  
High Resolution Imaging ◽  
Modelling Uncertainty ◽  
Model Predictions ◽  
Smooth Model ◽  
Resolution Imaging ◽  
K Band

ABSTRACT We report upon 3 years of follow-up and confirmation of doubly imaged quasar lenses through imaging campaigns from 2016 to 2018 with the Near-Infrared Camera2 (NIRC2) on the W. M. Keck Observatory. A sample of 57 quasar lens candidates are imaged in adaptive-optics-assisted or seeing-limited K′-band observations. Out of these 57 candidates, 15 are confirmed as lenses. We form a sample of 20 lenses adding in a number of previously known lenses that were imaged with NIRC2 in 2013–14 as part of a pilot study. By modelling these 20 lenses, we obtain K′-band relative photometry and astrometry of the quasar images and the lens galaxy. We also provide the lens properties and predicted time delays to aid planning of follow-up observations necessary for various astrophysical applications, e.g. spectroscopic follow-up to obtain the deflector redshifts for the newly confirmed systems. We compare the departure of the observed flux ratios from the smooth-model predictions between doubly and quadruply imaged quasar systems. We find that the departure is consistent between these two types of lenses if the modelling uncertainty is comparable.

scholarly journals High-Resolution Imaging of Retinal Vasculitis by Flood Illumination Adaptive Optics Ophthalmoscopy: A Follow-up Study

2019 ◽  
Vol 28 (8) ◽  
pp. 1171-1180 ◽  
Author(s):  
Marie-Hélène Errera ◽  
Marthe Laguarrigue ◽  
Florence Rossant ◽  
Edouard Koch ◽  
Céline Chaumette ◽  
...  
Keyword(s):  
High Resolution ◽  
Adaptive Optics ◽  
Retinal Vasculitis ◽  
High Resolution Imaging ◽  
Follow Up Study ◽  
Resolution Imaging

scholarly journals Follow-Up and Validation of K2 and TESS Planetary Systems With Keck NIRC2 Adaptive Optics Imaging

2021 ◽  
Vol 8 ◽  
Author(s):  
Joshua E. Schlieder ◽  
Erica J. Gonzales ◽  
David R. Ciardi ◽  
Rahul I. Patel ◽  
Ian J. M. Crossfield ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Planetary System ◽  
Planetary Systems ◽  
High Resolution Imaging ◽  
Validation Process ◽  
System Validation ◽  
Adaptive Optics Imaging ◽  
Resolution Imaging ◽  
Calibrated Images

High resolution imaging (HRI) is a critical part of the transiting exoplanet follow-up and validation process. HRI allows previously unresolved stellar companions and background blends to be resolved, vetting false positive signals and improving the radii measurements of true planets. Through a multi-semester Keck NIRC2 adaptive optics imaging program, we have pursued HRI of K2 and TESS candidate planet host systems to provide the transiting exoplanet community with necessary data for system validation and characterization. Here we present a summary of our ongoing program that includes an up to date list of targets observed, a description of the observations and data reduction, and a discussion of planetary systems validated by the community using these data. This observing program has been key in NASA's K2 and TESS missions reaching their goals of identifying new exoplanets ideal for continued follow-up observations to measure their masses and investigate their atmospheres. Once processed, all observations presented here are available as calibrated images and resulting contrast curves through the Exoplanet Follow-up Observing Program (ExoFOP) website. We encourage members of the exoplanet community to use these data products in their ongoing planetary system validation and characterization efforts.

scholarly journals Identification of peat type and humification by laboratory VNIR/SWIR hyperspectral imaging of peat profiles with focus on fen-bog transition in aapa mires

2020 ◽  
Author(s):  
L. Granlund ◽  
M. Keinänen ◽  
T. Tahvanainen
Keyword(s):  
Hyperspectral Imaging ◽  
Near Infrared ◽  
Support Vector ◽  
High Resolution Imaging ◽  
Factors Affecting ◽  
Vector Machines ◽  
Resolution Imaging ◽  
Shortwave Infrared ◽  
Type Classification ◽  
Wide Potential

Abstract Aims Hyperspectral imaging (HSI) has high potential for analysing peat cores, but methodologies are deficient. We aimed for robust peat type classification and humification estimation. We also explored other factors affecting peat spectral properties. Methods We used two laboratory setups: VNIR (visible to near-infrared) and SWIR (shortwave infrared) for high resolution imaging of intact peat profiles with fen-bog transitions. Peat types were classified with support vector machines, indices were developed for von Post estimation, and K-means clustering was used to analyse stratigraphic patterns in peat quality. With separate experiments, we studied spectral effects of drying and oxidation. Results Despite major effects, oxidation and water content did not impede robust HSI classification. The accuracy between Carex peat and Sphagnum peat in validation was 80% with VNIR and 81% with SWIR data. The spectral humification indices had accuracies of 82% with VNIR and 56%. Stratigraphic HSI patterns revealed that 36% of peat layer shifts were inclined by over 20 degrees. Spectral indices were used to extrapolate visualisations of element concentrations. Conclusions HSI provided reliable information of basic peat quality and was useful in visual mapping, that can guide sampling for other analyses. HSI can manage large amounts of samples to widen the scope of detailed analysis beyond single profiles and it has wide potential in peat research beyond the exploratory scope of this paper. We were able to confirm the capacity of HSI to reveal shifts of peat quality, connected to ecosystem-scale change.

scholarly journals Near-infrared High-resolution Imaging Polarimetry of FU Ori-type Objects: Toward a Unified Scheme for Low-mass Protostellar Evolution

2018 ◽  
Vol 864 (1) ◽  
pp. 20 ◽  
Author(s):  
Michihiro Takami ◽  
Guangwei Fu ◽  
Hauyu Baobab Liu ◽  
Jennifer L. Karr ◽  
Jun Hashimoto ◽  
...  
Keyword(s):  
High Resolution ◽  
Near Infrared ◽  
High Resolution Imaging ◽  
Imaging Polarimetry ◽  
Low Mass ◽  
Resolution Imaging ◽  
Fu Ori

scholarly journals Structural and Morphological Properties of Ultraluminous Infrared Galaxies at 1 < z < 3

2015 ◽  
Vol 24 (3) ◽  
Author(s):  
Guanwen Fang ◽  
Zhongyang Ma ◽  
Yang Chen ◽  
Xu Kong
Keyword(s):  
High Resolution ◽  
Near Infrared ◽  
Hubble Space Telescope ◽  
Morphological Properties ◽  
Wide Field ◽  
High Resolution Imaging ◽  
Infrared Galaxies ◽  
Morphology And Structure ◽  
Ultraluminous Infrared Galaxies ◽  
Resolution Imaging

AbstractUsing the Hubble Space Telescope (HST)/Wide Field Camera 3 (WFC3) near-infrared high-resolution imaging from the 3D-HST survey, we analyze the morphology and structure of 502 ultraluminous infrared galaxies (ULIRGs;

scholarly journals High-Resolution Imaging of Parafoveal Cones in Different Stages of Diabetic Retinopathy Using Adaptive Optics Fundus Camera

PLoS ONE ◽  
2016 ◽  
Vol 11 (4) ◽  
pp. e0152788 ◽  
Author(s):  
Mohamed Kamel Soliman ◽  
Mohammad Ali Sadiq ◽  
Aniruddha Agarwal ◽  
Salman Sarwar ◽  
Muhammad Hassan ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
High Resolution ◽  
Adaptive Optics ◽  
High Resolution Imaging ◽  
Fundus Camera ◽  
Resolution Imaging
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