scholarly journals Precision in ground-based solar polarimetry: simulating the role of adaptive optics

2012 ◽  
Vol 51 (33) ◽  
pp. 7953 ◽  
Author(s):  
Nagaraju Krishnappa ◽  
Alex Feller
Keyword(s):  
Adaptive Optics ◽  
Solar Polarimetry

scholarly journals Massive stellar systems: observational challenges and perspectives in the E-ELT era

2015 ◽  
Vol 12 (S316) ◽  
pp. 36-43 ◽  
Author(s):  
G. Bono ◽  
V. F. Braga ◽  
I. Ferraro ◽  
G. Fiorentino ◽  
R. Gilmozzi ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Globular Clusters ◽  
First Generation ◽  
Main Sequence ◽  
Near Infrared ◽  
Galactic Center ◽  
Pros And Cons ◽  
Absolute Age ◽  
The Impact

AbstractWe introduce the empirical framework concerning optical and near-infrared (NIR) photometry of crowded stellar fields. In particular, we address the impact that linear detectors and analytical PSF played in improving the accuracy and the precision of multi-band color-magnitude diagrams (CMDs). We focus our attention on recent findings based on deep NIR images collected with Adaptive Optics (AO) systems at the 8-10m class telescopes and discuss pros and cons of the different approaches. We also discuss the estimate of the absolute age of globular clusters using a well defined knee along the lower main sequence. We mention the role which the current AO-assisted instruments will have in addressing longstanding astrophysical problems of the Galactic center. Finally, we outline the role of first generation of E-ELT instruments upon photometry and spectroscopy of crowded stellar fields.

scholarly journals The Role of Multiplicity in Protoplanetary Disk Evolution

2009 ◽  
Vol 5 (H15) ◽  
pp. 766-766
Author(s):  
Adam L. Kraus ◽  
Michael J. Ireland
Keyword(s):  
Adaptive Optics ◽  
Binary Systems ◽  
Circumstellar Disks ◽  
Protoplanetary Disk ◽  
Nearby Star ◽  
Star Forming ◽  
Star Forming Regions ◽  
Disk Evolution ◽  
Sparse Aperture

AbstractInteractions with close stellar or planetary companions can significantly influence the evolution and lifetime of protoplanetary disks. It has recently become possible to search for these companions, directly studying the role of multiplicity in protoplanetary disk evolution. We have described an ongoing survey to directly detect these stellar and planetary companions in nearby star-forming regions. Our program uses adaptive optics and sparse aperture mask interferometry to achieve typical contrast limits of Δ K=5-6 at the diffraction limit (5–8 MJup at 5–30 AU), while also detecting similar-flux binary companions at separations as low as 15 mas (2.5 AU). In most cases, our survey has found no evidence of companions (planetary or binary) among the well-known “transitional disk” systems; if the inner clearings are due to planet formation, as has been previously suggested, then this paucity places an upper limit on the mass of any resulting planet. Our survey also has uncovered many new binary systems, with the majority falling among the diskless (WTTS) population. This disparity suggests that disk evolution for close (5–30 AU) binary systems is very different from that for single stars. As we show in Figure 1, most circumbinary disks are cleared by ages of 1–2 Myr, while most circumstellar disks are not. These diskless binary systems have biased the disk frequency downward in previous studies. If we remove our new systems from those samples, we find that the disk fraction for single stars could be higher than was previously suggested.

The role of AGN feedback in the baryon cycle at z ∼ 2

2019 ◽  
Vol 15 (S359) ◽  
pp. 51-56
Author(s):  
Vincenzo Mainieri
Keyword(s):  
Active Galactic Nuclei ◽  
Galaxy Evolution ◽  
Adaptive Optics ◽  
Spatial Resolution ◽  
Galactic Nuclei ◽  
Ionized Gas

AbstractIn this proceeding I will summarize our on-going observational campaign to characterize Active Galactic Nuclei (AGN) driven ionized gas outflows at z ˜ 2 and assess their impact on galaxy evolution. The results are mostly derived from a recently completed SINFONI/VLT Large Programme named SUPER, conducted with Adaptive Optics to reach a spatial resolution of ˜2 kpc at z ˜ 2.

scholarly journals Design of Elastomer-CNT Film Photoactuators for Nanolithography

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 314 ◽  
Author(s):  
Le Li ◽  
Zhongjie Huang ◽  
YuHuang Wang ◽  
Keith Brown
Keyword(s):  
Adaptive Optics ◽  
Composite Films ◽  
Scanning Probe ◽  
Rigid Substrate ◽  
Scanning Probe Lithography ◽  
Actuation Time ◽  
Polymer Pen Lithography ◽  
Working Efficiency ◽  
The Ideal

Polymer pen lithography (PPL) is an approach to multiplexing scanning probe lithography, in which an array of probes on a compliant film-coated rigid substrate are used to write patterns on a surface. Recently, it was shown that these nominally passive pen arrays can be rendered photo-active by making them out of a polydimethylsiloxane (PDMS)–carbon nanotube (CNT) composite. While such photoactuated pens in principle represent a rapid, maskless, and versatile nanomanufacturing strategy, a key challenge that remains is learning how to effectively control the writing of each pen, individually. In this research, we studied the design of PDMS–CNT thin-film photoactuators and experimentally explored the role of illumination radius, film thickness, and CNT concentration. Additionally, we have proposed a model that predicts actuation efficiency, actuation time, and the crosstalk between pens. Based upon these results, we have generated a map of working efficiency to elucidate the ideal choice for specific actuation requirements. This work lays the foundation for studying further photoactuatable composite films as actuators in applications beyond lithography including soft robotics and adaptive optics.

scholarly journals SDSS J1534+1615AB: A Novel T Dwarf Binary Found with Keck Laser Guide Star Adaptive Optics and the Potential Role of Binarity in the L/T Transition

2006 ◽  
Vol 647 (2) ◽  
pp. 1393-1404 ◽  
Author(s):  
Michael C. Liu ◽  
S. K. Leggett ◽  
David A. Golimowski ◽  
Kuenley Chiu ◽  
Xiaohui Fan ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Potential Role ◽  
Laser Guide Star ◽  
Guide Star ◽  
Laser Guide

Distant quasar host galaxies and their environments with multi-wavelength 3D spectroscopy

2020 ◽  
Vol 15 (S359) ◽  
pp. 78-81
Author(s):  
Andrey Vayner
Keyword(s):  
Adaptive Optics ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Massive Galaxies ◽  
Star Forming ◽  
Multi Wavelength ◽  
Integral Field Spectrograph ◽  
Guide Star ◽  
Laser Guide

AbstractWe have conducted a multi-wavelength survey of distant (1.3 < z < 2.6) luminous quasars host galaxies using the Keck integral field spectrograph (IFS) OSIRIS and laser guide star adaptive optics (LGS-AO) system, ALMA, HST and VLA. Studying distant quasar host galaxies is essential for understanding the role of active galactic nuclei (AGN) feedback on the interstellar medium (ISM), and its capability of regulating the growth of massive galaxies and their supermassive black holes (SMBH). The combination of LGS-AO and OSIRIS affords the necessary spatial resolution and contrast to disentangle the bright quasar emission from that of its faint host galaxy. We resolve the nebular emission lines, [OIII], [NII],, and [SII] at a sub-kiloparsec resolution to study the distribution, kinematics, and dynamics of the warm-ionized ISM in each quasar host galaxy. The goal of the survey was to search for ionized outflows and relate their spatial extent and energetics to the star-forming properties of the host galaxy. Combining ALMA and OSIRIS, we directly test whether outflows detected with OSIRIS are affecting the molecular ISM. We find that several mechanisms are responsible for driving the outflows within our systems, including radiation pressure in low and high column density environments as well as adiabatic and isothermal shocks driven by the quasar. From line ratio diagnostics, we obtain resolved measurements of the photoionization mechanisms and the gas-phase metallicity. We find that the quasars are responsible for photoionizing the majority of the ISM with metalicities lower than that of gas photoionized by AGN in the low redshift systems. We are now obtaining detailed observations of the circumgalactic medium (CGM) of these systems with the Keck Cosmic Web Imager (KCWI). The gas in the CGM may play an essential role in the evolution of these galaxies.

Role of dactinomycin in the improved survival of children with Wilms' tumor

JAMA ◽  
1966 ◽  
Vol 195 (12) ◽  
pp. 1005-1009 ◽  
Author(s):  
D. J. Fernbach
Keyword(s):  
Wilms Tumor

Role of the allergist in diagnosis and management of patients with uveitis

JAMA ◽  
1966 ◽  
Vol 195 (3) ◽  
pp. 167-172 ◽  
Author(s):  
T. E. Van Metre
Keyword(s):  
Diagnosis And Management

The power of norms to sway fused group members

2018 ◽  
Vol 41 ◽  
Author(s):  
Winnifred R. Louis ◽  
Craig McGarty ◽  
Emma F. Thomas ◽  
Catherine E. Amiot ◽  
Fathali M. Moghaddam
Keyword(s):  
Evolutionary Anthropology ◽  
Normative Systems ◽  
Violent Extremism ◽  
Identity Fusion ◽  
Group Members

AbstractWhitehouse adapts insights from evolutionary anthropology to interpret extreme self-sacrifice through the concept of identity fusion. The model neglects the role of normative systems in shaping behaviors, especially in relation to violent extremism. In peaceful groups, increasing fusion will actually decrease extremism. Groups collectively appraise threats and opportunities, actively debate action options, and rarely choose violence toward self or others.

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