The Cosmological Application of Very High Angular Resolution in Radio Astronomy

Small angle electron scattering (SAES) has been used to study structural features of up to several thousand angstroms in polymers, as well as in metals. SAES may be done either in (a) long camera mode by switching off the objective lens current or in (b) selected area diffraction mode. In the first case very high camera lengths (up to 7Ø meters on JEOL 1Ø ØCX) and high angular resolution can be obtained, while in the second case smaller camera lengths (approximately up to 3.6 meters on JEOL 1Ø ØCX) and lower angular resolution is obtainable. We conducted our SAES studies on JEOL 1ØØCX which can be switched to either mode with a push button as a standard feature.

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The circumstellar discs of Be stars

Proceedings of the International Astronomical Union ◽

10.1017/s1743921311010738 ◽

2010 ◽

Vol 6 (S272) ◽

pp. 325-336 ◽

Cited By ~ 5

Author(s):

Alex C. Carciofi

Keyword(s):

Angular Resolution ◽

Central Star ◽

High Angular Resolution ◽

Be Stars ◽

Keplerian Orbit ◽

Physical Processes ◽

Simple Description ◽

Model Predictions ◽

Mass Ejection ◽

Very High

AbstractCircumstellar discs of Be stars are thought to be formed from material ejected from a fast-spinning central star. This material possesses large amounts of angular momentum and settles in a quasi-Keplerian orbit around the star. This simple description outlines the basic issues that a successful disc theory must address: 1) What is the mechanism responsible for the mass ejection? 2) What is the final configuration of the material? 3) How the disc grows? With the very high angular resolution that can be achieved with modern interferometers operating in the optical and infrared we can now resolve the photosphere and immediate vicinity of nearby Be stars. Those observations are able to provide very stringent tests for our ideas about the physical processes operating in those objects. This paper discusses the basic hydrodynamics of viscous decretion discs around Be stars. The model predictions are quantitatively compared to observations, demonstrating that the viscous decretion scenario is currently the most viable theory to explain the discs around Be stars.

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Fused silica segments: a possible solution for x-ray telescopes with very high angular resolution like Lynx/XRS

Optics for EUV, X-Ray, and Gamma-Ray Astronomy VIII ◽

10.1117/12.2275228 ◽

2017 ◽

Author(s):

Bianca Salmaso ◽

Stefano Basso ◽

Marta M. Civitani ◽

Mauro Ghigo ◽

Joanna Holyszko ◽

...

Keyword(s):

Angular Resolution ◽

Fused Silica ◽

High Angular Resolution ◽

X Ray ◽

Very High

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Introduction to the Joint Commission Meeting on High Resolution Imaging from the Ground

Highlights of Astronomy ◽

10.1017/s1539299600008261 ◽

1989 ◽

Vol 8 ◽

pp. 545-546

Author(s):

John Davis

Keyword(s):

High Resolution ◽

Angular Resolution ◽

High Angular Resolution ◽

High Resolution Imaging ◽

Wide Range ◽

High Resolution Images ◽

Resolution Imaging ◽

Optical Wavelengths ◽

To Come ◽

Very High

As a result of advances in instrumentation and techniques, from radio through to optical wavelengths, we have before us the prospect of producing very high resolution images of a wide range of objects across this entire spectral range. This prospect, and the new knowledge and discoveries that may be anticipated from it, lie behind an upsurge in interest in high resolution imaging from the ground. Several new high angular resolution instruments for radio, infrared, and optical wavelengths are expected to come into operation before the 1991 IAU General Assembly.

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Investigation of the Chromosphere–Corona Interface with the Upgraded Very High Angular Resolution Ultraviolet Telescope (VAULT2.0)

Journal of Astronomical Instrumentation ◽

10.1142/s2251171716400031 ◽

2016 ◽

Vol 05 (01) ◽

pp. 1640003 ◽

Cited By ~ 5

Author(s):

Angelos Vourlidas ◽

Samuel Tun Beltran ◽

Georgios Chintzoglou ◽

Kevin Eisenhower ◽

Clarence Korendyke ◽

...

Keyword(s):

High Resolution ◽

Angular Resolution ◽

Solar Spectrum ◽

High Angular Resolution ◽

High Resolution Data ◽

Lyman Alpha ◽

And Performance ◽

White Sands ◽

Very High ◽

Resolution Data

Very high angular resolution ultraviolet telescope (VAULT2.0) is a Lyman-alpha (Ly[Formula: see text]; 1216[Formula: see text]Å) spectroheliograph designed to observe the upper chromospheric region of the solar atmosphere with high spatial ([Formula: see text]) and temporal (8[Formula: see text]s) resolution. Besides being the brightest line in the solar spectrum, Ly[Formula: see text] emission arises at the temperature interface between coronal and chromospheric plasmas and may, hence, hold important clues about the transfer of mass and energy to the solar corona. VAULT2.0 is an upgrade of the previously flown VAULT rocket and was launched successfully on September 30, 2014 from White Sands Missile Range (WSMR). The target was AR12172 midway toward the southwestern limb. We obtained 33 images at 8[Formula: see text]s cadence at arc second resolution due to hardware problems. The science campaign was a resounding success, with all space and ground-based instruments obtaining high-resolution data at the same location within the AR. We discuss the science rationale, instrument upgrades, and performance during the first flight and present some preliminary science results.

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Plans for the Australian Synthesis Telescope

Publications of the Astronomical Society of Australia ◽

10.1017/s1323358000014478 ◽

1976 ◽

Vol 3 (1) ◽

pp. 7-11 ◽

Cited By ~ 3

Author(s):

K. J. Wellington

Keyword(s):

Radio Astronomy ◽

Angular Resolution ◽

High Sensitivity ◽

Aperture Synthesis ◽

High Angular Resolution ◽

The Past ◽

New Synthesis

A major requirement of modern radio astronomy is the attainment of the highest possible angular resolution. This high angular resolution should be matched by a high sensitivity and by spectral and polarization capabilities. Study and experience have shown that no form of telescope is more effective in this respect than the aperture synthesis type. The past few years have seen a growing realization amongst astronomers, both here and overseas, of the need for a new synthesis telescope able to observe the full southern sky. This realization has been stimulated by several factors:

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Water masers and the near-stellar environment in YSOs

Symposium - International Astronomical Union ◽

10.1017/s0074180900222006 ◽

2002 ◽

Vol 206 ◽

pp. 27-34

Author(s):

Mark J. Claussen

Keyword(s):

Main Sequence ◽

Very Long Baseline Interferometry ◽

Angular Resolution ◽

Young Stellar Objects ◽

High Angular Resolution ◽

High Luminosity ◽

Stellar Objects ◽

Long Baseline ◽

Water Masers ◽

Very High

I present a review of observations of water masers, in particular very high angular resolution of water masers using Very Long Baseline Interferometry, with which it is possible to probe the environment of young stellar objects and forming stars within only a few A.U. of the protostar, its accretion disk, and therefore the base of outflowing material. Although reference is made to some high-luminosity sources, the main thrust of the review are the water masers found toward forming objects whose mass and luminosity will be approximately that of the Sun when they reach the main sequence.

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Interferometry and Stellar Magnetism

International Astronomical Union Colloquium ◽

10.1017/s0252921100055792 ◽

2000 ◽

Vol 175 ◽

pp. 174-177 ◽

Cited By ~ 1

Author(s):

O. Chesneau ◽

K. Rousselet-Perraut ◽

F. Vakili

Keyword(s):

Spectral Resolution ◽

Angular Resolution ◽

Zeeman Effect ◽

High Spectral Resolution ◽

Sensitivity Threshold ◽

High Angular Resolution ◽

Be Stars ◽

Long Baseline ◽

Instrumental Polarisation ◽

Very High

AbstractThe classical detection of magnetic fields in Be stars remains a challenge due to the sensitivity threshold and geometrical cancelation of the field effects. We propose to study the Zeeman effect using Spectro-Polarimetric INterferometry (SPIN) which consists of the simultaneous use of polarimetry and very high angular resolution provided by long baseline interferometers. As monitoring of the instrumental polarisation is mandatory in order to calibrate interferometric observations in any case, the polarised signal is a natural by-product of interferometers. This method will be tested on the GI2T interferometer thanks to its high spectral resolution and its polarimetric capabilities.

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Radio Source Variability as a Tool for Very High Resolution

Symposium - International Astronomical Union ◽

10.1017/s0074180900107582 ◽

1994 ◽

Vol 158 ◽

pp. 201-203

Author(s):

N. Shapirovskaya ◽

O. B. Slee ◽

P. Hughes ◽

G. Tsarevsky

Keyword(s):

High Resolution ◽

Radio Source ◽

Time Scale ◽

High Frequency ◽

Angular Resolution ◽

Good Evidence ◽

High Angular Resolution ◽

Intrinsic Variability ◽

Interstellar Plasma ◽

Very High

If flux density variability is intrinsic to extragalactic sources, then the shortest time scale of the variability yields an extremely high angular resolution. There is, however, good evidence that some of the variability is due to refractive scintillation in our galaxy's interstellar plasma turbulence. The effect, initially discovered at low radio frequencies, is here shown to extend into the GHz band, which, up to now, has been assumed to display only the intrinsic variability. We conclude that further study in both the intermediate and high frequency bands needed to separate the intrinsic and extrinsic components of variability.

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