Results 71 to 80 of about 9,059 (229)

VLBI surveys [PDF]

open access: yesProceedings of 8th European VLBI Network Symposium — PoS(8thEVN), 2007
Systematic surveys of astronomical objects often lead to discoveries, but always provide invaluable information for statistical studies of well-defined samples. They also promote follow-up investigations of individual objects or classes. Surveys using a yet unexplored observing wavelength, a novel technique or a new instrument are of special importance.
openaire   +2 more sources

Multiwavelength VLBI observations of Sagittarius A* [PDF]

open access: yesAstronomy & Astrophysics, 2010
14pages, 14 Figures, Accepted for publication in A& ...
Lu, R. -S.   +7 more
openaire   +2 more sources

Inter-comparison study of time and frequency transfer between VLBI and other techniques (GPS, ETS8(TCE), TW(DPN) and DMTD) [PDF]

open access: yes, 2011
We carried out the intercomparison ex- periments between VLBI and other techniques to show the capability of VLBI time and frequency transfer by using the current geodetic VLBI tech- nique and facilities as the summary of the exper- iments that we ...
Hama, S   +17 more
core  

Spectral Line VLBI Studies Using the ngEHT

open access: yesGalaxies, 2023
Spectroscopy in the mm/sub-mm wavelength range is a powerful tool to study the gaseous medium in various astrophysical environments. The next generation Event Horizon Telescope (ngEHT) equipped with a wide-bandwidth backend system has great potential for
Dong-Jin Kim, Vincent Fish
doaj   +1 more source

VLBI Astrometry [PDF]

open access: yesSymposium - International Astronomical Union, 1994
VLBI is at present the most accurate technique for measuring radiosource positions and the only method capable of high precision for a reasonable number of sources. The applications of VLBI astrometry in stellar, Galactic and extra-Galactic regimes are reviewed.
openaire   +1 more source

The first year of Antarctic VLBI observations [PDF]

open access: yes, 2005
P(論文)We are undertaking a series of geodetic VLBI observations between the Syowa Station 11-m antenna in Antarctica, and the 26-m antennas in Hobart Tasmania and Hartebeesthoek South Africa. These observations are the beginning of our campaign to monitor
Manabe, Seiji   +7 more
core   +2 more sources

Globally Critical Infrastructure: The Unique Risks and Challenges

open access: yesRisk Analysis, Volume 45, Issue 12, Page 4804-4817, December 2025.
ABSTRACT Critical infrastructure is typically identified at the national level. However, disruption to certain infrastructure systems, facilities, and assets can have negative consequences for global societies. Such globally critical infrastructure entails a distinct risk profile for both countries dependent on the infrastructure, and countries that ...
Zachary Kallenborn, Henry H. Willis
wiley   +1 more source

VLBI observations

open access: yesEos, Transactions American Geophysical Union, 1983
From the centers of quasars calculated to have velocities 10 times greater than that of light—the Einsteinian constant of the universe—astronomers are finding explanations of Doppler effect red shifts of emission. Very long baseline interferometry (VLBI) arrays have been used to examine the cores of seven known radio sources in space that are ...
openaire   +1 more source

Inter-comparison study of time and frequency transfer between VLBI and other techniques (GPS, ETS8(TCE), TW(DPN) and DMTD) [PDF]

open access: yes, 2012
We carried out the intercomparison ex- periments between VLBI and other techniques to show the capability of VLBI time and frequency transfer by using the current geodetic VLBI tech- nique and facilities as the summary of the exper- iments that we ...
Hama, S   +17 more
core  

Integration of Statistical Models and Deep Learning: A CEEMDAN‐Based Hybrid Framework for Frequency‐Domain Prediction of Polar Motion

open access: yesEarth and Space Science, Volume 12, Issue 10, October 2025.
Abstract High‐precision Earth Rotation Parameter (ERP) products often experience delays that range from several days to weeks. The use of precise forecasting models can effectively compensate for the impact of such delays. Based on a systematic analysis of the forecasting capabilities of the traditional harmonic least squares fitting and autoregressive
Chen Ren   +4 more
wiley   +1 more source

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