Related papers: ngVLA: Astrometry and Long Baseline Science
Episodic accretion may be a common occurrence in the evolution of young pre-main sequence stars and has important implications for our understanding of star and planet formation. Many fundamental aspects of what drives the accretion…
There is a long history of radio telescopes being used to augment the radio antennas regularly used to conduct telemetry, tracking, and command of deep space spacecraft. Radio telescopes are particularly valuable during short-duration…
The sensitivity and versatility of SKA will provide microarcsec astrometric precision and high quality milliarcsec-resolution images by simultaneously detecting calibrator sources near the target source. To reach these goals, we suggest…
This paper discusses compelling science cases for a future long-baseline interferometer operating at millimeter and centimeter wavelengths, like the proposed Next Generation Vary Large Array (ngVLA). We report on the activities of the…
Stellar occultations currently provide the most accurate ground-based measurements of the positions of natural satellites (down to a few kilometres for the Galilean moons). However, when using these observations in the calculation of…
The capabilities of the Global mm-VLBI Array are summarized and demonstrated through actual images from our monitoring of extragalactic radio jets. This sensitive 3mm-VLBI interferometer is able to provide images of up to 50 microarcseconds…
Lunar laser ranging has provided many of the best tests of gravitation since the first Apollo astronauts landed on the Moon. The march to higher precision continues to this day, now entering the millimeter regime, and promising continued…
This article is a sort of sequel of the earlier extensive review by Saha (1999a) where emphasis was laid down on the ground based single aperture, as well as on the working long baseline optical interferometers (LBI) situated at the various…
The advent of next-generation radio telescopes is set to transform radio astronomy by producing massive data volumes that challenge traditional processing methods. Deep learning techniques have shown strong potential in automating radio…
Searching for extrasolar planets by direct detection is extremely challenging for current instrumentation. Indirect methods, that measure the effect of a planet on its host star, are much more promising and have indeed led to the discovery…
In this paper, we propose a new approach to determining cosmological distances to active galactic nuclei (AGN) via light travel-time arguments, which can be extended from nearby sources to very high redshift sources. The key assumption is…
In combination with observations of the Cosmic Microwave Background, a measurement of the Hubble Constant provides a direct test of the standard $\Lambda$CDM cosmological model and a powerful constraint on the equation of state of dark…
We report on recent technical developments in the front- and back-ends for the four 20 m radio telescopes of the Japanese Very-Long-Baseline Interferometry (VLBI) project, VLBI Exploration of Radio Astrometry (VERA). We present a brief…
Very long baseline interferometry (VLBI) at millimeter (mm) wavelengths is being employed to resolve event-horizon scale structure of the environment surrounding the Milky-Way black hole, at an angular resolution of a few tens of…
To accurately link the radio and optical Celestial Reference Frames (CRFs) at optical bright end, i.e., with Gaia G band magnitude < 13, increasing number and improving sky distribution of radio stars with accurate astrometric parameters…
The recent development of a relatively inexpensive 16-Gbps data-recording system based on commercial off-the-shelf technology and open-source software, along with parallel development in broadband Very Long Baseline Interferometry (VLBI)…
The internet has been used for data transfer in radio astronomy ever since its inception; however it is only recently that network bandwidth capability means that the internet becomes competitive with traditional forms of data storage. Very…
What is long-baseline optical/IR stellar interferometry? A few years ago, many astronomers might not have been able to answer that question properly. This is today hopefully not the case anymore, because mainstream facilities, such as the…
With the exceptional progress e-VLBI has achieved over the last three years, the VLBI of the future has already started. At least for the EVN, it is argued that at some point all VLBI operations should be done in e-VLBI mode. This ambition…
I present an introductory review text, focusing on recent deep field studies using radio telescopes, including high-resolution, wide-field VLBI observations. The nature of the faint radio source population is discussed, taking into account…