Related papers: A Balloon-Borne Very Long Baseline Interferometry …
The Very Long Baseline Interferometry (VLBI) monitoring program TANAMI provides bi-monthly, dualfrequency (8GHz and 22GHz) observations of extragalactic jets with milliarcsecond resolution south of -30 deg declination using the Australian…
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…
High-resolution imaging of supermassive black holes is now possible, with new applications to testing general relativity and horizon-scale accretion and relativistic jet formation processes. Over the coming decade, the EHT will propose to…
We present the results of the pilot observations of the Deep Extragalactic VLBI-Optical Survey (DEVOS). Our ultimate aim is to collect information on compact structures in a large sample of extragalactic radio sources (~10000 objects) up to…
We present results from a large global VLBI(Very Long Baseline Interferometry) survey of compact radio sources at 86 GHz which started in October 2001. The main goal of the survey is to increase the total number of objects accessible for…
Observing the dynamics of compact astrophysical objects provides insights into their inner workings, thereby probing physics under extreme conditions. The immediate vicinity of an active supermassive black hole with its event horizon,…
A new generation of sub-orbital platforms will be operational in the next few years. These new telescopes will operate from airborne and balloon-borne platforms where the atmosphere is transparent enough to allow sensitive measurements to…
We discuss the advantages which the next generation interferometer SKA (the Square Kilometer Array) will bring for Very Long Baseline Interferometry (VLBI) at centimeter wavelengths. With a sensitivity to micro-Jy level flux density, a…
Relatively few Very Long Baseline Interferometry (VLBI) polarization observations have been carried out at 18 cm. The importance of such observations lies in their ability to reveal information about the jet magnetic ({\bf B}) field…
This work aims to explore the possibilities of determining the long-period part of the precession-nutation of the Earth with techniques other than very long baseline interferometry (VLBI). Lunar laser ranging (LLR) is chosen for its…
High-resolution millimeter wave very-long-baseline interferometry (mm-VLBI) is an ideal tool for probing the structure at the base of extragalactic jets in detail. The TeV blazar Mrk 501 is one of the best targets among BL Lac objects for…
We give an introduction to interferometrical concepts and their applicability to Be stars. The first part of the paper concentrates on a short historic overview and basic principles of two-beam interferometric observations. In the second…
Despite numerous search campaigns based on a diverse set of observational techniques, exomoons - prospective satellites of extrasolar planets - remain an elusive and hard-to-pin-down class of objects. Yet, the case for intensifying this…
Massive binaries are crucial laboratories that allow us to investigate processes occurring in quite extreme conditions, such as particle acceleration, high-energy emission, or even dust formation. All these processes are intimately…
Recent investigations reveal an important new class of transient radio phenomena that occur on sub-millisecond timescales. Often transient surveys' data volumes are too large to archive exhaustively. Instead, an on-line automatic system…
When VLBI observations are used to determine the position or motion of a radio source relative to reference sources nearby on the sky, the astrometric information is usually obtained via: (i) phase-referenced maps; or (ii) parametric model…
Context: Phase referencing is a standard calibration technique in radio interferometry, particularly suited for the detection of weak sources close to the sensitivity limits of the interferometers. However, effects from a changing…
Atmospheric propagation errors are a main constraint on the accuracy of Very Long Baseline Interferometry (VLBI) astrometry. For relative astrometry, differential techniques can mitigate these errors, but their effectiveness diminishes with…
The alignment between the radio-based International Celestial Reference Frame (ICRF) and the optical Gaia Celestial Reference Frame (Gaia-CRF) is critical for multi-waveband astronomy, yet systematic offsets at the optical bright end (G<13)…
The Shanghai Astronomical Observatory (SHAO) of the Chinese Academy of Sciences (CAS) is studying a space VLBI (Very Long Baseline Interferometer) program. The ultimate objective of the program is to image the immediate vicinity of the…