Related papers: The First Very Long Baseline Interferometric SETI …
We conducted a search for narrowband radio signals over four observing sessions in 2020-2023 with the L-band receiver (1.15-1.73 GHz) of the 100 m diameter Green Bank Telescope. We pointed the telescope in the directions of 62 TESS Objects…
The Optical Search for Extraterrestrial Intelligence (OSETI) attempts to detect collimated, narrowband pulses of electromagnetic radiation. These pulses may either consist of signals intentionally directed at the Earth, or signals between…
The space astrometry mission GAIA will construct a dense optical QSO-based celestial reference frame. For consistency between the optical and radio positions, it will be important to align the GAIA frame and the International Celestial…
We have a project to measure magnetic fields in the obscuring tori of AGNs. We observed five free-free absorbed jets in radio galaxies with polarimetric VLBI at 15 GHz to determine Faraday rotation measures. Surprisingly, all sources are…
We study the faint radio population using wide-field very long baseline interferometry (VLBI) observations of 2865 known radio sources in the Cosmic Evolution Survey (COSMOS) field. The main objective of the project was to determine where…
The Panoramic SETI (Search for Extraterrestrial Intelligence) experiment (PANOSETI) aims to detect and quantify optical transients from nanosecond to second precision over a large field-of-view ($\sim$4,450 square-degrees). To meet these…
We present results of Very Long Baseline Array (VLBA) observations of PKS 0528+134 at five frequencies (2.3, 5.0, 8.4, 15.4, and 22.2 GHz). These quasi-simultaneous data enable us to study the spectral distribution of Very Long Baseline…
Very Long Baseline Interferometry (VLBI) astrometry is a well established technique for achieving $\pm10~\mu$as parallax accuracies at frequencies well above 10~GHz. At lower frequencies, uncompensated interferometer delays associated with…
Polarization of radio emission in extragalactic jets at a sub-milliarcsecond angular resolution holds important clues for understanding the structure of the magnetic field in the inner regions of the jets and in close vicinity of the…
Supermassive black holes, with masses of 10^6 to more than 10^9 solar masses, are among the most spectacular objects in the Universe, and are laboratories for physics in extreme conditions. The primary goal of ARISE (Advanced Radio…
The Search for Extraterrestrial Intelligence aims to find evidence of technosignatures, which can point toward the possible existence of technologically advanced extraterrestrial life. Radio signals similar to those engineered on Earth may…
We present the first astrometry catalog from the Japanese VLBI (very long baseline interferometer) project VERA (VLBI Exploration of Radio Astrometry). We have compiled all the astrometry results from VERA, providing accurate trigonometric…
In 2025 July, the third-ever interstellar object, 3I/ATLAS, was discovered on its ingress into the Solar System. Similar to the NASA Voyager missions sent in 1977, science probes by extraterrestrial life ("artifact technosignatures") could…
In this paper we introduce a software package, the Very Long Baseline Interferometry Network SIMulator (VNSIM), which provides an integrated platform assisting radio astronomers to design the Very Long Baseline Interferometry (VLBI)…
Space-VLBI observations of stellar sources represent a challenge since there are few sources with sufficiently high brightness temperature for detection on space-ground baselines. X-ray binaries (XRB) are among the few types of stellar…
Context: We introduce the computation of global reference frames from Very Long Baseline Interferometry (VLBI) observations at the Vienna International VLBI Service for Geodesy and Astrometry (IVS) Analysis Center (VIE) in detail. We focus…
We present Very Long Baseline Array (VLBA) images of 20 TeV blazars (HBLs) not previously well-studied on the parsec scale. Observations were made between August and December 2013, at a frequency of 8.4 GHz. These observations represent the…
The Event Horizon Telescope (EHT) is a very long baseline interferometry (VLBI) array that comprises millimeter- and submillimeter-wavelength telescopes separated by distances comparable to the diameter of the Earth. At a nominal operating…
Very long baseline interferometry (VLBI) monitoring of the 6.7 GHz methanol maser allows us to measure the internal proper motions of the maser spots and therefore study the gas motion around high-mass young stellar objects. To this end, we…
From a combination of MERLIN (Multi-Element Radio-Linked Interferometer Network) and global VLBI (Very Long Baseline Interferometry) observations of the starburst galaxy M82, images of 36 discrete sources at resolutions ranging from ~3 to…