A5028888972- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Planetary Science and Exploration
- Astro and Planetary Science
- Geophysics and Gravity Measurements
- Gamma-ray bursts and supernovae
- Solar and Space Plasma Dynamics
- GNSS positioning and interference
- Ionosphere and magnetosphere dynamics
- Astronomical Observations and Instrumentation
- Stellar, planetary, and galactic studies
- Spacecraft and Cryogenic Technologies
- Astronomy and Astrophysical Research
- Space Science and Extraterrestrial Life
- Superconducting and THz Device Technology
- Spacecraft Design and Technology
- Plant tissue culture and regeneration
- Space exploration and regulation
- Space Exploration and Technology
- Astrophysics and Star Formation Studies
- Plant Reproductive Biology
- Phytoplasmas and Hemiptera pathogens
- Galaxies: Formation, Evolution, Phenomena
- Astrophysical Phenomena and Observations
- Plant Virus Research Studies
Joint Institute for VLBI ERIC
2015-2024
University of Tasmania
2004-2019
Aalto University
2019
Netherlands Institute for Radio Astronomy
2016-2019
SKA Observatory
2019
National Institute for Subatomic Physics
2019
Observatoire de la Côte d’Azur
2019
Centre National de la Recherche Scientifique
2019
Dutch Research Council
2019
Delft University of Technology
2019
Eight optical and four radio observatories have been intensively monitoring the BL Lac object 0716+714 in last years: 4854 data points collected UBVRI bands since 1994, while light curves extend back to 1978. Many of these are presented here for first time. The long-term trend shown by seems vary with a characteristic time scale about 3.3 years, longer period 5.5-6 years characterize variations. In general, colour indices only weakly correlated brightness. flux behaviour at different...
We present the results of several multi-station Very Long Baseline Interferometry (VLBI) experiments conducted with ESA spacecraft Venus Express as a target. To determine true capabilities VLBI tracking for future planetary missions in solar system, it is necessary to demonstrate accuracy method existing operational spacecraft. describe software pipeline processing phase referencing near-field observations and observing campaign 2010-2011. show that highly accurate determination...
Abstract We monitored the position of close-by (about 370 Mpc) gamma-ray burst GRB 190829A, which originated from a massive star collapse, through very long baseline interferometry (VLBI) observations with European VLBI Network and Very Long Baseline Array, carrying out total nine between 9 117 days after at 5 15 GHz, typical resolution few milliarcseconds. From state-of-the art analysis these data, we obtained valuable limits on source size expansion rate. The are in agreement evolution...
We present the data from 11 observing campaigns (carried out between 1989 and 1999) at Effelsberg 100 m radio telescope to study Intraday Variability in Active Galactic Nuclei. Most of these observations were performed total power linear polarization. give summary tables, light curves, structure functions sets. Due large number individual observations, only examples lightcurves will be presented here; complete set figures accessible online. variations are nearly all sources (detected during...
In the coming decade, JUICE and Europa Clipper radio-science will yield most accurate estimation to date of Galilean moons' physical parameters ephemerides. JUICE's PRIDE (Planetary Radio Interferometry Doppler Experiment) help achieve such a solution by providing VLBI (Very Long Baseline Interferometry) observations spacecraft's lateral position, complementing nominal measurements. this paper, we quantify how can contribute ephemerides determination, in terms attainable improvement...
The Jupiter Icy Moons Explorer (JUICE), launched by the European Space Agency on April 14th, 2023, is an eight-year journey to Jovian system, arriving in July 2031. Among its eleven experiments, the Planetary Radio Interferometric and Doppler Experiment (PRIDE) stands out conduction Earth-based radio measurements. PRIDE leverages a network of Very Long Baseline Interferometry (VLBI) telescopes worldwide perform science experiments [Gurvits 2023]. These include occultation...
Abstract The radio telescopes of the European VLBI Network (EVN) and University Tasmania (UTAS) conducted an extensive observation campaign Space Agency’s (ESA) Mars Express (MEX) spacecraft between 2013 2020. campaign, carried out under Planetary Radio Interferometry Doppler Experiment (PRIDE) framework, aimed to study interplanetary phase scintillation assess noise budget in closed-loop observations. average was determined be approximately 10 mHz at a 10-second integration time,...
The most important worldwide problem in citrus production is the bacterial disease Huanglongbing (HLB; greening) caused by a phloem-limited bacterium Candidatus Liberibacter asiaticus. earliest visible symptoms of HLB on leaves are vein yellowing and an asymmetrical chlorosis referred to as “blotchy mottle,” thought be result starch accumulation. We tested hypothesis that such not unique stem girdling 2-year-old seedlings two rootstocks with without drought stress greenhouse. After 31 days,...
The closest ever fly-by of the Martian moon Phobos, performed by European Space Agency's Mars Express spacecraft, gives a unique opportunity to sharpen and test Planetary Radio Interferometry Doppler Experiments (PRIDE) technique in interest studying planet - satellite systems. aim this work is demonstrate providing high precision positional measurements planetary spacecraft using spacecraft. will be used framework various missions, particular mode. We advanced novel approach data processing...
Aims. The phase scintillation of the European Space Agency's (ESA) Venus Express (VEX) spacecraft telemetry signal was observed at X-band (\lambda = 3.6 cm) with a number radio telescopes VLBI Network (EVN) in period 2009-2013. Methods. We found fluctuation spectrum along orbit nearly constant spectral index -2.42 +/-0.25 over full range solar elongation angles from 0{\deg} to 45{\deg}, which is consistent Kolmogorov turbulence. Radio astronomical observations signals within system give...
Adding VLBI capability to the SKA arrays will greatly broaden science of SKA, and is feasible within current specifications.SKA-VLBI can be initially implemented by providing phased-array outputs for SKA1-MID SKA1-SUR using these extremely sensitive stations with other radio telescopes, in SKA2 realising a distributed configuration baselines up thousands km, merging it existing networks.The motivation possible realization SKA-VLBI described this paper.
Context. Closed-loop Doppler data obtained by deep space tracking networks (e.g., NASA's DSN and ESA's Estrack) are routinely used for navigation science applications. By "shadow tracking" the spacecraft signal, Earth-based radio telescopes involved in Planetary Radio Interferometry Experiment (PRIDE) can provide open-loop when dedicated facilities operating closed-loop mode only. Aims. We explain detail processing pipeline, discuss capabilities of technique its potential applications...
The high brightness temperatures, $T_\mathrm{b}\gtrsim 10^{13}$ K, detected in several active galactic nuclei by RadioAstron space VLBI observations challenge theoretical limits. Refractive scattering the interstellar medium may affect such measurements. We quantify properties and sub-mas scale source parameters for quasar B0529+483. Using correlated flux density measurements at 1.7, 4.8, 22 GHz on projected baselines up to 240,000 km we find two characteristic angular scales core, about 100...
Context. Radio occultation is a technique used to study planetary atmospheres by means of the refraction and absorption spacecraft carrier signal through atmosphere celestial body interest, as detected from ground station on Earth. This usually employed deep space tracking communication facilities (e.g., NASA's Deep Space Network (DSN), ESA's Estrack). Aims. We want characterize capabilities Planetary Interferometry Doppler Experiment (PRIDE) for radio experiments, using telescopes equipped...
Stellar occultations currently provide the most accurate ground-based measurements of positions natural satellites (down to a few kilometres for Galilean moons). However, when using these observations in calculation satellite ephemerides, uncertainty planetary ephemerides dominates error budget occultation. We quantify local refinement central planet's position achievable by performing Very Long Baseline Interferometry (VLBI) tracking an in-system spacecraft temporally close demonstrate...
Interstellar scintillation has been conclusively demonstrated to be the principal cause of intraday variability (IDV) observed in centimeter-wavelength emission many active galactic nuclei. A few sources show large amplitude modulation their flux density on a timescale hours. However, majority IDV exhibit timescales day or more. Some have found an annual cycle pattern variability. Such occurs because relative speeds Earth and interstellar medium change as orbits Sun. To search for these...
Abstract The radio signal transmitted by the Mars Express (MEX) spacecraft was observed regularly between years 2013–2020 at X-band (8.42 GHz) using European Very Long Baseline Interferometry (EVN) network and University of Tasmania’s telescopes. We present a method to describe solar wind parameters quantifying effects plasma on our signal. In doing so, we identify all uncompensated see which coronal processes drive them. From technical standpoint, effect helps phase referencing for...
The Einstein Equivalence Principle (EEP) is a cornerstone of general relativity and predicts the existence gravitational redshift. We report on new results measuring this shift with RadioAstron (RA), space VLBI spacecraft launched into an evolving high eccentricity orbit around Earth geocentric distances reaching 353,000 km. ground tracking stations at Pushchino, Russia, Green Bank, USA, were each equipped hydrogen maser frequency standard allowing possible violation predicted redshift, in...