Results 51 to 60 of about 27,390 (189)

Modeling Nearby Low-Luminosity Active-Galactic-Nucleus Jet Images at All VLBI Scales

Galaxies, 2022
Relativistic jets from nearby low-luminosity active-galactic-nuclei (LLAGN) were observed by Very-Long Baseline Interferometry (VLBI) across many orders of magnitude in space, from milliparsec to sub-parsec scales, and from the jet base in the vicinity ...
Hung-Yi Pu, Keiichi Asada, Masanori Nakamura   +2 more
doaj   +1 more source

Comparison of VLBI, TV and traveling clock techniques for time transfer [PDF]

, 1982
A three part experiment was conducted to develop and compare time transfer techniques. The experiment consisted of (1) a very long baseline interferometer (VLBI), (2) a high precision portable clock time transfer system between the two sites, and (3) a ...
Angerhofer, P. E., Johnston, K. J., Kaplan, G. M., Klepczynski, W. J., Matsakis, D. N., Santini, N. J., Spencer, J. H., Waltman, E. B.   +7 more
core   +1 more source

The Gould's Belt Distances Survey

, 2012
Very Long Baseline Interferometry (VLBI) observations can provide the position of compact radio sources with an accuracy of order 50 micro-arcseconds. This is sufficient to measure the trigonometric parallax and proper motions of any object within 500 pc
Loinard, Laurent
core   +1 more source

The influence of Galactic aberration on precession parameters determined from VLBI observations [PDF]

, 2010
The influence of proper motions of sources due to Galactic aberration on precession models based on VLBI data is determined. Comparisons of the linear trends in the coordinates of the celestial pole obtained with and without taking into account Galactic ...
A. M. Clerke, C. Ma, E. A. Popova, J. Kovalevsky, J. L. Fanselow, J.-C. Liu, N. Capitaine, N. Capitaine, O. J. Sovers, O. Titov, O. Titov, O. Titov, O. Titov, O. Titov, O. Titov, S. A. Klioner, S. Kopeikin, T. M. Eubanks, V. E. Zharov, V. E. Zharov, V. V. Bobylev, V. V. Bobylev, W. Schlüter, Z. M. Malkin, Z. M. Malkin, Z. M. Malkin, Z. M. Malkin, Z. M. Malkin, Z. Malkin, Z. Malkin, Z. Malkin   +30 more
core   +1 more source

VLBI Pulsar Astrometry [PDF]

Symposium - International Astronomical Union, 2001
I briefly review the means by which VLBI observations can determine the position, proper motion, and parallax of a pulsar, consider a subset of the applications of such results, and highlight recent developments in pulsar gating at JIVE.
openaire   +1 more source

Decoherence in LOFAR-VLBI beamforming [PDF]

Astronomy & Astrophysics, 2020
We show that the use of a superstation (a phased array created using multiple stations of an interferometric array) created in post-processing for LOFAR-VLBI observations introduces a direction-dependent loss of signal in the image. We show this effect using simulations and real data.
Bonnassieux E., Edge A., Morabito L., Bonafede A.   +3 more
openaire   +3 more sources

Spectral Line VLBI Studies Using the ngEHT

Galaxies, 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

Simultaneous radio-interferometric and high-energy TeV observations of the gamma-ray blazar Mkn 421

, 2006
The TeV-emitting BL Lac object Mkn 421 was observed with very long baseline interferometry (VLBI) at three closely-spaced epochs one-month apart in March-April 1998.
Aharonian, B. Degrange, Bai, Barrau, Biermann, Blandford, Bucciferro, Bååth, Cawthorne, Celotti, Cui, D. C. Gabuzda, F. Piron, Fossati, Gabuzda, Gabuzda, Gaidos, Georganopoulos, Georganopoulos, Ghisellini, Ghisellini, H. Sol, Katarzynski, Kellermann, Kellermann, Kollgaard, Konopelko, Krawczynski, Le Bohec, Lin, Maraschi, Marscher, Marscher, Napier, Otterbein, P. Charlot, Phillips, Piner, Piner, Piner, Piron, Pohl, Polatidis, Pollack, Punch, Quinn, Sambruna, Takahashi, Unwin, Urry, Valtaoja, Wehrle, Wehrle, Witzel, Xu, Zensus, Zhang, Zhang   +57 more
core   +3 more sources

5 year Global 3-mm VLBI survey of Gamma-ray active blazars [PDF]

, 2015
The Global mm-VLBI Array (GMVA) is a network of 14 3\,mm and 7\,mm capable telescopes spanning Europe and the United States, with planned extensions to Asia.
Bremer, M., de Vicente, P., Hodgson, J. A., Jorstad, S. G., Krichbaum, T. P., Lindqvist, M., Marscher, A. P., Marti-Vidal, I., Sanchez, S., Zensus, J. A.   +9 more
core   +2 more sources

VLBI with TDRSS [PDF]

International Astronomical Union Colloquium, 1990
AbstractVLBI observations using a satellite in earth orbit and ground antennas in Japan and Australia were conducted in 1986, 1987, and 1988. Sources were detected on space-ground baselines at both observing frequencies: 2.3 and 15 GHz. The coherence on space-ground baselines for 340 s was 90% at 2.3 GHz and 76% at 15 GHz.
openaire   +1 more source