Results 31 to 40 of about 11,793 (207)

VLBI Astrometry of Radio-Emitting Stars [PDF]

Symposium - International Astronomical Union, 1995
High-accuracy astrometric VLBI observations of 7 radio stars are presented with applications to the connection between the Hipparcos and VLBI extragalactic reference frames, to the identification of the radio emitting region in the ternary system Algol and the detectabity of Jupiter-size planet orbiting the radio star σ2 CrB.
J.-F. Lestrade, D. L. Jones, R. A. Preston, R. B. Phillips, J. Kovalevsky, M. Froeschle, F. Mignard   +6 more
openaire   +1 more source

Dynamical masses of young stellar objects with the VLBA: DYNAMO-VLBA

Astronomy & Astrophysics
We present results from a multi-epoch Very Long Baseline Array (VLBA) survey of compact radio sources in the Orion complex, conducted within both the DYNAMO–VLBA and GOBELINS projects.
Dzib Sergio A., Ordóñez-Toro Jazmín, Loinard Laurent, Kounkel Marina, Ortiz-León Gisela N., Galli Phillip A. B., Rodríguez Luis F., Mioduszewski Amy J., Masqué Josep M., O’Kelly Eoin, Forbrich Jan, Moo-Herrera Karla   +11 more
doaj   +3 more sources

Probing the Heart of Active Narrow-line Seyfert 1 Galaxies with VERA Wideband Polarimetry

The Astrophysical Journal, 2023
We explored the parsec-scale nuclear regions of a sample of radio-loud narrow-line Seyfert 1 galaxies (NLSy1s) using the VLBI Exploration of Radio Astrometry wideband (at a recording rate of 16 Gbps) polarimetry at 22 and 43 GHz.
Mieko Takamura, Kazuhiro Hada, Mareki Honma, Tomoaki Oyama, Aya Yamauchi, Syunsaku Suzuki, Yoshiaki Hagiwara, Monica Orienti, Filippo D’Ammando, Jongho Park, Minchul Kam, Akihiro Doi   +11 more
doaj   +1 more source

Science with radio pulsar astrometry [PDF]

Proceedings of the International Astronomical Union, 2012
AbstractHigh precision astrometry on radio pulsars can provide model-independent estimates of their distances and velocities. Such estimates serve to calibrate models of the Galactic electron density distribution, thereby improving distance estimates for the entire pulsar population.
openaire   +1 more source

Ray tracing-based delay model for compensating gravitational deformations of VLBI radio telescopes

Journal of Geodetic Science, 2022
The precision and the reliability of very long baseline interferometry (VLBI) depend on several factors. Apart from fabrication discrepancies or meteorological effects, gravity-induced deformations of the receiving unit of VLBI radio telescopes are ...
Lösler Michael, Eschelbach Cornelia, Greiwe Ansgar, Brechtken Rainer, Plötz Christian, Kronschnabl Gerhard, Neidhardt Alexander   +6 more
doaj   +1 more source

VERA monitoring of the radio jet 3C 84 during 2007--2013: detection of non-linear motion [PDF]

, 2018
We present a kinematic study of the subparsec-scale radio jet of the radio galaxy 3C 84/NGC 1275 with the VLBI Exploration of Radio Astrometry (VERA) array at 22 GHz for 80 epochs from 2007 October to 2013 December.
Akiyama, Kazunori, Chida, Hikaru, D'Ammando, Filippo, Giovannini, Gabriele, Giroletti, Marcello, Hada, Kazuhiro, Hiura, Koichiro, Honma, Mareki, Kino, Motoki, Koyama, Shoko, Nagai, Hiroshi, Niinuma, Kotaro, Orienti, Monica, Orosz, Gabor, Sawada-Satoh, Satoko, Sorai, Kazuo   +15 more
core   +2 more sources

Improving the Accuracy of Radio Astrometry [PDF]

International Astronomical Union Colloquium, 2000
AbstractThe International Celestial Reference Frame (ICRF) is currently realized by the radio positions of compact extragalactic objects obtained by the technique of Very Long Baseline Interferometry (VLBI). The positions of the defining sources with the highest quality are estimated to be accurate at the 0.25 milliarcsecond (mas) level.
openaire   +1 more source

Improving the Reference Frame by Radio–and Optical Astrometry of Radio Stars [PDF]

International Astronomical Union Colloquium, 1991
AbstractA longterm program of precise radio – and optical astrometry of selected radio stars has been conducted in the last decade by our observatories using the VLA and astrographs on both hemispheres. Positions of 54 stars north of −26 deg. declination including 6 MASER stars have been obtained.
Chr. de Vegt, N. Zacharias, K.J. Johnston, R. Hindsley   +3 more
openaire   +1 more source

Radio source structures in VLBI astrometry [PDF]

Symposium - International Astronomical Union, 1988
In astrometry, celestial radio sources with extended structures are useful. An algorithm to correct for structure in VLBI delays and delay rates is developed. The radio source NRAO140 is mapped from data with limited u-v coverage by the hybrid method and the Maximum Entropy procedure.
Patrick Charlot, Jean-François Lestrade, Claude Boucher   +2 more
openaire   +1 more source

CCD astrometry of faint compact extragalactic radio sources. III. [PDF]

Astronomy & Astrophysics, 2001
Optical positions relative to the Hipparcos Catalogue (ESA 1997) have been obtained for the optical counterparts of 28 faint (B 20 23) southern compact extragalactic radio sources (CERS). Most of these sources are not adequately observable (or simply not visible) by means of direct photography with a conventional wide- eld telescope, so the positions ...
E. Costa, P. Loyola
openaire   +6 more sources