| Very Large Array Plus Pie Town Astrometry of 46 Radio Stars |
MAR 2007 |
12 pages |
| Authors:
D. A. Boboltz; A. L. Fey; W. K. Puatua; N. Zacharias; M. Claussen; K. J. Johnston; R. A. Gaume; NAVAL OBSERVATORY WASHINGTON DC
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 | We have used the Very Large Array, linked with the Pie Town Very Long Baseline Array antenna, to determine astrometric positions of 46 radio stars in the International Celestial Reference Frame (ICRF). Positions were obtained in the ICRF directly through phase referencing of the stars to nearby ICRF quasars whose positions are accurate at the 0.25 mas level. Radio star positions are estimated to be accurate at the 10 mas ... |
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| Relativistic Jets in the Radio Reference Frame Image Database. 1. Apparent Speeds From the First 5 Years of Data |
11 FEB 2007 |
33 pages |
| Authors:
B. G. Piner; M. Mahmud; A. L. Fey; K. Gospodinova; WHITTIER COLL CA DEPT OF PHYSICS AND ASTRONOMY
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| We present the results of an analysis of relativistic jet apparent speeds from VLBI images in the Radio Reference Frame Image Database (RRFID). The images are snapshot VLBI images at 8 and 2 GHz using the VLBA, plus up to 10 additional antennas that provide global VLBI coverage. We have analyzed the 8 GHz images from the first 5 years of the database (1994-1998), for all sources observed at three ... |
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| The Status and Future of the ICRF |
DEC 2006 |
7 pages |
| Authors:
A. L. Fey; NAVAL OBSERVATORY WASHINGTON DC
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| The International Celestial Reference Frame (ICRF) is currently defined by the radio positions of 212 extragalactic objects. Since its inception there have been two extensions to the ICRF. These extensions included revised positions of ICRF candidate and "other" sources, based on inclusion of additional observations, as well as positions of an additional 109 "new" sources. With continued applicable Very Long Baseline Interferometry (VLBI) observations and improvements in analysis a better ... |
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| Multifrequency Very Long Baseline Array Observations of the Compact Double B2 2050+36: Constraints on Interstellar Scattering Revisited |
20 OCT 2001 |
10 pages |
| Authors:
T. J. Lazio; A. L. Fey; NAVAL RESEARCH LAB WASHINGTON DC REMOTE SENSING DIV
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| We present multifrequency observations with the Very Long Baseline Array of the compact double radio source B2 2050+36. Our observations are at 0.33, 0.61, 1.67, 2.3, and 8.4 GHz, with the 0.61 GHz observations forming the third epoch of observation of this source at that frequency. At 0.61 GHz, the structure of B2 2050+36 is dominated by two components 56 mas apart. Within the uncertainties of the various measurements, this ... |
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