87 citations · 448 across the 16 of their papers we have counts for
16 papers
The Planetary Ephemeris Program: Capability, Comparison, and Open Source Availability
John F. Chandler, James B. R. Battat, Thomas W. Murphy +3
We describe for the first time in the scientific literature the Planetary Ephemeris Program (PEP), an open-source general-purpose astrometric data analysis program. We discuss, in…
VLBI for Gravity Probe B: The Guide Star IM Pegasi
N. Bartel, M. F. Bietenholz, D. E. Lebach +3
We review the radio very long baseline interferometry (VLBI) observations of the guide star, IM Peg, and three compact extragalactic reference sources, 3C 454.3, B2250+194, and B22…
VLBI for Gravity Probe B. V. Proper Motion and Parallax of the Guide Star, IM Pegasi
M. I. Ratner, N. Bartel, M. F. Bietenholz +4
We present the principal astrometric results of the very-long-baseline interferometry (VLBI) program undertaken in support of the Gravity Probe B (GP-B) relativity mission. VLBI ob…
VLBI for Gravity Probe B. III. A Limit on the Proper Motion of the "Core" of the Quasar 3C 454.3
N. Bartel, M. F. Bietenholz, D. E. Lebach +5
We made VLBI observations at 8.4 GHz between 1997 and 2005 to estimate the coordinates of the "core" component of the superluminal quasar, 3C 454.3, the ultimate reference point in…
Imaging an Event Horizon: submm-VLBI of a Super Massive Black Hole
Sheperd Doeleman, Eric Agol, Don Backer +20
A long standing goal in astrophysics is to directly observe the immediate environment of a black hole with angular resolution comparable to the event horizon. Realizing this goal w…
A Decade of SN1993J: Discovery of Wavelength Effects in the Expansion Rate
J. M. Marcaide, I. Marti-Vidal, A. Alberdi +15
We have studied the growth of the shell-like radio structure of supernova SN1993J in M81 from September 1993 through October 2003 with very-long-baseline interferometry (VLBI) obse…