Light Deflection under the Gravitational Field of Jupiter -- Testing General Relativity

Abstract

We measured the relative positions between two pairs of compact extragalactic sources (CESs), J1925-2219 \& J1923-2104 (C1--C2) and J1925-2219 \& J1928-2035 (C1--C3) on 2020 October 23--25 and 2021 February 5 (totaling four epochs), respectively, using the Very Long Baseline Array (VLBA) at 15 GHz. Accounting for the deflection angle dominated by Jupiter, as well as the contributions from the Sun, planets other than Earth, the Moon and Ganymede (the most massive of the solar system's moons), our theoretical calculations predict that the dynamical ranges of the relative positions across four epochs in R.A. of the C1--C2 pair and C1--C3 pair are 841.2 and 1127.9 $\mu$as, respectively. The formal accuracy in R.A. is about 20 $\mu$as, but the error in Decl. is poor. The measured standard deviations of the relative positions across the four epochs are 51.0 and 29.7 $\mu$as in R.A. for C1--C2 and C1--C3, respectively. These values indicate that the accuracy of the post-Newtonian relativistic parameter, $\gamma$, is $\sim 0.061$ for C1--C2 and $\sim 0.026$ for C1--C3. Combining the two CES pairs, the measured value of $\gamma$ is $0.984\pm 0.037$, which is comparable to the latest published results for Jupiter as a gravitational lens reported by Fomalont \& Kopeikin, i.e., $1.01\pm 0.03$.

22 pages, 7 figures, 3 tables, accepted for publication in ApJ

References in corpus (10)

• Array Programming with NumPy
• Trigonometric Parallaxes Of High-Mass Star Forming Regions: Our View Of The Milky Way
• DiFX: A software correlator for very long baseline interferometry using multi-processor computing environments
• The third realization of the International Celestial Reference Frame by very long baseline interferometry
• Progress in Measurements of the Gravitational Bending of Radio Waves Using the VLBA
• Gravitational bending of light by planetary multipoles and its measurement with microarcsecond astronomical interferometers
• Precise radio astrometry and new developments for the next generation of instruments
• Square Kilometre Array Science Data Challenge 1: analysis and results
• Electron density distribution and solar plasma correction of radio signals using MGS, MEX and VEX spacecraft navigation data and its application to planetary ephemerides
• The Science of Fundamental Catalogs