Testing Special Relativity with Geodetic VLBI
Geodetic Very Long Baseline Interferometry (VLBI) measures the group delay in the barycentric reference frame. As the Earth is orbiting around the Solar system barycentre with the velocity V of 30 km/s, VLBI proves to be a handy tool to detect the subtle effects of the special and general relativity theory with a magnitude of (V∕c)2. The theoretical correction for the second order terms reaches up to 300 ps, and it is implemented in the geodetic VLBI group delay model. The total contribution of the second order terms splits into two effects – the variation of the Earth scale, and the deflection of the apparent position of the radio source. The Robertson-Mansouri-Sexl (RMS) generalization of the Lorenz transformation is used for many modern tests of the special relativity theory. We develop an alteration of the RMS formalism to probe the Lorenz invariance with the geodetic VLBI data. The kinematic approach implies three parameters (as a function of the moving reference frame velocity) and the standard Einstein synchronisation. A generalised relativistic model of geodetic VLBI data includes all three parameters that could be estimated. Though, since the modern laboratory Michelson-Morley and Kennedy-Thorndike experiments are more accurate than VLBI technique, the presented equations may be used to test the VLBI group delay model itself.
KeywordsLorentz invariance Special relativity VLBI
The authors thank the anonymous reviewers for their suggestions and comments which helped to improve the manuscript significantly. We acknowledge the IVS and all its components for providing VLBI data (Nothnagel et al. 2015). Hana Krásná works within the Hertha Firnberg position T697-N29, funded by the Austrian Science Fund (FWF). This paper has been published with the permission of the Geoscience Australia CEO.
- Klioner S, Zschocke S, Soffel M, Butkevich A (2012) Testing local Lorentz invariance with high-accuracy astrometric observations. In: The twelfth Marcel Grossmann meeting, pp 1478–1480. https://doi.org/10.1142/9789814374552_0251
- Nothnagel A, Alef W, Amagai J, Andersen PH, Andreeva T, Artz T, Bachmann S, Barache C, Baudry A, Bauernfeind E et al (2015) The IVS data input to ITRF2014. GFZ Data Services, Helmoltz Centre, Potsdam, Germany. https://doi.org/10.5880/GFZ.1.1.2015.002
- Petit G, Luzum B (2010) IERS Conventions 2010. IERS Technical Note No. 36Google Scholar
- Tobar ME, Wolf P, Bize S, Santarelli G, Flambaum V (2010) Testing local lorentz and position invariance and variation of fundamental constants by searching the derivative of the comparison frequency between a cryogenic sapphire oscillator and hydrogen maser. Phys Rev D 81:022,003. https://doi.org/10.1103/PhysRevD.81.022003 CrossRefGoogle Scholar