Gravitational Red Shift effect measurement with orbital probe

by Prof. Rudenko Valentin N. (SAI MSU, Moscow)

Wednesday 6 Dec 2017, 16:00 → 17:00 Europe/Rome

Aula Rasetti (Dipartimento di Fisica - Ed. G. Marconi)

At present the Radioastron (RA) Earth's satellite having very elliptic orbit is used for probing of the gravitational red shift effect [1,2]. Objective of this test consists in the enhancing accuracy of measurement to prove the correspondence of the effect to the Einstein's theory at one order of value better then in was done in the GP-A experiment [3 ]. There are two H-masers in disposal, one at the board RA and other at the Land Tracking Station (LTS). One can compare its mutual time rate using communication radio links between RA and LTS. In contrast with the GP-A experiment for RA there is a possibility of measurement repetition and accumulation of data in the process of orbital circulation. It could be resulted in increasing of the integral accuracy. Receipt for a compensation of the coherent hindrances (Doppler, troposphere and ionosphere influence) developed during GP-A mission consists in simultaneously using the two modes communication of the LTS with RA: one way (H-maser) and two ways (Coherent) modes. However such opportunity was not foreseen for RA. Only a periodic switching between these modes is available. In this talk we investigate the achievable accuracy using a special algorithm of red shift extraction associated with technical specific of the RA satellite. Some experimental illustrations having been got during of RA functioning are presented as well as preliminary results of the red shift effect measurement. References 1. A.V. Biriukov, V.L. Kauts, V.V. Kulagin, D.A. Litvinov, V.N. Rudenko, Gravitational redshift test with the space radio telescope "RadioAstron", Astron. Rep. 58(11) (2014) 783-795, http://dx.doi.org/10.1134/S1063772914110018 2. 2. D. A. Litvinov, V. N. Rudenko, A. V. Alakoz et al Probing the gravitational redshift with an Earth-orbiting satellite. Physics Letters A v 381 (2017) 3. 3. R.F.C. Vessot, M.W. Levine, E.M. Mattison, et al. Test of relativistic gravitation with a space-borne hydrogen maser, Phys. Rev. Lett. 45 (1980) 2081-2084, http://dx.doi.org/10.1103/PhysRevLett.45.2081