Improved Test of General Relativity with Radio Doppler Data from the Cassini Spacecraft
This paper was withdrawn at the recommendation of the Cassini Radio Science Team.
gr-qc↗
arXiv subjects
Giacomo Giampieri
Publications and source records attributed to Giacomo Giampieri.
Gravitational Waves from a Population of Galactic Neutron Stars
The existence of a large number of asymmetric, rotating neutron stars, each individually emitting periodic or quasi-periodic gravitational waves in the frequency band around 100 Hz, raises the possibility of detecting their combined signals, by exploiting the amplitude modulation of the received waves as the antenna changes its orientation with respect to fixed stars. This modulation is directly related to the amount of anisotropy present in the source distribution, and, if detected, could give valuable information about the spatial distribution of neutron stars in our Galaxy.
astro-ph↗
Relativity Experiments in the Solar System
Recent theoretical works on alternative metric theories of gravity give greater significance to solar-system tests of General Relativity. In particular, it is suggested that the post-Newtonian parameter $γ$ ought to be determined with great precision in order to discover possible preferred frame effects or effects related to a tensor-scalar theory of gravitation. In this work we focus on a future experiment, based on Doppler tracking of an interplanetary spacecraft near superior conjunction.
astro-ph↗
Sinusoidal Gravitational Waves from the Nuclei of Active Galaxies
It is believed that most quasars and galaxies present two common features: the presence in their core of a supermassive object, and the experience of one or more encounters with other galaxies. In this scenario, it is likely that a substantial fraction of active galactic nuclei harbour a supermassive binary, fueled by an accretion disk. These binaries would certainly be among the strongest sources of sinusoidal gravitational waves. We investigate their evolution considering, simultaneously, the accretion of the black hole's masses from the disk, and the gravitational waves emitted during the orbital motion. We also consider other astrophysical scenarios involving a coalescing binary with non constant masses.
astro-ph↗