Search Publications
Time transfer functions as a way to validate light propagation solutions for space astrometry
Bertone, Stefano; Crosta, Mariateresa; Vecchiato, Alberto +3 more
Given the extreme accuracy of modern space astrometry, a precise relativistic modeling of observations is required. Concerning light propagation, the standard procedure is the solution of the null-geodesic equations. However, another approach based on the time transfer functions (TTF) has demonstrated its capability to give access to key quantitie…
The tension on the cosmological parameters from different observational data
Gao, Qing; Gong, Yungui
Planck measurements of the cosmic microwave background power spectra find a lower value of the Hubble constant H0 and a higher value of the fractional matter energy density Ωm0 for the concordance ΛCDM model, and these results are in tension with other measurements. The Planck group argued that the tension came either from so…
The spin of supermassive black holes
Reynolds, Christopher S.
Black hole spin is a quantity of great interest to both physicists and astrophysicists. We review the current status of spin measurements in supermassive black holes (SMBH). To date, every robust SMBH spin measurement uses x-ray reflection spectroscopy, so we focus almost exclusively on this technique as applied to moderately-luminous active galac…
The Cassini Ka-band gravitational wave experiments
Tinto, Massimo
Cassini, a joint American/European interplanetary scientific mission to Saturn, will be continuously and coherently tracked for 40 days during its solar oppositions in the next three years, starting on 26 November 2001. Doppler tracking searches for gravitational waves in the millihertz frequency band will be performed by using newly implemented K…