Search Publications
Test of general relativity during the BepiColombo interplanetary cruise to Mercury
Schettino, Giulia; Serra, Daniele; Tommei, Giacomo +1 more
The theory of general relativity first introduced the concept that space-time is curved by the presence of masses. As a consequence, any signal between two sources passing by a massive body is deflected and therefore experiences a transmission time delay with respect to the straight-line propagation. In the parametrized Post-Newtonian formalism—wh…
Effects of a caustic ring of dark matter on the distribution of stars and interstellar gas
Chakrabarty, Sankha S.; Sikivie, Pierre
Caustic rings of dark matter with tricusp cross section were predicted to lie in the galactic disk. Their radii increase on cosmological time scales at a rate of order 1 kpc /Gyr . When a caustic ring passes through the orbit of a star, the orbit is strongly perturbed. We find that a star moving in a nearly circular orbit is first attracted toward…
Closing in on the large-scale CMB power asymmetry
Moss, A.; Scott, D.; Contreras, D. +2 more
Measurements of the cosmic microwave background (CMB) temperature anisotropies have revealed a dipolar asymmetry in power at the largest scales, in apparent contradiction with the statistical isotropy of standard cosmological models. The significance of the effect is not very high, and is dependent on a posteriori choices. Nevertheless, a number o…
Observational constraints on warm quasi-exponential inflation
Videla, Nelson; Panotopoulos, Grigorios
In the present work, we study a warm inflationary model defined by a quasi-exponential inflaton potential and an inflaton decay rate proportional to the Hubble rate. The model is characterized by three free parameters. We compute the power spectrum, the scalar spectral index, as well as the tensor-to-scalar ratio within the framework of the model,…
Astrometric test of the weak equivalence principle
Xie, Yi
Weak equivalence principle (WEP) is, for the first time, tested by astrometry on quasars in the sky measured in two wavelengths. Compared to previous WEP tests based on the Shapiro time delay of massless particles, this one has profound superiority that nearly 1 700 quasars with best measured positions commonly in the optical and radio bands are a…
Gravitational wave effects on astrometric observables
Bini, Donato; Geralico, Andrea
Observational data from the European Space Agency astrometric mission Gaia determining the positions of celestial objects within an accuracy of a few microarcseconds will be soon fully available. Other satellite-based space missions are currently planned to significantly improve such precision in the next years. The data reduction process needs hi…
Strong lensing constraints on modified gravity models
Dai, De-Chang; Stojkovic, Dejan; Starkman, Glenn D.
We impose the first strong-lensing constraints on a wide class of modified gravity models where an extra field that modifies gravity also couples to photons (either directly or indirectly through a coupling with baryons) and thus modifies lensing. We use the nonsingular isothermal ellipsoid profile as an effective potential which produces flat gal…