arXiv subjects

Mariateresa Crosta

Publications and source records attributed to Mariateresa Crosta.

21 records · Page 2Linked to original sources

arXiv2013

Tracing a relativistic Milky Way within the RAMOD measurement protocol

Advancement in astronomical observations and technical instrumentation implies taking into account the general relativistic effects due the gravitational fields encountered by the light while propagating from the star to the observer. Therefore, data exploitation for Gaia-like space astrometric mission (ESA, launch 2013) requires a fully relativistic interpretation of the inverse ray-tracing problem, namely the development of a highly accurate astrometric models in accordance with the geometrical environment affecting light propagation itself and the precepts of the theory of measurement. This could open a new rendition of the stellar distances and proper motions, or even an alternative detection perspective of many subtle relativistic effects suffered by light while it is propagating and subsequently recorded in the physical measurements.

astro-ph.GA↗

arXiv2011

Tracing light propagation to the intrinsic accuracy of space-time geometry

Advancement in astronomical observations and technical instrumentation requires coding light propagation at high level of precision; this could open a new detection window of many subtle relativistic effects suffered by light while it is propagating and entangled in the physical measurements. Light propagation and its subsequent detection should indeed be conceived in a fully relativistic context, in order to interpret the results of the observations in accordance with the geometrical environment affecting light propagation itself, as an unicum surrounding universe. One of the most intriguing aspects is the boost towards the development of highly accurate models able to recon- struct the light path consistently with General Relativity and the precepts of measurements. This paper deals with the complexity of such a topic by showing how the geometrical framework of models like RAMOD, initially developed for astrometric observations, constitutes an appropriate physical environment for back tracing a light ray conforming to the intrinsic accuracy of space-time. This article discusses the reasons why RAMOD stands out among the existent approaches applied to the light propagation problem and provides a proof of its capability in recasting recent literature cases.

gr-qc↗

arXiv2009

Physical Reference Frames and Astrometric Measurements of Star Direction in General Relativity \\I. Stellar Aberration

The high accuracy of modern space astrometry requires the use of General Relativity to model the propagation of stellar light through the gravitational field encountered from a source to a given observer inside the Solar System. In this sense relativistic astrometry is part of fundamental physics. The general relativistic definition of astrometric measurement needs an appropriate use of the concept of reference frame, which should then be linked to the conventions of the IAU Resolutions (2000), which fix the celestial coordinate system. A consistent definition of the astrometric observables in the context of General Relativity is also essential to find uniquely the stellar coordinates and proper motion, this being the main physical task of the inverse ray tracing problem. Aim of this work is to set the level of reciprocal consistency of two relativistic models, GREM and RAMOD (Gaia, ESA mission), in order to garantee a physically correct definition of light direction to a star, an essential item for deducing the star coordinates and proper motion within the same level of measurement accuracy.

gr-qc↗