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Physics of gravitation and cosmology with high precision space astrometry

The improvement of the precision in the verification of General Relativity (GR) is of crucial importance for fundamental physics, having a cosmological and astrophysical impact on all scales. In fact, the study of the evolution of the Universe covering a timescale of 60 orders of magnitude, from the primordial to the present, depends essentially on the understanding of gravitational interaction, most reliably interpreted through General Relativity. The most used theoretical instrument to compare these theories on a local scale is the parameterized post Newtonian (PPN), in which each theory is characterised by precise assumed values from a parameter set estimated from experiments. Amongst these parameters, , (related to the curvature of space-time induced by mass) is the most studied, and also the most accessible via astrometric measurements. The estimation of this parameter allows tight constraints to be placed also on alternative formalisms that can appreciably modify the current estimate of the mass/dark energy ratio. In this sense the measurement of the parameter can be considered a powerful cosmological test using local measurements.

It is predicted that the GAIA mission can reach an accuracy of 10-6 for at the 3-sigma level, for nominal performance, by measuring the temporal evolution of the positions of a billion objects all over the celestial sphere. The numerical verifications and the relevant parts of the code are under development under an Agenzia Spaziale Italiana contract, coordinated with the activity of the European consortium DPAC (Data Processing and Analysis Consortium) for the reduction of GAIA data.

Farewell to Giovanni Bignami

May 26, 2017

Farewell to Giovanni Bignami Great astrophysicist and former President of INAF and ASI, Bignami passed away suddenly while in Madrid where he was carrying out his research activities.

INAF researcher involved in the discovery of a millisecond pulsar

May 20, 2017

INAF researcher involved in the discovery of a millisecond pulsar An international team of astronomers led by Ivan Zolotukhin of the Institut de Recherche en Astrophysique et Planétologie (IRAP) of Toulouse, also including Matteo Bachetti, a researcher of the INAF in Cagliari, has discovered that this pulsar is at the beginning of the recycle phase, i.e. the process that causes slow and "turned-off” neutron stars to turn on again as “millisecond pulsar”.

Cassini Scientist for a Day: the competition for young scientists sets new records

May 20, 2017

Cassini Scientist for a Day: the competition for young scientists sets new records New record numbers for the 15th edition of Cassini Scientist for a Day, the international competition launched by NASA and promoted in Europe by the European Space Agency (ESA), open to lower and upper secondary school students. In Italy, 181 students participated in the competition, sending a total of 81 essays to a panel of researchers and experts in science communication.