A5063625359- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Geophysics and Gravity Measurements
- Gamma-ray bursts and supernovae
- Cosmology and Gravitation Theories
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- Solar and Space Plasma Dynamics
- Scientific Research and Discoveries
- Pulsars and Gravitational Waves Research
- Relativity and Gravitational Theory
- Geomagnetism and Paleomagnetism Studies
- Astrophysics and Star Formation Studies
- History and Developments in Astronomy
- Adaptive optics and wavefront sensing
- Earth Systems and Cosmic Evolution
- Galaxies: Formation, Evolution, Phenomena
- Planetary Science and Exploration
- Historical and Architectural Studies
- Statistical and numerical algorithms
- Historical Astronomy and Related Studies
- Radio Astronomy Observations and Technology
- Advanced Frequency and Time Standards
- Geophysics and Sensor Technology
- Computational Physics and Python Applications
Osservatorio Astrofisico di Torino
2014-2024
National Institute for Astrophysics
2007-2023
University of Turin
2000-2022
Collegio Carlo Alberto
2022
Max Planck Society
2018
Astronomical Observatory
2000-2009
University of Padua
2003-2004
Istituto Nazionale di Fisica Nucleare, Sezione di Padova
2003-2004
Istituto Nazionale di Fisica Nucleare
2003
Gaia Data Release 2 (Gaia DR2) contains results for 1693 million sources in the magnitude range 3 to 21 based on observations collected by European Space Agency satellite during first 22 months of its operational phase. We describe input data, models, and processing used astrometric content DR2, validation these performed within astrometry task. Some 320 billion centroid positions from pre-processed CCD were estimate five parameters (positions, parallaxes, proper motions) 1332 sources,...
Gaia Early Data Release 3 (Gaia EDR3) contains results for 1.812 billion sources in the magnitude range G = to 21 based on observations collected by European Space Agency satellite during first 34 months of its operational phase. We describe input data, models, and processing used astrometric content EDR3, as well validation these performed within astrometry task. The broadly followed same procedures DR2, but with significant improvements modelling observations. For time data processing,...
Gaia Data Release 1 (Gaia DR1) contains astrometric results for more than billion stars brighter magnitude 20.7 based on observations collected by the satellite during first 14 months of its operational phase. We give a brief overview content data release and model assumptions, processing, validation results. For in common with Hipparcos Tycho-2 catalogues, complete single-star solutions are obtained incorporating positional information from earlier catalogues. other only their positions...
Context. The first data release from the Gaia mission contains accurate positions and magnitudes for more than a billion sources, proper motions parallaxes majority of 2.5 million Hipparcos Tycho-2 stars.
ABSTRACT Thanks to Gaia DR2, we proved for the first time that a general relativistic Milky Way rotation curve is statistically indistinguishable from its state-of-the-art dark matter analogue. Those results supported ansatz gravitational dragging can explain observed flatness of with consistent radial density profile. To challenge again such scenario, select 719 143 young disc stars within |z| < 1 kpc and up R ≃ 19 DR3 providing much larger sample high-quality astrometric...
We present results from the PARallaxes of Southern Extremely Cool objects (PARSEC) program, an observational program begun in 2007 April to determine parallaxes for 122 L and 28 T southern hemisphere dwarfs using Wide Field Imager on ESO 2.2 m telescope. The presented here include 10 targets observations over 18 months a first version proper motion catalog. motions were obtained by combining PARSEC astrometrically reduced with respect Second US Naval Observatory CCD Astrograph Catalog, Two...
The discovery and subsequent detailed study of T dwarfs have provided many surprises pushed the physics modelling cool atmospheres in unpredicted directions. Distance is a critical parameter for studies these objects to determine intrinsic luminosities, test binarity measure their motion Galaxy. We describe new observational programme distances across full range T-dwarf subtypes using New Technology Telescope (NTT)/SOFI telescope/instrument combination. present preliminary results ten...
In the context of ESA M5 (medium mission) call we proposed a new satellite mission, Theia, based on relative astrometry and extreme precision to study motion very faint objects in Universe. Theia is primarily designed local dark matter properties, existence Earth-like exoplanets our nearest star systems physics compact objects. Furthermore, about 15 $\%$ mission time was dedicated an open observatory for wider community propose complementary science cases. With its unique metrology system...
Flat rotation curves in disk galaxies represent the main evidence for large amounts of surrounding dark matter. Despite difficulty identifying matter contribution to total mass density our Galaxy, stellar kinematics, as tracer gravitational potential, is most reliable observable gauging different components. This work tests flatness MW curve with a simple general relativistic model suitable geometry stationary axisymmetric dust metric at sufficiently distance from central body. Circular...
Sky survey telescopes and powerful targeted play complementary roles in astronomy. In order to investigate the nature characteristics of motions very faint objects, a flexibly-pointed instrument capable high astrometric accuracy is an ideal complement current surveys unique tool for precision astrophysics. Such space-based mission will push frontier astrometry from evidence Earth-mass habitable worlds around nearest stars, distant Milky Way out Local Group galaxies. As we enter era James...
ABSTRACT This work presents the results of a kinematic analysis Galaxy that uses new model as applied to newest available Gaia data. We carry out Taylor decomposition velocity field up second order for 18 million high luminosity stars (i.e. OBAF-type stars, giants, and subgiants) from DR3 determine components mean stellar velocities their first partial derivatives (relative cylindrical coordinates) more than 28 thousand points in plane our Galaxy. estimate Oort’s constants A, B, C, K other...
The global astrometric observations of a GAIA-like satellite were modeled within the PPN formulation Post-Newtonian gravitation. An extensive experimental campaign based on realistic end-to-end simulations was conducted to establish sensitivity astrometry parameter γ, which measures amount space curvature produced by unit rest mass. results show that, with just few thousands relatively bright, photometrically stable, and astrometrically well behaved single stars, among ~109 objects that will...
We develop here a new approach for the relativistic modeling of photons moving into quasi-Minkowskian spacetime, where metric is generated by an arbitrary N-body distribution within isolated solar system. Our model built on prescriptions theory general relativity and leaves choices metric, as well that motion observer, arbitrary. Adopting expression accurate to order (v/c)2, we conduct thorough numerical test campaign verify correctness reliability equations. The results show behaves...
The detectors designed for Gaia, the next ESA space astrometry mission to be launched in 2011, will allow observe repeatedly stars very close Jupiter's limb. This open a unique opportunity test General Relativity by performing many Eddington-like experiments through comparison between pattern of starfield observed with or without Jupiter. We have derived main formulas relevant monopole and quadrupole light deflection an oblate planet developed simulator investigate processing Gaia...
Through the contributions of Galileo, Newton, and Einstein, we recall universality free fall (UFF), weak equivalence principle (WEP), strong (SEP), in order to stress that general relativity requires all test masses be equally accelerated a gravitational field; is, it UFF WEP hold. The possibility testing this crucial fact with null, highly sensitive experiments makes these most powerful tests theory. Following Schiff, derive redshift from special show that, as long clocks are affected by...
Modern astrometry is based on angular measurements at the microarcsecond level. At this accuracy, a fully general relativistic treatment of data reduction required. This paper concludes series articles dedicated to problem light propagation, presenting final, version astrometric model that enables us trace back path its source through nonstationary gravitational field moving bodies in solar system. The previous used as test bed for numerical comparisons with present one. We also different...
The direct detection of gravitational waves by ground-based optical interferometers has opened a new window in astronomy. Besides, the sensitivity these linear detectors to direction arrival an incoming wave is limited compared current prospects high-precision, space-based, astrometry. Indeed, advanced methods differential relativistic astrometry offer unique opportunity overcome that situation. Here, we present novel concept for antenna uses angles between close pairs point-like sources as...
The high accuracy achievable by modern space astrometry requires the use of General Relativity to model stellar light propagation through gravitational field encountered from a source given observer inside Solar System. general relativistic definition an astrometric measurement needs appropriate concept reference frame, which should then be linked conventions IAU resolutions. On other hand, observables in context is also essential for finding coordinates and proper motion uniquely, this...
Space-born measuring devices require an accurate determination of the satellite rest frame. This frame consists a clock and triad orthonormal axes which provide local Cartesian reference system. The aim this paper is to find mathematical representation in two cases may correspond actual attitudes. First we construct Fermi can be operationally fixed by set three mutually orthogonal gyroscopes, then corresponds expected attitude GAIA was ESA approved fly not later than 2012. In latter case,...