Reference Frames in Astronomy

Johnston, K. J.; Vegt, C. de

doi:10.1146/annurev.astro.37.1.97

Cited by 25 publications

(21 citation statements)

References 83 publications

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“…The GAIA catalogue will permit a definition of the ICRS more accurate by one or two orders of magnitude than the present realizations (e.g. Feissel & Mignard 1998;Johnston & de Vegt 1999).…”

Section: The Radio/optical Reference Framementioning

confidence: 88%

GAIA: Composition, formation and evolution of the Galaxy

Perryman

Boer

Gilmore

et al. 2001

A&A

1,034

1,023

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Abstract. The GAIA astrometric mission has recently been approved as one of the next two "cornerstones" of ESA's science programme, with a launch date target of not later than mid-2012. GAIA will provide positional and radial velocity measurements with the accuracies needed to produce a stereoscopic and kinematic census of about one billion stars throughout our Galaxy (and into the Local Group), amounting to about 1 percent of the Galactic stellar population. GAIA's main scientific goal is to clarify the origin and history of our Galaxy, from a quantitative census of the stellar populations. It will advance questions such as when the stars in our Galaxy formed, when and how it was assembled, and its distribution of dark matter. The survey aims for completeness to V = 20 mag, with accuracies of about 10 µas at 15 mag. Combined with astrophysical information for each star, provided by on-board multi-colour photometry and (limited) spectroscopy, these data will have the precision necessary to quantify the early formation, and subsequent dynamical, chemical and star formation evolution of our Galaxy. Additional products include detection and orbital classification of tens of thousands of extra-Solar planetary systems, and a comprehensive survey of some 10 5 −10 6 minor bodies in our Solar System, through galaxies in the nearby Universe, to some 500 000 distant quasars. It will provide a number of stringent new tests of general relativity and cosmology. The complete satellite system was evaluated as part of a detailed technology study, including a detailed payload design, corresponding accuracy assesments, and results from a prototype data reduction development.

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Section: The Radio/optical Reference Framementioning

confidence: 88%

GAIA: Composition, formation and evolution of the Galaxy

Perryman

Boer

Gilmore

et al. 2001

A&A

1,034

1,023

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“…In the Conclusions we comment on the gauge problem in GR, discussed in the Conclusions of paper II, and on how our explanation of dark matter may help in finding the PM extension of the Celestial reference frame (ICRS) [5] outside the Solar System. Then we show which lines of development are opened by our formulation, especially in cosmology and in particular for the possibility to reformulate the back-reaction approach for the elimination of dark energy, based on averages of scalar quantities in 3-volumes of 3-space, in the York canonical basis.…”

Section: Outline Of the Papermentioning

confidence: 97%

The Einstein–Maxwell-particle system in the York canonical basis of ADM tetrad gravity. Part 3. The post-minkowskian N-body problem, its post-newtonian limit in nonharmonic 3-orthogonal gauges and dark matter as an inertial effect ¹This paper is one of three companion papers published in the same issue of Can. J. Phys.

Alba

Lusanna

2012

Can. J. Phys.

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We conclude the study of the post-minkowskian (PM) linearization of ADM tetrad gravity in the York canonical basis for asymptotically minkowskian space-times in the family of nonharmonic 3-orthogonal gauges parametrized by the York time 3 K. ; / (the inertial gauge variable, not existing in Newton gravity, describing the general relativistic remnant of the freedom in clock synchronization in the definition of the shape of the instantaneous 3-spaces as 3-submanifolds of space-time). As matter we consider only N scalar point particles with a Grassmann regularization of the self-energies and with an ultraviolet cutoff making possible the PM linearization and the evaluation of the PM solution for the gravitational field. We study in detail all the properties of these PM space-times emphasizing their dependence on the gauge variable 3 K .1/ D .1=4/ 3 K .1/ (the nonlocal York time): Riemann and Weyl tensors, 3-spaces, time-like and null geodesics, red-shift, and luminosity distance. Then we study the post-newtonian (PN) expansion of the PM equations of motion of the particles. We find that in the two-body case at the 0.5PN order there is a damping (or antidamping) term depending only on 3 K .1/ . This opens the possibility of explaining dark matter in Einstein theory as a relativistic inertial effect: the determination of 3 K .1/ from the masses and rotation curves of galaxies would give information on how to find a PM extension of the existing PN celestial frame used as an observational convention in the 4-dimensional description of stars and galaxies. Dark matter would describe the difference between the inertial and gravitational masses seen in the noneuclidean 3-spaces, without a violation of their equality in the 4-dimensional space-time as required by the equivalence principle. PACS Nos.: 04.20.Fy, 04.20.Ha, 04.30.-w, 04.40.Nr, 95.35.+dRésumé : Nous concluons l'étude de la linéarisation post-minkowskienne (PM) de la gravité tétrade de ADM dans la base canonique de York pour des espace-temps asymptotiquement minkowskiens dans la famille des jauges 3-orthogonales paramétrées par le temps de York 3 K (la variable de jauge inertielle, qui n'existe pas en gravité de Newton, décrivant ce qui reste, provenant de la relativité générale, de la liberté de synchronisation de l'horloge dans la définition du 3-espace instantané). La seule matière considérée ici est constituée de N particules scalaires ponctuelles avec une régularisation de Grassmann des self énergies et avec une coupure ultraviolette rendant possible la linéarisation PM et l'évaluation des solutions PM pour le champ de gravité. Nous étudions en détails toutes les propriétés de l'espace-temps PM, insistant sur leur dépendance sur la variable de jauge 3 K .1/ D 1=4 3 K .1/ (le temps de York non local) : les tenseurs de Riemann et de Weyl, les géodésiques de type temps (3D) et nulles, le déplacement vers le rouge et la distance de luminosité. Nous étudions alors l'expansion post-newtonienne (PN) des équations PM du mouvement des particules. Nous trouvons que dan...

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“…they have been obtained by processing the planetary data in the standard ICRF frame which is a frame with the origin in the (known) solar system's barycenter and having the mean ecliptic at J2000 epoch as reference plane with the x axis directed towards the Vernal point [22]. This is particularly important when there is some physical feature, like a static body in a given direction as in our case, which breaks the spatial symmetry: assuming that n X , which is actually apriori unknown, coincides with one of the frame's axes just to simplify the calculation is, in principle, incorrect.…”

Section: The Action Of a Distant Body And Of Mond's External Field Efmentioning

confidence: 99%

The Perihelion Precession of Saturn, Planet X/Nemesis and MOND~!2009-09-17~!2009-10-08~!2010-05-05~!

Iorio¹

2010

TOAAJ

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Abstract:We show that the anomalous retrograde perihelion precession of Saturn !& " , recently estimated by different teams of astronomers by processing ranging data from the Cassini spacecraft and amounting to some milliarcseconds per century, can be explained in terms of a localized, distant body X, not yet directly discovered in the remote periphery of the solar system. From the determination of its tidal parameter K ! GM X / r X 3 as a function of its ecliptic longitude X ! and latitude X ! , we calculate the distance at which X may exist for different values of its mass, ranging from the size of Mars to that of the Sun. The minimum distance would occur for X located perpendicularly to the ecliptic, while the maximum distance is for X lying in the ecliptic. We find for rock-ice planets of the size of Mars and the Earth that they would be at about 80-150 au, respectively, while a Jupiter-sized gaseous giant would be at approximately 1 kau. A typical brown dwarf would be located at about 4 kau, while an object with the mass of the Sun would be at approximately 10 kau, so that it could not be Nemesis for which a solar mass and a heliocentric distance of about 88 kau are predicted. If X was directed towards a specific direction, i.e. that of the Galactic Center, it would mimick the action of a recently proposed form of the External Field Effect (EFE) in the framework of the MOdified Newtonian Dynamics (MOND).

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Reference Frames in Astronomy

Cited by 25 publications

References 83 publications

GAIA: Composition, formation and evolution of the Galaxy

GAIA: Composition, formation and evolution of the Galaxy

The Perihelion Precession of Saturn, Planet X/Nemesis and MOND~!2009-09-17~!2009-10-08~!2010-05-05~!

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