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3 results on '"Chelli, Alain"'

1. Multiple-beam Fringe Tracking for the VLTI

Author

Cassaing, Frédéric, Baron, Fabien, Mocoeur, Isabelle, Mugnier, Laurent M., Rousset, Gérard, Sorrente, Béatrice, Delplancke, Francoise, Paresce, Francesco, Chelli, Alain E., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Astronomie du LESIA, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
Interferometry, Optics, Computer science, business.industry, Phase diversity, Multiple beam, Piston (optics), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Phase retrieval, business, Tracking (particle physics), Deformable mirror
Abstract

The performance of interferometric instruments is strongly linked to the quality of piston stabilization. Next generation VLTI instruments plan to use 4to8 beams simultaneously. In the current VLTI implementation, the maximum number of beams that can be phased using FINITO and PRIMA/FSU simultaneously is5. Therefore, a new fringe sensor is required for the VLTI.

Published
2007

2. Scientific Prospects for VLTI in the Galactic Centre: Getting to the Schwarzschild Radius

Author

Paumard, Thibaut, Perrin, Guy, Eckart, Andreas, Genzel, Reinhard, Léna, Pierre, Schödel, Rainer, Eisenhauer, Frank, Müller, Thomas G., Gillessen, S., Delplancke, Francoise, Paresce, Francesco, Chelli, Alain E., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Astronomie du LESIA, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
Physics, Proper motion, Astrophysics::High Energy Astrophysical Phenomena, Astronomy, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Galaxy, Black hole, Star cluster, Binary black hole, Intermediate-mass black hole, Stellar black hole, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Schwarzschild radius, Astrophysics::Galaxy Astrophysics
Abstract

The centre of our Galaxy is by far the closest galactic nucleus to theEarth. Not surprisingly, Sgr A*, the super-massive black hole candidate lyingat its gravitational centre, is the black hole (BH) candidate which offersthe best spatial resolution in terms of Schwarzschild radius tpRs, thanksto the good compromise between its mass (≃3.6×106 M⊙)and distance (≃8 kpc). For a 3.6×106 M⊙ BH,tpRs=14 R⊙ (≃8 umuas at 8 kpc). This is still twoorders of magnitudes smaller than the spatial resolution offered by theVLTI, but it is the right scale for studies involving only astrometry withPRIMA. We will show how this property can be used to tremendously improvethe knowledge of the central mass distribution, constrain the properties ofthe BH, and even directly probe the space-time around this object.

Published
2007

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