GRAVITY: getting to the event horizon of Sgr A*
Abstract
We present the second-generation VLTI instrument GRAVITY, which currently is in the preliminary design phase. GRAVITY is specifically designed to observe highly relativistic motions of matter close to the event horizon of Sgr A*, the massive black hole at center of the Milky Way. We have identified the key design features needed to achieve this goal and present the resulting instrument concept. It includes an integrated optics, 4-telescope, dual feed beam combiner operated in a cryogenic vessel; near infrared wavefront sensing adaptive optics; fringe tracking on secondary sources within the field of view of the VLTI and a novel metrology concept. Simulations show that the planned design matches the scientific needs; in particular that 10 microarcsecond astrometry is feasible for a source with a magnitude of K=15 like Sgr A*, given the availability of suitable phase reference sources.
Keywords
Cite
@article{arxiv.0808.0063,
title = {GRAVITY: getting to the event horizon of Sgr A*},
author = {F. Eisenhauer and G. Perrin and W. Brandner and C. Straubmeier and A. Richichi and S. Gillessen and J. P. Berger and S. Hippler and A. Eckart and M. Schoeller and S. Rabien and F. Cassaing and R. Lenzen and M. Thiel and Y. Clenet and J. R. Ramos and S. Kellner and P. Fedou and H. Baumeister and R. Hofmann and E. Gendron and A. Boehm and H. Bartko and X. Haubois and R. Klein and K. Dodds-Eden and K. Houairi and F. Hormuth and A. Graeter and L. Jocou and V. Naranjo and R. Genzel and P. Kervella and T. Henning and N. Hamaus and S. Lacour and U. Neumann and M. Haug and F. Malbet and W. Laun and J. Kolmeder and T. Paumard and R. -R. Rohloff and O. Pfuhl and K. Perraut and J. Ziegleder and D. Rouan and G. Rousset},
journal= {arXiv preprint arXiv:0808.0063},
year = {2009}
}
Comments
13 pages, 11 figures, to appear in the conference proceedings of SPIE Astronomical Instrumentation, 23-28 June 2008, Marseille, France