- Nombre : THE DARK HALOS OF ISOLATED ELLIPTICAL GALAXIES
- Número/Código : GS-2010B-Q-77
- Nombre Concurso : CONCURSO PROPUESTAS DE OBSERVACIÓN ASTRONÓMICA PARA TIEMPO CHILENO EN EL OBSERVATORIO GEMINI PRIMER SEMESTRE DE 2010B
- Año Concurso : 2010
- Tiempo de Observación : 15 hrs.
The existence of a tight baryonic Tully-Fisher relation (BTFR) among disk galaxies over 5 orders of magnitude in mass, confirming a prediction of Modified Newtonian Dynamics (MOND), is a disturbing finding for the reigning CDM paradigm of galaxy formation. The claimed universality of MOND, however, still lacks a convincing proof/disproof in the realm of early-type galaxies. Elliptical field galaxies, not being exposed to external fields and without interaction history, which could modify their dark halos, are key objects. The dark halos (or ''ghost halos'' in the MOND case) of isolated elliptical galaxies cannot be investigated by dynamical tracers like globular clusters or planetary nebulae because of mostly large distances and poor cluster systems. The remaining possibility is to use the galaxy light itself at large radii. Here we propose to investigate the dynamics of the isolated elliptical galaxy NGC 1162 out to 3 effective radii by the technique of ultradeep mask spectroscopy of its diffuse light. Velocity dispersions and higher moments will constrain the circular velocity and probe its consistency with the BTFR of spiral galaxies.