Merging of Elliptical Galaxies as a Possible Origin of the Intergalactic Stellar Population
[EN]We present N-body simulations of elliptical galaxy encounters into dry mergers to study the resulting unbound intergalactic stellar population, in particular that of the post-main-sequence stars. The systems studied are pairs of spherical galaxies without dark halos. The stellar content of the m...
| Autores: | , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2006 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/75139 |
| Acceso en línea: | http://hdl.handle.net/10261/75139 |
| Access Level: | acceso abierto |
| Palabra clave: | Galaxies: elliptical and lenticular, cD Galaxies: interactions Galaxies: stellar content Planetary nebulae: general stars: AGB and post-AGB Incipit Instituto de Ciencias del Patrimonio Institute of Heritage Sciences |
| Sumario: | [EN]We present N-body simulations of elliptical galaxy encounters into dry mergers to study the resulting unbound intergalactic stellar population, in particular that of the post-main-sequence stars. The systems studied are pairs of spherical galaxies without dark halos. The stellar content of the model galaxies is distributed into mass bins representing low- and intermediate-mass stars (0.85-8 M☉) according to the Salpeter initial mass function. Our models follow the dynamical evolution of galaxy encounters colliding head-on from initial low-energy parabolic or high-energy mildly hyperbolic orbits and for a choice of initial mass ratios. The merging models with initial parabolic orbits have M2/M1 = 1 and 10, and they leave behind, respectively, 5.5% and 10% of the total initial mass as unbound stellar mass. The merging model with an initial hyperbolic orbit has M2/M1 = 1 and leaves behind 21% of its initial stellar mass as unbound mass, showing that the efficiency in producing intergalactic stars through a high-energy hyperbolic encounter is about 4 times that of a parabolic encounter of the same initial mass ratio. By assuming that all progenitor galaxies, as well as the merger remnants, are homologous systems we find that the intergalactic starlight is 17% and 28% of the total starlight, respectively, for the parabolic and hyperbolic encounters with M2/M1 = 1. In all models, stars of different mass have the same probability of becoming unbound and feeding the intergalactic stellar population. |
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