0 a todos los radios. De estos resultados concluimos que no es posible distinguir entre ambos modelos.]]>
0 at all radii. Finally, from these results we conclude that is not possible to distinguish between both models.]]>
Fidel Cruz, Héctor Velázquez, and Héctor Aceves
Instituto de Astronomía, Universidad Nacional Autónoma de México, Apdo. Postal 877, 22860 Ensenada, B. C., México (aceves@astrosen.unam.mx, fidel@astrosen.unam.mx, hmv@astrosen.unam.mx)
Received 2006 March 16
Accepted 2006 October 13
RESUMEN
]]> Estudiamos las propiedades morfológicas y cinemáticas de sistemas triaxiales formados por colapso gravitacional usando simulaciones de N–cuerpos. Se consideran dos modelos; en uno de ellos el agujero negro supermasivo (SBH) ya existe antes del colapso gravitacional; en el otro caso el SBH crece de manera adiabática después de que el sistema se ha colapsado y se encuentra en equilibrio virial. El análisis de las isofotas de densidad a lo largo de los ejes principales muestra que la presencia del SBH tiende a hacer las isofotas más rectangulares que cuando no hay SBH. Los resultados de la cinemática utilizando la expansión de Gauss–Hermite muestran que la dispersión de velocidades central aumenta en presencia del SBH, y permanece constante para modelos sin SBH. El parámetro h4 es positivo dentro del radio de influencia del SBH, y cambia de signo fuera de esta región. Para el modelo sin SBH h4> 0 a todos los radios. De estos resultados concluimos que no es posible distinguir entre ambos modelos.
ABSTRACT
Using N–body simulations we study the morphological and kinematical properties of triaxial systems formed through cold gravitational collapses. Two models are considered; in one case, the supermassive black hole SBH already exists before the gravitational collapse, and in the other the SBH grows adiabatically after the collapsed system has reached virial equilibrium. Isophotal analysis along the principal projected axes shows that the SBH tends to make the isophotes more boxy than in the case without a central SBH. Also, the kinematics obtained from a Gauss–Hermite expansion shows that the central velocity dispersion increases in presence of the SBH while it remains almost constant for models without a SBH. Furthermore, the h4 parameter is positive inside the radius of influence of the central black hole while it is negative beyond of this region. For models without a SBH h4 > 0 at all radii. Finally, from these results we conclude that is not possible to distinguish between both models.
Key Words: GALAXIES: ELLIPTICAL — GALAXIES: FORMATION — GALAXIES NUCLEI — METHODS: NUMERICAL
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ACKNOWLEDGEMENTS
We thank the anonymous referee for several suggestion that improved this paper. This research was supported by DGAPA grant IN113403, Universidad Nacional Autónoma de México.
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