Evidence of a Distinct Stellar Population in the Counterrotating Core of NGC 1700

Autores
Dr.
Alexandre Vazdekis
Fecha y hora
24 Mayo 2011 - 00:00 Europe/London
Dirección

Aula

Idioma de la charla
Inglés
Idioma de la presentación
Inglés
Número en la serie
1
Descripción

We find a distinct stellar population in the counterrotating and kinematically decoupled core of the isolated massive elliptical galaxy NGC 1700. Coinciding with the edge of this core, we find a significant change in the slope of the gradient of various representative absorption line indices. Our age estimate for this core is markedly younger than the main body of the galaxy. We find lower values for the age, metallicity, and Mg/Fe abundance ratio in the center of this galaxy when we compare them with other isolated elliptical galaxies with similar velocity dispersion. We discuss the different possible scenarios that might have lead to the formation of this younger kinematically decoupled structure and conclude that, in light of our findings, the ingestion of a small stellar companion on a retrograde orbit is the most favored.