Bibcode
La Barbera, F.; Pasquali, A.; Ferreras, I.; Gallazzi, A.; de Carvalho, R. R.; de la Rosa, I. G.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 445, Issue 2, p.1977-1996
Advertised on:
12
2014
Citations
43
Refereed citations
41
Description
A detailed analysis of how environment affects the star formation
history of early-type galaxies (ETGs) is undertaken via high
signal-to-noise ratio stacked spectra obtained from a sample of 20 977
ETGs (morphologically selected) from the Sloan Digital Sky Survey-based
SPIDER survey. Two major parameters are considered for the study: the
central velocity dispersion (σ), which relates to local drivers of
star formation, and the mass of the host halo, which relates to
environment-related effects. In addition, we separate the sample between
centrals (the most massive galaxy in a halo) and satellites. We derive
trends of age, metallicity, and [α/Fe] enhancement, with σ.
We confirm that the major driver of stellar population properties in
ETGs is velocity dispersion, with a second-order effect associated with
the central/satellite nature of the galaxy. No environmental dependence
is detected for satellite ETGs, except at low σ - where satellites
in groups or in the outskirts of clusters tend to be younger than those
in the central regions of clusters. In contrast, the trends for centrals
show a significant dependence on halo mass. Central ETGs in groups (i.e.
with a halo mass >1012.5 M⊙) have younger
ages, lower [α/Fe], and higher internal reddening, than `isolated'
systems (i.e. centrals residing in low-mass, <1012.5
M⊙, haloes). Our findings imply that central ETGs in
groups formed their stellar component over longer time scales than
`isolated' centrals, mainly because of gas-rich interactions with their
companion galaxies.
Related projects
Traces of Galaxy Formation: Stellar populations, Dynamics and Morphology
We are a large, diverse, and very active research group aiming to provide a comprehensive picture for the formation of galaxies in the Universe. Rooted in detailed stellar population analysis, we are constantly exploring and developing new tools and ideas to understand how galaxies came to be what we now observe.
Ignacio
Martín Navarro