The initial mass function of a massive relic galaxy
Date Issued
2015
Author(s)
Ignacio Martín-Navarro
•
•
Alexandre Vazdekis
•
Anna Ferré-Mateu
•
Ignacio Trujillo
•
Michael A. Beasley
Abstract
Massive relic galaxies formed the bulk of their stellar component before z~2
and have remained unaltered since then. Therefore, they represent a unique
opportunity to study in great detail the frozen stellar population properties
of those galaxies that populated the primitive Universe. We have combined
optical to near-infrared line-strength indices in order to infer, out to 1.5
Reff, the IMF of the nearby relic massive galaxy NGC 1277. The IMF of this
galaxy is bottom-heavy at all radii, with the fraction of low-mass stars being
at least a factor of two larger than that found in the Milky Way. The excess of
low-mass stars is present throughout the galaxy, while the velocity dispersion
profile shows a strong decrease with radius. This behaviour suggests that local
velocity dispersion is not the only driver of the observed IMF variations seen
among nearby early-type galaxies. In addition, the excess of low-mass stars
shown in NGC 1277 could reflect the effect on the IMF of dramatically different
and intense star formation processes at z~2, compared to the less extreme
conditions observed in the local Universe.
Volume
451
Issue
1
Start page
1081
Issn Identifier
0035-8711
Ads BibCode
2015MNRAS.451.1081M
Rights
open.access
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