Bibcode
Pierce, Michael; Brodie, Jean P.; Forbes, Duncan A.; Beasley, Michael A.; Proctor, Robert; Strader, Jay
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 358, Issue 2, pp. 419-431.
Fecha de publicación:
4
2005
Número de citas
31
Número de citas referidas
29
Descripción
We have obtained Keck spectra for 16 globular clusters (GCs) associated
with the merger remnant elliptical NGC 1052, as well as a long-slit
spectrum of the galaxy. We derive ages, metallicities and abundance
ratios from simple stellar population models using the recently
published methods of Proctor & Sansom, applied to extragalactic GCs
for the first time. A number of GCs indicate the presence of strong blue
horizontal branches that are not fully accounted for in the current
stellar population models. We find all of the GCs to be ~13 Gyr old
according to simple stellar populations, with a large range of
metallicities. From the galaxy spectrum we find NGC 1052 to have a
luminosity-weighted central age of ~2 Gyr and metallicity of
[Fe/H]~+0.6. No strong gradients in either age or metallicity were found
to the maximum radius measured (0.3re~= 1 kpc). However, we
do find a strong radial gradient in α-element abundance, which
reaches a very high central value. The young central starburst age is
consistent with the age inferred from the HI tidal tails and infalling
gas of ~1 Gyr. Thus, although NGC 1052 shows substantial evidence for a
recent merger and an associated starburst, it appears that the merger
did not induce the formation of new GCs, perhaps suggesting that little
recent star formation occurred. This interpretation is consistent with
`frosting' models for early-type galaxy formation.