Young globular clusters in NGC 1316

SESTO, L. A.; FAIFER, F. R.; SMITH CASTELLI, A. V.; FORTE, J. C.; ESCUDERO, C. G.

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2018 vol. 479 p. 478 - 494

0035-8711

We present multi-object spectroscopy of the inner zone of the globularcluster (GC) system associated with the intermediate-age merger remnantNGC 1316. Using the multi-object mode of the GMOS camera, we obtainedspectra for 35 GCs. We find pieces of evidence that the innermost GCs ofNGC 1316 rotate almost perpendicular to the stellar component of thegalaxy. In a second stage, we determined ages, metallicities andα-element abundances for each GC present in the sample, throughthe measurement of different Lick/IDS indices and their comparison withsimple stellar population models. We confirmed the existence of multipleGC populations associated with NGC 1316, where the presence of adominant subpopulation of very young GCs, with an average age of 2.1Gyr, metallicities between -0.5 < [Z/H] < 0.5 dex andα-element abundances in the range -0.2 < [α/Fe] < 0.3dex, stands out. Several objects in our sample present subsolar valuesof [α/Fe] and a large spread of [Z/H] and ages. Some of theseobjects could actually be stripped nuclei, possibly accreted duringminor merger events. Finally, the results have been analyzed with theaim of describing the different episodes of star formation and thusprovide a more complete picture about the evolutionary history of thegalaxy. We conclude that these pieces of evidence could indicate thatthis galaxy has cannibalized one or more gas-rich galaxies, where thelast fusion event occurred about 2 Gyr ago.