Morphologies and stellar populations of galaxies in the core of Abell 2218 (original) (raw)

We present a study of the stellar populations and morphologies of galaxies in the core of the galaxy cluster Abell 2218. Integral field spectroscopy (IFS) observations were performed using PMAS in the PPAK mode covering a field-of-view of ∼74"×64" centred on the core of the cluster, in order to obtain spectroscopy of an unbiased flux limited sample of cluster galaxies. Forty-three objects were detected in the IFS data, 31 of them with enough signal-to-noise to derive the redshift, all of them brighter than I <21.5 mag. Twenty-eight are at the redshift of the cluster (17 with previously unknown redshift). Individual spectra of the cluster members were extracted and compared with single stellar population models to derive the luminosity-weighted ages and metallicities. In addition, deep HST/ACS F475W, F555W, F625W and F850LP-band images centred on the cluster core were obtained from the HST archive (z lim ∼28 mag). A detailed morphological analysis of all the galaxies within the field-of-view of these images down to z lim <22.5 mag was performed classifying them as late-type, intermediate and early-type, on the basis of their Sérsic indices. The literature was scanned to look for spectroscopically confirmed cluster members located within the field-of-view of the ACS image. The final sample of 59 galaxies comprises our reported sample of 28 galaxies in the core, and 31 additional galaxies in the outer regions. In addition, multiband broad-band photometry was extracted from the literature for all objects.