2010A&A...519A..59B

The very center (r≪r_e) of NGC 3610, a clearly disturbed giant elliptical that is generally assumed to be a post-merger remnant, appears dominated in the mid-UV (2500-3200Å spectral region) by a stellar population that is markedly different from that dominating the bulk of its stellar body. We make use of the mid-UV spectra of NGC 3610 as seen through tiny (∼1'') and large (10''x20'') apertures as a diagnostic population tool. We compare archive IUE/LWP large aperture and HST/FOS UV data of NGC3610. The strength of mid-UV triplet (dominated by the turnoff population) shows a remarkable drop when switching from the galaxy central arcsec (FOS aperture) to an aperture size comparable to ∼0.5r_e (IUE). The sub-arsec (mid)-UV properties of this galaxy involved in a past merger reveal a central metal enrichment which left the bulk of its pre-existing population intact.