The globular cluster system of NGC 1316 IV. Nature of the star cluster complex SH2

摘要: The light of the merger remnant NGC 1316 is dominated by old and intermediate-age stars. only sign current star formation in this big galaxy HII region SH2, an isolated cluster complex with a ring-like morphology estimated age 0.1 Gyr at galactocentric distance about 35 kpc. A nearby globular cluster, surrounded weak line emission few more young clusters, kinematically associated. origin enigmatic. nebular lines permit metallicity determination which can discriminate between dwarf or other possible precursors. We used Integrated Field Unit VIMOS instrument Very Large Telescope European Southern Observatory to study morphology, kinematics, employing maps, velocity diagnostics characteristic spectra. ratios different spectra vary, indicating highly structured regions, but define locus uniform metallicity. strong-line diagnostic diagrams empirical calibrations point nearly solar even super-solar oxygen abundance. dispersion gas highest offset from bright clusters. Star may be active on low level. There evidence for large-scale disk-like structure would make similar radial easier understand. high does not fit as progenitor. favour scenario free-floating gaseous having its 2 ago. Over long period densities increased secularly until finally threshold was reached. SH2 illustrates how massive clusters form outside starbursts without considerable field population.