Nuclei of dwarf spheroidal galaxies KKs3 and ESO269-66 and their counterparts in our Galaxy

Abstract

We present the analysis of medium-resolution spectra obtained at the Southern African Large Telescope (SALT) for nuclear globular clusters (GCs) in two dwarf spheroidal galaxies (dSphs). The galaxies have similar star formation histories, but they are situated in completely different environments. ESO269-66 is a close neighbour of the giant S0 NGC5128. KKs3 is one of the few truly isolated dSphs within 10 Mpc. We estimate the helium abundance $Y=0.3$, $\mathrm{age}=12.6\pm 1$ Gyr, $[Fe/H]=-1.5,-1.55\pm 0.2$ dex, and abundances of C, N, Mg, Ca, Ti, and Cr for the nuclei of ESO269-66 and KKs3. Our surface photometry results using HST images yield the half-light radius of the cluster in KKs3, ${\mathrm{r}}_{\mathrm{h}}=4.8\pm 0.2$ pc. We demonstrate the similarities of medium-resolution spectra, ages, chemical compositions, and structure for GCs in ESO269-66 and KKs3 and for several massive Galactic GCs with $[Fe/H]\sim -1.6$ dex. All Galactic GCs posses Extended Blue Horizontal Branches and multiple stellar populations. Five of the selected Galactic objects are iron-complex GCs. Our results indicate that the sample GCs observed now in different environments had similar conditions of their formation $\sim$1 Gyr after the Big Bang.

14 pages, 8 figures, 10 tables. Table 1 and two references were corrected. Accepted for publication in MNRAS

References in corpus (20)

• The ACS Virgo Cluster Survey. VIII. The Nuclei of Early-Type Galaxies
• Updated Nearby Galaxy Catalog
• The ACS Survey of Galactic Globular Clusters. I. Overview and Clusters Without Previous HST Photometry
• Scaled solar tracks and isochrones in a large region of the Z-Y plane I. From the ZAMS to the TP-AGB end for 0.15 - 2.5 Mo stars
• Spectroscopic and Photometric evidence of two stellar populations in the Galactic Globular Cluster NGC6121 (M4)
• Thermohaline mixing: A physical mechanism governing the photospheric composition of low-mass giants
• The Hubble flow around the CenA / M83 galaxy complex
• First science with SALT: peering at the accreting polar caps of the eclipsing polar SDSS J015543.40+002807.2
• Iron and s-elements abundance variations in NGC5286: comparison with anomalous globular clusters and Milky Way satellites
• Iron and neutron-capture element abundance variations in the globular cluster M2 (NGC 7089)
• Catalogues of isolated galaxies, isolated pairs, and isolated triplets in the local Universe
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. II. The seven stellar populations of NGC7089 (M2)
• The metallicity extremes of the Sagittarius dSph using SALT spectroscopy of PNe
• Photometric properties of Local Volume dwarf galaxies
• On the primordial scenario for abundance variations within globular clusters. The isochrone test
• Scl-dE1 GC1: An Extended Globular Cluster in a Low-Luminosity Dwarf Elliptical Galaxy
• A new isolated dSph galaxy near the Local Group
• FORS2/VLT survey of Milky Way globular clusters I. Description of the method for derivation of metal abundances in the optical and application to NGC 6528, NGC 6553, M 71, NGC 6558, NGC 6426 and Terzan 8
• Globular Cluster Abundances from High-Resolution, Integrated-Light Spectroscopy. II. Expanding the Metallicity Range for Old Clusters and Updated Analysis Techniques
• Gemini spectroscopy of the outer disk star cluster BH176

Cited by in corpus (8)

• The Gas Content and Stripping of Local Group Dwarf Galaxies
• The spatial distribution of globular clusters in dwarf spheroidal galaxies and the timing problem
• Investigation of the Prompt SNe Ia progenitor nature through the analysis of the chemical composition of globular clusters and circumgalactic clouds
• Analysis of integrated-light spectra of Galactic globular clusters
• The Stellar Population and Orbit of the Galactic Globular Cluster Palomar 3
• Age and chemical composition of the globular cluster NGC 6652
• Spectroscopy of globular clusters in the dwarf spheroidal galaxy IKN
• Horizontal branch structure, age, and chemical composition for very metal-poor extragalactic globular clusters