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| Paper: |
Properties of Globular Cluster Candidates in the Local Volume Dwarf Galaxies from the HST |
| Volume: |
316, Order and Chaos in Stellar and Planetary Systems |
| Page: |
267 |
| Authors: |
Sharina, M.E. |
| Abstract: |
Forty five nearby dwarf galaxies were searched for globular cluster candidates (GCCs) by using Hubble Space Telescope WFPC2 imaging in V and I. The sample consists of 8 dwarf spheroidal (dSph), 28 irregular (dIrr) and 7 “transition” type (dIrr/dSph) galaxies with angular dimensions less than 2′ situated at the distance 1.9–6.3 Mpc in the field and in the nearby groups: M81, Centaurus A, Sculptor, Canes Venatici I cloud. Additionally, I found GCCs in KK084, dSph companion of NGC3115, situated at the distance of about 9.7 Mpc (Tonry et al. 2001), and Holmberg IX, the tidal dwarf companion of M81 (Boyce et al. 2001). dSph and dIrr/dSph galaxies comprise the weakest part of our sample with mean surface brightness μV > 24.6m/☐″ and μV > 24.0m/☐″ respectively. Four dSphs—KK211, KK221, Scu22, and KK084—were found to host 16 globular cluster candidates with integral colors 0.9 < V - I < 1.4. There are no GCCs in dIrr/dSph galaxies. Eleven dIrr galaxies have low surface brightness μV > 24.0m/☐″. Only two of them, DDO53 and KK200, contain GCCs. Eighteen dIrr galaxies have mean surface brightnesses falling in the range of 22.4m/□″ - 24.0m/□″. Nine of them contain 67 GCCs including 31 GCCs of UGC3755 and 22 GCCs of Holmberg IX. The majority of GCCs have absolute visual magnitudes -9.0 ÷ -5.1, and linear half-light radii 3–11 pc, which are within values typical for Galactic globular clusters. Almost all GCCs (90%) show pronounced concentration toward the galaxy centers with linear projected separation 0.6 ± 0.3 kpc. The histogram of color distribution for all GCCs in dIrrs shows obvious bimodality with the peaks near V - I = 0.6 and V - I = 0.95. |
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