Abstract
We present spectroscopic observations of a massive globular cluster in the dwarf irregular galaxy Sextans B, discovered by us on the Hubble Space Telescope Wide Field and Planetary Camera 2 (HST WFPC2) images. Long-slit spectra were obtained with the SCORPIO spectrograph on the 6-m telescope at the Special Astrophysical Observatory of the Russian Academy of Sciences. We determine the age, metallicity and alpha-element abundance ratio for the globular cluster to be 2 ± 1 Gyr, −1.35 ±0.25 dex, and 0.1 ± 0.1 dex, respectively. Main photometric and structural parameters of it were determined using our surface photometry on the HST images. The mass (∼105 M⊙), luminosity and structural parameters appear to be typical of the globular clusters in our own Galaxy. Our findings shed new light on the evolutionary history of Sextans B.
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Original Russian Text © M.E. Sharina, T.H. Puzia, A.S. Krylatyh, 2007, published in Astrofozicheskij Byulleten, 2007, Vol. 62, No. 3, pp. 225–232.