SBSG 0335-052W: An extremely low metallicity dwarf galaxy

We present Multiple Mirror Telescope and Keck II telescope spectrophotometr y and 3.5 m Calar Alto telescope R, I photometry of the western component o f the extremely low metallicity blue compact galaxy SBSG 0335-052. The comp onents, separated by 22 kpc, appear to be members of a unique, physically c onnected system. It is shown that SBSG 0335-052W consists of at least three stellar clusters and has the same redshift as SBSG 0335-052. The oxygen ab undance in its two brightest knots is extremely low, 12 + log (O/H)= 7.22 /- 0.03 and 7.13 +/- 0.08, respectively. These values are lower than in SBS G 0335-052 and are nearly the same as those in I Zw 18. The R-I color profi les are very blue in both galaxies because of the combined effects of ioniz ed gas and a young stellar population emission. We argue that SBSG 0335-052 W is likely to be a nearby, young dwarf galaxy.