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D. Maoz (Tel-Aviv U., Columbia U.), L.C. Ho (OCIW), A. Sternberg (Tel-Aviv U.)
We present long-slit 3000-10000 Å\ spectroscopy of the
bright super star cluster A (SSC-A) in the irregular
starburst galaxy NGC~1569, obtained with STIS on board
the Hubble Space Telescope (HST). The 0.05" HST
angular resolution allows, for the first time, to probe for
spatial variations in the stellar population of a ~106
M\odot SSC. Integrated ground-based spectra of SSC-A
have previously revealed young Wolf-Rayet (WR) signatures
that coexist with features from older, red giant,
populations. We find that the WR emission complexes come
solely from the subcluster A2, identified in previous HST
imaging, and are absent from the main cluster A1. The
equivalent widths of the WR features in A2 -- including the
C~IV~\lambda 5808 complex which we detect for the first
time in this object -- are much larger than predicted by
models with sub-solar metallicity, posing a new problem. On
the ``clean'' NW side of A1, we find no evidence for radial
gradients in the stellar population between 0.05" The author(s) of this abstract have provided an email address
for comments about the abstract:
dani@astro.columbia.edu