  We present observations of a massive star cluster near the nuclear region of
the nearby starburst galaxy NGC 253. The peak of near-infrared emission, which
is spatially separated by 4" from the kinematic center of the galaxy, is
coincident with a super star cluster whose properties we examine with
low-resolution (R ~ 1,200) infrared CTIO spectroscopy and optical/near-infrared
HST imaging. Extinction, measured from [FeII] lines, is estimated at Av = 17.7
+/- 2.6. The age of the cluster is estimated at 5.7 Myr, based on Bry
equivalent width for an instantaneous burst using Starburst99 modeling.
However, a complex star formation history is inferred from the presence of both
recombination emission and photospheric CO absorption. The ionizing photon flux
has a lower limit of 7.3 +/- 2.5 x 10^53 inverse seconds, corrected for
extinction. Assuming a Kroupa IMF, we estimate a cluster mass of 1.4 +/- 0.4 x
10^7 solar masses. We observe a strong Wolf-Rayet signature at 2.06 microns and
report a weak feature at 2.19 microns which may be due to a massive stellar
population, consistent with the derived mass and age of this cluster.

Solar and Stellar Astrophysics