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%astro-ph/0205186

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\shorttitle{}
\shortauthors{S. Gezari}

\begin{document}

\title{Adaptive Optics Near-Infrared Spectroscopy \\ of the Sgr A*
Cluster}

\author{S. Gezari, A.M. Ghez\footnote{Also affiliated with UCLA's
Institute
of Geophysics and Planetary Physics.}, E.E. Becklin,
J. Larkin, I.S. McLean, M. Morris}
\vspace{1cm}
\affil{Department of Physics and Astronomy \\ University of California,
    at Los Angeles, CA 90095-1562}
\email{suvi@astro.ucla.edu}

\begin{abstract}
We present K-band $\lambda$/$\Delta\lambda$ $\sim$ 2600
spectroscopy of five stars
(K $\sim$ 14 - 16 mag) within 0.''5 of Sgr A*, the radio source
associated with the compact massive object suspected to be a
2.6 x 10$^{6}$ \msun black hole at the center of our Galaxy.
High spatial resolution of $\sim$ 0.''09, and good strehl ratios of $\sim$
0.2
achieved with adaptive optics on the 10-meter Keck telescope
make it possible to measure moderate-resolution spectra of these
stars individually for the first time.
Two stars (S0-17 and S0-18) are identified as late-type stars by the
detection of CO bandhead absorption in their spectra.  Their absolute
K magnitudes and CO bandhead absorption strengths are consistent with
early
K giants.  Three stars (S0-1, S0-2, and S0-16), with r$_{proj}$ $<$ 0.0075
pc
($\sim$ 0.''2) from Sgr A*, lack CO bandhead absorption, confirming
the results of earlier lower spectral and lower spatial resolution
observations
that the majority of the stars in the Sgr A* Cluster are
early-type stars.  The absolute K magnitudes of the early-type stars
suggest
that they are late O - early B main sequence stars of ages $<$ 20 Myr.
The presence of young stars in the Sgr A* Cluster, so close to the central
supermassive black hole, poses the intriguing problem of how
these stars could have formed, or could have been brought, within its
strong tidal field.
\end{abstract}
\end{document}