------------------------------------------------------------------------
 paumard06disks.tex ApJ, 2006, in press
From: Thibaut Paumard <paumard@iap.fr>
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Date: Fri, 03 Mar 2006 11:34:08 +0100
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%astro-ph/0601268
\documentclass{aastex}

\newcommand{\sunmass}{M_\sun}

\shorttitle{Stellar disks in the Galactic Center}
\shortauthors{Paumard et al.}

\begin{document}
\title{The  Two  Young  Star  Disks  in  the Central  Parsec  of  the
                               Galaxy:
                  Properties, Dynamics and Formation}

\author{T.~Paumard\altaffilmark{1}, R.~Genzel\altaffilmark{1,2},
  F.~Martins\altaffilmark{1}, S.~Nayakshin\altaffilmark{3,4},
  A.~M.~Beloborodov\altaffilmark{5,6}, Y.~Levin\altaffilmark{7,8},
  S.~Trippe\altaffilmark{1}, F.~Eisenhauer\altaffilmark{1},
  T.~Ott\altaffilmark{1}, S.~Gillessen\altaffilmark{1},
  R.~Abuter\altaffilmark{1}, J.~Cuadra\altaffilmark{3},
  T.~Alexander\altaffilmark{9,10}, A.~Sternberg\altaffilmark{11}}
(MPE), Giessenbachstra{\ss}e, 85748 Garching, Germany}
\altaffiltext{2}{Department of Physics, University of California, 366
LeConte Hall, Berkeley, CA 94720, USA}
\altaffiltext{3}{Max-Planck Institut f\"ur Astrophysik (MPA),
  Karl-Schwarzschild-Str. 1, 85741 Garching, Germany}
\altaffiltext{4}{Theoretical Astrophysics Group, Department of Physics
\& Astronomy, University of Leicester, Leicester, LE1 7RH, United
Kingdom}
\altaffiltext{5}{Physics Department and Columbia Astrophysics
Laboratory, Columbia University, New York, USA}
\altaffiltext{6}{Astro-Space Center of Lebedev Physical Institute, 84/32
Profsoyuznaya st., Moscow, 117997, Russia}
\altaffiltext{7}{Canadian Institute for Theoretical Astrophysics,
University of Toronto, 60 St. George Street, Toronto, Ontario, M5S 3H8,
Canada}
\altaffiltext{8}{Sterrewacht Leiden, Leiden University, P.O. Box
9513,NL-2300 RA  Leiden, The Netherlands}
\altaffiltext{9}{Faculty of Physics, Weizmann Institute of Science,
Rehovot 76100, Israel}
\altaffiltext{10}{William Z. and Eda Bess Novick career development
chair}
\altaffiltext{11}{School of Physics \& Astronomy, Tel Aviv University,
  P.O. Box 39040, Tel Aviv 69978, Israel}

\begin{abstract}
  We report the definite spectroscopic identification of $\simeq40$ OB
  supergiants, giants and main sequence stars in the central parsec of
  the Galaxy. Detection of their absorption lines have become possible
  with the high spatial and spectral resolution and sensitivity of the
  adaptive optics integral field spectrometer SPIFFI/SINFONI on the ESO
  VLT.  Several of these OB stars appear to be helium and nitrogen rich.
  Almost all of the $\simeq80$ massive stars now known in the central
  parsec (central arcsecond excluded) reside in one of two somewhat
  thick ($\langle|h|/R\rangle\simeq0.14$) rotating disks.  These stellar
  disks have fairly sharp inner edges ($R\simeq1\arcsec$) and surface
  density profiles that scale as $R^{-2}$. We do not detect any OB stars
  outside the central $0.5$~pc. The majority of the stars in the
  clockwise system appear to be on almost circular orbits, whereas most
  of those in the `counter-clockwise' disk appear to be on eccentric
  orbits.  Based on its stellar surface density distribution and
  dynamics we propose that IRS~13E is an extremely dense cluster
  ($\rho_\mathrm{core}\gtrsim3\times10^8\sunmass$~pc$^{-3}$), which has
  formed in the counter-clockwise disk.  The stellar contents of both
  systems are remarkably similar, indicating a common age of $\simeq6
  \pm2$~Myr.  The K-band luminosity function of the massive stars
  suggests a top-heavy mass function and limits the total stellar mass
  contained in both disks to $\simeq1.5\times10^4\sunmass$. Our data
  strongly favor in situ star formation from dense gas accretion disks
  for the two stellar disks.  This conclusion is very clear for the
  clockwise disk and highly plausible for the counter-clockwise system.
\end{abstract}
\keywords{stars: early-type -- Galaxy: center {--}
stars:formation {--} stellar dynamics {--}  stars: luminosity function,
mass function}
\end{document}