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 ms.tex  ApJS, vol.118, 455-515
content-length: 3197

\documentstyle[12pt,aasms4]{article}
\lefthead{Oka et al.}
\righthead{A LARGE-SCALE CO SURVEY OF THE GALACTIC CENTER}


\def\kms{\hbox{km s$^{-1}$}}
\def\VLSR{\hbox{$V_{\rm LSR}$}}
\def\hh{\hbox{$^{\rm h}$}}
\def\mm{\hbox{$^{\rm m}$}}
\def\ss{\hbox{$^{\rm s}$}}


\begin{document}
\title{A LARGE-SCALE CO SURVEY OF THE GALACTIC CENTER}


\author{Tomoharu Oka\altaffilmark{1}, Tetsuo Hasegawa\altaffilmark{2},
Fumio Sato\altaffilmark{3}, Masato Tsuboi\altaffilmark{4},
and Atsushi Miyazaki\altaffilmark{4}}

\altaffiltext{1}{{\footnotesize The Institute of Physical and Chemical
Research (RIKEN),
2-1 Hirosawa, Wako, Saitama 351-0198, Japan.}}
\authoremail{oka@postman.riken.go.jp}
\altaffiltext{2}{{\footnotesize Institute of Astronomy, Faculty of Science,
The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan.}}
\altaffiltext{3}{{\footnotesize Department of Astronomy and Earth Sciences,
Tokyo Gakugei University, 4-1-1 Nukui-kita, Koganei, Tokyo 184-8501, Japan.}}
\altaffiltext{4}{{\footnotesize Institute of Astrophysics and Planetary
Science,
Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512, Japan.}}

%\slugcomment{}
\begin{center}
{Submitted to ApJ Supplement (version: 24 April 1998)}
\end{center}



\begin{abstract}
We present high-resolution CO images of the Galactic center region taken
with the 2$\times$2
focal-plane array receiver mounted on the 45 m telescope of Nobeyama Radio
Observatory\footnotemark[1] .
We have collected about 44000 $^{12}$C$^{16}$O ({\it J}=1--0) spectra and over
13000 $^{13}$C$^{16}$O ({\it J}=1--0) spectra with a 34\arcsec (1.4 pc)
grid spacing.
$^{12}$CO mapping area is roughly  $-1.5\arcdeg \leq l \leq +3.4\arcdeg$
and  $-0.6\arcdeg \leq b \leq +0.6\arcdeg$,
which covers almost the full extent of the molecular gas concentration in
the Galactic center.
These CO images demonstrate extremely complex distribution and kinematics
of molecular gas in the Galactic center.
While its large-scale behavior can be attributed to the well-known
coherent features,
bright CO emission arises from a number of compact ($d \leq 10$ pc)
clouds with large velocity widths ($\Delta V \geq 30$ \kms ).
Small-scale structure of molecular gas is characterized by filaments, arcs,
and shells.
The boisterous molecular gas kinematics there may be a result of violent
release of kinetic energy by
a number of supernova explosions and/or Wolf-Rayet stellar winds.
\end{abstract}
\keywords{Galaxy: center - galaxies: nuclei  - galaxies: starburst -
galaxies: ISM - ISM: clouds}

\footnotetext[1]{Nobeyama Radio Observatory (NRO), a branch of the National
Astronomical Observatory,
is a radio observing facility open to outside users. }

\clearpage



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Tomoharu OKA　

Cosmic Radiation Laboratory
The Institute of Physical and Chemical Research (RIKEN)
2-1 Hirosawa, Wako, Saitama 351-0198, JAPAN
TEL    :        +81-48-462-1111 ex.3227
     (midnight +81-48-467-9336)
FAX     :      +81-48-462-4640
E-mail  :       oka@postman.riken.go.jp
URL:            http://cruiser.riken.go.jp/oka/
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