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%astro-ph/0502058
%http://www.z.phys.nagoya-u.ac.jp/~shogo/papers/DistinctStructure.pdf


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\begin{document}

\title{A Distinct Structure Inside the Galactic Bar}

\author{Shogo Nishiyama\altaffilmark{1,\bigstar}, 
Tetsuya Nagata\altaffilmark{2}, Daisuke Baba\altaffilmark{1},
Yasuaki Haba\altaffilmark{1}, Ryota Kadowaki\altaffilmark{1},
Daisuke Kato\altaffilmark{1}, Mikio Kurita\altaffilmark{1},
Chie Nagashima\altaffilmark{1}, 
Yasushi Nakajima\altaffilmark{3}, Motohide Tamura\altaffilmark{3},
Hidehiko Nakaya\altaffilmark{4}, Koji Sugitani\altaffilmark{5},
Takahiro Naoi\altaffilmark{6}, Noriyuki Matsunaga\altaffilmark{7}, 
Toshihiko Tanab$\mathrm{\acute{e}}$\altaffilmark{7},

\altaffiltext{1}{Department of Astrophysics, Nagoya University, 
Nagoya, 464-8602, Japan}

\altaffiltext{$\bigstar$}{\myemail}

\altaffiltext{2}{Department of Astronomy, Kyoto University, 
Kyoto, 606-8502, Japan}

\altaffiltext{3}{National Astronomical Observatory of Japan, 
Mitaka, 181-8588, Japan}

\altaffiltext{4}{Subaru Telescope,  National Astronomical Observatory of
Japan, 650 North A'ohoku Place, Hilo, HI 96720, U.S.A.}

\altaffiltext{5}{Institute of Natural Science, Nagoya City University,
Nagoya, 464-8602, Japan}

\altaffiltext{6}{Department of Earth and Planetary Sciences The
University of Tokyo, Tokyo, 113-0033, Japan}
 
\altaffiltext{7}{Institute of Astronomy, School of Science, 
The University of Tokyo, Tokyo, 181-0015, Japan}

\altaffiltext{8}{Department of Astronomy and Earth Sciences,
Tokyo Gakugei University, Tokyo, 184-8501, Japan}


We present the result of a near-infrared ($J H K_S$) survey
along the Galactic plane,
$-10\fdg5 \leq l \leq 10\fdg5$ and $b=+1\degr$,
with the IRSF 1.4m telescope and the SIRIUS camera.
$K_S$ vs. $H-K_S$ color-magnitude diagrams
reveal a well-defined population of red clump (RC) stars
whose apparent magnitude peak
changes continuously along the Galactic plane,
from $K_S=13.4$ at $l=-10\degr$ to $K_S=12.2$ at $l=10\degr$
after dereddening.
This variation can be explained by 
the bar-like structure found in previous studies,
but
we find an additional
inner structure at $\mid l \mid\la 4^\circ$, 
where the longitude - apparent magnitude relation is distinct 
from the outer bar, and the 
apparent magnitude peak 
changes by only 
$\thickapprox$ 0.1 mag 
over the central $8^\circ$.  
The exact nature of
this inner structure is as yet uncertain.

\end{document}