ASTE CO (3-2) Observations of the Barred Spiral Galaxy M 83: I. Correlation between CO (3-2)/ CO (1-0) Ratios and Star Formation Efficiencies
ASTE CO (3-2) Observations of the Barred Spiral Galaxy M 83: I. Correlation between CO (3-2)/ CO (1-0) Ratios and Star Formation Efficiencies
复制标题
DOI：
10.1093/pasj/59.1.43
复制
发表时间：
2007-01
影响因子：
2.3
通讯作者：
K. Muraoka;K. Kohno;T. Tosaki;N. Kuno;K. Nakanishi;K. Sorai;T. Okuda;S. Sakamoto;A. Endo;B. Hatsukade;K. Kamegai;Kunihiko Tanaka;J. Cortes;H. Ezawa;N. Yamaguchi;T. Sakai;R. Kawabe
中科院分区：
文献类型：
--
作者：
K. Muraoka;K. Kohno;T. Tosaki;N. Kuno;K. Nakanishi;K. Sorai;T. Okuda;S. Sakamoto;A. Endo;B. Hatsukade;K. Kamegai;Kunihiko Tanaka;J. Cortes;H. Ezawa;N. Yamaguchi;T. Sakai;R. Kawabe
我们目前的CO（J = 3-2）发射观测与ASTE对50 - 50（或6.6 kpc-6.6 kpc的距离D = 4.5 Mpc）附近的棒旋星系M83的区域。我们成功解决了主要结构，即，核星爆区，酒吧，和内旋臂的分辨率为2200（480秒差距），表现出良好的空间一致性之间的CO和6厘米的连续排放。我们发现了一个全球光度，LCO.3 2/，5：1 10 K km s 1 pc的观测区域内。我们还在4：2 10 K km s 1 pc的盘区（0：5 < r < 3：5 kpc）中发现了LCO.3 2/，表明盘区（J = 3-2）的发射对全球LCO.3 2/有显著贡献。通过将CO（J = 3-2）数据与Nobeyama 45 m望远镜测量的CO（J = 1-0）强度进行比较，我们发现CO（J = 3-2）=CO（J = 1-0）积分强度比的径向轮廓R3 2=1 0，在中心区域几乎为1（r < 0：25 kpc），而在圆盘区域则下降到恒定值0.6-0.7。由6cm射电连续谱和CO（J = 1-0）辐射测定的星星形成效率（SFE）径向分布与R32 =1 - 0的径向分布具有相同的趋势。在棒端（r2：4kpc），分子气体和大质量恒星的数量相对于盘的其它区域有所增加，而在该区域没有过量的R32 = 10和SFE.这意味着简单地将棒端和盘端的恒星形成区相加不能再现M83的核星爆，这意味着由R32 = 10所追踪的致密气体部分的空间变化决定了M83的SFE的空间变化。
We present CO (J = 3–2) emission observations with the ASTE toward the 50 50 (or 6.6 kpc 6.6 kpc at the distance D = 4.5 Mpc) region of the nearby barred spiral galaxy M 83. We successfully resolved the major structures, i.e., the nuclear starburst region, bar, and inner spiral arms at a resolution of 2200 (480 pc), showing a good spatial coincidence between CO and 6 cm continuum emissions. We found a global luminosity, LCO.3 2/, of 5:1 10 K km s 1 pc within the observed region. We also found LCO.3 2/ in a disk region (0:5 < r < 3:5 kpc) of 4:2 10 K km s 1 pc, indicating that (J = 3–2) emission in the disk region significantly contributes to the global LCO.3 2/. From a comparison of CO (J = 3–2) data with CO (J = 1–0) intensities measured with the Nobeyama 45m telescope, we found that the radial profile of the CO (J = 3–2)=CO (J = 1–0) integrated intensity ratio, R3 2=1 0, is almost unity in the central region (r < 0:25 kpc), whereas it drops to a constant value, 0.6–0.7, in the disk region. The radial profile of star formation efficiencies (SFEs), determined from 6 cm radio continuum and CO (J = 1–0) emission, shows the same trend as that of R3 2=1 0. At the bar-end (r 2:4 kpc), the amounts of molecular gas and the massive stars are enhanced when compared with other disk regions, whereas there is no excess of R3 2=1 0 and SFE in that region. This means that a simple summation of the star-forming regions at the bar-end and the disk cannot reproduce the nuclear starburst of M 83, implying that the spatial variation of the dense gas fraction traced by R3 2=1 0 governs the spatial variation of SFE in M 83.