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arXiv 1901.00640astro-ph.GA
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CO邻近Galerkin的多线成像(COMING)。VII。分子气体速度场的傅里叶分解与条形图速度

CO Multi-line Imaging of Nearby Galaxies (COMING). VII. Fourier decomposition of molecular gas velocity fields and bar pattern speed

Dragan Salak, Yuto Noma, Kazuo Sorai, Yusuke Miyamoto, Nario Kuno, Alex R. Pettitt, Hiroyuki Kaneko, Takahiro Tanaka, Atsushi Yasuda, Shoichiro Kita, Yoshiyuki … 展开作者

Dragan Salak, Yuto Noma, Kazuo Sorai, Yusuke Miyamoto, Nario Kuno, Alex R. Pettitt, Hiroyuki Kaneko, Takahiro Tanaka, Atsushi Yasuda, Shoichiro Kita, Yoshiyuki Yajima, Shugo Shibata, Naomasa Nakai, Masumichi Seta, Kazuyuki Muraoka, Mayu Kuroda, Hiroyuki Nakanishi, Tsutomu T. Takeuchi, Moe Yoda, Kana Morokuma-Matsui, Yoshimasa Watanabe, Naoko Matsumoto, Nagisa Oi, Hsi-An Pan, Ayumi Kajikawa, Yu Yashima, Ryusei Komatsuzaki

摘要:

利用傅立叶分解方法,对野边山射电天文台“邻近星系CO多线成像”(COMING)遗留项目中的20个邻近旋涡星系的$^{12}$ CO $(J=1\rightarrow0)$速度场进行了分析,确定了它们的基本运动学性质,如圆速度和非圆速度。平均而言,调查的酒吧(SAB和SB)星系表现出的非圆形的分子气体的圆形速度比的1.5-2倍比非酒吧(SA)的螺旋星系在半径内的酒吧半长轴$a_\mathrm{b}$在1千秒差距的分辨率,在半径为$R/a_\mathrm{b}\sim0.3$的最大值。从数据中减去模型速度场得到的剩余速度场图像表明,这种趋势是由Kpc尺度的分子气体在棒区的流动运动引起的。应用一种基于径向速度反演的新方法,估算了七个SAB和SB系统的共转半径$R_\mathrm{CR}$和条斑速度$Ω_\mathrm{b}$。共转棒半径的比例被发现是在一个范围内的$\mathcal{R}\equiv R_\mathrm{CR}/a_\mathrm{b}\sim0.8\mathrm{-}1.6$,这表明中间(SBb-SBc),明亮的棒旋星系主机快速和慢速旋转棒。实验中发现$Ω_\mathrm{b}$与$a_\mathrm{b}$和$Ω_\mathrm{b}$与恒星总质量$M_\ast$之间存在负相关,这表明大质量盘中的棒更大,旋转更慢,可能是角动量转移的结果。SAB和SB星系的运动学性质,来自傅立叶分解,最近的数值模拟,将各种旋转曲线模型和星系的相互作用进行比较。

英文摘要:

The $^{12}$CO $(J=1\rightarrow0)$ velocity fields of a sample of 20 nearby spiral galaxies, selected from the CO Multi-line Imaging of Nearby Galaxies (COMING) legacy project of Nobeyama Radio Observatory, have been analyzed by Fourier decomposition to determine their basic kinematic properties, such as circular and noncircular velocities. On average, the investigated barred (SAB and SB) galaxies exhibit a ratio of noncircular to circular velocities of molecular gas larger by a factor of 1.5-2 than non-barred (SA) spiral galaxies at radii within the bar semimajor axis $a_\mathrm{b}$ at 1 kpc resolution, with a maximum at a radius of $R/a_\mathrm{b}\sim0.3$. Residual velocity field images, created by subtracting model velocity fields from the data, reveal that this trend is caused by kpc-scale streaming motions of molecular gas in the bar region. Applying a new method based on radial velocity reversal, we estimated the corotation radius $R_\mathrm{CR}$ and bar pattern speed $Ω_\mathrm{b}$ in seven SAB and SB systems. The ratio of the corotation to bar radius is found to be in a range of $\mathcal{R}\equiv R_\mathrm{CR}/a_\mathrm{b}\sim0.8\mathrm{-}1.6$, suggesting that intermediate (SBb-SBc), luminous barred spiral galaxies host fast and slow rotator bars. Tentative negative correlations are found for $Ω_\mathrm{b}$ vs. $a_\mathrm{b}$ and $Ω_\mathrm{b}$ vs. total stellar mass $M_\ast$, indicating that bars in massive disks are larger and rotate slower, possibly a consequence of angular momentum transfer. The kinematic properties of SAB and SB galaxies, derived from Fourier decomposition, are compared with recent numerical simulations that incorporate various rotation curve models and galaxy interactions.

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