arXiv 0806.04712008-06-03astro-ph

基于模型的38个棒星系的图案速度估计

Model-based pattern speed estimates for 38 barred galaxies

P. Rautiainen, H. Salo, E. Laurikainen

备注：: 18 pages, 13 figures, accepted for publication in MNRAS
DOI：: 10.1111/j.1365-2966.2008.13522.x

摘要：

我们用俄亥俄州立大学明亮螺旋星系巡天的近红外和光学数据模拟了38个棒星系。我们从$H$波段光度测量中构造了星系的引力势，假定质光比为常数。我们选择的光晕分量对应于所谓的通用旋转曲线。在每种情况下，我们使用的响应气体和恒星粒子盘刚性旋转势来确定的图案速度。我们发现棒的图案速度大致取决于形态类型。共转共振半径对杆半径的平均值$\mathcal{R}$从SB 0/a - SBab型的$1.15 \pm 0.25$增加到SBb型的$1.44 \pm 0.29$和SBbc-SBc型的$1.82\pm 0.63$。在模式速度和棒半径的误差估计，SBab型或更早的所有星系都有一个快速的酒吧（$\mathcal{R} \le 1.4$），而酒吧后类型的星系包括快速和慢速旋转。在16个标称值为$\mathcal{R} > 1.4$的晚型星系中，有5个星系的快旋杆被采用的误差估计所排除。我们还研究了参数$\mathcal{R}$和其他星系性质之间的相关性。最明显的相关性是与棒的大小：与星系大小相比，最慢的棒也是最短的棒。在慢柱倾向于较弱的意义上，与柱强度的相关性较弱。这些相关性为一种可能性留下了空间，即在许多星系中确定的模式速度实际上对应于螺旋的速度，螺旋的旋转速度比棒慢。无论是星系的光度还是颜色都没有明显的相关性。

英文摘要：

We have modelled 38 barred galaxies by using near-IR and optical data from the Ohio State University Bright Spiral Galaxy Survey. We constructed the gravitational potentials of the galaxies from $H$-band photometry, assuming constant mass-to-light ratio. The halo component we chose corresponds to the so called universal rotation curve. In each case, we used the response of gaseous and stellar particle disc to rigidly rotating potential to determine the pattern speed. We find that the pattern speed of the bar depends roughly on the morphological type. The average value of corotation resonance radius to bar radius, $\mathcal{R}$, increases from $1.15 \pm 0.25$ in types SB0/a -- SBab to $1.44 \pm 0.29$ in SBb and $1.82\pm 0.63$ in SBbc -- SBc. Within the error estimates for the pattern speed and bar radius, all galaxies of type SBab or earlier have a fast bar ($\mathcal{R} \le 1.4$), whereas the bars in later type galaxies include both fast and slow rotators. Of 16 later type galaxies with a nominal value of $\mathcal{R} > 1.4$, there are five cases, where the fast rotating bar is ruled out by the adopted error estimates. We also study the correlation between the parameter $\mathcal{R}$ and other galactic properties. The clearest correlation is with the bar size: the slowest bars are also the shortest bars when compared to the galaxy size. A weaker correlation is seen with bar strength in a sense that slow bars tend to be weaker. These correlations leave room for a possibility that the determined pattern speed in many galaxies corresponds actually that of the spiral, which rotates more slowly than the bar. No clear correlation is seen with either the galaxy luminosity or colour.

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英文摘要：

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