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arXiv 1104.5693astro-ph.CO
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棒星系动力学与恒星形成的关系

The relation between dynamics and star formation in barred galaxies

Eric E. Martínez-García, Rosa A. González-Lópezlira

摘要:

我们分析了11个棒旋星系样本的光学和近红外数据,以建立恒星形成和棒旋/螺旋动力学之间的联系。我们发现,22个区域位于酒吧,和20个区域的螺旋臂超出酒吧的结束呈现方位角的颜色/年龄梯度,可能是由于恒星形成触发。假设一个圆周运动的动力学模型,我们比较观察到的年龄梯度候选者与恒星星族合成模型。然后,可以建立一个链接与磁盘的动力学,使我们能够获得参数,如模式的酒吧或螺旋的速度,以及共振半径的位置。随后,我们将推导出的模式速度与文献中的理论和观测结果(例如,接近共转结束的条)。我们发现一种倾向,高估酒吧的颜色梯度在酒吧在小半径,远离共转的速度,这种趋势可以归因于非圆形运动的年轻恒星出生在酒吧区域。在螺旋区域中,我们发现约50%的颜色梯度候选是“逆”的,即,恒星的老化方向与自转方向相反。在旋臂中发现的另一半梯度具有与旋转相同的恒星年龄增加。在9个具有条形和螺旋渐变的对象中,6个(67%)似乎具有类似Omega_p的条形和螺旋,而3个(33%)没有。

英文摘要:

We analyze optical and near-infrared data of a sample of 11 barred spiral galaxies, in order to establish a connection between star formation and bar/spiral dynamics. We find that 22 regions located in the bars, and 20 regions in the spiral arms beyond the end of the bar present azimuthal color/age gradients that may be attributed to star formation triggering. Assuming a circular motion dynamic model, we compare the observed age gradient candidates with stellar populations synthesis models. A link can then be established with the disk dynamics that allows us to obtain parameters like the pattern speed of the bar or spiral, as well as the positions of resonance radii. We subsequently compare the derived pattern speeds with those expected from theoretical and observational results in the literature (e.g., bars ending near corotation). We find a tendency to overestimate bar pattern speeds derived from color gradients in the bar at small radii, away from corotation; this trend can be attributed to non-circular motions of the young stars born in the bar region. In spiral regions, we find that ~ 50% of the color gradient candidates are "inverse", i.e., with the direction of stellar aging contrary to that of rotation. The other half of the gradients found in spiral arms have stellar ages that increase in the same sense as rotation. Of the 9 objects with gradients in both bars and spirals, six (67%) appear to have a bar and a spiral with similar Omega_p, while three (33%) do not.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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