The star formation rate in disc galaxies: thresholds and dependence on gas amount
The star formation rate in disc galaxies: thresholds and dependence on gas amount
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盘状星系中的恒星形成率：阈值和对气体量的依赖性
DOI：
10.1111/j.1365-2966.2003.07170.x
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发表时间：
2003
影响因子：
4.8
通讯作者：
G. Gavazzi
中科院分区：
文献类型：
--
作者：
S. Boissier;N. Prantzos;A. Boselli;G. Gavazzi
我们重新评估了 Toomre 准则在星系盘中的适用性，并研究了 16 个盘状星系中的局部恒星形成规律，并公布了这些星系的丰度梯度。我们使用的数据包括恒星光剖面、原子和分子气体（从 CO 推导出来，并具有与金属丰度相关的转换因子）、恒星形成速率（来自 Ha 发射率）、金属丰度、色散速度和旋转曲线。我们证明托姆雷准则成功地适用于银河系盘的情况，但它对我们样本数据的成功有限；根据稳定性分析中是否包含恒星成分，我们发现气体表面密度与临界表面密度的阈值比的平均值在0.5-0.7范围内。我们还测试了文献中提出的各种恒星形成定律，即考虑了动力学因素的简单施密特定律或其修改。就我们数据的整体拟合度而言，我们发现它们之间只有很小的差异；特别是，我们发现所有三个恒星形成定律（参数来自于我们的数据拟合）与银河系圆盘中的观测结果特别吻合。在所有情况下，我们发现我们最适合的恒星形成率的指数 n 的值略高于其他最近的工作，并且我们提出了可能导致这种差异的几个原因。
We reassess the applicability of the Toomre criterion in galactic discs and we study the local star formation law in 16 disc galaxies for which abundance gradients are published. The data we use consist of stellar light profiles, atomic and molecular gas (deduced from CO with a metallicity-dependent conversion factor), star formation rates (from Ha emissivities), metal-licities, dispersion velocities and rotation curves. We show that the Toomre criterion applies successfully to the case of the Milky Way disc, but it has limited success with the data of our sample; depending on whether or not the stellar component is included in the stability analysis, we find average values for the threshold ratio of the gas surface density to the critical surface density in the range 0.5-0.7. We also test various star formation laws proposed in the literature, i.e. either the simple Schmidt law or modifications of it, that take into account dynamical factors. We find only small differences among them as far as the overall fit to our data is concerned; in particular, we find that all three star formation laws (with parameters derived from the fits to our data) match observations in the Milky Way disc particularly well. In all cases we find that the exponent n of our best-fitting star formation rate has slightly higher values than in other recent works and we suggest several reasons that may cause that discrepancy.