论文标题
附近星系中的分层恒星形成
Hierarchical star formation in nearby galaxies
论文作者
论文摘要
目的：这项工作的目的是研究附近三个星系中年轻人口的空间分布的特性，以便更好地了解恒星形成的第一阶段。 方法：我们使用了ACS/HST光度法和“路径链接标准”，以便获得Galaxy NGC 2403中的年轻恒星组（YSG）的目录。我们使用Q参数研究了这些YSG中星体的内部分布。我们将这些分析扩展到NGC 300和NGC 253中检测到的YSGS。我们为这三个星系建造了年轻恒星的密度图。通过这些地图，我们能够在较大尺度上识别和研究年轻的恒星结构。 结果：我们在Galaxy NGC 2403中发现了573 YSG，为此我们得出了它们的各个大小，密度，光度功能和其他基本特征。我们发现，NGC 2403，NGC 300和NGC 253中的绝大多数YSG呈现内部结构，遵循我们在这些星系中较大尺度上在较大尺度上观察到的相同的等级行为。我们在〜1.5和1.6之间得出了分形维的值。这些值与在其他恒星形成星系中获得的值非常相似，在星际介质中，这表明恒星形成过程受超音速湍流调节。
Aims: The purpose of this work is to study the properties of the spatial distribution of the young population in three nearby galaxies in order to better understand the first stages of star formation. Methods: We used ACS/HST photometry and the "path-linkage criterion" in order to obtain a catalog of young stellar groups (YSGs) in the galaxy NGC 2403. We studied the internal distribution of stars in these YSGs using the Q parameter. We extended these analyses to the YSGs detected in in NGC 300 and NGC 253 our previous works. We built the young stars' density maps for these three galaxies. Through these maps, we were able to identify and study young stellar structures on larger scales. Results: We found 573 YSGs in the galaxy NGC 2403, for which we derived their individual sizes, densities, luminosity function,and other fundamental characteristics. We find that the vast majority of the YSGs in NGC 2403, NGC 300 and NGC 253 present inner clumpings, following the same hierarchical behavior that we observed in the young stellar structures on larger scales in these galaxies. We derived values of the fractal dimension for these structures between ~ 1.5 and 1.6. These values are very similar to those obtained in other star forming galaxies and in the interstellar medium, suggesting that the star formation process is regulated by supersonic turbulence.
