The spatial distribution of star and cluster formation in M 51
The spatial distribution of star and cluster formation in M 51
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DOI：
10.1051/0004-6361:200811068
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发表时间：
2008-12
影响因子：
6.5
通讯作者：
R. Scheepmaker;H. Lamers;P. Anders;S. Larsen
中科院分区：
文献类型：
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作者：
R. Scheepmaker;H. Lamers;P. Anders;S. Larsen
目标。我们研究了空间分辨的星星形成和年轻的星星团之间的连接在整个磁盘的M 51。方法.我们结合联合收割机星星集群数据的基础上，B，V，和I波段哈勃太空望远镜ACSimaging，连同新的WFPC 2 U波段测光推导出年龄，质量，和1580年解决星星集群使用SSP模型。这些数据相结合的空间分辨星星形成率和气体表面密度，以及手20厘米无线电连续谱（RC）的发射，这使我们能够研究星星形成和星星集群之间的空间相关性的数据。本文用两点自相关函数研究了星星团的成簇性，并将其作为空间尺度和年龄的函数。结果我们发现，星星集群之间的集群减少与空间尺度和年龄，符合等级星星形成。在1.2-1.6的范围内，自相关函数的斜率与投影分维一致，这与其它星系的分维相似，从而证明等级星星形成的分维具有普遍性。星星和星系团的形成峰值都出现在银河中心半径为1.25和1.55 kpc处，我们初步认为这是由于4：1共振和共旋半径的存在。最年轻（<1千万年）的星星团的位置与旋臂、H β和RC辐射的相关性最强，这些相关性随着年龄的增长而减弱。星系团的方位角分布在远离旋臂的运动学年龄方面表明，大多数星系团在其母气云到达旋臂中心之前就形成了1500 - 2000万年。
Aims. We study the connection between spatially resolved star formation and young star clusters across the disc of M 51. Methods. We combine star cluster data based on B, V, and I-band Hubble Space Telescope ACSimaging, together with new WFPC2 U-band photometry to derive ages, masses, and extinctions of 1580 resolved star clusters using SSP models. This data is combined with data on the spatially resolved star formation rates and gas surface densities, as well as Hand 20 cm radio-continuum (RC) emission, which allows us to study the spatial correlations between star formation and star clusters. Two-point autocorrelation func- tions are used to study the clustering of star clusters as a fu nction of spatial scale and age. Results. We find that the clustering of star clusters among themselves decreases both with spatial scale and age, consistent with hierarchical star formation. The slope of the autocorrelat ion functions are consistent with projected fractal dimens ions in the range of 1.2-1.6, which is similar to other galaxies, therefore sugg esting that the fractal dimension of hierarchical star form ation is universal. Both star and cluster formation peak at a galactocentric rad ius of∼2.5 and∼5 kpc, which we tentatively attribute to the presence of the 4:1 resonance and the co-rotation radius. The positions of the youngest (< 10 Myr) star clusters show the strongest correlation with the spiral arms, H�, and the RC emission, and these correlations decrease with age. The azimuthal distribution of clusters in terms of kinematic age away from the spiral arms indicates that the majority of the clusters formed∼ 5-20 Myr before their parental gas cloud reached the centre of the spiral arm.