论文标题
Hubble太空望远镜观测t t ta tadpole Galaxies Kiso 3867，SBS0，SBS1和UM461
Hubble Space Telescope Observations of Tadpole Galaxies Kiso 3867, SBS0, SBS1, and UM461
论文作者
论文摘要
t是金属贫困的矮人，通常是一个主要的恒星形成区域，在倾斜时为它们提供了尾巴结构。头部的金属度下降表明，具有较低金属性的气体积聚刺激了恒星的形成。在这里，我们介绍了附近四个（<25 mpc）t，SBS0，SBS1，KISO 3867和UM461的多播HST WFC3和ACS图像，这些图像是为了它们以前的光谱研究中所示的清晰金属性下降。测量恒星复合物和紧凑型簇的性能。每个星系包含3至10个年轻的恒星络合物，其恒星〜3-10 Myr Old。在复合物之间，磁盘的典型年龄为〜3 Gyr。许多恒星簇覆盖了综合体内外的星系。通过在堆叠前将质量和计数标准化的组合群质量函数是一个幂定律，在日志图中的斜率为-1.12+-0.14，并且群集寿命衰减的组合分布函数随着年龄的增长为t^{ - 0.65+-0.24}。鉴于它们的质量和年龄，从所有群集中的求和理论Lyman连续体（LYC）发射之间的比较可与某些星系中观察到的HALPHA激发所需的LYC相当，表明LYC在Halo中被粉尘或未发现的气体吸收，或者可能是Galaxy Essce。
Tadpole galaxies are metal-poor dwarfs with typically one dominant star-forming region, giving them a head-tail structure when inclined. A metallicity drop in the head suggests that gas accretion with even lower metallicity stimulated the star formation. Here we present multiband HST WFC3 and ACS images of four nearby (<25 Mpc) tadpoles, SBS0, SBS1, Kiso 3867, and UM461, selected for their clear metallicity drops shown in previous spectroscopic studies. Properties of the star complexes and compact clusters are measured. Each galaxy contains from 3 to 10 young stellar complexes with 10^3-10^5 Msun of stars ~3-10 Myr old. Between the complexes, the disk has a typical age of ~3 Gyr. Numerous star clusters cover the galaxies, both inside and outside the complexes. The combined cluster mass function, made by normalizing the masses and counts before stacking, is a power law with a slope of -1.12+-0.14 on a log-log plot and the combined distribution function of cluster lifetime decays with age as t^{-0.65+-0.24}. A comparison between the summed theoretical Lyman continuum (LyC) emission from all the clusters, given their masses and ages, is comparable to or exceeds the LyC needed to excite the observed Halpha in some galaxies, suggesting LyC absorption by dust or undetected gas in the halo, or perhaps galaxy escape.
