标题： LITTLE THINGS矮不规则星系中恒星、气体和恒星形成盘之间的关系：暗分子气体显著比例的间接证据 显示英文标题

标题： Relationships between the Stellar, Gaseous, and Star Formation Disks in LITTLE THINGS Dwarf Irregular Galaxies: Indirect Evidence for Substantial Fractions of Dark Molecular Gas

摘要： 在附近dIrrs的LITTLE THINGS样本中的恒星、气体和年轻恒星盘用函数进行拟合，以寻找参数之间的相关性。 我们发现，HI径向轮廓在中心通常更平坦，在外区下降得比V波段轮廓更快，而年轻恒星则更集中在中心，特别是当HI更中心平坦时。 这种模式表明，中心的HI正在转化为分子，分子云正在形成恒星和FUV。 一个假设分子面密度与总气体面密度成1.5次方或2次方比例的模型，类似于Kennicutt-Schmidt关系，可以再现可见光与HI尺度长度比值和HI Sersic指数之间的关系。 通过使用常规校准将FUV转换为分子面密度，估计每个星系的分子分数随半径的变化。 在3R_D内的平均分子分数为23+/-17%。 然而，恒星表面亮度轮廓的断裂没有与恒星形成相关的统一示踪物。 显示英文摘要

摘要： The stellar, gaseous and young stellar disks in the LITTLE THINGS sample of nearby dIrrs are fitted with functions to search for correlations between the parameters. We find that the HI radial profiles are generally flatter in the center and fall faster in the outer regions than the V-band profiles, while young stars are more centrally concentrated, especially if the HI is more centrally flat. This pattern suggests that the HI is turning into molecules in the center and the molecular clouds are forming stars and FUV. A model that assumes the molecular surface density is proportional to the total gas surface density to a power of 1.5 or 2, in analogy with the Kennicutt-Schmidt relation, reproduces the relationship between the ratio of the visible to the HI scale length and the HI Sersic index. The molecular fraction is estimated as a function of radius for each galaxy by converting the FUV to a molecular surface density using conventional calibrations. The average molecular fraction inside 3R_D is 23+/-17%. However, the break in the stellar surface brightness profile has no unified tracer related to star formation.