标题： 低密度环境中近邻矮星系的结构特性——大小、表面亮度和颜色梯度 显示英文标题

标题： The structural properties of nearby dwarf galaxies in low density environments -- size, surface brightness and colour gradients

摘要： 我们使用一个完整的样本，包含211个附近的矮星系（红移 z < 0.08，恒星质量 10^8 MSun < Mstar < 10^9.5 Msun），这些星系位于低密度环境中，研究它们的结构特性：有效半径（R_e）、有效面亮度（mu_e）和颜色梯度。 我们探讨了这些性质与恒星质量和在一篇相关论文（Lazar 等人）中识别出的三种主要矮星形态类型的关系 -- 早期型星系（ETGs）、晚期型星系（LTGs）和无特征系统。 LTGs 和无特征星系的有效半径中值比 ETGs 大约 2 倍和 1.2 倍。虽然 ETGs 和 LTGs 的有效面亮度中值相似，但无特征类别的星系则比 ETGs 暗约 1 镁每平方秒弧度。 尽管它们的有效半径中值相似，但无特征和 ETG 类别在它们的有效面亮度中值上存在显著差异，这表明它们的演化过程不同，并且无特征星系并非 ETGs 的子集。 虽然大质量 ETGs 通常表现出负或平坦的颜色梯度，但矮小 ETGs 一般显示出正颜色梯度（中心更蓝）。 因此，随着我们从矮小星系过渡到大质量星系，ETGs 的增长从“外向内”转变为“内向外”。 然而，矮小和大质量 LTGs 的颜色梯度是相似的。 大约 46% 的矮小 ETGs 显示出明显的、肉眼可辨认的蓝色核心，延伸至约 1.5 R_e。 最后，与非相互作用的矮星系相比，相互作用的矮星系在所有半径上更大、更蓝，并且表现出类似的 mu_e 中值，这表明相互作用通常在整个星系范围内增强恒星形成。 XMATHX0 显示英文摘要

摘要： We use a complete sample of 211 nearby (z<0.08) dwarf (10^8 MSun < Mstar < 10^9.5 Msun) galaxies in low-density environments, to study their structural properties: effective radii (R_e), effective surface brightnesses (mu_e) and colour gradients. We explore these properties as a function of stellar mass and the three principal dwarf morphological types identified in a companion paper (Lazar et al.) -- early-type galaxies (ETGs), late-type galaxies (LTGs) and featureless systems. The median R_e of LTGs and featureless galaxies are factors of ~2 and ~1.2 larger than the ETGs. While the median mu_e of the ETGs and LTGs is similar, the featureless class is ~1 mag arcsec^-2 fainter. Although they have similar median R_e, the featureless and ETG classes differ significantly in their median mu_e, suggesting that their evolution is different and that the featureless galaxies are not a subset of the ETGs. While massive ETGs typically exhibit negative or flat colour gradients, dwarf ETGs generally show positive colour gradients (bluer centres). The growth of ETGs therefore changes from being `outside-in' to `inside-out' as we move from the dwarf to the massive regime. The colour gradients of dwarf and massive LTGs are, however, similar. Around 46 per cent of dwarf ETGs show prominent, visually-identifiable blue cores which extend out to ~1.5 R_e. Finally, compared to their non-interacting counterparts, interacting dwarfs are larger, bluer at all radii and exhibit similar median mu_e, indicating that interactions typically enhance star formation across the entire galaxy.