AI 中文总结
研究低质量星系光学形态，从SAGAbg目录选样本，利用遗产调查多波段成像及STATMORPH计算形态参数，发现分辨率等对测量的影响，揭示形态与恒星质量、形成率及红移演化的关系，推断不同质量星系形态特征。
AI 中文摘要
低质量星系的光学形态可用于直接追踪其组装过程并约束星系演化模型。我们从SAGAbg目录中选取了6211个低质量（$7\lesssim {\rm log}(M_{\ast}/M_{\odot})\lesssim 10$）的恒星形成星系样本，该样本在低红移（$z<0.1$）时具有高完整性。我们在遗产调查的$griz$波段获得它们的星系图，并应用STATMORPH计算非参数形态测量，包括基尼指数、$M_{20}$测量和CAS参数。我们研究分辨率和信噪比如何影响形态测量，发现 bulge 强度测量最可靠。基尼 - $M_{20}$空间中的序列与星系的恒星形成序列直接相关，且以Sb/Sc/Ir形态为主。$g$波段的光分布在所有波段中最不集中。$M_{20}$相对于恒星质量和GALEX NUV衍生特定恒星形成率（sSFR）的系统趋势强烈表明，光轮廓较平的星系质量较小但sSFR较高，反之亦然。我们通过统计推断出，恒星形成的低质量星系主要具有盘状形态，而在质量较高（${\rm log}(M_{\ast}/M_{\odot})\gtrsim 9$）且已熄灭的系统中 bulge 变得更加突出。
英文摘要
The optical morphologies of low-mass galaxies can be used to directly trace their assembly and constrain models of galaxy evolution. We select a sample of 6211 low-mass ($7\lesssim {\rm log}(M_{\ast}/M_{\odot})\lesssim 10$) star-forming galaxies from the SAGAbg catalog that has high-completeness at low-redshifts ($z<0.1$). We obtain their galaxy maps in the $griz$ - bands of the Legacy Surveys and apply STATMORPH to calculate non-parametric morphological measures including the Gini index, $M_{20}$ measure, and CAS parameters. We study how resolution and signal-to-noise affect the morphology measures and find that the bulge strength measurements are the most reliable. The sequence in Gini$-M_{20}$ space is directly linked to the star-forming sequence of galaxies and is dominated by Sb/Sc/Ir morphologies. The $g$-band light distributions are the least concentrated among all the bands. The systematic trends of $M_{20}$ with respect to stellar mass and GALEX NUV-derived specific star formation rate (sSFR) strongly indicate that the galaxies with flatter light profiles are less massive with higher sSFR and vice-versa. We statistically infer that star-forming low-mass galaxies predominantly have disk morphologies with bulges becoming more prominent in quenched systems at higher masses (${\rm log}(M_{\ast}/M_{\odot})\gtrsim 9$).
Comments24 pages, 16 figures. Submitted to ApJ
