“绿豌豆”的恒星形成历史和金属含量。三个星系的新的详细GTC-OSIRIS分光光度法
The star formation history and metal content of the "Green Peas". New detailed GTC-OSIRIS spectrophotometry of three galaxies
摘要：
我们提出了深宽波段成像和长缝光谱的三个紧凑，低质量的星暴星系在红移z \sim 0.2-0.3，也被称为绿豆（GP）。我们测量电离气体的物理性质，并获得高精度的几个物种的丰度。我们发现，这三个GP显示相对较低的消光，低的氧丰度，和显着高的N/O比，我们还报告在这些星系中的沃尔夫-拉叶星（WR）的检测清晰的签名。我们进行了试点光谱合成研究，使用人口和进化合成模型的组合。他们的输出是在定性协议，强烈建议的形成历史占主导地位的恒星爆发。与WR星的存在一致，这些模型表明，这些GP目前正在经历一次主要的星暴，产生约4%至约20%的恒星质量。然而，正如模型所暗示的那样，它们是古老的星系，在几个Gyr之前形成了大部分恒星质量。通过对其中一个星系的Mg I 5167、5173吸收线的探测，用光谱学方法证实了老星的存在。此外，我们进行了表面测光的基础上HST数据的研究，这表明，这三个星系的低表面亮度包络指数。如果由于恒星的排放，后者是结构上兼容的发光BCD/HII星系的演化主机，这表明GPS是可识别的本地BCD的组装历史中的主要情节。这些结论突出了这些天体作为研究宇宙晚期星系演化实验室的重要性。
英文摘要：
We present deep broad-band imaging and long-slit spectroscopy of three compact, low-mass starburst galaxies at redshift z\sim0.2-0.3, also referred to as Green Peas (GP). We measure physical properties of the ionized gas and derive abundances for several species with high precision. We find that the three GPs display relatively low extinction, low oxygen abundances, and remarkably high N/O ratios We also report on the detection of clear signatures of Wolf-Rayet (WR) stars in these galaxies. We carry out a pilot spectral synthesis study using a combination of both population and evolutionary synthesis models. Their outputs are in qualitative agreement, strongly suggesting a formation history dominated by starbursts. In agreement with the presence of WR stars, these models show that these GPs currently undergo a major starburst producing between ~4% and ~20% of their stellar mass. However, as models imply, they are old galaxies having had formed most of their stellar mass several Gyr ago. The presence of old stars has been spectroscopically verified in one of the galaxies by the detection of Mg I 5167, 5173 absorption line. Additionally, we perform a surface photometry study based on HST data, that indicates that the three galaxies posses an exponential low-surface brightness envelope. If due to stellar emission, the latter is structurally compatible to the evolved hosts of luminous BCD/HII galaxies, suggesting that GPs are identifiable with major episodes in the assembly history of local BCDs. These conclusions highlight the importance of these objects as laboratories for studying galaxy evolution at late cosmic epochs.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
