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arXiv 1911.04496astro-ph.GAastro-ph.IMastro-ph.SR
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LEGUS矮星系(III)的恒星形成历史:23个恒星形成矮星系的非爆发性质

Star formation histories of the LEGUS dwarf galaxies (III): the non-bursty nature of 23 star forming dwarf galaxies

M. Cignoni, E. Sacchi, M. Tosi, A. Aloisi, D. O. Cook, D. Calzetti, J. C. Lee, E. Sabbi, D. A. Thilker, A. Adamo, D. A. Dale, B. G. Elmegreen, J. S. Gallagher, … 展开作者

M. Cignoni, E. Sacchi, M. Tosi, A. Aloisi, D. O. Cook, D. Calzetti, J. C. Lee, E. Sabbi, D. A. Thilker, A. Adamo, D. A. Dale, B. G. Elmegreen, J. S. Gallagher, E. K. Grebel, K. E. Johnson, M. Messa, L. J. Smith, L. Ubeda

摘要:

我们推导出最近的恒星形成历史的23个活跃的矮星系HST观测的遗产河外紫外线调查(LEGUS)。我们应用色星等图拟合技术,使用两个独立的恒星模型,PARSEC-COLIBRI和MIST。尽管最近的活动不容忽视,但在过去的1亿年里,23颗恒星形成矮星中没有一颗的增强超过1亿年平均水平的三倍。在过去的1亿年中,单个SFH的未加权平均值也与相当恒定的活动一致,与原子气体分数无关。我们证实了以前的结果,矮星系的CMD为基础的平均恒星形成率(SFR)一般高于FUV为基础的SFR。对于一半的样本,基于CMD的6000万年平均SFR是FUV SFR的两倍多。相比之下,我们发现显着的协议之间的10万年平均CMD为基础的SFR和H $α$为基础的SFR。最后,使用核心氦燃烧恒星的中间质量,我们研究了过去60万年的恒星形成空间进展的模式,并推测可能的触发器和连接的恒星形成活动与这些星系生活的环境。我们的星系中大约有一半显示了过去6000万年来恒星形成的空间进展,和/或与RGB恒星相比最近的扩散和偏离中心的活动。

英文摘要:

We derive the recent star formation histories of 23 active dwarf galaxies using HST observations from the Legacy Extragalactic UV Survey (LEGUS). We apply a color-magnitude diagram fitting technique using two independent sets of stellar models, PARSEC-COLIBRI and MIST. Despite the non-negligible recent activity, none of the 23 star forming dwarfs show enhancements in the last 100 Myr larger than three times the 100-Myr-average. The unweighted mean of the individual SFHs in the last 100 Myr is also consistent with a rather constant activity, irrespective of the atomic gas fraction. We confirm previous results that for dwarf galaxies the CMD-based average star formation rates (SFRs) are generally higher than the FUV-based SFR. For half of the sample, the 60-Myr-average CMD-based SFR is more than two times the FUV SFR. In contrast, we find remarkable agreement between the 10-Myr-average CMD-based SFR and the H$α$-based SFR. Finally, using core helium burning stars of intermediate mass we study the pattern of star formation spatial progression over the past 60 Myr, and speculate on the possible triggers and connections of the star formation activity with the environment in which these galaxies live. Approximately half of our galaxies show spatial progression of star formation in the last 60 Myr, and/or very recent diffuse and off-center activity compared to RGB stars.

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。

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