Star Formation Histories of the LEGUS Dwarf Galaxies. III. The Nonbursty Nature of 23 Star-forming Dwarf Galaxies
Star Formation Histories of the LEGUS Dwarf Galaxies. III. The Nonbursty Nature of 23 Star-forming Dwarf Galaxies
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DOI：
10.3847/1538-4357/ab53d5
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发表时间：
2019-11
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通讯作者：
M. Cignoni;E. Sacchi;M. Tosi;A. Aloisi;D. Cook;D. Calzetti;J. Lee;E. Sabbi;D. Thilker;A. Adamo;D. Dale;B. Elmegreen;J. Gallagher;E. Grebel;K. Johnson;M. Messa;L. Smith;L. U. D. O. P. -. U. O. Pisa-L.-U.-D.-O.-P.-.-U.-O.-Pisa-2264114655;Pisa;Italy;Infn;I. D. A. E. S. D. Spazio-I.-D.-A.-E.-S.-D.-Spazio-103233738;Bologna;Stsci;Baltimore.;Usa;D. PhysicsAstronomy;C. I. O. Technology.;Pasadena;IPACCaltech;D. O. Astronomy;U. O. Massachusetts;Amherst;The Oskar Klein Centre;S. University;Sweden;D. O. Physics;Astronomy;U. Wyoming;Ibm Research Division;T. W. R. Center;Ny;A. Rechen-Institut;Zentrum fur Astronomie der Universitat Heidelberg;Heidelberg;Germany;European Space AgencySpace Telescope Science Institute-European-Space-AgencySpace-Telescope-Science-2263371457;T. J. H. University;B. U. D. O. Astronomy;U. Wisconsin--Madison-U.-Wisconsin--Madison-1387898181;U. Virginia;Charlottesville
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作者：
M. Cignoni;E. Sacchi;M. Tosi;A. Aloisi;D. Cook;D. Calzetti;J. Lee;E. Sabbi;D. Thilker;A. Adamo;D. Dale;B. Elmegreen;J. Gallagher;E. Grebel;K. Johnson;M. Messa;L. Smith;L. U. D. O. P. -. U. O. Pisa-L.-U.-D.-O.-P.-.-U.-O.-Pisa-2264114655;Pisa;Italy;Infn;I. D. A. E. S. D. Spazio-I.-D.-A.-E.-S.-D.-Spazio-103233738;Bologna;Stsci;Baltimore.;Usa;D. PhysicsAstronomy;C. I. O. Technology.;Pasadena;IPACCaltech;D. O. Astronomy;U. O. Massachusetts;Amherst;The Oskar Klein Centre;S. University;Sweden;D. O. Physics;Astronomy;U. Wyoming;Ibm Research Division;T. W. R. Center;Ny;A. Rechen-Institut;Zentrum fur Astronomie der Universitat Heidelberg;Heidelberg;Germany;European Space AgencySpace Telescope Science Institute-European-Space-AgencySpace-Telescope-Science-2263371457;T. J. H. University;B. U. D. O. Astronomy;U. Wisconsin--Madison-U.-Wisconsin--Madison-1387898181;U. Virginia;Charlottesville
利用哈勃空间望远镜的银河系外紫外巡天观测资料，我们获得了23个活动矮星系的近期星星形成历史。我们应用色星等图（CMD）拟合技术，使用两个独立的恒星模型，PARSEC-COLIBRI和MIST。尽管最近的活动不可忽视，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1亿年平均值的三倍。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，对于矮星系，基于CMD的平均星星形成率（SFR）一般高于基于FUV的SFR。对于一半的样本，基于CMD的6千万年平均SFR是FUV SFR的两倍多。相比之下，我们发现1000万年平均CMD为基础的SFR和Hα为基础的SFR之间的显着协议。最后，使用核心氦燃烧的恒星的中间质量，我们研究的模式星星形成的空间进展在过去的60万年，并推测可能的触发器和连接的星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星星形成的空间进展，在过去的60万年和/或最近的扩散和偏离中心的活动相比，RGB恒星。
We derive the recent star formation histories (SFHs) of 23 active dwarf galaxies using Hubble Space Telescope observations from the Legacy Extragalactic UV Survey. We apply a color–magnitude diagram (CMD) fitting technique using two independent sets of stellar models, PARSEC-COLIBRI and MIST. Despite the nonnegligible 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 SFRs. 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 Hα-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.