The Resolved Stellar Populations in the LEGUS Galaxies1
The Resolved Stellar Populations in the LEGUS Galaxies1
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DOI：
10.3847/1538-4365/aaa8e5
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发表时间：
2018-01
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通讯作者：
E. Sabbi;D. Calzetti;L. Úbeda;A. Adamo;M. Cignoni;D. Thilker;A. Aloisi;B. Elmegreen;D. Elmegreen;D. Gouliermis;D. Gouliermis;E. Grebel;M. Messa;L. J. Smith;M. Tosi;A. Dolphin;J. E. Andrews;G. Ashworth;S. Bright;T. Brown;R. Chandar;C. Christian;G. C. Clayton;D. Cook;D. Cook;Daniel A. Dale;S. D. Mink;C. Dobbs;A. S. Evans;A. S. Evans;M. Fumagalli;J. S. Gallagher;K. Grasha;A. Herrero;A. Herrero;D. Hunter;Kelsey E. Johnson;L. Kahre;R. Kennicutt;Hwihyun Kim;M. Krumholz;Janice C. Lee;D. Lennon;C. Martin;P. Nair;A. Nota;G. Ostlin;A. Pellerin;J. Prieto;M. Regan;J. Ryon;E. Sacchi;E. Sacchi;D. Schaerer;D. Schiminovich;F. Shabani;S. V. Dyk;R. Walterbos;B. Whitmore;A. Wofford
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文献类型：
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作者：
E. Sabbi;D. Calzetti;L. Úbeda;A. Adamo;M. Cignoni;D. Thilker;A. Aloisi;B. Elmegreen;D. Elmegreen;D. Gouliermis;D. Gouliermis;E. Grebel;M. Messa;L. J. Smith;M. Tosi;A. Dolphin;J. E. Andrews;G. Ashworth;S. Bright;T. Brown;R. Chandar;C. Christian;G. C. Clayton;D. Cook;D. Cook;Daniel A. Dale;S. D. Mink;C. Dobbs;A. S. Evans;A. S. Evans;M. Fumagalli;J. S. Gallagher;K. Grasha;A. Herrero;A. Herrero;D. Hunter;Kelsey E. Johnson;L. Kahre;R. Kennicutt;Hwihyun Kim;M. Krumholz;Janice C. Lee;D. Lennon;C. Martin;P. Nair;A. Nota;G. Ostlin;A. Pellerin;J. Prieto;M. Regan;J. Ryon;E. Sacchi;E. Sacchi;D. Schaerer;D. Schiminovich;F. Shabani;S. V. Dyk;R. Walterbos;B. Whitmore;A. Wofford
遗产河外紫外线巡天（LEGUS）是哈勃太空望远镜上的一个多波长周期21国库计划。它研究了从近紫外到i波段的5个波段的50个附近的恒星形成星系，结合了新的宽视场相机3的观测结果和存档的高级巡天相机数据。LEGUS的设计目的是研究恒星的形成是如何在小尺度和大尺度上发生和发展的，以及它与银河系环境的关系。在本文中，我们给出了在50个LEGUS星系中发现的所有明显的单星的光度表。所有滤镜的光度目录和拼接图像可供下载。我们给出了所有星系的光学和近紫外色星等图。对于每一个星系，我们都得到了到红巨星分支尖端的距离。然后，我们使用NUV彩色星等图来识别质量大于14 M⊙的恒星，并将它们的数量与GALEX FUV光度预测的大质量恒星的数量进行比较。我们的分析表明，在星团和恒星组合中形成的大质量恒星的比例与恒星形成速率大致恒定。这种关系的缺乏表明，非束缚结构蒸发的时间尺度相当于或超过10兆热当量。在低恒星形成率的情况下，这意味着与星团演化的模型预测相比，星团环境中的质量过剩，这表明很大一部分恒星是在非束缚系统中形成的。
The Legacy ExtraGalactic UV Survey (LEGUS) is a multiwavelength Cycle 21 Treasury program on the Hubble Space Telescope. It studied 50 nearby star-forming galaxies in 5 bands from the near-UV to the I-band, combining new Wide Field Camera 3 observations with archival Advanced Camera for Surveys data. LEGUS was designed to investigate how star formation occurs and develops on both small and large scales, and how it relates to the galactic environments. In this paper we present the photometric catalogs for all the apparently single stars identified in the 50 LEGUS galaxies. Photometric catalogs and mosaicked images for all filters are available for download. We present optical and near-UV color–magnitude diagrams for all the galaxies. For each galaxy we derived the distance from the tip of the red giant branch. We then used the NUV color–magnitude diagrams to identify stars more massive than 14 M⊙, and compared their number with the number of massive stars expected from the GALEX FUV luminosity. Our analysis shows that the fraction of massive stars forming in star clusters and stellar associations is about constant with the star formation rate. This lack of a relation suggests that the timescale for evaporation of unbound structures is comparable or longer than 10 Myr. At low star formation rates this translates to an excess of mass in clustered environments as compared to model predictions of cluster evolution, suggesting that a significant fraction of stars form in unbound systems.