A GLOBAL STAR-FORMING EPISODE IN M31 2–4 GYR AGO
A GLOBAL STAR-FORMING EPISODE IN M31 2–4 GYR AGO
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2-4 年前 M31 的全球恒星形成阶段
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
E. Skillman
中科院分区：
文献类型：
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作者：
B. Williams;J. Dalcanton;A. Dolphin;D. Weisz;A. Lewis;D. Lang;E. Bell;M. Boyer;M. Fouesneau;K. Gilbert;A. Monachesi;E. Skillman
我们已经确定了一个主要的全球性增强星星形成的内部M31磁盘之间发生2-4 Gyr前，产生的恒星质量的60%，在过去的5 Gyr。这一幕在内盘的存在是通过模拟M31（3 < R < 20 kpc）主盘低消光区的光学分辨星星色星等图发现的，这是全色哈勃仙女座宝库的一部分。这一测量结果证实并扩展了最近的测量结果，即在外盘中有一个类似年龄的广泛分布的星星形成增强，这表明这次爆发是巨大的全球性爆发。在星系范围的爆发之后，M31的星星形成率显著下降。我们简要地讨论了M31进化历史的这些特征的可能原因，包括与M32，M33和/或合并的相互作用。
We have identified a major global enhancement of star formation in the inner M31 disk that occurred between 2–4 Gyr ago, producing ∼60% of the stellar mass formed in the past 5 Gyr. The presence of this episode in the inner disk was discovered by modeling the optical resolved star color–magnitude diagrams of low extinction regions in the main disk of M31 (3 < R < 20 kpc) as part of the Panchromatic Hubble Andromeda Treasury. This measurement confirms and extends recent measurements of a widespread star formation enhancement of similar age in the outer disk, suggesting that this burst was both massive and global. Following the galaxy-wide burst, the star formation rate of M31 has significantly declined. We briefly discuss possible causes for these features of the M31 evolutionary history, including interactions with M32, M33, and/or a merger.