Origin of Multiple Nuclei in Ultraluminous Infrared Galaxies
Origin of Multiple Nuclei in Ultraluminous Infrared Galaxies
复制标题
超光红外星系中多核的起源
DOI：
10.1088/0004-637x/746/1/26
复制
发表时间：
2012
影响因子：
4.9
通讯作者：
他7名、N.Yoshida
中科院分区：
文献类型：
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作者：
H.Matsui;他7名、N.Yoshida
经常观测到具有多个（⩾ 3）核的超亮红外星系（ULIRG）。有人认为这些核是由星系的多次重大合并产生的。然而，这种合并的预期速度太低，无法重现观察到的多核 ULIRG 数量。我们对两个富含气体的盘状星系的合并进行了高分辨率模拟。我们发现，在星系之间第一次或第二次相遇后，受到强烈扰动的气盘会形成质量极大且致密的星团。这种团簇的质量达到∼10 8 M☉，半质量半径为20-30 pc。由于这些星团由年轻恒星组成，因此它们在银河系中心区域（∼ kpc）中表现为几个明亮的核心。这些星团的峰值光度达到合并星系总光度的~10%。这些巨大而致密的团簇与 ULIRG 中观察到的多核特征一致。多次合并并不需要解释 ULIRG 中的多个核。
Ultraluminous infrared galaxies (ULIRGs) with multiple (⩾ 3) nuclei are frequently observed. It has been suggested that these nuclei are produced by multiple major mergers of galaxies. The expected rate of such mergers is, however, too low to reproduce the observed number of ULIRGs with multiple nuclei. We have performed high-resolution simulations of the merging of two gas-rich disk galaxies. We found that extremely massive and compact star clusters form from the strongly disturbed gas disks after the first or second encounter between the galaxies. The mass of such clusters reaches∼ 10 8 M☉ and their half-mass radii are 20–30 pc. Since these clusters consist of young stars, they appear as several bright cores in the galactic central region (∼ kpc). The peak luminosity of these clusters reaches∼ 10% of the total luminosity of the merging galaxy. These massive and compact clusters are consistent with the characteristics of the observed multiple nuclei in ULIRGs. Multiple mergers are not necessary to explain multiple nuclei in ULIRGs.