CLUMPY AND EXTENDED STARBURSTS IN THE BRIGHTEST UNLENSED SUBMILLIMETER GALAXIES
CLUMPY AND EXTENDED STARBURSTS IN THE BRIGHTEST UNLENSED SUBMILLIMETER GALAXIES
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DOI：
10.3847/2041-8205/829/1/l10
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发表时间：
2016-09
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通讯作者：
D. Iono;M. Yun;I. Aretxaga;B. Hatsukade;D. Hughes;S. Ikarashi;T. Izumi;R. Kawabe;K. Kohno;Minju M. Lee;Y. Matsuda;K. Nakanishi;T. Saito;Y. Tamura;J. Ueda;H. Umehata;G. Wilson;T. Michiyama;M. Ando
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作者：
D. Iono;M. Yun;I. Aretxaga;B. Hatsukade;D. Hughes;S. Ikarashi;T. Izumi;R. Kawabe;K. Kohno;Minju M. Lee;Y. Matsuda;K. Nakanishi;T. Saito;Y. Tamura;J. Ueda;H. Umehata;G. Wilson;T. Michiyama;M. Ando
利用阿塔卡马大型毫米/亚毫米波阵列（阿尔马）获得的0. 015-0. 05（120-360 pc）860 μm连续谱图像，研究了三个最亮的z = 3-4亚毫米波无透镜星系的中心结构. AzTEC 1和AzTEC 8在中央千秒差距内的分布非常复杂，它们由多个200 pc的团块组成。AzTEC 4由两个源组成，它们之间的距离为1.5kpc，表明它们处于中期合并阶段。在中央团块的最高星星形成率密度为300-3000 M yr−1 kpc−2，这表明在爱丁顿极限附近有极端的星星形成区域。通过比较阿尔马和亚毫米波阵列的辐射通量，我们发现，在AzTEC 4和8中，68%-90%的辐射被扩展（约1 kpc）。对于AzTEC 1，我们确定至少11个额外的紧凑（约200 pc）在扩展的3-4 kpc区域的团块。总的来说，这里提供的数据表明，在150 pc尺度下观测到的光度表面密度与在局部ULIRGs中观测到的大致相似，如在阿普220的东核中。860 μm的连续光谱中，有10%到30%集中在中心千秒差距的星团结构中，而其余的通量则分布在10.1千秒差距的区域，其中一些也可能是星团。这些来源可以用气体的快速流入来解释，例如富含气体的星系合并，周围环绕着扩展和cluerous星暴。然而，不排除冷模吸积模型。
The central structure in three of the brightest unlensed z = 3–4 submillimeter galaxies is investigated through 0.″015–0.″05 (120–360 pc) 860 μm continuum images obtained using the Atacama Large Millimeter/submillimeter Array (ALMA). The distribution in the central kiloparsec in AzTEC1 and AzTEC8 is extremely complex, and they are composed of multiple ∼200 pc clumps. AzTEC4 consists of two sources that are separated by ∼1.5 kpc, indicating a mid-stage merger. The peak star formation rate densities in the central clumps are ∼300–3000 M⊙ yr−1 kpc−2, suggesting regions with extreme star formation near the Eddington limit. By comparing the flux obtained by ALMA and Submillimeter Array, we find that 68%–90% of the emission is extended (≳1 kpc) in AzTEC4 and 8. For AzTEC1, we identify at least 11 additional compact (∼200 pc) clumps in the extended 3–4 kpc region. Overall, the data presented here suggest that the luminosity surface densities observed at ≲150 pc scales are roughly similar to that observed in local ULIRGs, as in the eastern nucleus of Arp 220. Between 10% and 30% of the 860 μm continuum is concentrated in clumpy structures in the central kiloparsec, while the remaining flux is distributed over ≳1 kpc regions, some of which could also be clumpy. These sources can be explained by a rapid inflow of gas such as a merger of gas-rich galaxies, surrounded by extended and clumpy starbursts. However, the cold mode accretion model is not ruled out.