High-resolution ALMA observations of SDP.81. II. Molecular clump properties of a lensed submillimeter galaxy at z = 3.042
High-resolution ALMA observations of SDP.81. II. Molecular clump properties of a lensed submillimeter galaxy at z = 3.042
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SDP.81 的高分辨率 ALMA 观测结果。
DOI：
10.1093/pasj/psv061
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
M.
中科院分区：
文献类型：
--
作者：
Hatsukade;B.;Tamura;Y.;Iono;D.;Matsuda;Y.;Hayashi;M.;Oguri;M.
利用阿塔卡马大型毫米/亚毫米波阵列（阿尔马）观测了引力透镜亚毫米星系H-ATLAS J090311.6+003906（SDP.81）（atz= 3.042）中分子气体和尘埃的空间分辨性质.我们在CO（5-4）谱线数据中鉴定了14个分子团簇。团簇的分子气体表面密度（）和恒星形成率（α-SFR）比本地螺旋星系高出三个数量级以上。这些团簇在-ε SFR平面上以“爆发”序列排列，表明分子团簇遵循从局部星暴星系导出的恒星形成定律。我们的引力透镜模型，在源平面的位置推导出的分子团，尘埃团，和恒星组件中确定的哈勃太空望远镜的图像。分子和尘埃团被限制在10.2 kpc的区域内，而恒星成分的空间范围则高达10.6 kpc，并向西偏移。分子团在南北方向上具有系统的速度梯度，这可能表明旋转的气体盘。一种可能的情况是，分子气体、尘埃和恒星的成分分布在一个几千秒差距尺度的旋转盘中，恒星的辐射被中心恒星形成区域的尘埃严重遮蔽。另外，SDP.81可以用合并系统来解释，在合并系统中，尘埃星暴发生在两个星系碰撞的区域，被恒星成分中的潮汐特征所包围。
We present spatially resolved properties of molecular gas and dust in a gravitationally lensed submillimeter galaxy H-ATLAS J090311.6+003906 (SDP.81) atz= 3.042 revealed by the Atacama Large Millimeter/submillimeter Array (ALMA). We identified 14 molecular clumps in the CO(5–4) line data. The surface density of molecular gas () and star-formation rate (ΣSFR) of the clumps are more than three orders of magnitude higher than those found in local spiral galaxies. The clumps are placed in the “burst” sequence in the–ΣSFRplane, suggesting thatz∼ 3 molecular clumps follow the star-formation law derived for local starburst galaxies. With our gravitational lens model, the positions in the source plane are derived for the molecular clumps, dust clumps, and stellar components identified in the Hubble Space Telescope image. The molecular and dust clumps are confined within a ∼ 2 kpc region, while the spatial extent of the stellar components is as large as ∼ 6 kpc and offset toward the west. The molecular clumps have a systematic velocity gradient in the north–south direction, which may indicate a rotating gas disk. One possible scenario is that the components of molecular gas, dust, and stars are distributed in a several-kpc-scale rotating disk, and the stellar emission is heavily obscured by dust in the central star-forming region. Alternatively, SDP.81 can be explained by a merging system, where dusty starbursts occur in the region where the two galaxies collide, surrounded by tidal features traced in the stellar components.