SMA CO(J=6-5) and 435 micron interferometric imaging of the nuclear region of Arp 220
Satoki Matsushita, Daisuke Iono, Glen R. Petitpas, Richard C. -Y. Chou, Mark A. Gurwell, Todd R. Hunter, Jeremy Lim, Sebastien Muller, Alison B. Peck, Kazushi S… 展开作者
Satoki Matsushita, Daisuke Iono, Glen R. Petitpas, Richard C. -Y. Chou, Mark A. Gurwell, Todd R. Hunter, Jeremy Lim, Sebastien Muller, Alison B. Peck, Kazushi Sakamoto, Satoko Sawada-Satoh, Martina C. Wiedner, David J. Wilner, Christine D. Wilson
备注：
13 pages (emulateapj), 10 figures, Accepted for publication in ApJ
我们利用亚毫米波阵列（SMA）对12 CO J=6-5谱线和435微米（690 GHz）连续谱向附近ULIRG Arp 220中心区域的发射进行了首次干涉观测（光束尺寸~1”）。这些观测分辨出东、西两个原子核的分子谱线和尘埃连续辐射。在435微米处，西核的峰值强度比东核强，并且峰值强度的差异小于较长波长处。拟合一个简单的模型，以1.3毫米和435微米之间观察到的尘埃排放表明，尘埃发射率幂律指数在西部的核是接近统一和陡峭的东核，约2，和尘埃排放的光学厚度在较短的波长。与单碟测量结果的比较表明，干涉仪观测结果丢失了约60%的尘埃排放，最有可能是来自这些观测结果不敏感的空间扩展分量。~（12）CO J=6-5谱线观测清楚地分辨了两个原子核的运动学性质。12 CO J=6-5谱线的分布和运动学似乎与在类似分辨率下观测到的低JCO谱线非常相似。多个12 CO线强度的分析表明，在两个核的分子气体有类似的激发条件，虽然西部的核是温暖和密度。激发条件与其他极端环境中的条件相似，包括M82、Mrk 231和BR 1202-0725。对12 CO、13 CO和C18 O J=2-1谱线的同时低分辨率观测表明，13 CO和C18 O谱线具有相似的强度，这表明这两条谱线都是光学粗的，或者可能是极高质量的恒星形成产生了过量的C18 O。
英文摘要：
We have used the Submillimeter Array (SMA) to make the first interferometric observations (beam size ~1") of the 12CO J=6-5 line and 435 micron (690 GHz) continuum emission toward the central region of the nearby ULIRG Arp 220. These observations resolve the eastern and western nuclei from each other, in both the molecular line and dust continuum emission. At 435 micron, the peak intensity of the western nucleus is stronger than the eastern nucleus, and the difference in peak intensities is less than at longer wavelengths. Fitting a simple model to the dust emission observed between 1.3 mm and 435 micron suggests that dust emissivity power law index in the western nucleus is near unity and steeper in the eastern nucleus, about 2, and that the dust emission is optically thick at the shorter wavelength. Comparison with single dish measurements indicate that the interferometer observations are missing ~60% of the dust emission, most likely from a spatially extended component to which these observations are not sensitive. The 12CO J=6-5 line observations clearly resolve kinematically the two nuclei. The distribution and kinematics of the 12CO J=6-5 line appear to be very similar to lower J CO lies observed at similar resolution. Analysis of multiple 12CO line intensities indicates that the molecular gas in both nuclei have similar excitation conditions, although the western nucleus is warmer and denser. The excitation conditions are similar to those found in other extreme environments, including M82, Mrk 231, and BR 1202-0725. Simultaneous lower resolution observations of the 12CO, 13CO, and C18O J=2-1 lines show that the 13CO and C18O lines have similar intensities, which suggests that both of these lines are optically thick, or possibly that extreme high mass star formation has produced in an overabundance of C18O.
Continuum and spectral line observations of the OH Megamaser galaxy Arp 220
我们目前MERLIN观测的连续（1.6和5 GHz）和OH脉泽发射到Arp 220。揭示了银河系各组成部分的正确空间结构。在东部的组成部分的脉泽被证明是一般符合较大规模的连续辐射，在西部，脉泽和连续不一般出现在同一位置。在MERLIN尺度下，在东核区发现了一个速度梯度（0.32+/-0.03km/s/pc），这个梯度比在OH中看到的小三倍，这意味着OH气体位于HI内部。重新分析以前提供的全球VLBI数据（Lonsdale et al.1998）显示，其中一个分量的速度梯度很高（18.67+/-0.12km/s/pc），可能是一个被严重遮蔽的活动星系核所在地。
SMA CO(J=3-2) interferometric observations of the central region of M51
我们利用亚毫米阵列（SMA）对塞弗特2星系M51的中心进行了首次干涉CO（J=3-2）观测（光束大小为3.9“x1.6”或160 pc x 65 pc）。图像显示了在核心处的强烈集中和从螺旋臂向西北方向的微弱发射。CO（J=3-2）中心成分的积分强度几乎是CO（J=1-0）中心成分的两倍，这表明在原子核半径约80 pc范围内的分子气体是温暖的（>~100 K）和致密的（~10^4 cm^-3）。类似的强度比在我们的银河系中的冲击区域中看到，这表明这些气体性质可能与AGN或星暴活动有关。中心分量显示出垂直于射电连续喷流的线性速度梯度（~1.4 km/s/pc），与以前的观测结果相似，并被解释为围绕塞弗特2核的环核分子盘/环面。此外，我们确定了沿射流的线性速度梯度（~0.7 km/s/pc）。从能量学的角度来看，速度梯度可以用超新星爆炸或通过相互作用从喷流到分子气体的能量和动量转移来解释，这与高强度比是一致的。
Modeling Stellar Atmospheres with a Spherically Symmetric Version of the Atlas Code: Testing the Code by Comparisons to Interferometric Observations and PHOENIX Models
