A detailed view of a molecular cloud in the far outer disk of M 33. Molecular cloud formation in M 33
A detailed view of a molecular cloud in the far outer disk of M 33. Molecular cloud formation in M 33
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M 33 远外盘分子云的详细视图。M 33 中分子云的形成
DOI：
10.1051/0004-6361/201220093
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发表时间：
2012
影响因子：
6.5
通讯作者：
N. Brouillet
中科院分区：
文献类型：
--
作者：
J. Braine;P. Gratier;Y. Contreras;K. Schuster;N. Brouillet
螺旋星系中存在的氢气量仍然不确定，特别是在昏暗的外部区域和低金属丰度环境中。我们利用Plateau de Bure干涉仪对本星系群M 33中最遥远的分子云进行了高分辨率CO(1-0)观测。分子云是一个单一的实体，而不是原始单碟观测的宽光束内的一组较小的云。尽管光束尺寸不同，干涉仪和单碟通量非常相似，并且线宽无法区分。在 10 pc 的空间分辨率下，超出 M 33 的光学半径，CO 亮度温度达到 2.4 开尔文。云的维里质量估计得出的质量为 4.3 × 104 Ms，比率 N(H2)/ICO(1-0) ≃ 3.5 × 1020 cm-2/(K km s-1)。虽然在发射强的地方看不到速度梯度，但速度红移到极端的西南方向，蓝移到远端的东北方向。如果云的方向沿着圆盘的平面（即不垂直），那么这些速度对应于缓慢的坠落或吸积。相当适度的流入率约为 2 × 10-4 Ms yr-1。基于 IRAM Plateau de Bure 干涉仪进行的观测。 IRAM 受 INSU/CNRS（法国）、MPG（德国）和 IGN（西班牙）的支持。FITS 文件中的数据立方体只能通过匿名 ftp 到 cdsarc.u-strasbg.fr (130.79.128.5) 或通过 http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/548/A52 在 CDS 上获得
The amount of H2 present in spiral galaxies remains uncertain, particularly in the dim outer regions and in low-metallicity environments. We present high-resolution CO(1-0) observations with the Plateau de Bure interferometer of the most distant molecular cloud in the local group galaxy M 33. The cloud is a single entity rather than a set of smaller clouds within the broad beam of the original single-dish observations. The interferometer and single-dish fluxes are very similar and the line widths are indistinguishable, despite the difference in beamsize. At a spatial resolution of 10 pc, beyond the optical radius of the M 33, the CO brightness temperature reaches 2.4 Kelvins. A virial mass estimate for the cloud yields a mass of 4.3 × 104 Ms and a ratio N(H2)/ICO(1-0) ≃ 3.5 × 1020 cm-2/(K km s-1). While no velocity gradient is seen where the emission is strong, the velocity is redshifted to the extreme SW and blue-shifted to the far NE. If the orientation of the cloud is along the plane of the disk (i.e. not perpendicular), then these velocities correspond to slow infall or accretion. The rather modest infall rate would be about 2 × 10-4 Ms yr-1. Based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).Data cube in FITS files is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/548/A52
M33 的 PACS 和 SPIRE 光度计图：Herschel M33 扩展勘测 (HERM33ES) 的第一个结果
影响因子：
6.5
作者：
Kramer
通讯作者：
Kramer