Kinematics of the atomic ISM in M33 on 80 pc scales
Kinematics of the atomic ISM in M33 on 80 pc scales
复制标题
M33 中原子 ISM 的运动学在 80 pc 尺度上
DOI：
10.1093/mnras/sty1674
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发表时间：
2018
影响因子：
4.8
通讯作者：
Stanimirović, Snežana
中科院分区：
文献类型：
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作者：
Koch, Eric W;Rosolowsky, Erik W;Lockman, Felix J;Kepley, Amanda A;Leroy, Adam;Schruba, Andreas;Braine, Jonathan;Dalcanton, Julianne;Johnson, Megan C;Stanimirović, Snežana
我们介绍了用卡尔·g·杨斯基甚大阵列获得的80pc分辨率的螺旋星系M33的新波段（1 - 2ghz）观测结果。与之前的观测结果相比，Hiobservations与Green Bank望远镜的Himeasurements相结合，提高了光谱分辨率和灵敏度（0.2通道中2.8 K rms噪声）。我们发现单个的轮廓通常是非高斯的，庇护线翼，多组件和不对称。鉴于这种光谱的复杂性，我们通过光谱的力矩分析来量化原子星际介质中的运动，并适合于排列，堆叠的剖面。Hiline宽度的测量值在很大程度上取决于所使用的方法，与峰值速度对齐的速度堆叠剖面给出最小值σ = 7，而所有其他方法给出更高的值（σ ~ 10）。线宽的所有测量结果都显示出浅径向趋势，σ从mrgal = 0到al= 8 kpc减小了~ 2。我们考虑了一些可能维持线宽以抵抗湍流耗散的能量源，但没有一个单一的能量源是足够的。我们发现，相对于高斯，在堆叠的剖面线翼中，根据光谱的排列方式，过量的发射从9%到26%不等。通过将线翼分成对称和非对称两部分，我们发现滞后旋转盘占线翼通量的三分之一。我们还在远离星系旋转轴的多个离散hicloud中发现了发射，包括一个投影长度为~ 8 kpc的灯丝。
We present newL-band (1–2 GHz) observations of the nearby spiral galaxy M33 with 80 pc resolution obtained with the Karl G. Jansky Very Large Array. The Hiobservations, combined with Himeasurements from the Green Bank Telescope, improve the spectral resolution and sensitivity (2.8 K rms noise in a 0.2channel) compared to previous observations. We find individual profiles are usually non-Gaussian, harbouring line wings, multiple components, and asymmetries. Given this spectral complexity, we quantify the motions in the atomic interstellar medium through moment analysis of the spectra and fits to aligned, stacked profiles. The measured value of the Hiline width depends strongly on the method used, with the velocity stacked profiles aligned to the peak velocity giving the minimum value of σ = 7and all other methods giving higher values (σ ∼ 10). All measurements of the line width show a shallow radial trend, with σ decreasing by ∼2fromRgal= 0 toRgal= 8 kpc. We consider a number of energy sources that might maintain the line width against turbulent dissipation, but no single source is adequate. We find excess emission relative to a Gaussian in the stacked profile line wings, ranging from 9 per cent to 26 per cent depending on how the spectra are aligned. By splitting the line wings into symmetric and asymmetric components, we find that the lagging rotational disc accounts for one-third of the line wing flux. We also find emission far from the rotation-axis of the galaxy in multiple discrete Hiclouds, including a filament with a projected length of ∼8 kpc.