HALOGAS: H i OBSERVATIONS AND MODELING OF THE NEARBY EDGE-ON SPIRAL GALAXY NGC 4565
HALOGAS: H i OBSERVATIONS AND MODELING OF THE NEARBY EDGE-ON SPIRAL GALAXY NGC 4565
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HALOGAS：H i 附近边缘螺旋星系 NGC 4565 的观测和建模
DOI：
10.1088/0004-637x/760/1/37
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
G. Józsa
中科院分区：
文献类型：
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作者：
L. Zschaechner;R. Rand;G. Heald;G. Gentile;G. Józsa
我们展示了 NGC 4565（附近的边缘螺旋星系）中中性氢的 21 厘米观测结果和模型，作为本地 GAlaxieS 调查中 Westerbork 氢吸积的一部分。这些模型提供了有关盘上方和盘内部 H i 的形态和运动学的见解。 NGC 4565 呈现出明显扭曲和不对称的圆盘，并带有喇叭形层。我们的模型没有提供任何证据表明存在巨大的、延伸的H i光环。我们看到了条形和相关径向运动的证据。此外，有迹象表明盘内有径向运动，可能与密度较高的环有关。我们看到在接近和后退的一半中，旋转速度随着盘平面上方的高度（滞后）分别大幅降低 -40+5 − 20 km s−1 kpc−1 和 -30+5 − 30 km s−1 kpc−1 。这种滞后仅在接近的一半的内部~4.′75（14.9 kpc）和后退的一半的~4.′25（13.4 kpc）内可见，这使得这是一个径向变浅的滞后，现在在几个星系的H i层中都可以看到。当比较 NGC 4565 和其他星系的结果时，初步迹象表明单位面积的高恒星形成率与光晕的存在有关。最后，H i 在两个伴星系中被发现，其中一个明显与 NGC 4565 相互作用。
We present 21 cm observations and models of the neutral hydrogen in NGC 4565, a nearby, edge-on spiral galaxy, as part of the Westerbork Hydrogen Accretion in LOcal GAlaxieS survey. These models provide insight concerning both the morphology and kinematics of H i above, as well as within, the disk. NGC 4565 exhibits a distinctly warped and asymmetric disk with a flaring layer. Our modeling provides no evidence for a massive, extended H i halo. We see evidence for a bar and associated radial motions. Additionally, there are indications of radial motions within the disk, possibly associated with a ring of higher density. We see a substantial decrease in rotational velocity with height above the plane of the disk (a lag) of −40+5 − 20 km s−1 kpc−1 and −30+5 − 30 km s−1 kpc−1 in the approaching and receding halves, respectively. This lag is only seen within the inner ∼4.′75 (14.9 kpc) on the approaching half and ∼4.′25 (13.4 kpc) on the receding half, making this a radially shallowing lag, which is now seen in the H i layers of several galaxies. When comparing results for NGC 4565 and those for other galaxies, there are tentative indications of high star formation rate per unit area being associated with the presence of a halo. Finally, H i is found in two companion galaxies, one of which is clearly interacting with NGC 4565.