Rotational properties of 21 SC galaxies with a large range of luminosities and radii, from NGC 4605 /R = 4kpc/ to UGC 2885 /R = 122 kpc/
Rotational properties of 21 SC galaxies with a large range of luminosities and radii, from NGC 4605 /R = 4kpc/ to UGC 2885 /R = 122 kpc/
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DOI：
10.1086/158003
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发表时间：
1980-06
期刊：
影响因子：
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通讯作者：
V. Rubin;W. Ford;N. Thonnard
中科院分区：
文献类型：
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作者：
V. Rubin;W. Ford;N. Thonnard
对于21 Sc星系，其属性包括一个广泛的半径，质量和光度，我们已经获得了主轴光谱延伸到微弱的外部区域，并推导出旋转曲线。星系的倾斜度很高，因此在视线倾斜角度和长轴位置角度的不确定性被最小化。它们的半径范围从4到122 kpc（H = 50 km s-1 Mpc-1）;一般来说，自转曲线延伸到83%或R25 i. b。当在没有比例的线性尺度上绘制时，最小星系的旋转曲线落在较大星系旋转曲线的初始部分上。所有曲线都表明，在R = 5 kpc时，速度相当快地上升到V = 125 km s-1，此后上升较慢。大多数旋转曲线即使在最远的测量点也是缓慢上升的。无论是高亮度还是低亮度的Sc星系都没有下降的自转曲线。所有光度的Sc星系都必须有相当大的质量位于光学图像之外。log Vmax和log R之间的线性关系可以从所有Sc的共同旋转曲线的形状以及较小星系在任何R处的速度都比该R处的大星系低的趋势中得出。Tully和Fisher发现的这个关系的斜率要小得多，这归因于他们使用了各种哈勃类型的星系，以及Vmax与哈勃类型的已知相关性。具有非常大的中心速度梯度的星系往往是大的，高光度的，有质量的，致密的核。它们的核光谱通常显示出红色的强恒星连续谱，[N II]的发射线比H α强。这些星系也往往是13厘米射电连续源。由于旋转曲线的形式，小星系经历许多短周期，非常微分，旋转。大型星系（在其外部）经历很少的，只有轻微的差异，旋转。这表明形态，旋转性能，和货车登伯格光度分类，这是讨论之间的关系。UGC 2885是样本中最大的Sc，自宇宙起源以来，其外部经历了不到10次旋转，但具有规则的双臂螺旋模式，没有明显的速度不对称性。这一观测结果对星系形成和演化的模型提出了限制。
For 21 Sc galaxies whose properties encompass a wide range of radii, masses, and luminosities, we have obtained major axis spectra extending to the faint outer regions, and have deduced rotation curves. The galaxies are of high inclination, so uncertainties in the angle of inclination to the line of sight and in the position angle of the major axis are minimized. Their radii range from 4 to 122 kpc (H = 50km s-1 Mpc-1); in general, the rotation curves extend to 83% or R25i.b. When plotted on a linear scale with no scaling, the rotation curves for the smallest galaxies fall upon the initial parts of the rotation curves for the larger galaxies. All curves show a fairly rapid velocity rise to V ˜ 125 km s-1 at R ˜ 5 kpc, and a slower rise thereafter. Most rotation curves are rising slowly even at the farthest measured point. Neither high nor low luminosity Sc galaxies have falling rotation curves. Sc galaxies of all luminosities must have significant mass located beyond the optical image. A linear relation between log Vmax and log R follows from the shape of the common rotation curve for all Sc's, and the tendency of smaller galaxies, at any R, to have lower velocities than the large galaxies at that R. The significantly shallower slope discovered for this relation by Tully and Fisher is attributed to their use of galaxies of various Hubble types and the known correlation of Vmax with Hubble type. The galaxies with very large central velocity gradients tend to be large, of high luminosity, with massive, dense nuclei. Often their nuclear spectra show a strong stellar continuum in the red, with emission lines of [N II] stronger than Halpha. These galaxies also tend to be 13 cm radio continuum sources. Because of the form of the rotation curves, small galaxies undergo many short-period, very differential, rotations. Large galaxies undergo (in their outer parts) few, only slightly differential, rotations. This suggests a relation between morphology, rotational properties, and the van den Bergh luminosity classification, which is discussed. UGC 2885, the largest Sc in the sample, has undergone fewer than 10 rotations in its outer parts since the origin of the universe but has a regular two-armed spiral pattern and no significant velocity asymmetries. This observation puts constraints on models of galaxy formation and evolution.