Circumnuclear kinematics in NGC 5248: the origin of nuclear spiral arms
Circumnuclear kinematics in NGC 5248: the origin of nuclear spiral arms
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NGC 5248 中的环核运动学：核旋臂的起源
DOI：
10.1046/j.1365-8711.2001.04338.x
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发表时间：
2001
影响因子：
4.8
通讯作者：
M. Matthias
中科院分区：
文献类型：
--
作者：
Seppo Laine;Seppo Laine;J. Knapen;D. Pérez;P. Englmaier;M. Matthias
我们提出了第一次的二维速度场的中心区域的大设计的螺旋星系NGC 5248，在0.9角秒的空间分辨率。H速度场主要由圆周旋转控制。虽然没有系统的流运动被认为是在该地区的核大设计的螺旋或环核，剩余速度的幅度，减去模型的圆形速度场后，达到20公里s-1的投影。旋转曲线水平在140公里秒1左右，经过一个很好的解决和相当浅的上升。我们已经生成了一个分析模型的核螺旋，并将其安装到我们的观察，以获得估计的模式速度的螺旋和声速在中央区域的NGC 5248。我们的结果与低模式速度一致，表明核螺旋旋转与NGC 5248中的主螺旋结构相同，因此螺旋结构从几百秒差距到几千秒差距的尺度耦合。我们还比较了NGC 5248和M100核区的结构和运动学。几个相似之处和不同之处进行了讨论，包括长轴和短轴上的峰值发射区域的位置，和螺旋臂流运动。我们没有发现NGC 5248中存在核棒的运动学证据。
We present for the first time a two-dimensional velocity field of the central region of the grand-design spiral galaxy NGC 5248, at 0.9 arcsec spatial resolution. The Hvelocity field is dominated by circular rotation. While no systematic streaming motions are seen in the area of the nuclear grand-design spiral or the circumnuclear ring, the amplitude of residual velocities, after subtracting a model circular velocity field, reaches 20 km s 1 in projection. The rotation curve levels out at around 140 km s 1 , after a well-resolved and rather shallow rise. We have generated an analytical model for the nuclear spiral and fitted it to our observations to obtain estimates of the pattern speed of the spiral and the sound speed in the central region of NGC 5248. Our results are consistent with a low pattern speed, suggesting that the nuclear spiral rotates with the same rate as the main spiral structure in NGC 5248, and thus that the spiral structure is coupled from scales of a few hundred parsecs to several kiloparsecs. We have also compared the observed structure and kinematics between the nuclear regions of NGC 5248 and M100. Several similarities and differences are discussed, including the location of the peak emission regions on major and minor axes, and the spiral arm streaming motions. We find no kinematic evidence for a presence of a nuclear bar in NGC 5248.