论文标题
使用螺旋臂螺距角度测量在多个波长下确定螺旋星系的共旋转半径
Determining the Co-Rotation Radii of Spiral Galaxies Using Spiral Arm Pitch Angle Measurements at Multiple Wavelengths
论文作者
论文摘要
跨越磁盘星系的螺旋臂被认为是由通过银河盘传播的密度波创建的。我们提出了一种新的方法，可以找到共旋转半径，其中螺旋臂模式速度与磁盘内恒星的速度相匹配。我们的方法使用图像覆盖技术，该技术涉及在不同波长中观察到的图像上追踪螺旋星系的臂。密度波理论预测，从不同波长观察到的螺旋臂在共旋转半径处显示出相交。为了这项研究，在四个不同的波长中分析了20个附近的星系，并通过两种独立方法进行了俯仰角度测量。我们使用了光波长图像（$ b $ -band 440nm），Spitzer提供的两个红外波长图像（3.6 $ $ $ m和8 $ $ m）和来自Galex（1350Å，1750Å）的紫外图像。将结果与文献中发现的其他记录进行了比较和验证。然后，我们发现了六个星系的旋转曲线数据，并使用我们的共旋转半径估计值来测量在恒星形成之间会经过的时间，并在$ b $ band螺旋中移动到其观察到的位置。发现此动作的平均时间流逝为$ \ sim $ 50 MYR。这种新方法找到共旋转半径的成功以非常直接的方式证实了密度波理论。
The spiral arms spanning disk galaxies are believed to be created by density waves that propagate through galactic disks. We present a novel method of finding the co-rotation radius where the spiral arm pattern speed matches the velocities of the stars within the disk. Our method uses an image-overlay technique, which involves tracing the arms of spiral galaxies on images observed in different wavelengths. Density wave theory predicts that spiral arms observed from different wavelengths show a phase crossing at the co-rotation radius. For the purpose of this study, 20 nearby galaxies were analyzed in four different wavelengths with pitch angle measurements performed by two independent methods. We used optical wavelength images ($B$-band 440nm), two infrared wavelength images provided by Spitzer (3.6$μ$m and 8$μ$m) and ultraviolet images from GALEX (1350Å, 1750Å). The results were compared and verified with other records found in the literature. We then found rotation curve data for six of our galaxies and used our co-rotation radii estimates to measure the time that would elapse between star formation and moving to their observed positions in the $B$-band spirals. The average time lapse for this motion was found to be $\sim$ 50 Myr. The success of this new method of finding the co-rotation radius confirms density wave theory in a very direct way.
