SpArcFiRe: SCALABLE AUTOMATED DETECTION OF SPIRAL GALAXY ARM SEGMENTS
SpArcFiRe: SCALABLE AUTOMATED DETECTION OF SPIRAL GALAXY ARM SEGMENTS
复制标题
SpArcFiRe：螺旋星系臂片段的可扩展自动检测
DOI：
10.1088/0004-637x/790/2/87
复制
发表时间：
2014
期刊：
影响因子：
--
通讯作者：
W. Hayes
中科院分区：
文献类型：
--
作者：
Darren R. Davis;W. Hayes
给定一个螺旋星系的近似中心图像，我们描述了一个完全自动化的方法，发现，中心，和大小的星系（可能掩盖附近的恒星和其他物体，如果必要的话，以隔离星系本身），然后自动提取有关螺旋臂的结构信息。对于发现的每个手臂节段，我们列出该节段中的像素，从而允许基于每个手臂节段进行图像分析。我们还执行一个最小二乘拟合的对数螺旋弧的像素在该段，给每弧参数，如俯仰角，臂段长度，位置等算法需要大约一分钟，每个星系，可以很容易地使用并行缩放。我们已经在所有644，000个斯隆天体上运行了它，这些天体大于40像素，并被归类为“星系”。我们发现我们的螺旋结构的定量描述和银河动物园人类提供的定性描述之间有很好的相关性。我们对结构的客观、定量测量表明，很难准确定义什么是螺旋“臂”，这使我们更喜欢“臂段”一词。我们发现，在一个螺旋星系中，俯仰角往往会在不同的星系段之间发生显著的变化，这使得很难定义单个星系的俯仰角。我们演示了如何查询我们的新数据库的臂段，以找到满足特定的定量视觉标准的星系。例如，即使我们的代码没有明确地找到环，一个很好的替代是寻找有一个长的，低俯仰角的臂的星系-这就是我们的代码如何看待环星系。SpArcFiRe可在http://sparcfire.ics.uci.edu上获得。
Given an approximately centered image of a spiral galaxy, we describe an entirely automated method that finds, centers, and sizes the galaxy (possibly masking nearby stars and other objects if necessary in order to isolate the galaxy itself) and then automatically extracts structural information about the spiral arms. For each arm segment found, we list the pixels in that segment, allowing image analysis on a per-arm-segment basis. We also perform a least-squares fit of a logarithmic spiral arc to the pixels in that segment, giving per-arc parameters, such as the pitch angle, arm segment length, location, etc. The algorithm takes about one minute per galaxies, and can easily be scaled using parallelism. We have run it on all ∼644,000 Sloan objects that are larger than 40 pixels across and classified as “galaxies.” We find a very good correlation between our quantitative description of a spiral structure and the qualitative description provided by Galaxy Zoo humans. Our objective, quantitative measures of structure demonstrate the difficulty in defining exactly what constitutes a spiral “arm,” leading us to prefer the term “arm segment.” We find that pitch angle often varies significantly segment-to-segment in a single spiral galaxy, making it difficult to define the pitch angle for a single galaxy. We demonstrate how our new database of arm segments can be queried to find galaxies satisfying specific quantitative visual criteria. For example, even though our code does not explicitly find rings, a good surrogate is to look for galaxies having one long, low-pitch-angle arm—which is how our code views ring galaxies. SpArcFiRe is available at http://sparcfire.ics.uci.edu.