NASA·APOD每日天文一图2022.5.17 [超高清]

Astronomers turn detectives when trying to figure out the cause of startling sights like NGC 1316. Investigations indicate that NGC 1316 is an enormous elliptical galaxy that started, about 100 million years ago, to devour a smaller spiral galaxy neighbor, NGC 1317, just on the upper right. Supporting evidence includes the dark dust lanes characteristic of a spiral galaxy, and faint swirls and shells of stars and gas visible in this wide and deep image. One thing that >remains unexplained is the unusually small globular star clusters, seen as faint dots on the image. Most elliptical galaxies have more and brighter globular clusters than NGC 1316. Yet the observed globulars are too old to have been created by the recent spiral collision. One hypothesis is that these globulars survive from an even earlier galaxy that was subsumed into NGC 1316. Another surprising attribute of NGC 1316, also known as Fornax A, is its giant lobes of gas that glow brightly in radio waves. 

当天文学家试图找出NGC1316等令人震惊的景象的原因时，他们会变成侦探。研究表明，NGC 1316是一个巨大的椭圆星系，大约在1亿年前开始吞噬右上角一个较小的旋涡星系邻居NGC 1317。支持证据包括螺旋星系特有的暗尘埃带，以及在这张宽而深的图像中可见的恒星和气体的微弱漩涡和外壳。有一件事仍然无法解释，那就是异常小的球状星团，在图像上被视为暗点。大多数椭圆星系的球状星团比NGC 1316更多、更亮。然而，观测到的球状星体太古老了，不可能是最近的螺旋碰撞产生的。一种假设是，这些球状星体来自一个更早期的星系，该星系被归入NGC1316。NGC 1316的另一个令人惊讶的特性，也被称为Fornax A，是其巨大的气体叶，在无线电波中发出明亮的光。