银河炖牛肉

One definition for goulash, according to the Merriam-Webster dictionary, is a mixture of heterogeneous elements, or jumble. This 2017 image of galaxy Arp 299 is just that.

Arp 299 is a system located about 140 million light-years from Earth, containing two galaxies that are merging, which has created a partially blended mix of stars from each galaxy.

Data from the Chandra X-Ray Observatory reveals 25 bright X-ray sources sprinkled throughout the Arp 299 concoction. Fourteen of these sources are such strong emitters of X-rays that astronomers categorize them as “ultra-luminous X-ray sources,” or ULXs.

This composite image of Arp 299 contains X-ray data from Chandra (pink), higher-energy X-ray data from NuSTAR (purple), and optical data from the Hubble Space Telescope (white and faint brown). Arp 299 also emits copious amounts of infrared light that have been detected by observatories such as the Spitzer Space Telescope.

Image Credit: X-ray: NASA/CXC/Univ of Crete/K. Anastasopoulou et al, NASA/NuSTAR/GSFC/A. Ptak et al; Optical: NASA/STScI

根据韦氏词典，炖肉的定义是混合了各种不同的元素，或者说是混杂在一起。Arp 299星系的这张2017年图片就是如此。

Arp 299是一个距离地球约1.4亿光年的系统，包含两个正在合并的星系，它产生了来自每个星系的部分混合恒星。

来自钱德拉X射线天文台的数据显示，有25个明亮的X射线源散布在Arp 299的混合体中。其中14个源是非常强的X线发射源，以至于天文学家将它们归类为 “超亮X射线源”，或者叫ULXs。

这张 Arp 299的合成图像包含来自钱德拉的X射线数据（粉红色）、来自NuSTAR的高能X射线数据（紫色）以及来自哈勃太空望远镜的光学数据（白色和淡棕色）。Arp 299还发出大量红外光，这些光已被斯皮策太空望远镜等天文台探测到。

影像来源：X-ray: NASA/CXC/Univ of Crete/K. Anastasopoulou et al, NASA/NuSTAR/GSFC/A. Ptak et al; Optical: NASA/STScI