Dust and gas pervade galaxies in regions between stars, and is called the interstellar medium (ISM). Astronomers can observe radiation from the ISM and discover its properties. This article describes observations of the ISM in a galaxy that has recently collided with another galaxy, helping astronomers better understand the properties of this system.

http://www.raa-journal.org/raa/index.php/raa/article/view/1209