Herschel view of the merging galaxy pair HXMM01
This image shows the source HXMM01, which was discovered in a survey from ESA's Herschel Space Observatory and comprises a pair of massive and gas-rich galaxies in the process of merging.
In the Herschel image, every dot is a galaxy, and HXMM01 stands out as an exceptionally bright one. Follow-up observations providing a higher resolution view of this source revealed that HXMM01 consists of two physically distinct galaxies lying at redshift 2.310 and 2.307 and currently in the process of merging. The galactic encounter took place when the Universe was only about three billion years old and would go on to form a very massive elliptical galaxy with hardly any star formation activity.
The image is a false-colour composite which combines data acquired with the SPIRE instrument on board Herschel at 250 microns (shown in blue), 350 microns (shown in green) and 500 microns (shown in red).
The angular size of the image is about 20 arc minutes on each side.