ESA Science & Technology - Composite near-infrared and X-ray image of the galaxy cluster CL J1449+0856

This image shows the X-ray emission (in purple) coming from the diffuse intra-cluster medium of the galaxy cluster CL J1449+0856 as detected by XMM-Newton.

The X-ray signal is superimposed onto a composite image of very long exposures taken at near-infrared wavelengths with ESO's Very Large Telescope in Chile and the Subaru telescope on Hawaii. Most of the objects visible in the field are very faint and distant galaxies: the galaxy cluster is visible as a clump of faint, red objects near the centre.

Located at a redshift z~2, CL J1449+0856 is the most distant mature cluster ever detected.

The cluster luminosity (L) is approximately 7 × 10⁴³ erg/s in the soft X-ray energy range (0.1-2.4 keV), and corresponds to a temperature of 2 keV (about 23 million Kelvin) and an estimated mass of 5-8 × 10¹³ solar masses.

The region depicted above is about 100 arc minutes on a side.