3C 438 is a member of agalaxy cluster and three galaxies are located close to it, the closest one being 4 arcseconds to the northeast.[5] The galaxy cluster has been found when observed by theChandra X-ray Observatory to have hotintergalactic gas, with a temperature of about 11KeV, which when discovered in 2007 was the highest ever found, slightly hotter than theBullet Cluster.[6] The high temperature is the result of the merger of two galaxy clusters, as the relative movement of one subcluster has created a bow shock in the hot gas.[7]
^Madrid, Juan P.; Chiaberge, Marco; Floyd, David; Sparks, William B.; Macchetto, Duccio; Miley, George K.; Axon, David; Capetti, Alessandro; O’Dea, Christopher P.; Baum, Stefi; Perlman, Eric; Quillen, Alice (June 2006). "Hubble Space Telescope Near-Infrared Snapshot Survey of 3CR Radio Source Counterparts at Low Redshift".The Astrophysical Journal Supplement Series.164 (2):307–333.arXiv:astro-ph/0603239.Bibcode:2006ApJS..164..307M.doi:10.1086/504480.S2CID118882508.
^Kraft, R. P.; Forman, W. R.; Hardcastle, M. J.; Jones, C.; Nulsen, P. E. J. (1 August 2007). "The Disturbed 17 keV Cluster Associated with the Radio Galaxy 3C 438".The Astrophysical Journal.664 (2):L83 –L86.arXiv:0706.4014.Bibcode:2007ApJ...664L..83K.doi:10.1086/520955.S2CID17918659.
