3C 438 is a member of a
galaxy 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 the
Chandra X-ray Observatory to have hot
intergalactic gas, with a temperature of about 11
KeV, which when discovered in 2007 was the highest ever found, slightly hotter than the
Bullet 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]
^Hardcastle, M. J.; Alexander, P.; Pooley, G. G.; Riley, J. M. (11 July 1997). "High-resolution observations at 3.6 cm of seventeen FR II radio galaxies with 0.15". Monthly Notices of the Royal Astronomical Society. 288 (4): 859–890.
doi:
10.1093/mnras/288.4.859.
^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.