X-ray emission from filament gas between Abell 3391 and Abell 3395
X-ray emission from gas residing in a filament has been discovered by Mark Henriksen and myself. The gas lies between the clusters Abell 3391 and Abell 3395 (z=0.05). ASCA GIS and SIS data detected the gas with an observation aimed between the clusters.
The detection of emission from filamentary gas is a significant discovery, since warm gas in the intercluster medium is believed to harbor up to 80% of the baryons in the universe. There has never been a confirmed detection of emission from intercluster gas in a filament at any wavelength.
The A3391-A3395 system is aligned along the line of sight which leads to a longer emission column than would otherwise be possible. This alignment effectively raises the surface luminosity to detectable levels.
Given the inclination of the system of about 10 degrees, the clusters are about 30 Mpc apart. There is evidence that the pair are part of a larger system containing MS 0620.6-5239 and Abell 3380. This linear arrangement of clusters spans 7 degrees on the sky and extends 60 Mpc in length.
The results are to be published in the December 20 volume of Astrophysical Journal.
Figure 1 X-ray emission from intercluster gas in a filament between galaxy clusters Abell 3391 and Abell 3395.