Back to Volume
Paper: The Impact of Galaxy Evolution on Galaxy Systems
Volume: 176, Observational Cosmology: The Development of Galaxy Systems
Page: 64
Authors: Ponman, Trevor J.; Helsdon, Stephen F.; Finoguenov, Alexis
Abstract: The injection of hot, metal-rich gas into the intergalactic medium (IGM) by forming galaxies leaves clear signatures in the X-ray properties of galactic systems. The additional energy has most impact on low mass systems, which have lower virial temperatures, and pushes gas outwards, flattening the X-ray surface brightness profile. By comparing X-ray profiles across a range of system masses, we find direct evidence for such a trend in properties. This effect reduces the X-ray luminosity, and a study of loose groups confirms the trend found previously in compact groups, for the X-ray L:T relation to steepen substantially relative to the cluster trend in low mass systems. Using data from the ASCA SIS, the abundances of several different metals can be mapped in the brightest galaxy groups. This enables the contribution to metal enrichment from supernovae of type Ia and type II to be distinguished. The picture which emerges is one in which energy, predominantly from SNII, is injected into the IGM before cluster collapse. This preheats the gas and inhibits its collapse to high central density in galaxy groups.
Back to Volume