Active Galaxies and Clusters of Galaxies
X-ray observations of clusters of galaxies have shown that the entropy of the intracluster medium (ICM), is higher than that expected from gravitational processes. This is believed to be the result of nongravitational processes. We discuss the role of active galaxies in clusters in changing the entropy of the ICM. A central AGN can inject buoyant bubbles into the ICM, and heat it up by doing pdV work as they rise and expand. Energetic particles from AGN can also increase the entropy by coulomb interaction with the ICM, and this process can also explain the abundance of 6Li in halo metal poor stars. We then discuss the implications of a recent radio obser vation of four poor clusters with enhanced entropy. The upper limit on the emission at low frequency supports the pre-heating scenario in which ICM is heated before the assembly of galaxy cluster.
ISM molecules ISM structure instabilities
Biman B. Nath
Raman Research Institute, Sadashiuanagar, Bangalore 560080, India
国际会议
The 10th Asian-Pacific Regional International Astronomical Union Meeting(第十届亚洲及太平洋地区天文学大会 APRIM)
昆明
英文
248-251
2008-08-03（万方平台首次上网日期，不代表论文的发表时间）