Study of Poor Cluster of Galaxies with X-ray

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Following new results were obtained from the observations of early type galaxies with ASCA.1.X-ray spectrum consists of a low temperature plasma component and a hard component. 2.The hard component is dominated by LMXB.3.Abundances of heavy elements are about a half solar value. 4.A positive correlation is seen between X-ray luminosity and temperature of the plasma component. ASCA observation of M87 at the center of the Virgo cluster of galaxies shows as follows ; 1.X-ray emitting plasma in M87 consists of a high temperature component bounded by the cluster gravity and a low temperature component bounded by M87.2.Apparent iron concentration at the M87 center is seen. Heavy metals contained by poor clusters are thought to be ejected from primordial-galaxies. Starburst galaxies are proto-type of such early phase of galaxies. Observations of the starburst galaxy M82 shows following results ; 1.Oxygen lines expected to be synthesized by type II SN are weak. 2.Iron abundance is low. 3.On the other hand, silicon and sulfa are rich. 4.The results indicate that the origin of metals in poor clusters cannot be explained simply by ejection from starburst galaxies. The observation of a distant poor cluster of galaxies MS0839.8 at z=0.194 shows the following results ; 1.No difference on temperature and X-ray luminosity between near and distant clusters is seen. 2.The result implies no strong evolution has not been occurred from z=0.2 until the present.