Coma Cluster: Hot and Cool Mixture

Publications of the Astronomical Society of Japan

Ishizaka, Chiharu¹  Mineshige, Shin¹ 

[1] Department of Astronomy, Faculty of Science, Kyoto University, Sakyo-ku, Kyoto 606-01

关键词: "Clusters of galaxies: individual (Coma cluster)";    "Galaxies: intergalactic medium";    Hydrodynamics;   

DOI  :  10.1093/pasj/48.3.L37

学科分类：天文学(综合)

来源: Oxford University Press

【 摘 要 】

ASCAhasrevealedarathercomplextemperaturestructureintheintraclustermedium(ICM)aroundtheComacluster.Significantly,hotparts(withkT≥10keV)arelocatedfar(∼1Mpc)distantfromboththecenteroftheComaclusterandthegalaxygroupNGC4839.Therealsoexistrelativelycoolregions(withkT≲5keV).UsingN-body+Hydrodynamicsimulations,wehavedemonstratedthatsuchanobservedtemperaturedistributionisnaturallyaccountedforifthesubgroupNGC4839passedthroughthecenteroftheComaclusterabout1Gyrago,whichwasfirstproposedbyBurnsetal.WhenthesubclusterpassedthroughtheComacluster,theICMinthesubclusterwascompressedduetotherampressurebytheICMintheComa,andthereformedabowshockwithanarcshapejustbetweenthetwocenters.TheICMhasthusbeenheatedthere,emittinghardradiation.ApartoftheICMisreflectedbytheshockfront,andflowsbackward(withrespecttothedirectionofthesubclustermotion)aroundtheComaclustercenter,beingcooledduetoanadiabaticexpansion.Afterdetouringthecenter,cooledgascollideswitheachotherattheoppositesideoftheComacluster(totheplaceofthesubcluster),producinganotherhotregion.ThesesimulatedfeaturesareingoodagreementwithwhatASCAfound.Further,wepresentratheruniquefeaturesinthetemperatureprofilesthatcanbecausedbyamerger(oranencounter)withasubgroupofgalaxies.

【 授权许可】

Unknown