cl.clus pw index.php,RXTE and ASCA Constraints on Non-thermal Emission from the A2256 Galaxy Cluster
An 8.3 hour observation of the Abell 2256 galaxy cluster using the Rossi X-ray Timing Explorer proportional counter array produced a high quality spectrum in the 2 - 30 keV range. Joint fitting with the 0.7 - 11 keV spectrum obtained with the Advanced Sate
RXTEandASCAConstraintsonNon-thermalEmissionfromthe
A2256GalaxyCluster
MarkHenriksen
arXiv:astro-ph/9903311v1 20 Mar 1999
PhysicsDepartment,UniversityofNorthDakota,GrandForks,ND58202-7129
mahenrik@plains.NoDak.edu
ABSTRACT
An8.3hourobservationoftheAbell2256galaxyclusterusingtheRossiX-rayTimingExplorer(RXTE)proportionalcounterarray(PCA)producedahighqualityspectruminthe2-30keVrange.Joint ttingwiththe0.7-11keVspectrumobtainedwiththeAdvancedSatelliteforAstrophysicsandCosmology(ASCA)GasImagingspectrometer(GIS)givesanupperlimitof～2.3×10 7photonscm 2sec 1keV 1fornon-thermalemissionat30keV.Thisyieldsalowerlimittothemeanmagnetic eldof0.36µGandanupperlimitof1.8×10 13ergscm 3forthecosmic-rayelectronenergydensity.Theresultinglowerlimittothecentralmagnetic eldis～1-3µG.Whileamagnetic eldof～0.1-0.2µGcanbecreatedbygalaxywakes,amagnetic eldofseveralµGisusuallyassociatedwithacooling owor,asinthecaseoftheComacluster,asubclustermerger.However,forA2256,theevidenceforamergerisweakandthemainclustershowsnoevidenceofacooling ow.Thus,thereispresentlynosatisfactoryhypothesisfortheoriginofanaverageclustermagnetic eldashighas>0.36µGintheA2256cluster.Subjectheadings:galaxies:clusters:individual(A2256)–galaxies:intergalacticmedium–galaxies:magnetic elds–X-rays:galaxies