Wide-Band X-Ray Spectra and Images of the Starburst Galaxy M82

摘要

TheASCAresultsofthestarburstgalaxyM82arepresented.TheX-raysinthe0.5a€“10keVbandexhibitathinthermalspectrumwithemissionlinesfromhighlyionizedmagnesium,silicon,andsulfur,aswellasahardtailextendingtohigherthan10keVenergy.ThesoftX-raysarespatiallyextended,whilethehardX-raysshowanunresolvedpoint-likestructurewithpossiblealong-termfluxvariability.Thefluxratiooftheemissionlinesandthespatiallyextendedstructureinthelow-energybandindicatethatatleasttwo-temperaturethinthermalplasmasarepresent.Theabundancesoftheoxygen,neon,magnesium,silicon,sulfur,andironinthethinthermalplasmasarefoundtobesignificantlylowerthanthecosmicvalue.Neithertype-Ianortype-IIsupernovaexplosionscanreproducetheobservedabundanceratio.TheoriginoftheunresolvedhardX-raysisuncertain,butisprobablyanobscuredlow-luminosityAGN.