资源描述：
《The star formation history of resolved galaxies Composite H-R diagram》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。
1、Stars,GasandDustinGalaxies8ASPConferenceSeries,Vol.3×10,2000D.Alloin,G.Galaz&K.Olsen,eds.Thestarformationhistoryofresolvedgalaxies:CompositeH-Rdiagram.CarmeGallartAndesFellow.AstronomyDept.YaleUniversity.P.O.Box208101.NewHaven,CT06520-8101,USAandDepartamentodeAstronom´ıa,UniversidaddeChile.
2、Casilla36-D.LasCondes.Santiago.ChileAbstract.Idiscusstheinformationprovidedbycolor-magnitudedi-agramsofdifferentabsolutemagnitudelimitsinthestudyofthestarformationhistoriesofnearbygalaxies.Ireviewtherecentprogressmadeinthefield,withemphasisontheresultsforLocalGroupdwarfgalaxies.1.Introduction
3、WecanstudytheevolutionofthenearestgalaxiesinexquisitedetailfromtheinformationcontainedintheH-Rdiagram-orColor-MagnitudeDiagram,CMD-oftheirresolvedstars.Fromit,itispossibletoretrievethestarformationandchemicalenrichmenthistories(SFHandZ(t)),withalevelofdetailthatmainlydependsonthemagnitudeli
4、mitoftheavailableCMD.ForCMDsreachingtheoldestmain-sequence(MS)turnoffs,itispossibletobreaktheage-metallicitydegeneracythataffectsmostmethodsofretrievingSFHs.EvenifwecanpursuethiskindofstudyonlyinaverylimitedvolumeoftheUniverse,itisaworthwhiletask,keytounderstandgalaxyformationandevolutioninge
5、neral,because:•Inourneighborhood,wehaverepresentativesofalmostanykindofgalax-iesintheUniverse:intheLocalGrouptherearethreespirals,andalargenumberofdwarf-bothdIranddSph-galaxies;thenearestgE,NGC5128isatarXiv:astro-ph/0007239v117Jul2000≃4.0Mpc,andsimilarly,thenearestBCDandLSBgalaxiesareintheM
6、81group,alsoat≃4.0Mpc.Inaddition,bystudyingthedetailsoftheSFHsinthenearestgalaxies,wemaybeabletoidentifytheevolvedcounterpartsofdistantobjectsthatareexperiencingcharacteristicstarformingepisodes.•Thiskindofstudyprovidesdetailedinformationonthefirsteventsofstarformationinthenearestgalaxies.Th
7、erefore,wecanaddressquestionslike“havetheoldeststarsingalaxiesallthesameage?”or,“aretheredifferences,intheepochorstrengthoftheearlystarformation,dependingonenvironment”.•Wecantestthehypothesisofgalaxiesbeingassembledbymergingthroughthealmostdirectobservat
