Small-scale structure of dark matter and microlens

astro-ph/980131430Jan1998Abstract.Ithasbeenrevealedusingmicrolensingthatacon-siderablepart,possiblymorethanhalf,ofthedarkmatterinthehaloofourGalaxyconsistsofobjectswithamassspectrumrangingfrom0.05to0.8ofthesolarmass.Whatisthenatureoftheseobjects?Thereexisttwohypotheses.Accordingtoone,theseareJupitertypeplanetsorsmallstars(brownandwhitedwarfs)consistingofnormalbaryonicmatter.Accordingtotheother,thesearenon-compactobjects,i.e.,small-scaleforma-tionsinnon-baryonicdarkmatter.Here,atheoryisproposeddescribingthepossibilityoftheexistenceofnon-compactob-jectsinthehaloofourGalaxy,theirstructureandformationfromnon-baryonicmatter.Thetheoryofmicrolensingoncom-pactandnon-compactobjectsisconsideredindetail.Theresultsofmicrolensingobservationsaredescribedandcomparedwiththeory.Possibleastrophysicalmanifestationsofthepresenceofsmall-scalestructurearepointedout.Thefieldisbeingexten-sivelystudiedandisoffundamentalinterestforcosmologyandastrophysics.1.IntroductionObservationsshowthatthegreaterpart(over90%)ofthematterintheUniverseismadeupofinvisible(dark)matter[1],anditremainsunknownwhatparticlesitconsistsof.Fromanalysisoftheprocessesofprimarynucleosynthesisandgalaxyformationitfollows,however,thatdark-matterparticlesmustbeofnon-baryonicoriginandmustinteractratherweaklybothamongthemselvesandwithbaryonicmatter.Theseparticlesaretypicallyassumedtobeeitherthehypotheticalheavyparticlespredictedbysupersymmetrytheory(customarilyreferredtoasneutralinos),orlightaxions,orcosmicstrings.Theyallmayconstitutetheso-calledcolddarkmatter(CDM)[2,3].Non-dissipativedarkmatterplaysadecisiveroleintheformationofthelarge-scalestructureoftheUniverse,i.e.,galaxies,clustersofgalaxies,andsuperclusters.AttheAVGurevich,KPZybin,VASirotaPNLebedevPhysicsInstitute,RussianAcademyofSciences,Leninski|flprosp.53,117924Moscow,RussiaTel.(7-095)1326414,1326050,1326171E-mail:[e-mail],[e-mail],[e-mail]8April1997UspekhiFizicheskikhNauk167(9)913–943(1997)TranslatedbyMVTsaplina;editedbyLVSemenovaREVIEWSOFTOPICALPROBLEMSPACSnumbers:95.35.+d,98.35.–aSmall-scalestructureofdarkmatterandmicrolensingAVGurevich,KPZybin,VASirotaContents1.1.IntroductionIntroduction8698692.2.Minimaldark-matterobjectsMinimaldark-matterobjects8708702.1Primaryspectrumcut-off;2.2Lineargrowthoffluctuations;2.3Massoftheminimaldark-matterobjects;2.1Primaryspectrumcut-off;2.2Lineargrowthoffluctuations;2.3Massoftheminimaldark-matterobjects;2.4Scaleoftheminimalobjects2.4Scaleoftheminimalobjects3.3.HierarchicalstructureHierarchicalstructure8738733.1Clustering;3.2Thelifetimeofentrappedobjects;3.3Destructionofobjectsinthehierarchicalstructure;3.1Clustering;3.2Thelifetimeofentrappedobjects;3.3Destructionofobjectsinthehierarchicalstructure;3.4Small-scalestructure—themainhypothesis;3.5Lifetimeofsmall-scaleobjectsintheGalaxy3.4Small-scalestructure—themainhypothesis;3.5Lifetimeofsmall-scaleobjectsintheGalaxy4.4.Structureofnon-compactobjectsStructureofnon-compactobjects8778774.1Coefficientofnonlinearcompression;4.2Densitydistributioninnon-compactobjects;4.3Influenceof4.1Coefficientofnonlinearcompression;4.2Densitydistributioninnon-compactobjects;4.3Influenceofbaryoniccomponentonthestructureofnon-compactobjects;4.4Structureofnon-compactobjectsinthehalo;baryoniccomponentonthestructureofnon-compactobjects;4.4Structureofnon-compactobjectsinthehalo;4.5Non-compactobjectsintheGalacticdisc4.5Non-compactobjectsintheGalacticdisc5.5.Theoryofmicrolensingonnon-compactobjectsTheoryofmicrolensingonnon-compactobjects8808805.1Microlensingoncompactbodies;5.2Microlensingonnon-compactobjects;5.3Comparisonoflightcurves5.1Microlensingoncompactbodies;5.2Microlensingonnon-compactobjects;5.3Comparisonoflightcurvescreatedbycompactandnon-compactlenses;5.4Influenceofthebaryoniccoreonthelensingcurveforanon-createdbycompactandnon-compactlenses;5.4Influenceofthebaryoniccoreonthelensingcurveforanon-compactobject;5.5Opticaldepthcompactobject;5.5Opticaldepth6.6.Microlensing—resultsofobservationsandcomparisonwiththetheoryMicrolensing—resultsofobservationsandcomparisonwiththetheory8858856.1Microlensingofobjectsinthehaloandthecentralpart(bulge)oftheGalaxy;6.2Resultsofobservationsinthe6.1Microlensingofobjectsinthehaloandthecentralpart(bulge)oftheGalaxy;6.2Resultsofobservationsinthehalo;6.3Comparisonofthedataofobservationsinthehalowiththetheoryofmicrolensingonnon-compacthalo;6.3Comparisonofthedataofobservationsinthehalowiththetheoryofmicrolensingonnon-compactobjects;6.4ResultsofobservationsinthecentralregionoftheGalaxyandacomparisonwiththeoryobjects;6.4ResultsofobservationsinthecentralregionoftheGalaxyandacomparisonwiththeory7.7.NeutralinostarsNeutralinostars8898897.1Extragalacticdiffusivegamma-radiation;7.2Diffusivegamma-radiationfromthegalactichalo;7.3Diffusive7.1Extragalacticdiffusivegamma-radiation;7.2Diffusivegamma-radiationfromthegalactichalo;7.3Diffusivegamma-radiationoftheGalaxy;7.4Discretesourcesofgamma-radiation;7.5Galaxiesasdistributedsourcesofgamma-radiationoftheGalaxy;7.4Discretesourcesofgamma-radiation;7.