Observational Evidence of AGN Feedback PDF
Preview Observational Evidence of AGN Feedback
Introduction TheradiativeorWindMode ThekineticMode BaryonProfilesmassscalesandAGNfeedback Futurestudies Summary Observational Evidence of AGN Feedback AndyFabian 10demaiode2012 AndyFabian ObservationalEvidenceofAGNFeedback Introduction TheradiativeorWindMode ThekineticMode BaryonProfilesmassscalesandAGNfeedback Futurestudies Summary Sumário Introduction TheradiativeorWindMode AGNwinds Galaxyoutflows FromthepeaktothelateevolutionofAGNandquasars Mergersorsecularevolution? ThekineticMode StrongEvidences Heating/CoolingBalance Cool,ColdGasandStarFormation Theevolutionofcoolcoreinclusters Themostluminousclusters Hotgasingroupsandellipticalgalaxies BaryonProfilesmassscalesandAGNfeedback Futurestudies Summary AndyFabian ObservationalEvidenceofAGNFeedback Introduction TheradiativeorWindMode ThekineticMode BaryonProfilesmassscalesandAGNfeedback Futurestudies Summary The AGN feedback ◮ Theinteractionprocessbetweentheblackholeatthecentreofagalaxyandthe galaxyisknownasAGNfeedback. ◮ Ittakesplacethroughaninteractionbetweentheenergyandradiationgenerated byaccretionontothemassiveblackholeandthegasinthehostgalaxy. ◮ Thedetailsofthefeedbackarecomplexandtheobservationalevidenceisnot alwaysclear. AndyFabian ObservationalEvidenceofAGNFeedback Introduction TheradiativeorWindMode ThekineticMode BaryonProfilesmassscalesandAGNfeedback Futurestudies Summary Kinds of AGN feedback ◮ Twomajormodeshavebeenidentified,differentiatedbythenatureoftheenergy outflowneartheblackhole: ◮ theradiativemode(quasarorwindmode):whentheaccretingblackholewasclose totheEddingtonlimit. ◮ thekinecticmode(radiojetormaintencemode):whenthegalaxyhasahothalo andtheaccretingblackholehaspowerfuljets. AndyFabian ObservationalEvidenceofAGNFeedback Introduction TheradiativeorWindMode ThekineticMode BaryonProfilesmassscalesandAGNfeedback Futurestudies Summary Effects ◮ Thegrowthofthecentralblackholebyaccretioncanhaveaprofoundeffectonits hostgalaxy. ◮ Accretionenergydoesn’tsignificantlyaffectthestaralreadyexisting,butitcan couplestronglywiththegasfromwhichnewstarforms. ◮ ThereislittleornoevidenceatthepresenttimeforAGNfeedbackoperatinginlow massgalaxieswherestellarfeedbackisimportant. ◮ TheclearestobservationalevidenceforAGNfeedbackisfoundinthemost massivegalaxiesknown,BCGincoolcoreclusters. ◮ AGNfeedbackisarelativelyyoungtopic,andawiderangeofargumentand opinionhasbeenexpressed. AndyFabian ObservationalEvidenceofAGNFeedback Introduction TheradiativeorWindMode AGNwinds ThekineticMode Galaxyoutflows BaryonProfilesmassscalesandAGNfeedback FromthepeaktothelateevolutionofAGNandquasars Futurestudies Mergersorsecularevolution? Summary Accretion in galaxies ◮ Theequationwhichcanpreventtheaccretionintoagalaxyatthemaximum possibleratebyaquasarattheEddingtonlimitis: fσ4σ MBH = πG2mTp (1) whereσ istheThomsoncrosssectionforelectronscatteringandfisthefractionof T thegalaxymassingas. ◮ TheagreementthatthissimpleformulagiveswiththeobservedMBH−σrelation canbeinterpretedas(weak)observationalevidenceforAGNfeedback. AndyFabian ObservationalEvidenceofAGNFeedback Introduction TheradiativeorWindMode AGNwinds ThekineticMode Galaxyoutflows BaryonProfilesmassscalesandAGNfeedback FromthepeaktothelateevolutionofAGNandquasars Futurestudies Mergersorsecularevolution? Summary ◮ Ifthemaininteractionisduetowinds,nottoradiationpressure,thenthewind needstohaveahighcolumndensityN,highvelocityν,highcoverginfractionfall atlargeradiusr.Thekineticluminosityofawindis: Lw = f r ν 3 N (2) LEDD 2rg (cid:18)cc(cid:19) NT ◮ ToproduceMBH ∝σ4scalingthethrustofthewindneedstobeproportionalto theEddingtonlimit. ◮ ThecommonestwayinwhichAGNwindsareobservedisbylineabsorptionofthe quasarcontinuumbyinterveningwindmaterial. ◮ Generally,goodevidenceforAGNwindsoccursinunobscuredAGN,wherethe UVspectrumcanbedirectlyseen. AndyFabian ObservationalEvidenceofAGNFeedback Introduction TheradiativeorWindMode AGNwinds ThekineticMode Galaxyoutflows BaryonProfilesmassscalesandAGNfeedback FromthepeaktothelateevolutionofAGNandquasars Futurestudies Mergersorsecularevolution? Summary Galaxy outflows ◮ EvidencesofAGNfeedbackisclearlyseen insomegalacticoutflows. ◮ AnimportantobjectwhereboththeAGN andouftlowareseenisthelowredshift,z= 0.04,quasar/mergerMrk231. ◮ Ithaveavelocityof∼1100kms−1andan ouflowrateof420M⊙yr−1,severaltimes greaterthanthestarformationrate. AndyFabian ObservationalEvidenceofAGNFeedback Introduction TheradiativeorWindMode AGNwinds ThekineticMode Galaxyoutflows BaryonProfilesmassscalesandAGNfeedback FromthepeaktothelateevolutionofAGNandquasars Futurestudies Mergersorsecularevolution? Summary The downsizing of AGN ◮ Itwasanimportantdiscovery. ◮ ThemostluminousandmassiveAGNweremostnumerousatreshiftsof2-2.5, theless-luminouspeakedatsuccessivelylowerredshiftswiththeleastluminous peakingaroundredshiftone. ◮ DownsizingofAGNwasfirstseeninX-raysurveys. ◮ ThebehaviouristheoppositeofwhatissimplypredictedinahierarchicalCDM universe,wherethemostmassiveobjectsformlast. ◮ Itindicatesthatsomethingisquenchingquasarbehaviourandthemostwidely acceptedsolutionisthatisisduetoAGNfeedback. AndyFabian ObservationalEvidenceofAGNFeedback Introduction TheradiativeorWindMode AGNwinds ThekineticMode Galaxyoutflows BaryonProfilesmassscalesandAGNfeedback FromthepeaktothelateevolutionofAGNandquasars Futurestudies Mergersorsecularevolution? Summary ◮ Manytheoreticalmodelsforquasarevolutionarebasedongalaxy-galaxymergers beingthetriggerforgasinfallontoablackhole. ◮ ButtheevidenceforthemtriggeringAGNisweak. ◮ Theevidenceisbuildingthatbetweenredshiftsof2andthecurrentepoch,much oftheevolutionofAGNissecular. AndyFabian ObservationalEvidenceofAGNFeedback
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