G a la c ti c s u p e rn o v a e

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9–1

1 0 . S u p e rn o v a e

9–2 Supernovae1

H is to ri c a l S u p e rn o v a e

Novae=newstars,alsotermedgueststars(Chinese) Novaeincreaseinmagnitudetypicallyby15mag. Supernovae(termcoinedbyBaade&Zwicky,1934)by20mag ThegueststarofAD393,Wang,Qu&Chen1997,A&A318,L59

9–3 Supernovae2

H is to ri c a l S u p e rn o v a e

TychoBrahe’sSupernova1572JohannesKepler’sSupernova1604 9–4 Supernovae3

G a la c ti c s u p e rn o v a e

Yearofconstellationmagnitudevisibility appearancemonths 185Centaurus-86? 386Sagittarius+1.5 393Scorpius0 1006Lupus-7.524 1054Taurus-624 1181Cassiopeia06 1572Cassiopeia-616 1604Ophiuchus-312 1667Cassiopeiaobscured-

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9–5 Supernovae4

E x tr a g a la c ti c S u p e rn o v a e

SAndromedae=Supernova1885intheAndromedagalaxy ErnstHartwig(Dorpat=Tartu) 20.8.1885:discoveryofSAnd 1.1.1886:directorofRemeisobservatory Bamberg SN1994d(HSTWFPC)

9–7 Supernovae6

E x tr a g a la c ti c S u p e rn o v a e

TypeIISN2001cminNGC5965(2.56mNOT,HåkonDahle;NORDITA) 9–8 Supernovae7

E x tr a g a la c ti c S u p e rn o v a e

LightcurvesofSNeIallvery similar,SNeIIhavemuchmore scatter. SNeII-L(“linear”)resemble SNeI SNeII-P(“plateau”)haveconst. brightnesstowithin1mag forextendedperiodoftime.

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9–9 Supernovae8

E x tr a g a la c ti c S u p e rn o v a e

Roughclassification(Minkowski,1941): TypeI:nohydrogeninspectra; subtypesIa,Ib,Ic TypeII:hydrogenpresent,subtypes II-L,II-P Note:pre1985subtypesIa,Ibhaddifferentdefinition thantoday=⇒bewarewhenreadingoldertexts. 9–10 Supernovae9

S N -s p e c tr a

SNTypI:NohydrogenBalmerlines TypIa:Earlyphase:Ca,Fe,S,O,strongabsorptionat6150Å(SiII6347/6371Å). LatePhase:Fe,Co-emissionlines TypIb:EarlyPhase:NoSiII-absorptionat6150ÅstrongHeI-absorptionlines Latephase:Ca,O-emissionlines TypIc:Earlyphase:noSiII-absorptionat6150Å Latephase:Ca,O-emissionlines SNTypII Earlyphase:strongBalmerlines Latephase:Balmerlinesremain,otherwisesimilartoSNIb/Ic,butlinesare weaker

9–11 Supernovae10

S N -s p e c tr a

9–12 Supernovae11

S N -s p e c tr a

http://supernova.lbl.gov/~dnkasen/tutorial/p-cygni/pcygni_form.jpg Dopplerblueshifts≈20000km/s

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9–13 Supernovae12

S u p e rn o v a S ta ti s ti c s

Clueonoriginfromsupernovastatistics: •SNeII,Ib,Ic:neverseeninellipticalgalaxies,whicharevoidofgasandhave nonewstarformation;generallyassociatedwithspiralarmsandHIIregions inspiralgalaxies,i.e.,withstarformingregions =⇒progenitorofSNeII,Ib,Ic:massivestars(&8M⊙)=⇒“corecollapse supernova” •SNeIa:alltypesofgalaxies,comingfrombothyoungandoldstellar populations. =⇒stellarprogenitorsofSNeIacannotbemassivestars,becausesuchstars donolongerexistinoldstellarpopulations. 9–16 Supernovae15

S N 1 9 8 7 a

SN1987AintheLargeMagellanicCloud,February23,1987 •distancewellknown=50kpc •visibletothenakedeye(Vmax=4.5),firstafter300yrs •forthefirsttimeitwaspossibletoidentifytheprogenitorstar •progenitorSanduleak-69202=massivestar,i.e.bluesupergiant •supportscorecollapsemodel •lightcurvehasbeenmeasuredover20yrs,presentlyV=21mag •spectralchangeshavebeenmonitoredovermanyyears

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9–17 Supernovae16

S N 1 9 8 7 a

Expandingenvelopeispowerbyradioactivedecayofshortlivedisotopes createdinthecorecollapse 9–18 Supernovae17

S N 1 9 8 7 a

ExpandingenvelopeofSNepoweredbyradioactivedacay 56 Ni−→56 Co+e+ +νe+γτ1/2=6.1d 56 Co−→56 Fe+e+ +νe+γτ1/2=77.7d 22Naτ1/2=2.6a 44Tiτ1/2=47a Slopeoflightcurve: SNII,SNIb,SNIc:0.01mag/d⇔56Cohalflife SNIa:0.015mag/d⇔decreasingefficiencyofconversionofγ-radiationintovisiblelight.

9–19 Supernovae18

S N 1 9 8 7 a

BolometriclightcurveofSN1987a Modellingyields 0.075M⊙56 Nibzw.56 Co 0.009M⊙57 Co 1·10−4 M⊙44 Ti 2·10−6 M⊙22 Na 9–20 Supernovae19

S N 1 9 8 7 a

Directdetectionofγ-rayemissionfromthe56 CodecayinSN1987a Truelleretal.1990,ApJ351,41 60Coγtransitionsat847keVand 1238keVdetectedbyballoon-borne experiments.

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9–21 Supernovae20

S N 1 9 8 7 a : lig h t e c h o s

9–22 Supernovae21

L ig h t e c h o s

•Lightechosareproducedwhenaflashisreflectedbyinterstellardust •Lightfromtheflashreachestheobserverfirstwhilethereflectedlightreaches theobserverafterwards •Reflectionthroughscatteringandabsorption/re-emission

9–23 Supernovae22

L ig h t e c h o s

9–24 Supernovae23

T y c h o s S u p e rn o v a

•Tychofoundthatthe"newstar"must liefarbeyondtheMoon. ⇒greatcontradictiontotheviewthat theskyisfixed •FromhistoricaldatafollowstypeIa butlightcurvescannotexcludetype IborII-L •OneofthebestcandidatesfortypeIa intheMilkyWayduetoitsproximity

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9–25 Supernovae24

T y c h o ’s S N : P h o to m e tr y

Restetal.2006,ApJ681,L81 9–26 Supernovae25

T y c h o ’s S N : S p e c tr o s c o p y

Krauseetal.2008,Nature456,617 Spectrumofasupernovathatexploded1572

9–27 Supernovae26

T y c h o ’s S N : S p e c tr o s c o p y

Tycho’SNfrom1572wasanormalSNIa 9–28 Supernovae27

N e u tr in o s fr o m S N 1 9 8 7 a

Neutrinosdetectedas predictedbycorecol- lapsemodelCernCourier

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(ESOVLT/FORS2) Crabnebula:youngremnantofSNof1054,observedlightdueto synchrotronradiation(radiationemittedbyelectronsacceleratedin magneticfield) 5000–10000yearoldIC1340/VeilNebula/CygnusLoop(cLokeKunTan) Oldersupernovaremnants:“wispystructure”duetointeractionwith interstellarmedium,radiation(lineemission)mainlycausedby heatingduetoshocks.