what powers the brightest supernovae? time-domain astronomy a data driven revolution Palomar-48 inch optical ASASSN-15lh superluminous PTF-13ajg supernovae scp06f6 2005ap ptf09cnd 2008es 2006gy 2007bi type Ia ordinary core collapse supernovae ultra-long duration gamma-ray bursts levan et al 2014 Two ways to blow up a massive star gravity thermonuclear powered by core collapse to powered by runaway nuclear burning neutron star or black hole no compact object formed hongfeng Yu Argonne NL F. Ropke MPA Type I - no hydrogen spectral classification: Type II - hydrogen evolution of a shock light curve core collapse supernova breakout H envelope SN shock He core C/O core ? shock revival core collapse shock stall Fe core fallback accretion neutrino neutron star spindown? GW emission cooling neutron star bounce pre-bounce Core collapse supernova simulation 2D neutrino powered explosion Austin Harris (LBNL) with ORNL Chimera code core collapse supernova energetics ordinary case gravitational energy released in neutron star formation 2 GM 53 Eg GM 2 10 ergs ⇡ Rns ⇡ 53 Eg 2 10 ergs energy of supernova⇡ GMR explosionns ⇡ (kinetic53 and thermal energy) Eg Mni✏ni 10 ergs R td/tni Lni⇡ 1 ns 2 ⇡ e−51 Eke ⇡Mvtni 10 ergs ⇡ 21 2⇡ 51 Eke Mv 10 ergs total energy radiated⇡ 2 in ordinary⇡ supernova light curve M M10 ✏ 15 M ni ni td/tni L ⇡ − e−49 Elcni L∆t 10 ergs ⇡⇡ tni⇡ 42 43 1 L 10 10 ergs s− ⇡ − M M10ni✏ni15 Mtd/tni Lni ⇡ − e− ⇡ tni td 50 150 days 42 43 1 L 10⇡ −10 ergs s− ⇡M −10 15 M ⇡ − Esn 1 10 B td 4250⇡ 150−43 days 1 L 10⇡ −10 ergs s− ⇡ − 13 R? 10 cm Esn ⇡1 10 B td 50⇡ −150 days ⇡ − 1 R(t) − Eth(t)=E013 R? 10 Rcm Esn⇡ 1 100 B ⇡ − Esn Rsh 1 Rsh 45R(t) − 1 Lsn 10 13 ergs s− 4 ⇡ td ERthsn(tR)=?⇠E100 cm 10 R ⇡ R 0 4 15 E RshR 10 R 10 cm1 R sn sh⇡ 45⇡R(t) −1 sh Lsn Eth(t)=10E0 ergs s− 4 ⇡ td Rsn ⇠ R0 10 R 1 100 km s− tsh = Rsh/vsh =4 2 years 15 EsnRshRsh10 R 45 10 cmv1sh Rsh Lsn ⇡ 10 ⇡ergs s− 4 ⇡ td Rsn ⇠ 10 R Esn R? 45 1 R1? 100 km s− Lsn 4 10 ergs15 s− 4 tsh⇡=tRdRshsh/vRsnsh 10=⇠ 2R years 10 cm 10 R v ⇡ ⇡ sh R R M 1 Etdsn= ⌧R? = ⇢45R 1001 km sR−? Lsntsh = Rsh/vshc = 210 yearsergsc s⇠− Rc 4 ⇡ td Rsn ⇠ v 10 R sh M Esn RR? td R M R? L td = ⌧ =⇠⇢10(45Rvt)ergsc s 1 sn c c ⇠− Rc 4 ⇡ td R sn ⇠ 10 R 1/2 1/2 1/2 1/2 M M v − R M R M td 29 dayst 9 ⇠ vc td⇡= ⌧ d = M⇢R 0.1 10 c ✓⇠ (vt)◆c c ✓⇠ Rc◆ ✓ ◆ 1/2 1 2 511/2 1/2 1/2 M Esn Mv M10M ergs 1 B v − t ⇡292 daystd ⇡ ⌘ d ⇠ vc ⇡ ⇠M(vt)c 0.1 109 ✓ ◆ ✓ ◆ ✓ ◆ 2 4 1/2 L =4⇡R σSB1/T2 1/2 1/2 M 1 2 M 51 v − t Esn 29Mv days 10 ergs 1 B d ⇠ vc ⇡⇡ 2 ⇡M ⌘0.1 109 ✓ ◆ ✓ ◆ ✓ ◆ 1 1 1 credit: ASASSN Team 1051-1052 radiated energy! super-luminous supernova “ordinary” supernova superluminous supernova spectra Halpha Type II quimbySmith+ 2006et al. 2010 Type I Quimby+ 2007 Type I superluminous spectra SCP06f6 C/O model FeII CII/MgII OII/CII CII stripped envelope progenitor CIII/CII Howell, kasen, et al., 2013 supernova light curve basics debris expands at v ~ 0.03c, cools by pdV work at t ~ weeks-months r ~ 1015 cm ~ 100 AU ρ ~ 10-13 g cm-3 translucent reheated to engine T ~ 5000-20000 K ? Z Z-1 9 e+ L >~ 10 Lsun Υ radioactive decay νν 56Ni -> 56Co -> 56Fe supernova light curve basics light curve duration set by diffusion time the diffusion time of photons through optically thick remnant but since the remnant is expanding, R = vt solving for time (td ~ telapsed) e.g., arnett (1979) supernova light curve basics luminosity of the light curve energy loses for adiabatically expanding radiation (pdV work) simple estimate of emergent luminosity assuming diffusion time td ~ 106 s How to power a super-luminous supernova light curve dump in energy after the ejecta has expanded (at t ~ tdiff) so radiation can escape immediately • radioactivity: decay of freshly synthesized isotopes: e.g., 56Ni • shocks: interaction of the supernova ejecta with a dense surrounding medium • engines: later time energy injection from a central source (neutron star or black hole) Milisecond magnetar “Collapsar” Pulsational Pair instability Birth star: ~30-70 radioactivity ~1 MeV per 56Ni ASASSN-15lh need Mni >> Msun scp06f6 2005ap ptf09cnd 2008es 2006gy 2007bi ej = M MNi type Ia ej ordinary = 0.1 M core collapse MNi supernovae pair instability supernovae Rakavy, Shaviv, and Zinamon (1967), Bakrat, Rakavy, and Sack (1967) Bond, Arnett, and Carr (1984), Umeda and Nomoto (2001) Heger and Woosley (2002), Scannapeico et al 2005, Woosley (2007) progenitor masses M ~ 150-260 Msun H H He He Si/Mg C/O Si/O56 pairs trigger Ni e+/e- collapse and runaway thermonuclear burning total exposion energy: 1051- 1053 ergs radioactive 56Ni produced: 0-50 Msun pair instability light curve models M = 130 helium star M = 250 M = 250 blue supergiant red supergiant kasen, woosley, & heger (2011) type Ia type II pan, kasen, & Loeb (2012) ASASSN-15lh scp06f6 2004ap2005ap ptf09cnd 2008es He 2006gy BSG RSG 2007bi type Ia ordinary core collapse supernovae pair instability supernovae SN2007bi as a pair instability SN? Gal Yam et al., Nature (2009) helium stars bolometric New early time observations show rise too fast Nicholl et al 2013 shock powered light curves from interaction with circumstellar material eta carinae interacting“tamped” supernovae supernova models supernova ejecta slow moving debris at ~100 AU ejection ~2 years prior Mass loss from late stage nuclear burning? oxygen burning lasts ~1 year releases ~1052 ergs! Tap that energy somehow: convectively driven waves, burning instabilitiies, pair instability Quataert & Shiode (2012) Quataert, Fernandez, Kasen, et al (2016) Smith & Arnett (2014) Arnett & Meakin (2011) Woosley et al (2007) density colliding shell velocity toy model colliding shell supernovae ~30% efficiency of conversion of kinetic energy to light shell Esn = 1052 ergs Rsh = 1015 cm colliding shell model pair instability (100 Msun He star) 4 Smith et al. 482 SMITH ET AL. Vol. 686 signatures of interaction Fig. 3.— Lick Observatory spectra of SN 2006gy at two different epochs,correctedforarangeofassumedhost-galaxyreddening corresponding to thenarrow values of A Rlinelisted emission at right (Cardelli et al. 1989). This extinction is in addition to Galactic extinction of AR =0.43 mag. These are compared to the day 32 spectrum of the Type IIn SN2006tf(black)fromourdatabase,whichisaSNwithaspectrum similar to that of SNas 2006gy, in Type but seems II to SLSNe show little reddening. We adopt AR =1.25smith± 0.25 et mag al., for 2006, SN 2006gy; 2008 see text. Fig. 16.—Cartoon illustration of the components of SN 2006tf at about 60 days after discovery, during the decline from the main light-curve peak. The primary feature is the massive postshock shell of gas, composed of the swept-up opaque pre-SN envelope around the star ejected in the decade before core collapse. Most of the mass is in the cold dense shell (CDS), bounded by the forward shock ( FS) and the reverse shock ( RS). Diffusion of radiation from this shocked shell produces the main continuum photosphere (1) and the intermediate-width component of H . This shell expands at constant speed into the preshock CSM (dense wind of the progenitor). The interior of the shell is filled by freely expanding SN ejecta, the outermost parts of which are ionized by radiation (wavy lines) propagating inward from the reverse shock, exciting the broad He i and O i features seen in the spectrum. There is also a second photosphere (2) in the SN ejecta, which is fainter than the main photosphere and can only be seen if the main shell thins or develops clumps as time proceeds. Right: More detailed depiction of the postshock gas, including the clumpy structure that forms due to instabilities in the cold dense shell layer. The dashed line here represents the photosphere at some arbitrary early time, working its way from left to right through the clumpy CDS as the SN expands. When it reaches a dense clump, the recombination photosphere will proceed through that clump, but for the regions between clumps it will eventually break through, allowing an observer to see the underlying SN ejecta. needed to power the late-time luminosity (see previous point), shock by this time after explosion (Fig. 15). The broad features Fig. 4.— Dereddened visual-wavelength spectra ofand SN fully 2006gy consistent at t within= 36 the d anduncertainty 96 d after of the explosion, late-time lu- obtainedare also at seen Lick in Observatory P Cygni absorption and in He i k5876 and O i k7774. with the Keck II telescope, respectively. Several narrowminosity ab estimate.sorption This lines is also in aour factor high-resolution of 10 lower than Keck the spectrumThe absorption have be requiresen marked, some additional but background continuum there are some remaining unidentified lines. Also plottednecessary is mass-lossaspectrumoftheTypeIaSN1991Tat rate in the decade just before core collapse,t = 35 dlight (Filippenko source, which et is al. likely 1992) to be for the diffusion of radiation from comparison with our day 36 spectrum of SN 2006gy;signifying there is a esssharpentially boost in noM˙ immediately similarity between before the star’s the two death.