Exploring the global properties of SNe Ia Paolo A. Mazzali Max-Planck Institut fϋr Astrophysik, Garching Astronomy Department and RESearch Centre for the Early Universe, University of Tokyo Istituto Naz. di Astrofisica, OATs

Spectra of Supernovae: the photospheric phase SN Ia SN II SN Ic SN Ib Florence, 5.10.06 Galileo Galilei Institute

SNe Ia have similar light curves Are they also equally luminous? Branch & Tammann 1992 Florence, 5.10.06 Galileo Galilei Institute

87 SNe Ia: Observed B Light Curves Florence, 5.10.06 Galileo Galilei Institute

87 SNe Ia: Normalised B Light Curves Florence, 5.10.06 Galileo Galilei Institute

87 SNe Ia: Stretched B Light Curves Florence, 5.10.06 Galileo Galilei Institute

The Phillips Relation (Absolute Magnitude - Decline Rate) Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute Cosmology with SNe Ia Distant SNe are FAINT for their redshift From B.Schmidt Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute Cosmology with SNe Ia Riess et al. 1999 Florence, 5.10.06 Galileo Galilei Institute

SN Ia as distance indicators fainter brighter nearer further High-z SN Search Team (Riess et al. 1998) Supernova Cosmology Project (Perlmutter et al. 1999) empty universe surprising result: Distant SNe Ia appear fainter than standard candles in an empty Friedmann model of the universe! SN Ia luminosity distances indicate accelerated expansion! Are SNIa Standard Candles independent of age? Or is there some evolution of SN Ia luminosity with age? Spectroscopy is a powerful tool to search for differences! Florence, 5.10.06 Galileo Galilei Institute

Cosmology with SNe Ia: the Cosmological Constant From E.Baron Florence, 5.10.06 Galileo Galilei Institute

Bolometric Light Curves Contardo et al. 2000 Florence, 5.10.06 Galileo Galilei Institute

Supernova Spectra evolve Soon after explosion (first few weeks), ejecta density is high enough for a `pseudo-photosphere’ to form. “Photospheric Epoch” (early time) P-Cygni Profiles superposed on continuum Later on, photosphere disappears as densities decrease. “Nebular Epoch” (late time) Emission-line spectrum Florence, 5.10.06 Galileo Galilei Institute

SNIa Spectral Evolution Gomez & Lopez 1998 Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute Early-time spectrum Homologous expansion (v ≈ R) Ejecta are dense “Photospheric Epoch” absorption continuum τ=1 Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute Early-time spectrum Lines have P-Cygni profiles with But velocities are high: many lines overlap: “Line Blanketing” Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute SNe Ia @ maximum “Branch normals” Florence, 5.10.06 Galileo Galilei Institute

SNe Ia @ 20 days after maximum “Branch normal” Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute Late-time spectra Ejecta are thin: “Nebular Epoch” Gas heated by deposition of γ’s and cooled by forbidden line emission Spectrum: no continuum. Emission line profiles depend on velocity, abundance distribution. Homologous expansion, homogenous density and abundance: parabolic profiles τ < 1 Florence, 5.10.06 Galileo Galilei Institute

SNe Ia: late-time spectra Δm15(B) 1.93 1.77 1.27 1.51 0.87 Mazzali et al. 1998 Florence, 5.10.06 Galileo Galilei Institute

Thermonuclear SNe (Type Ia) White Dwarf in Binary System WD accretes H until MWD~1.4M⊙, T~109K Thermonuclear burning (C burning) to NSE Explosion (KE~1051 erg) Total disruption of WD 56Ni produced (~0.7M⊙) RG CO-WD C, O Si, S 56Ni Florence, 5.10.06 Galileo Galilei Institute

Type Ia SN 1996X spectral evolution Salvo et al. 2000 Florence, 5.10.06 Galileo Galilei Institute

The Classical SN Ia explosion model: W7 Branch et al. 1985 Florence, 5.10.06 Galileo Galilei Institute

I. Using observables to understand SNe Ia Questions Properties of SNe Ia (eg Phillips rel’n) Mode of explosion (deflagration, delayed detonation, other even less reasonable modes…) Cosmology? Methods Look at/model spectra & light curves Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute What we need Excellent photometric and spectroscopic coverage of a number of nearby SNe Ia Comparison with the high-z sample 3D models of the explosion Florence, 5.10.06 Galileo Galilei Institute

How we get it: the EU-RTN 16 well observed SNe (2002-2006)  Abundance Tomography  More signatures of CSM interaction Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute Data: SNe 2002bo, 2003du Florence, 5.10.06 Galileo Galilei Institute

Modelling early-time spectra Monte Carlo code Composition Density Luminosity Velocity Florence, 5.10.06 Galileo Galilei Institute

Abundance Stratification Model sequence of spectra to derive composition layering How did the star burn? Stehle et al 2005 Florence, 5.10.06 Galileo Galilei Institute

Model late-time spectra Monte Carlo LC code + NLTE nebular code No radiative transfer Get full view of inner ejecta (56Ni zone) Estimate masses Florence, 5.10.06 Galileo Galilei Institute

Composion in a typical SN Ia Elements more mixed than in typical 1D models Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute Test: Light Curve Monte Carlo code Use W7 density Composition from tomography (56Ni ~0.50M⊙ )  Model LC matches data very well Florence, 5.10.06 Galileo Galilei Institute

II. Outer regions of the ejecta: HVFs Nearly all SNe show very high velocity (~20000 km/s) absorption features (HVF) in Ca II (some also in Si II) Florence, 5.10.06 Galileo Galilei Institute

HVFs come in various forms Mazzali et al. (2005) Tanaka et al. (2006) Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute What makes the HVFs Abundance enhancement unlikely Density enhancement more reasonable Ejection of blobs or CSM interaction? Blobs: line profiles depend on orientation Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute Distribution of HVFs Any model should reproduce the observed distribution of HVF wavelength (blob velocity) and strength (optical depth, covering factor) Single blob does not Florence, 5.10.06 Galileo Galilei Institute

Need a few blobs or a thick torus Florence, 5.10.06 Galileo Galilei Institute

Use blobs to fit spectra Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute 3D Simulations (MPA) Reinecke et al. 2000 Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute III. The Global View Late time spectra suggest M(56Ni)  Δm15(B) [ M(Bol)]  v(Fe) Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute Role of 54Fe, 58Ni Stable Fe group isotopes radiate but do not heat Some anticorrelation between 56Ni and (54Fe, 58Ni) Very good correlation beween Σ(NSE) and Δm15(B) Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute Composition Layering Outer extent of Fe zone varies ( Δm15(B), Lum) Inner extent of IME matches outer extent of Fe Outer extent of IME ~ const. Florence, 5.10.06 Galileo Galilei Institute

Include 54Fe, 58Ni: “Zorro” diagram A basic property of SNe Ia Mass probably constant Amount of burned material also probably constant KE ~ const What does it all mean? Delayed detonation? Multi-spot ignited deflagration? Other possibilities….? Florence, 5.10.06 Galileo Galilei Institute

IV. Role of Fe-group, IME on LC 56Ni: light, opacity, KE 54Fe, 58Ni: opacity, KE IME: KE, (some opacity) CO (if any): little opacity Florence, 5.10.06 Galileo Galilei Institute

Explaining Phillips’ Relation 56Ni: light, opacity, KE Reproduce 54Fe, 58Ni: opacity, KE Phillips’ Relation IME: KE, (some opacity) CO (if any): little opacity (Mazzali et al. 2001) Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute Spectra @ -7 days Mazzali et al. 2001 Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute Spectra @ Maximum Mazzali et al. 2001 Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute Spectra @ +15 days Mazzali et al. 2001 Florence, 5.10.06 Galileo Galilei Institute

Using Zorro to reconstruct Phillips’ Rel’n Use composition to compute LC parameters  Derive Phillips Relation  Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute Effect of 54Fe, 58Ni Amount of 54Fe, 58Ni may be a fn. of WD metallicity (Timmes et al. 2003) Ratio 56Ni/NSE affects light, not KE or opacity LCs w/ different peak brightness, same decline rate May explain spread in Phillips’ Relation. Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute Effect on Cosmology? Evolution in Z may mimic cosmology Star-forming galaxies at z~1 may have been metal-rich w/r to present (Galaxy Downsizing) More neutronization  dimmer SNe with same LC May be consistent with Ωm=0.3, ΩΛ=0.0 Universe, but not with Ωm=1 Universe (Podsiadlowski et al. 2006) Florence, 5.10.06 Galileo Galilei Institute

Uncertainty on cosmological parameters A variation in Z may be interpreted as a variation in Ωm, w0, or wa. Florence, 5.10.06 Galileo Galilei Institute

Galileo Galilei Institute Conclusions There is some regularity among SNe Ia (surprise surprise…) Ejecta reflect stratified composition of models Total mass burned may be constant 56Ni determines luminosity (not new) Total NSE determines LC shape Degree of neutronization can give rise to dispersion in luminosity-decline rate relation Z evolution may confuse cosmological parameters Florence, 5.10.06 Galileo Galilei Institute

Effect on scale factor with Z Different cosmologies (Linder et al) v. Metallicity evolution Florence, 5.10.06 Galileo Galilei Institute