the theoretical understanding of Type Ia Supernovae Daniel Kasen

Supernova Discovery History Asiago Catalog (all supernova types) SN cosmology “super-nova”

Supernova Factory Lick observatory SN search CfA SN group Carnegie SN project ESSENCE Supernova Legacy Survey Supernova Discovery Future Rough predictions and promises… PanStarrs Dark Energy Survey JDEM Large Synoptic Survey Telescope (LSST) Proposed Dark Energy Measurements Systematic error, not statistical error, is the issue (e.g., luminosity evolution) Aim for Type Ia SNe as reliable standard candles to a few %

SN Ia Progenitors Accreting white dwarf near the Chandrasekhar limit Accretion rate: M sun / year

White Dwarf Ignition Kuhlen, Woosley, and Glaitzmeier (2006)

t = 0.0 sect = 0.5 sect = 1.0 sec 3D Deflagration Model Subsonic turbulent flame burning t = 1.5 sec Roepke et al. (2005)

C/O boom Fe 56 Ni Si/S/Ca C/O

Type Ia Supernova Light Curves powered by the beta decay: 56 Ni 56 Co 56 Fe

Type Ia Supernova Spectrum 20 days after explosion

Spectroscopic Homogeneity and Diversity monitoring silicon expansion velocities from Leonard et al, ApJ 2006

Type Ia Width-Luminosity Relation brighter supernovae have broader light curves

Supernova Ejecta Opacity blending of millions of line transitions FeII bound-bound FeIII bound-bound

free expansion Light Curves / Spectra (~100 days) radioactive decay / radiative transfer Type Ia supernova theoretical simulation challenge ignition Presupernova Evolution (~ years) accreting, convective white dwarf Explosion (~1-100 secs) turbulent nuclear combustion / hydrodynamics Observations DOE: Scientific Discovery through Advanced Computing (SciDAC) The “Computational Astrophysics Consortium” (CAC) Stan Woosley (PI) UC Santa Cruz, UC Berkeley, Stanford, Arizona, Stony Brook, JHU, LANL, LLNL, LBNL Models

3-dimensional Time-Dependent Monte Carlo Radiative Transfer SEDONA Code Expanding atmosphere Realistic opacities Three-dimensional Time-dependent Multi-wavelength Includes spectropolarization Includes radioactive decay and gamma-ray transfer Iterative solution for thermal equilibrium Kasen et al 2006 ApJ

Large Scale Computing Jacquard, NERSC Incite award, Oak Ridge Lab: 4 million hours/year Atlas “grand challenge” LLNL: 4 million hours/year NERSC award, LBL: 3 million hours/year

EJECTA MODEL

Fe 56 Ni Si/S/Ca C/O Grid of Type Ia Supernova Models w/ Stan Woosley Sergei Blinikov Elena Sorokina 130 one-dimensional Chandrasekhar mass models with varied composition Parameters M Fe M Ni M Si “mixing” M Fe + M Ni + M Si + M co = M CH

Broadband Synthetic Light Curves Model Compared to observations of SN 2001el Kasen (2006) ApJ Parameters M Fe = 0.1 M sun M Ni = 0.6 M sun M Si = 0.4 M sun Kasen, ApJ 2006

Day 35 after explosion Time Evolution of Spectrum Recession of photosphere reveals deeper layers Fe 56 Ni Si/S/Ca C/O Day 15 after explosion Model SN1994D

Width-Luminosity Relationship Kasen and Woosley, ApJ, 2007 Vary 56 Ni production M Ni = 0.35 to 0.70 M sun

The Width-Luminosity Relationship Kasen and Woosley, ApJ, 2007 Vary 56 Ni production Brighter models are hotter and more ionized and have different opacity behavior

The Width-Luminosity Relationship Kasen and Woosley, ApJ, 2007 Vary 56 Ni production Vary silicon production ( explosion energy)

Multi-Dimensional Models Roepke et al (2005)

2D Deflagration Model M Ni = 0.2 M sun E K = 0.3 x ergs Roepke, Kasen, Woosley

Deflagration To Detonation Khokhlov (1991) Hoeflich (1994) Gamezo et al (2005) But how to detonate? Gamezo et al.

2D Delayed Detonation M Ni = 0.5 M sun E K = 1.2 x ergs Roepke, Kasen, Woosley Earlier Detonation (higher densities) gives more 56 Ni production

Off-Center Ignition University of Chicago FLASH Center

Detonation From Failed Deflagration Plewa, ApJ (2007) Is the transition robust in 3-dimensional calculations?

Off-center Explosion Plewa (2007) Kasen and Plewa (2007)

Asymmetry and SN Ia Diversity Maximum Light Spectrum

Asymmetry and SN Ia Diversity B-band Light Curve and the Phillips Relation

How and where does ignition happen? How might the deflagration transition into a detonation? Can we reproduce the observed spectra and light curves from first principles? How do the light curves depend upon progenitor environment? Pressing Questions The Theoretical Understanding of Type Ia Supernovae