The theoretical understanding of type ia supernovae
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the theoretical understanding of Type Ia Supernovae. Daniel Kasen. SN cosmology. “super-nova”. Supernova Discovery History Asiago Catalog (all supernova types). Proposed. Supernova Factory Lick observatory SN search CfA SN group Carnegie SN project ESSENCE Supernova Legacy Survey.

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the theoretical understanding of Type Ia Supernovae

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the theoretical understanding of Type Ia Supernovae

Daniel Kasen


SN cosmology

“super-nova”

Supernova Discovery HistoryAsiago Catalog (all supernova types)


Proposed

Supernova Factory

Lick observatory SN search

CfA SN group

Carnegie SN project

ESSENCE

Supernova Legacy Survey

PanStarrs

Dark Energy Survey

JDEM

Large Synoptic Survey

Telescope (LSST)

Supernova Discovery FutureRough predictions and promises…

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 ProgenitorsAccreting white dwarf near the Chandrasekhar limit

Accretion rate:

10-7 Msun / year


White Dwarf IgnitionKuhlen, Woosley, and Glaitzmeier (2006)


t = 0.0 sec

t = 0.5 sec

t = 1.0 sec

t = 1.5 sec

3D Deflagration ModelSubsonic turbulent flame burning

Roepke et al. (2005)


C/O

Si/S/Ca

56Ni

Fe

C/O

boom


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


Type Ia Supernova Spectrum

20 days after explosion


Spectroscopic Homogeneity and Diversitymonitoring silicon expansion velocities

from Leonard et al, ApJ 2006


Type Ia Width-Luminosity Relationbrighter supernovae have broader light curves


FeII bound-bound

Supernova Ejecta Opacityblending of millions of line transitions

FeIII bound-bound


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

Presupernova Evolution

(~100-109 years)

accreting, convective white dwarf

Type Ia

supernova

theoretical

simulation

challenge

ignition

Explosion

(~1-100 secs)

turbulent nuclear combustion / hydrodynamics

free expansion

Light Curves / Spectra

(~100 days)

radioactive decay / radiative transfer

Observations


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

Incite award, Oak Ridge Lab: 4 million hours/year

Atlas “grand challenge” LLNL: 4 million hours/year

NERSC award, LBL: 3 million hours/year

Jacquard, NERSC


C/O

Si/S/Ca

56Ni

Fe

Grid of Type Ia Supernova Models

w/ Stan Woosley

Sergei Blinikov

Elena Sorokina

130 one-dimensional

Chandrasekhar mass

models with

varied composition

Parameters

MFe

MNi

MSi

“mixing”

MFe +MNi +MSi + Mco = MCH


Broadband Synthetic Light CurvesModel Compared to observations of SN 2001el

Parameters

MFe = 0.1 Msun

MNi = 0.6 Msun

MSi = 0.4 Msun

Kasen, ApJ 2006

Kasen (2006) ApJ


Day 15 after explosion

Time Evolution of SpectrumRecession of photosphere reveals deeper layers

Day 35 after explosion

C/O

Si/S/Ca

Model

SN1994D

56Ni

Fe


Width-Luminosity RelationshipKasen and Woosley, ApJ, 2007

Vary 56Ni production

MNi = 0.35 to 0.70 Msun


The Width-Luminosity RelationshipKasen and Woosley, ApJ, 2007

Brighter models are hotter and

more ionized and have different

opacity behavior

Vary 56Ni production


The Width-Luminosity RelationshipKasen and Woosley, ApJ, 2007

Vary silicon production

(explosion energy)

Vary 56Ni production


Multi-Dimensional ModelsRoepke et al (2005)


2D Deflagration Model

Roepke, Kasen, Woosley

MNi = 0.2 Msun

EK = 0.3 x 1051 ergs


DeflagrationToDetonationKhokhlov (1991)Hoeflich (1994)Gamezo et al (2005)

Gamezo et al.

But how to detonate?


2D Delayed Detonation

Roepke, Kasen, Woosley

Earlier Detonation (higher densities)

gives more 56Ni production

MNi = 0.5 Msun

EK = 1.2 x 1051 ergs


Off-Center Ignition

University of Chicago

FLASH Center


Detonation From Failed DeflagrationPlewa, ApJ (2007)

Is the transition robust in

3-dimensional calculations?


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


Asymmetry and SN Ia DiversityMaximum Light Spectrum


Asymmetry and SN Ia DiversityB-band Light Curve and the Phillips Relation


The Theoretical Understanding of Type Ia Supernovae

Pressing Questions

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?


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