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Ay 123: Supernovae contd..

Ay 123: Supernovae contd. Nucleosynthesis - revisited . Fe peak. Z. Z. N. Hydrostatic equilibrium slowly builds up He 4 through Fe 56 Equilibrium `e-process’ postulated to explain `Fe peak’ abundances: more stable = more abundant. A. Decay of Nuclei and SN II light curves. Ni 56 t=6.1d

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Ay 123: Supernovae contd..

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  1. Ay 123: Supernovae contd..

  2. Nucleosynthesis - revisited Fe peak Z Z N Hydrostatic equilibrium slowly builds up He4 through Fe56 Equilibrium `e-process’ postulated to explain `Fe peak’ abundances: more stable = more abundant A

  3. Decay of Nuclei and SN II light curves Ni56 t=6.1d Co56 t=77d SN1987A: McCray ARAA 31, 175 (1993)

  4. The Ring Around SN1987A Original FOC image (1990) Post-repair image 1.66” IUE observes a brightening in UV emission lines 413d after SN explosion - pre-SN ejecta is being illuminated by the explosion. Resolving the diameter of the ring gives its size and an absolute distance to the LMC Panagia et al Ap J 380, L29 (1991)

  5. Cosmological Distances from SN II P Flux, temperature & expansion velocity during `plateau phase’

  6. Hubble Diagram for SNe IIP scatter = 0.26 mag (for Ia scatter~0.20) Could detect acceleration with present technology (~15 SNIIP) More effectively probe to high z with JWST/TMT (Nugent et al 2006)

  7. SN Ia Light Curve Shape - Luminosity Correlation Reduces scatter on `Hubble diagram’ No correction Correction Phillips 1993 Ap J 413, L105; Riess et al 1995 Ap J 438, 17

  8. Host Galaxy Dependence of SNe Ia Properties Ia rate SFR/mass Width of light curve SN Ia rate correlates with specific SFR of host galaxy Light curve `stretch’ likewise correlates SN properties depend on mix of stellar population Sullivan et al Ap J 648, 868 (2006)

  9. Routes to a SNeIa in single degenerate C-O WD systems (Nomoto et al astro-ph/9907386) AGB with C+O core RG+He core WD + MS in common envelope WD + red giant Wind reduces rate Short time delay Significant time delay

  10. Cosmic Acceleration From SNe Ia Perlmutter et al 1999 • Light curve corrected peak luminosities give luminosity distance • Redshifts give cosmic expansion velocities • SNe Ia are too faint for a given redshift c.f. decelerating models!

  11. Implications of Cosmic Acceleration • Why not ? two puzzles: • expect = 8GmP4 • (10120 larger) • Why acceleration now? • M  R-3 (matter) • vac = const (vacuum) Perlmutter et al 1999 Alternative: new physics - “dark energy”: quintessence: equation of state p = w ;  R-3(1+w) dynamical scalar field w = w(t)

  12. Deep HST Survey Riess et al Ap J 659, 98 (2007)

  13. First Year Results from CFHT SNLS Astier et al A&A 447, 31 (2006) 71 homogenously studied SNe Ia w = -1.023 ± 0.090 i.e. equivalent to Cosmological Constant

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