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Ay 123 Lecture 11 - Supernovae & Neutron Stars Timescales for HS Burning faster and faster..
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Structure of Massive Star at End of HS Burning
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Neutrinos Arrive from SN1987A Hirata et al Phys. Rev. Lettt 58, 1490 (1987)
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Neutrino Trapping
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Supernova Discoveries
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Supernovae Light Curves II Plateau II Linear Ia Doggett & Branch AJ 90, 2303 (1985)
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Supernovae Spectra Thermonuclear: Type Ia: Si, no H Core Collapse: Type II: H emission Type Ib: He, weak H Type Ic: no H, no He Review: Filippenko, ARAA 35, 309 (1997)
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Origin of `P Cygni’ Profile P Cygni: luminous blue variable with blue-shifted (absorbing) outflow against core emission
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Delayed Explosions
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Decay of Nuclei and SN II light curves SN1987A: McCray ARAA 31, 175 (1993) Ni 56 t=6.1d Co 56 t=77d
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The Ring Around SN1987A 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 Original FOC image (1990) Post-repair image Panagia et al Ap J 380, L29 (1991) 1.66”
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Cosmological Distances from SN II P Flux, temperature & expansion velocity during `plateau phase’
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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)
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SN Ia Light Curve Shape - Luminosity Correlation Reduces scatter on `Hubble diagram’ Phillips 1993 Ap J 413, L105; Riess et al 1995 Ap J 438, 17 No correction Correction
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Host Galaxy Dependence of SNe Ia Properties Ia rate SFR/mass 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) Width of light curve
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Routes to a SNeIa in single degenerate C-O WD systems (Nomoto et al astro-ph/9907386) WD + red giant Wind reduces rate Short time delay WD + MS in common envelope AGB with C+O core RG+He core Significant time delay
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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!
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Implications of Cosmic Acceleration Perlmutter et al 1999 Why not ? two puzzles: expect = 8 Gm P 4 (10 120 larger) Why acceleration now? M R -3 (matter) vac = const (vacuum) Alternative: new physics - “dark energy”: quintessence: equation of state p = w ; R -3(1+w) dynamical scalar field w = w(t)
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Riess et al Ap J 659, 98 (2007) Deep HST Survey
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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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