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Distances to Supernovae with the Expanding Shock Front Method

Distances to Supernovae with the Expanding Shock Front Method. Norbert Bartel and Michael Bietenholz (York University). Contents. The Expanding Shock Front Method SN 1993J - Images - Radio Expansion - Optical Expansion

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Distances to Supernovae with the Expanding Shock Front Method

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  1. Distances to Supernovae with the Expanding Shock Front Method Norbert Bartel and Michael Bietenholz (York University)

  2. Contents • The Expanding Shock Front Method • SN 1993J - Images - Radio Expansion - Optical Expansion - Distance • SN 1979C - Image - Radio Expansion - Optical Expansion - Distance • Conclusions

  3. Angular expansion of SN1993J 66 radius measure-ments

  4. Radial velocity from optical lines

  5. SN1993J Highest rel. resolution

  6. The Expanding Shock Front Method Vopt. max ηκ D = --------------- • Θo Vopt. max = max. radial velocity from opt. lines (v of reverse shock) • Θo = angular velocity of outer boundary of radio shell (of forward shock) η= outer to inner angular radius of radio shell Κ = isotropy factor, 1 for spherical symmetry

  7. Shell profiles Ratio of outer to inner radius, η, determined within 3%

  8. Astrometry: M81* core - SN1993J Explosion center: ± 45 µas or ± 160 AU Proper motion: ± 9 µas/yr or ± 160 km/s Peculiar proper motion: 320 ±160 km/s to south Limit on anisotropic expansion: 5.5%

  9. Radio and optical velocities Forward shock M81: D=4.3±0.6 Mpc Reverse shock

  10. M100 in the Virgo Cluster SN 1979C

  11. VLBI image of SN 1979C at t=22 yr Modelfit: Circularly symmetric within 9%

  12. Visibility curve of SN 1979C at t=22 yr

  13. The expansion of SN 1979 C ±0.03 consistent with almost free expansion for 22 yr

  14. Radial velocity from optical lines

  15. Radio and optical velocities 1. Forward shock Reverse shock M100: D=16.5±2.0 Mpc

  16. Conclusions • The Expanding Shock Front Method allows geometric distance measurements to be made for supernovae < 30 Mpc. • SN 1993J in M81 D=4.3±0.6 Mpc (3.6±0.4 Mpc from Cepheids) • SN 1979C in M100 in Virgo D=16.5±2.5 Mpc (uniform sphere) D=19.8±3.0 Mpc (shell) (15.2 --16.5±1.3 Mpc Ceph.)

  17. D=3.6±0.4 Mpc From Cepheids, Freedman et al. (2001)

  18. With velocity error of reverse shock

  19. 1. With velocity error of reverse shock

  20. Image with highest resolution Composite Image made from data from three epochs combined

  21. The expansion of SN 1979C Strong deceleration Marcaide et al. 2002

  22. Optical-Radio Velocity comparison for D=16.5 Mpc Forward shock Reverse shock

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