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NIRI Observations of Type Ia Supernovae

Christopher L. Gerardy University of Texas, Austin Peter Garnavich Notre Dame Peter Hoeflich, UT Austin J. Craig Wheeler, G. “Howie” Marion Robert A. Fesen Dartmouth College K. Nomoto Univ. Tokyo K. Motohara K. Maeda Gemini Science 2004 24 May 2004.

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NIRI Observations of Type Ia Supernovae

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  1. Christopher L. Gerardy University of Texas, Austin Peter Garnavich Notre Dame Peter Hoeflich, UT Austin J. Craig Wheeler, G. “Howie” Marion Robert A. Fesen Dartmouth College K. Nomoto Univ. Tokyo K. Motohara K. Maeda Gemini Science 2004 24 May 2004 NIRI Observations of Type Ia Supernovae

  2. Created with BinSim by R. Hynes Type Ia SNe • WD in a close binary • Grows to near Mch via accretion • Thermonuclear runaway • C/O => 56Ni, Si/S, Mg/O/Ne • Standard(izable) candles

  3. Devil in the details... • Progenitor Systems? • Final stages prior to runaway? • Physics of the burning front • Ignition • Detonation or Deflagration • Relevance to Cosmology: • Bias, evolution, “Secondary Parameters”

  4. Devil in the details... • Progenitor Systems? • Final stages prior to runaway? • Physics of the burning front • Ignition • Detonation or Deflagration • Relevance to Cosmology: • Bias, evolution, “Secondary Parameters”

  5. Burning Physics: Deflagration • Propagates via thermal conduction • Subsonic • Unburned layers have time to react=> expand • quenches burning • RT unstable • Plumes, mixing of chemical layers • Large unburned mass Gamezo et al. 2004

  6. Burning Physics: Detonation • Propagates via compression • Supersonic • No time to react • Pure detonation=> complete burning to Ni • “Delayed Detonation” • Early phase of slow burning; expansion • Layered structure • Nearly complete burning C/O

  7. Burning Physics: Detonation • Propagates via compression • Supersonic • No time to react • Pure detonation=> complete burning to Ni • “Delayed Detonation” • Early phase of slow burning; expansion • Layered structure • Nearly complete burning C/O Ni

  8. Burning Physics: Detonation • Propagates via compression • Supersonic • No time to react • Pure detonation=> complete burning to Ni • “Delayed Detonation” • Early phase of slow burning; expansion • Layered structure • Nearly complete burning C/O Mg/O/Ne Si/S Ni

  9. Why NIR observations? • Probe different chemical species • Particularly C I for SNe Ia • Clean line profiles • Large Vel. • Severe blending in UV/Optical Filippenko 1997, ARA&A, 35, 309

  10. Why NIR observations? • Probe different chemical species • Particularly C I for SNe Ia • Clean line profiles • Large Vel. • Severe blending in UV/Optical • NIR: Fewer strong lines, less blending Gerardy, 2002

  11. NIRI Spectroscopy

  12. NIRI Spectroscopy • SN 2002fk: • No C I

  13. NIRI Spectroscopy • SN 2002fk: • No C I • MgII velocities 10500-14500 km/s

  14. NIRI Spectroscopy • SN 2002fk: • No C I • MgII velocities 10500-14500 km/s • >90% of the WD mass has undergone nuclear burning • No large mass of unburned C/O

  15. NIRI Spectroscopy

  16. NIRI Spectroscopy • SN 2003hv: • Fe-edge velocity ~13,000 km/s • Sharp rise; sawtooth shaped line profile. Only highest Fe/Ni/Co emission seen • Abrupt Fe-Si interface • No Plumes

  17. Future Prospects • Time-series • Combined constraints from “full scan” through ejecta envelope • High S/N • Detailed examination of line-profiles • Small-scale structure • Multi-wavelength • NIR: Fe,Mg,C/O; Opt: Si/S, CSM; UV:opacity, clumping, metallically; MIR: Isotopes, IR catastrophe? • Late-epoch observations

  18. Late-Epoch Observations • @ late-epoch (>200 d) NIR Fe II becomes optically thin • Probe global distribution of 56Ni • Kinematic Offset from off-center detonation • Signature of high-density burning • New physics • Will affect LC (~0.1mag) SN 2003du ~+300d Subaru/OHS

  19. Summary • NIR spectroscopy is a powerful tool for probing the physics of Type Ia SNe • More detonation-like, not very deflagration-like • New physics in early phases of explosion • “Secondary Parameters?” • Coming soon to Gemini? • GNIRS key project • Optical/NIR coordinated w/Spitzer MIR obs.

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