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

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

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 Ni Si/S C/O Mg/O/Ne

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. 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. 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 56 Ni Kinematic Offset from off-center detonation Signature of high-density burning –New physics –Will affect LC (~0.1mag) Subaru/OHS SN 2003du ~+300d

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.