1. Model Spectra of Neutron Star Surface Thermal Emission Department of Physics National Tsing Hua University Lun-Wen Yeh 2004.5.6

2. Structure of neutron star Radiation transfer equation Temperature correction Flux ≠const Flux = const Spectrum P(τ) ρ(τ) T(τ)

3. Assumptions  Plane-parallel atmosphere( local model)  Radiative equilibrium( energy transported solely by radiation )  Equation of state is ideal gas( ionized H)  Neglect conduction and convection  Hydrostatics  No magnetic field  The physical properties independent of time

4. Structure of NS  Gray atmosphere  Equation of state  Oppenheimer-Volkoff

6. Structure of NS  Rosseland mean

7. Radiation transfer equation Absorption Spontaneous emissionInduced emission Scattering

8. Radiation transfer equation Diffusion approimation

9. Feautrier method Mean intensity like Flux like

10. Feautrier method Surface normal n

11. Feautrier method

12. d=2,3,……,D-2,D-1 μ=1,2,……M

13. Feautrier method I 1 I 2 I 3.. I 1 I 2 I 3.. I 1 I 2 I 3.. d=1 d=2 d=3…..

14. Test Feautrier method Scattering

17. Test Feautrier method Scattering and free-free absorption

18. 46~91 4.9% 91~901 4.1% 901~9001 0.39%

19. 46~91 0.29% 91~901 0.17% 901~9001 0.0079%

20. 46~91 0.19% 91~901 0.065% 901~9001 0.0058%

24. 46~91 4.2% 91~901 3.6% 901~9001 0.30%

25. Future work  Run my program with many directions, and carry out temperature-correction.  Add magnetic filed in local model