2. What would a neutron star look like? – surface thermal emission from neutron stars Chang, Hsiang-Kuang ( 張祥光 ) Department of Physics & Institute of Astronomy National Tsing Hua University

3.  Where are neutron stars ?  Neutron star models  What would a neutron star look like ?  Surface thermal emission from neutron stars  Current status: observations and modelling

4.  The proposal of neutron stars 1932 Landau 1934 Baade & Zwicky 1939 Oppenheimer & Volkoff  The discovery of radio pulsars 1967 Bell & Hewish  Other neutron star sources : X-ray pulsars, X-ray bursters Soft Gamma Repeaters (SGRs) Anomalous X-ray Pulsars (AXPs) radio-quiet isolated neutron stars Where are neutron stars ?

5. Neutron star models a model of neutron stars

6. (Baym & Pethick, 1979, ARA&A 17, 415) Neutron star models huge uncertainty in neutron star models

7. (Scientific American, Feb. 2003) Neutron star models the atmosphere of neutron stars

8. ? What would a neutron star look like ?

14.  Better observed in X-rays  Physical properties at the surface of neutron stars (B, g, T, C)  Earlier results  Modelling the emergent spectra and surface structure of neutron stars Surface thermal emission from neutron stars

15. Some theoretical works Current status: modelling and observations (Ho & Lai 2001, MNRAS 327, 1081)

16. Some theoretical works Current status: modelling and observations log B = 13 (long-dashed) log B = 14 (solid) log B = 15 (short-dashed) (Oezel 2001, ApJ 563, 276)

17. The Vela pulsar’s Chandra spectrum Current status: modelling and observations (Pavlov et al. 2001, ApJ 552, L129)

18. The case of 1E1207.4-5209 Current status: modelling and observations PN (top) & MOS (bottom) spectra fitted with two blackbodies (kT = 0.211 keV, 0.40 keV) (Bignami et al. 2003, Nature 423, 725)

19. The case of 1E1207.4-5209 Current status: modelling and observations PN spectra for different phases (Bignami et al. 2003, Nature 423, 725)

20. Modelling the observed spectra Coming next… Thank You! Measuring the polarization Are neutron stars really neutron stars?

24. Taylor, Manchester & Lyne 1993, ApJS 88, 529

31. The Hubble image of RX J1856.5-3754

34. Possenti et al. 1996, A&A 313, 565

35. Greiveldinger et al. 1996, ApJ 465, L35

36. Finley et al. 1992, ApJ 394, L21