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On the Emission Site of Gamma Rays from Pulsars Hsiang-Kuang Chang and Cheng Ho

On the Emission Site of Gamma Rays from Pulsars Hsiang-Kuang Chang and Cheng Ho. 徐佩君 清華大學天文研究所. Gamma-Ray Pulsars. Their spectra. (Thompson et al. 1999). Models. Polar-cap Outer-gap. (Harding 2000). Power-law Spectra. (Nolan et al. 1996). Photon Indices. Assumption.

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On the Emission Site of Gamma Rays from Pulsars Hsiang-Kuang Chang and Cheng Ho

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  1. On the Emission Site of Gamma Rays from PulsarsHsiang-Kuang Chang and Cheng Ho 徐佩君 清華大學天文研究所

  2. Gamma-Ray Pulsars

  3. Their spectra (Thompson et al. 1999)

  4. Models • Polar-cap • Outer-gap (Harding 2000)

  5. Power-law Spectra (Nolan et al. 1996)

  6. Photon Indices

  7. Assumption • a steady cooling population of charged particles • Synchrotron radiation P=2 → Γ＝3/2 • Curvature radiation P=4 → Γ＝5/3

  8. Method

  9. The distance of the inferred emission site from the stellar center curvature radiation synchrotron radiation Requiring that at the emission site

  10. Bending Energy (Eb) of PSR B1509-58 ~ 50 keV (Matz et al. 1994)

  11. Eb of Vela 10~70 MeV (Strickman et al. 1996)

  12. Eb of PSR B1706-44 10 keV ~ 30 MeV (Ray, Harding & Strickman 1999)

  13. Eb of PSR B1951+32 70 keV ~ 3 MeV (Chang & Ho 1997; Chang & Guo 2000)

  14. Eb of Geminga 10~30 MeV (Mayer-Hasselwander et al. 1994) (Jackson et al. 2002)

  15. Eb of PSR B1055-52 1 keV ~ 70 MeV (Thompson et al. 1999)

  16. Determining the emission site (H-K Chang)

  17. Result

  18. Discussion • Under the assumption that the gamma-ray emission comes from a steady cooling population of charged particles, the synchrotron radiation in outer magnetospheres as the emission mechanism is consistent with the spectral behavior of most gamma-ray pulsars. • Exception: Crab pulsar, PSR B1509-58 • The inverse Compton scattering is not considered in this method

  19. Reference • Peter Meszaros, 1992, The University of Chicago Press, “High-Energy Radiation from Magnetized Neutron Stars” • Harding A. K., 2000, arXiv:astro-ph/0012268 • George B. Rybicki, Alan P. Lightman, New York :Wiley,c1979. “Radiative processes in astrophysics” • Chang H.-K., Guo T.-F., 2000, Chinese Journal of Physics, 38, 429 • Chang H.-K., Ho C., 1997, ApJ, 479, L125 • Jackson M. S. et al., 2002, ApJ, 578,935 • Matz S. M. et al., 1994, ApJ, 434, 288 • Mayer-Hasselwander H. A. et al., 1994, ApJ, 421, 276 • Nolan P. L. et al., 1996, A&AS, 120, C61 • Ray A., Harding A. K., Strickman M., 1999, ApJ, 513, 919 • Strickman M. S. et al., 1996, ApJ, 460, 735 • Thompson D. J. et al., 1999, ApJ, 516, 297

  20. Thank you !

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