中国物理B ›› 2009, Vol. 18 ›› Issue (2): 825-844.doi: 10.1088/1674-1056/18/2/069

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Development of the spectrum of gamma-ray burst pulses influenced by the intrinsic spectral evolution and the curvature effect

覃一平   

  1. Center for Astrophysics, Guangzhou University,Guangzhou 510006, China;  Physics Department, Guangxi University, Nanning 530004, China
  • 收稿日期:2007-09-17 修回日期:2008-08-07 出版日期:2009-02-20 发布日期:2009-02-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos 10573005 and 10747001).

Development of the spectrum of gamma-ray burst pulses influenced by the intrinsic spectral evolution and the curvature effect

Qin Yi-Ping(覃一平)a)b)   

  1. a Center for Astrophysics, Guangzhou University,Guangzhou 510006, China; b Physics Department, Guangxi University, Nanning 530004, China
  • Received:2007-09-17 Revised:2008-08-07 Online:2009-02-20 Published:2009-02-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos 10573005 and 10747001).

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摘要： The spectral evolution of gamma-ray burst pulses assumed to arise from the emission of fireballs is explored. It is found that due to the curvature effect, the integrated flux is well related to peak energy by a power law in the decaying phase of pulses, where the index is about 3, which does not depend on intrinsic emission and the Lorentz factor. The spectra of pulses in the decaying phase are slightly different from each other when different intrinsic spectral evolution patterns are considered, indicating that it is dominated by the curvature effect. In the rising phase, the integrated flux keeps increasing whilst the peak energy remains unchanged when the intrinsic emission bears an unchanged spectrum. Within this phase, the flux decreases with the increase of the peak energy for a hard-to-soft intrinsic spectrum, and for a soft-to-hard-to-soft intrinsic spectrum, the flux generally increases with the increase of the peak energy. An intrinsic soft-to-hard-to-soft spectral evolution within a co-moving pulse would give rise to a pulse-like evolutionary curve for the peak energy.

关键词: gamma-ray bursts, gamma-rays, relativity

Abstract: The spectral evolution of gamma-ray burst pulses assumed to arise from the emission of fireballs is explored. It is found that due to the curvature effect, the integrated flux is well related to peak energy by a power law in the decaying phase of pulses, where the index is about 3, which does not depend on intrinsic emission and the Lorentz factor. The spectra of pulses in the decaying phase are slightly different from each other when different intrinsic spectral evolution patterns are considered, indicating that it is dominated by the curvature effect. In the rising phase, the integrated flux keeps increasing whilst the peak energy remains unchanged when the intrinsic emission bears an unchanged spectrum. Within this phase, the flux decreases with the increase of the peak energy for a hard-to-soft intrinsic spectrum, and for a soft-to-hard-to-soft intrinsic spectrum, the flux generally increases with the increase of the peak energy. An intrinsic soft-to-hard-to-soft spectral evolution within a co-moving pulse would give rise to a pulse-like evolutionary curve for the peak energy.

Key words: gamma-ray bursts, gamma-rays, relativity

中图分类号:  (γ-ray sources; γ-ray bursts)

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