变化磁场中相对论电子系集体的共振逆康普顿散射谱

Collective Radiation Spectra of the Resonant Inverse Compton Scattering of the Assembly of Relativistic Electrons in A Variable Magnetic Field

强磁场中的共振逆康普顿散射(RICS)是产生伽玛射线的有效机制.在前文工作的基础上,导出强磁场中子星中具有幂律能谱的大量相对论电子沿中子星磁轴向外运动时在变化磁场中产生的集体RICS辐射谱(RICS谱光度)的基本公式.由此得到在中子星周边几种典型的低频辐射场中集体RICS辐射谱形的简单解析表示(如热轫致辐射场、黑体辐射场,以及非热低频幂律谱辐射场),以便与实际观测谱形比较.计算表明:在满足匹配条件(即近似共振条件)下,RICS辐射效率很高,其谱形都是两段式(折断的)的幂律谱形式,与周边低频场性质无关.通过计算,再一次论证RICS机制是伽玛射线脉冲星和伽玛暴(GRBs)在高能射线段(硬X-射线和伽玛射线)辐射的一个理想的高效辐射机制.

The resonant inverse Compton scattering (RICS) of the relativistic electrons in an intense magnetic field is an efficient radiation mechanism to produce the high energy gamma rays. For the purpose of the practical applications of the RICS process, in this paper, we present a basic formula of the collective RICS spectrum for an assembly of relativistic electrons moving along the direction of near-magnetic axis of a strongly magnetized neutron star or strange star. The derivation of the formula is based on the simple RJCS emission spectrum of a single fast electron given in our previous paper (you et al. 2003). By using this basic formula, we calculate a series of collective RICS spectra for various typical ambient low-frequency radiation fields around the central neutron star, e.g. the bremsstrahlung, the black body radiation, and the nonthermal field with power law form spectrum, etc. We thus obtain the collective RICS spectra in quite simple analytical expressions, which is in favor of the comparison with the observed spectra. Our results show that the RICS process is a very efficient radiation mechanism if the 'accommodation condition' is satisfied. We show that various RICS spectra have a common broken power-law form (different power-laws in two sections), despite of the form of the ambient low-frequency field. Our calculation confirms that the RICS process is an important radiation mechanism in the high energy band (hard X-rays and γ-rays) with high efficiency, which should be taken into account for the exploration of the γ-ray bursts (GRBs) and the γ-ray pulsars (GRPs).