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arXiv 1503.08336astro-ph.HEastro-ph.GA
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稳态电子分布的同步辐射和康普顿谱

Synchrotron and Compton Spectra from a Steady-State Electron Distribution

Yoel Rephaeli, Massimo Persic

摘要:

在银河系和星系团内的相对论性电子和质子的能量密度通常由射电光谱和(很少)$γ$射线测量确定。与时间无关的粒子谱密度分布通常被假设为在相关能量范围内具有幂律(PL)形式。通常采用电子和质子的能量密度之间的理论关系,并调用能量均分来确定发射区的平均磁场强度。我们表明,对于典型的条件下,在恒星形成和星爆星系,这些估计需要按比例缩小,由于显着的能量损失,(有效地)平坦的电子谱密度分布,从而导致在一个低得多的能量密度比推导时的分布假设有PL形式。稳态电子分布在星爆星系的核区域计算通过占库仑,韧致辐射,康普顿,和同步辐射损失,后两个过程的相应的发射光谱计算和比较各自的PL光谱。我们还确定了质子稳态分布,考虑到库仑和π介子生产损失,并简要讨论了我们的稳态粒子谱估计质子能量密度和磁场的影响。

英文摘要:

Energy densities of relativistic electrons and protons in extended galactic and intracluster regions are commonly determined from spectral radio and (rarely) $γ$-ray measurements. The time-independent particle spectral density distributions are commonly assumed to have a power-law (PL) form over the relevant energy range. A theoretical relation between energy densities of electrons and protons is usually adopted, and energy equipartition is invoked to determine the mean magnetic field strength in the emitting region. We show that for typical conditions, in both star-forming and starburst galaxies, these estimates need to be scaled down substantially due to significant energy losses that (effectively) flatten the electron spectral density distribution, resulting in a much lower energy density than deduced when the distribution is assumed to have a PL form. The steady-state electron distribution in the nuclear regions of starburst galaxies is calculated by accounting for Coulomb, bremsstrahlung, Compton, and synchrotron losses; the corresponding emission spectra of the latter two processes are calculated and compared to the respective PL spectra. We also determine the proton steady-state distribution by taking into account Coulomb and pion production losses, and briefly discuss implications of our steady-state particle spectra for estimates of proton energy densities and magnetic fields.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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