On the radio spectra of Galactic millisecond pulsars
On the radio spectra of Galactic millisecond pulsars
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银河系毫秒脉冲星的射电光谱
DOI：
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发表时间：
2022
期刊：
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通讯作者：
D. Lorimer
中科院分区：
文献类型：
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作者：
K. Aggarwal;D. Lorimer
随着银河盘射电勘测灵敏度的不断提高，毫秒脉冲星（MSP）的数量近年来大幅增加，因此现在可以比过去更详细地研究它们的人口统计特性。我们研究了可以从 MSP 群体的无线电频谱中了解到什么。使用在 0.135–6.6 GHz 范围内的无线电频率进行的 11 次调查中检测到的 179 个 MSP 样本，我们对该范围内的 MSP 无线电频谱行为进行了详细建模。采用马尔可夫链蒙特卡罗模拟来探索多维参数空间，并准确地考虑观测选择效应，我们发现强有力的证据支持 MSP 总体具有随频率 ν 缩放的二分量幂律谱模型。具体来说，我们发现 MSP 磁通密度谱在 320 MHz 以下大致与频率无关，在较高频率下与 ν−1.5 成正比。这种参数化的性能明显优于单一幂律模型，后者过度预测了低频 (100–200 MHz) 调查中出现的 MSP 数量。我们将我们的结果与早期的工作以及当前对正常脉冲星群的理解进行了比较，并使用我们的模型对即将进行的调查中的 MSP 产量进行预测。我们证明，在未来十年中，观察到的 MSP 样本可能会增加两倍。
With recent advances in the sensitivity of radio surveys of the Galactic disk, the number of millisecond pulsars (MSPs) has increased substantially in recent years such that it is now possible to study their demographic properties in more detail than in the past. We investigate what can be learned about the radio spectra of the MSP population. Using a sample of 179 MSPs detected in eleven surveys carried out at radio frequencies in the range 0.135– 6.6 GHz, we carry out detailed modeling of MSP radio spectral behaviour in this range. Employing Markov Chain Monte Carlo simulations to explore a multi-dimensional parameter space, and accurately accounting for observational selection effects, we find strong evidence in favour of the MSP population having a two-component power-law spectral model scaling with frequency, ν. Specifically, we find that MSP flux density spectra are approximately independent of frequency below 320 MHz, and proportional to ν−1.5 at higher frequencies. This parameterization performs significantly better than single power-law models which over predict the number of MSPs seen in low-frequency (100–200 MHz) surveys. We compared our results with earlier work, and current understanding of the normal pulsar population, and use our model to make predictions for MSP yields in upcoming surveys. We demonstrate that the observed sample of MSPs could triple in the coming decade.