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arXiv 0904.3102astro-ph.HE
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脉冲星对Gamma-Ray背景的贡献

The Pulsar Contribution to the Gamma-Ray Background

C. -A. Faucher-Giguere, Abraham Loeb

摘要:

我们估计的贡献,银河系的恒星,普通和毫秒恒星(MSP),高能量(>100 MeV)的伽马射线背景。我们特别注意的高纬度部分的背景,可能会混淆与河外的组成部分,在现有的分析,减去银河宇宙线模型。我们的脉冲星人口模型校准的结果,大规模的无线电调查,我们采用了一个简单的经验伽玛射线光度校准的自旋下降率,提供了一个很好的适合现有的数据。我们发现,虽然普通的类星体预计只能贡献高纬度伽马射线强度(I_X~ 1 × 10 ^-5 ph s^-1 cm^-2 sr^-1)的一小部分~10^-3,但MSP可以提供更大的贡献,甚至有可能过度产生,这取决于模型参数。我们探索这些依赖性,使用一系列的MSP模型作为指导,伽玛射线测量可以有效地约束MSP人口。现有的伽马射线背景测量和源计数已经排除了几种模型。最后,我们展示了如何在伽玛射线天空中的波动可以用来区分不同的背景源。

英文摘要:

We estimate the contribution of Galactic pulsars, both ordinary and millisecond pulsars (MSPs), to the high-energy (>100 MeV) gamma-ray background. We pay particular attention to the high-latitude part of the background that could be confused with an extragalactic component in existing analyses that subtract a Galactic cosmic-ray model. Our pulsar population models are calibrated to the results of large-scale radio surveys and we employ a simple empirical gamma-ray luminosity calibration to the spin-down rate that provides a good fit to existing data. We find that while ordinary pulsars are expected to contribute only a fraction ~10^-3 of the high-latitude gamma-ray intensity (I_X~1x10^-5 ph s^-1 cm^-2 sr^-1), MSPs could provide a much larger contribution and even potentially overproduce it, depending on the model parameters. We explore these dependences using a range of MSP models as a guide to how gamma-ray measurements can usefully constrain the MSP population. Existing gamma-ray background measurements and source counts already rule out several models. Finally, we show how fluctuations in the gamma-ray sky can be used to distinguish between different sources of the background.

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