arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2004.05179astro-ph.COastro-ph.GAhep-phphysics.optics
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轴子星的射电辐射

Radio-emission of axion stars

D. G. Levkov, A. G. Panin, I. I. Tkachev

摘要:

研究了致密轴子暗物质结构衰变为辐射光子的参数不稳定性。相应的天体--玻色(轴子)星、它们的星团和弥散轴子云--在后暴涨的佩西-奎因场景中大量形成。我们发展的一般描述参数共振结合有限体积效应,反作用,轴子速度和他们的(在)相干性。通过额外的粗粒化,我们的形式再现了维里化轴子与光子相互作用的动力学方程。我们推导出上述每一个对象的参数不稳定性的条件,以及在坍缩轴子星,评估光子共振模式和它们的增长指数。作为副产品,我们计算了玻色星和漫射轴子的受激发射,认为前者对射电背景的贡献较大。在QCD轴子的情况下,如果轴子-光子耦合超过原始KSVZ值两个数量级,玻色星发光,坍缩星辐射。后者的约束是减轻了几个附近的轴子星共振和缺席的轴子类粒子。我们的研究结果表明,参数效应可能会揭示自己的观测,从FRB过量的无线电背景。

英文摘要:

We study parametric instability of compact axion dark matter structures decaying to radiophotons. Corresponding objects - Bose (axion) stars, their clusters, and clouds of diffuse axions - form abundantly in the postinflationary Peccei-Quinn scenario. We develop general description of parametric resonance incorporating finite-volume effects, backreaction, axion velocities and their (in)coherence. With additional coarse-graining, our formalism reproduces kinetic equation for virialized axions interacting with photons. We derive conditions for the parametric instability in each of the above objects, as well as in collapsing axion stars, evaluate photon resonance modes and their growth exponents. As a by-product, we calculate stimulated emission of Bose stars and diffuse axions, arguing that the former can give larger contribution into the radiobackground. In the case of QCD axions, the Bose stars glow and collapsing stars radioburst if the axion-photon coupling exceeds the original KSVZ value by two orders of magnitude. The latter constraint is alleviated for several nearby axion stars in resonance and absent for axion-like particles. Our results show that the parametric effect may reveal itself in observations, from FRB to excess radiobackground.

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