球状星团中毫秒脉冲星的伽马射线与射电族群
Gamma-ray and radio populations of millisecond pulsars in globular clusters
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中文总结 AI 辅助
本研究通过蒙特卡洛模拟对比两种毫秒脉冲星光度模型，发现对数正态分布模型预测的球状星团毫秒脉冲星数量更多、本征射电光度更暗，符合观测证据，可通过未来射电巡天验证并约束其演化。
中文摘要 AI 辅助
银河系球状星团（GC）系统中的毫秒脉冲星（MSP）族群，是研究多种致密恒星环境下中子星演化的有力诊断工具。我们利用118个银河系球状星团的属性，对费米卫星（Fermi）观测到的它们的伽马射线流量开展了蒙特卡洛模拟。我们对比了两种光度模型：三维基本平面模型（模型A）和对数正态分布模型（模型B）。两种模型都能复现观测到的伽马射线流量，也都符合球状星团恒星碰撞率的标度律——该标度律已在低质量X射线双星和射电毫秒脉冲星中得到确立。由于模型B的平均伽马射线光度更低，它预测的毫秒脉冲星族群规模（$5150^{+720}_{-710}$）是模型A（$770\boldsymbol{\rm \textpm}60$）的6-7倍。此外，两种模型都准确预测了族群层面的预期结果：约有3个星团的总伽马射线辐射由单个明亮毫秒脉冲星主导。借助射电-伽马射线光度标度关系（$L_r \boldsymbol{\rm \textsim} 3.5 \boldsymbol{\rm \times} 10^{-7} L_γ$），我们发现模型B预测的平均射电伪光度（$\boldsymbol{\rm \textlog} L_{\rm pseudo} \boldsymbol{\rm \textsim} -1.6$）比标准脉冲星更暗。这一结果与近期的证据一致，即银河系毫秒脉冲星的表观暗弱源于几何效应。相比之下，模型A对应的族群本征光度更高（$\boldsymbol{\rm \textlog} L_{\rm pseudo} \boldsymbol{\rm \textsim} -0.3$），缺乏明确的物理依据，也与银河系脉冲星的研究结果不符。模型B预测的数量更多、光度更暗的本征毫秒脉冲星族群，可通过新兴射电设备开展的灵敏巡天进行探测，从而进一步约束毫秒脉冲星的演化路径。
英文摘要
The populations of millisecond pulsars (MSPs) across the Milky Way's globular cluster (GC) system serve as powerful diagnostics of neutron star evolution in a variety of dense stellar environments. Using properties of 118 Galactic GCs, we performed Monte Carlo simulations of their gamma-ray fluxes observed by Fermi. We compared two luminosity models: a 3D fundamental plane (model A) and a lognormal distribution (model B). Both models reproduce the observed gamma-ray fluxes and mirror the scaling law with the GC stellar encounter rate established for low-mass X-ray binaries and radio MSPs. Due to its lower average gamma-ray luminosities, model B predicts a 6-7 times larger MSP population ($5150^{+720}_{-710}$) than model A ($770\pm60$). Furthermore, both models accurately predict a population-wide expectation of roughly three clusters whose aggregate gamma-ray emission is dominated by a single bright MSP. Invoking a radio-to-gamma-ray luminosity scaling ($L_r \sim 3.5 \times 10^{-7} L_γ$), we find that model B predicts a mean radio pseudoluminosity ($\log L_{\rm pseudo} \sim -1.6$) that is fainter than canonical pulsars. This result is consistent with recent evidence attributing the apparent faintness of Galactic MSPs to geometric effects. In contrast, model A implies an intrinsically brighter population ($\log L_{\rm pseudo} \sim -0.3$) that lacks a clear physical basis and is inconsistent with the results found for Galactic pulsars. The larger underlying population of faint millisecond pulsars predicted by model B could be probed by sensitive surveys with emerging radio facilities to further constrain the evolutionary pathways of MSPs.
