发表机构
Astronomy Department, Harvard University（哈佛大学天文学系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
研究光帆驱动光束泄漏产生的光学瞬变，提出利用Roman、Rubin和Euclid巡天数据以零额外成本探测银河系内光帆活动，并给出发射率约束窗口。
AI 中文摘要
火箭推进的主要挑战在于加速航天器自身燃料的负担。光帆将推进剂留在地球上，其可达到的速度由帆面积、材料的热耐受性以及驱动阵列的功率决定。在GL15中，我们展示了在宜居世界之间驱动此类光帆的微波阵列的泄漏会产生央斯基级射电瞬变，持续数十秒，距离为100秒差距。我们将该泄漏扩展到光学和近红外波段，其中菲涅耳匹配会将孔径缩小至1微米波长下的约20至100米，但该孔径上的强度为2×10^8瓦每平方米，比已发表的定向能量载荷高出五个数量级。在约20千瓦每平方米下散布1.5太瓦需要约10公里的相控阵，这给发射器带来压力；Lubin的10^3瓦每平方米载荷则需要40公里的阵列，虽然舒适但更昂贵。在40米瓦片上施加十分之一波长的延迟，且瓦片尺寸使得一片仍覆盖帆时，会泄漏0.054的功率（80吉瓦）进入光晕。典型的银河系探测是在8千秒差距处F146波段中约30秒的单次峰值，m_AB约为19.4；相隔87秒的一对信号（约五分之一概率）是确认测试。Roman的银河系凸起时域巡天在暗宿主上以8σ置信度达到109千秒差距，因此如果光束指向我们，该光晕的指向性闪光在银河系任何位置都可见。对于10至40公里的光学发射器，在最大速度大于等于250公里每秒时保持约λ/10的精度，N_det=1需要Γ_6h约为16，而零结果搜索将Γ_6h限制在小于等于49，发射率存在三倍窗口。真正的阈值由PSF重合的恒星和仪器瞬变设定。如果强度受限的光学发射器在我们的星系中普遍使用，这一活动可能被Roman、Rubin和Euclid以零额外观测成本揭示。
英文摘要
The primary challenge of rocket propulsion is the burden of accelerating the spacecraft's own fuel. Light sails leave the propellant at home, with the achievable speed set by the sail area, the thermal tolerance of its material, and the power of the driving array. In GL15 we showed that leakage from a microwave array driving such a sail between habitable worlds produces Jansky-level radio transients lasting tens of seconds at $100$~pc. We take that leak to optical and near-infrared, where Fresnel matching would shrink the aperture to $\sim\!20$--$100$~m at $1\,μ{\rm m}$, but the intensity on that aperture is $2\times10^{8}\,{\rm W\,m^{-2}}$, five orders above published directed-energy loadings. Spreading $1.5$~TW at $\sim20\,{\rm kW\,m^{-2}}$ is a $\sim10$~km phased array, pushing the emitters; Lubin's $10^{3}\,{\rm W\,m^{-2}}$ loading is a $40$~km array, comfortable but more expensive. A tenth-wave delay on $40$~m tiles sized so one tile still covers the sail leaks $0.054$ of the power ($80$~GW) into a halo. The typical Galactic detection is a single $\sim30$~s peak at $m_{\rm AB}\simeq19.4$ in F146 at $8$~kpc; a pair $87$~s apart, about one in five, is the confirmation test. \emph{Roman}'s Galactic Bulge Time Domain Survey reaches $109$~kpc at $8σ$ on a faint host, so a pointed flash of that halo is visible from anywhere in the Galaxy if the beam points at us. For $10$--$40$~km optical beamers held to $\simλ/10$ at $v_{\rm max}\gtrsim250\,{\rm km\,s^{-1}}$, $N_{\rm det}=1$ wants $Γ_{6{\rm h}}\simeq16$ and a null search limits $Γ_{6{\rm h}}\lesssim49$, a factor-of-three window in launch rate. The real threshold is set by PSF-coincident stellar and instrumental transients. If intensity-limited optical beamers are commonly employed in our galaxy, this activity could be revealed by Roman, Rubin and Euclid at no additional observing cost.
Comments17 pages, 4 figures. Submitted to the Open Journal of Astrophysics
