论文标题
在快速漂移扫描调查中检测L Band的无线电超速矮小的潜力
The Potential of Detecting Radio-flaring Ultracool Dwarfs at L band in the FAST Drift-scan Survey
论文作者
论文摘要
五百米的光圈球形射电望远镜（FAST）完成了调试，并开始了2020年的Comensal Radio Survatomy Fast Survey（Crafts），这是一项为期多年的调查，覆盖了60％的天空。我们在2020年进行了预测，对可能可以通过手工艺品检测到的射电式超级型Ultracool矮人（UCDS（UCD））进行了预测。根据文献中许多无偏见的无线电调查的观察到的燃烧UCD，我们得出了$ \ ge $ 3％的检测率。假设UCD Flares的平坦无线电频谱$ b_ν\ propto propto p propto c c n propto c n propto c n/d l \ propto $ d n/d n/d l \ propto l^{ - 1.96 \ pm 0.45} $（这里$ l = c $ l = c n = c c $ c $ c $）。发现手工艺品对UCD的耀斑足够敏感，最高$ \ sim $ 180。考虑到银河系薄磁盘，我们对UCD人群进行了3D蒙特卡洛模拟，然后将其喂食以模拟工艺观测。我们估计，$ \ sim $ 170燃烧的UCD将通过圆形极化的瞬态搜索来检测。尽管仅对UCD的尺度高度敏感，但结果对假定的光谱指数$β$非常敏感。对于$β$从0到-2.5，预期检测的数量从$ \ sim $ 20增加到$ \ sim $ 3460。我们还考虑了跟踪UCD的候选候选者的策略，并讨论了调查结果对提高我们对UCD行为的了解的含义，以$ l $ band和dynamos的了解。
The Five-hundred-meter Aperture Spherical radio Telescope (FAST) completed its commissioning and began the Commensal Radio Astronomy FasT Survey (CRAFTS), a multi-year survey to cover 60% of the sky, in 2020. We present predictions for the number of radio-flaring ultracool dwarfs (UCDs) that are likely to be detected by CRAFTS. Based on the observed flaring UCDs from a number of unbiased, targeted radio surveys in the literature, we derive a detection rate of $\ge$3%. Assuming a flat radio spectrum $νL _ν\propto ν^{β+1} $ with $β$ = -1.0 for UCD flares, we construct a flare luminosity function $d N/d L \propto L^{-1.96 \pm 0.45}$ (here $L=νL_ν$). CRAFTS is found to be sensitive enough for flares from UCDs up to $\sim$180 pc. Considering the Galactic thin disk, we carry out a 3D Monte Carlo simulation of the UCD population, which is then fed to mock CRAFTS observations. We estimate that $\sim$170 flaring UCDs would be detected through transient searches in circular polarization. Though only marginally sensitive to the scale height of UCDs, the results are very sensitive to the assumed spectral index $β$. For $β$ from 0 to -2.5, the number of expected detections increases dramatically from $\sim$20 to $\sim$3460. We also contemplate the strategies for following up candidates of flaring UCDs, and discuss the implications of survey results for improving our knowledge of UCD behavior at $L$ band and dynamos.
