FREDDA消色散算法对利用快速射电暴估算哈勃常数H₀的影响
The impact of the FREDDA dedispersion algorithm on $H_0$ estimations with FRBs
AI总结：
本文通过将13个ASKAP探测到的FRB信号注入FREDDA系统，经验性地刻画其消色散灵敏度，并评估该灵敏度对利用FRB估算哈勃常数H₀所引入的系统误差，发现该误差在约400个定位FRB之前不显著，但未来可能影响哈勃张力的解决。
摘要：
快速射电暴（FRBs）是源自河外的瞬态射电信号，会受到色散和散射等传播效应的影响。因此，这些信号携带着其所穿越介质的信息，可作为宇宙学的探针来研究宇宙。近期，FRBs被用于独立测量哈勃常数H₀，有望在探测到足够数量的FRBs后解决哈勃张力问题。此类宇宙学研究依赖于FRB种群统计、宇宙学参数和探测偏差，因此准确刻画其中每一项都至关重要。在本工作中，我们经验性地刻画了快速实时消色散幅度引擎（FREDDA）的灵敏度，该系统是澳大利亚平方千米阵列探路者（ASKAP）当前的探测系统。我们对13个ASKAP探测到的FRB的高时间分辨率数据进行相干再色散，并将其注入FREDDA，以确定恢复的信噪比随色散量（DM）的变化关系。我们发现，对于13个FRB中的11个，这些结果与注入理想化脉冲的结果一致。当H₀是唯一自由参数时，用理论预测近似该灵敏度函数会在H₀上引入0.3 km s⁻¹ Mpc⁻¹的系统误差。若允许额外参数变化，该系统性误差可能增大至约1 km s⁻¹ Mpc⁻¹。我们估计，在探测到约400个定位FRB之前，该系统误差不会产生显著影响，但在解决哈勃张力问题时可能会变得重要。
英文摘要：
Fast radio bursts (FRBs) are transient radio signals of extragalactic origins that are subjected to propagation effects such as dispersion and scattering. It follows then that these signals hold information regarding the medium they have traversed and are hence useful as cosmological probes of the Universe. Recently, FRBs were used to make an independent measure of the Hubble Constant $H_0$, promising to resolve the Hubble tension given a sufficient number of detected FRBs. Such cosmological studies are dependent on FRB population statistics, cosmological parameters and detection biases, and thus it is important to accurately characterise each of these. In this work, we empirically characterise the sensitivity of the Fast Real-time Engine for Dedispersing Amplitudes (FREDDA) which is the current detection system for the Australian Square Kilometer Array Pathfinder (ASKAP). We coherently redisperse high-time resolution data of 13 ASKAP-detected FRBs and inject them into FREDDA to determine the recovered signal-to-noise ratios as a function of dispersion measure (DM). We find that for 11 of the 13 FRBs, these results are consistent with injecting idealised pulses. Approximating this sensitivity function with theoretical predictions results in a systematic error of 0.3$\,$km$\,$s$^{-1}\,$Mpc$^{-1}$ on $H_0$ when it is the only free parameter. Allowing additional parameters to vary could increase this systematic by up to $\sim1\,$km$\,$s$^{-1}\,$Mpc$^{-1}$. We estimate that this systematic will not be relevant until $\sim$400 localised FRBs have been detected, but will likely be significant in resolving the Hubble tension.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
