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A SETI survey of the Vela region using the Murchison Widefield Array: Orders of magnitude expansion in search space
Publications of the Astronomical Society of Australia ( IF 6.3 ) Pub Date : 2020-09-07 , DOI: 10.1017/pasa.2020.27
C. D. Tremblay , S. J. Tingay

Following the results of our previous low-frequency searches for extraterrestrial intelligence (SETI) using the Murchison Widefield Array (MWA), directed towards the Galactic Centre and the Orion Molecular Cloud (Galactic Anticentre), we report a new large-scale survey towards the Vela region with the lowest upper limits thus far obtained with the MWA. Using the MWA in the frequency range 98–128 MHz over a 17-h period, a $400\,\textrm{deg}^{2}$ field centred on the Vela Supernova Remnant was observed with a frequency resolution of 10 kHz. Within this field, there are six known exoplanets. At the positions of these exoplanets, we searched for narrow-band signals consistent with radio transmissions from intelligent civilisations. No unknown signals were found with a 5 $\sigma$ detection threshold. In total, across this work plus our two previous surveys, we have now examined 75 known exoplanets at low frequencies. In addition to the known exoplanets, we have included in our analysis the calculation of the Effective Isotropic Radiated Power (EIRP) upper limits towards over 10 million stellar sources in the Vela field with known distances from Gaia (assuming a 10-kHz transmission bandwidth). Using the methods of Wright, Kanodia, & Lubar (2018) to describe an eight-dimensional parameter space for SETI searches, our survey achieves the largest search fraction yet, two orders of magnitude higher than the previous highest (our MWA Galactic Anticentre survey), reaching a search fraction of $\ \sim2\,{\times}\,10^{-16}$ . We also compare our results to previous SETI programs in the context of the $\mbox{EIRP}_{\textrm{min}}$ —Transmitter Rate plane. Our results clearly continue to demonstrate that SETI has a long way to go. But, encouragingly, the MWA SETI surveys also demonstrate that large-scale SETI surveys, in particular for telescopes with a large field-of-view, can be performed commensally with observations designed primarily for astrophysical purposes.

中文翻译:

使用 Murchison 宽场阵列对 Vela 地区的 SETI 调查:搜索空间中的数量级扩展

根据我们之前使用默奇森宽场阵列(MWA)对银河中心和猎户座分子云(银河反中心)进行低频搜索的结果,我们报告了一项针对银河系中心的新的大规模调查。迄今为止使用 MWA 获得的具有最低上限的 Vela 区域。在 17 小时内使用 98-128 MHz 频率范围内的 MWA, $400\,\textrm{度}^{2}$ 以 10 kHz 的频率分辨率观察到以 Vela 超新星遗迹为中心的场。在这个领域内,有六颗已知的系外行星。在这些系外行星的位置,我们搜索了与智能文明无线电传输一致的窄带信号。5 未发现未知信号 $\sigma$ 检测阈值。总的来说,通过这项工作加上我们之前的两次调查,我们现在已经检查了 75 颗已知的低频系外行星。除了已知的系外行星,我们在分析中还包括了对距离已知距离的船帆场中超过 1000 万个恒星源的有效全向辐射功率 (EIRP) 上限的计算。盖亚(假设传输带宽为 10 kHz)。使用 Wright、Kanodia 和 Lubar (2018) 的方法来描述用于 SETI 搜索的八维参数空间,我们的调查实现了迄今为止最大的搜索分数,比之前的最高值高两个数量级(我们的 MWA 银河反中心调查) ,达到搜索分数 $\ \sim2\,{\times}\,10^{-16}$ . 我们还将我们的结果与之前的 SETI 计划进行比较 $\mbox{EIRP}_{\textrm{min}}$ — 发射机速率平面。我们的结果清楚地继续表明SETI还有很长的路要走。但是,令人鼓舞的是,MWA SETI 调查还表明,大规模的 SETI 调查,特别是对于具有大视场的望远镜,可以与主要用于天体物理学目的的观测一起进行。
更新日期:2020-09-07
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