论文标题

有针对性的搜索MWA重复快速无线电爆发

A targeted search for repeating fast radio bursts with the MWA

论文作者

Tian, J., Anderson, G. E., Hancock, P. J., Miller-Jones, J. C. A., Sokolowski, M., James, C. W., Bhat, N. D. R., Swainston, N. A., Ung, D., Meyers, B. W.

论文摘要

我们提出了针对低频(144---215 \,MHz)的有针对性搜索,该搜索使用五个重复的FRB,使用23.3 \,使用23.3 \,在2014年9月至2020年5月之间使用Murchison Widefield阵列(MWA)电压捕获系统(VCS)获取的档案数据的HR。这是MWA VCS首次用于搜索已知中继器的FRB信号,这比以前使用标准MWA相关器模式更敏感的FRB搜索。我们进行了标准的单脉冲搜索,分别以$ 400 \,μ$ s和10 \,kHz为$ 100 \,\ text {pc} \,\ text {cm}^{ - 3} $分散量(dm)范围的每个已知的重复率frb的范围。未检测到超过$6σ$阈值的FRB。 The fluence upper limits in the range of 32--1175\,Jy\,ms and 36--488\,Jy\,ms derived from 10 observations of FRB 20190711A and four observations of FRB 20201124A respectively, allow us to constrain the spectral indices of their bursts to $\gtrsim-1$ if these two repeaters were active during the MWA observations.如果免费吸收对我们的非检测负责,我们可以根据电子温度$ t $限制吸收介质的大小至$ <1.00 \ times(t/10^4 \ text {k})^{ - 1.35} $ <0.92 \ times(t/10^4 \ text {k})^{ - 1.35} \,\ text {pc} $和$ <[0.22 \ text { - } 2.50] \ times \ times(t/10^4 \ text {k})和20201124a。但是,鉴于这些中继器的活动未得到很好的特征,我们的非目录也可能表明它们在MWA观察过程中没有活性。

We present a targeted search for low-frequency (144--215\,MHz) FRB emission from five repeating FRBs using 23.3\,hr of archival data taken with the Murchison Widefield Array (MWA) Voltage Capture System (VCS) between 2014 September and 2020 May. This is the first time that the MWA VCS has been used to search for FRB signals from known repeaters, which enables much more sensitive FRB searches than previously performed with the standard MWA correlator mode. We performed a standard single pulse search with a temporal and spectral resolution of $400\,μ$s and 10\,kHz, respectively, over a $100\,\text{pc}\,\text{cm}^{-3}$ dispersion measure (DM) range centred at the known DM of each studied repeating FRB. No FRBs exceeding a $6σ$ threshold were detected. The fluence upper limits in the range of 32--1175\,Jy\,ms and 36--488\,Jy\,ms derived from 10 observations of FRB 20190711A and four observations of FRB 20201124A respectively, allow us to constrain the spectral indices of their bursts to $\gtrsim-1$ if these two repeaters were active during the MWA observations. If free-free absorption is responsible for our non-detection, we can constrain the size of the absorbing medium in terms of the electron temperature $T$ to $<1.00\times(T/10^4\text{K})^{-1.35}\,\text{pc}$, $<0.92\times(T/10^4\text{K})^{-1.35}\,\text{pc}$ and $<[0.22\text{--}2.50]\times(T/10^4\text{K})^{-1.35}\,\text{pc}$ for FRB 20190117A, 20190711A, and 20201124A, respectively. However, given that the activities of these repeaters are not well characterised, our non-detections could also suggest they were inactive during the MWA observations.

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