A Parkes “Murriyang” Search for Pulsars and Fast Transients in the Large Magellanic Cloud
A Parkes “Murriyang” Search for Pulsars and Fast Transients in the Large Magellanic Cloud
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DOI：
10.3847/1538-4357/ac5802
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发表时间：
2022-02
期刊：
影响因子：
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通讯作者：
S. Hisano;F. Crawford;Victoria Bonidie;Md F. Alam;Keitaro Takahashi;D. Lorimer;J. Ridley;M. Mclaughlin;B. Perera
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文献类型：
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作者：
S. Hisano;F. Crawford;Victoria Bonidie;Md F. Alam;Keitaro Takahashi;D. Lorimer;J. Ridley;M. Mclaughlin;B. Perera
我们报告的最新结果的Parkes多波束调查的大麦哲伦云（LMC）的射电暴和分散。我们进行了周期性和单脉冲搜索在一个更大的范围内的试验分散措施（DM）比以前搜索。我们检测到229个信噪比（S/N）> 7的单脉冲，这些脉冲被深度学习网络FETCH分类为真实的（具有>90%的可能性），其中9个来自已知的巨脉冲发射脉冲星PSR B 0540 −69。两个可能重复的来源被检测到与DM，这表明他们位于LMC内，但这些需要确认。220个未知脉冲中只有三个具有S/N > 8，并且这些检测到的脉冲的DM分布随着DM的增加遵循指数衰减，并且在LMC预期的DM值处没有显示任何过量的信号。这些特征表明，检测到的脉冲不太可能是真实的，尽管它们在视觉上引人注目。我们还报告了在周期搜索中发现的一颗新脉冲星（PSR J 0556 −67）。这颗脉冲星的自旋周期为791 ms，DM为71 cm−3 pc，1400 MHz的通量密度估计为1.000.12 mJy，并且没有显示出双星运动的证据。未来的观测也许能够确认我们在单脉冲和周期性搜索中发现的任何微弱但有希望的候选者，包括我们的两个可能的中继站，是否是真实的。
We report on the latest results of a Parkes multibeam survey for pulsars and dispersed radio bursts in the Large Magellanic Cloud (LMC). We conducted both periodicity and single-pulse searches at a much larger range of trial dispersion measures (DMs) than previously searched. We detected 229 single pulses with signal-to-noise ratio (S/N) > 7 that were classified by the deep-learning network FETCH as being real (with >90% likelihood), of which nine were from the known giant-pulse-emitting pulsar PSR B0540−69. Two possibly repeating sources were detected with DMs suggesting that they lie within the LMC, but these require confirmation. Only three of the 220 unknown pulses had S/N > 8, and the DM distribution for these detected pulses follows an exponential falloff with increasing DM and does not show any excess of signals at DM values expected for the LMC. These features suggest that the detected pulses are not likely to be real, although they are visually compelling. We also report the discovery of a new pulsar (PSR J0556−67) in our periodicity search. This pulsar has a spin period of 791 ms, a DM of 71 cm−3 pc, an estimated 1400 MHz flux density of ∼0.12 mJy, and shows no evidence of binary motion. Future observations may be able to confirm whether any of the weak but promising candidates in our single-pulse and periodicity searches, including our two possible repeaters, are real or not.