标题： 关于在LPA LPI搜寻磁星SGR1935+2154的脉冲辐射 显示英文标题

标题： About the search for pulsed radiation from the magnetar SGR1935+2154 at the LPA LPI

摘要： J1935+2154 被知为软伽马射线辐射源。 磁星的超耀斑在 2020 年 5 月被 FAST 望远镜在 1.25 GHz 的频率上探测到。 磁星进入了在 LPA 射电望远镜上进行的调查，工作频率为 111 MHz。 对之前发表的（Fedorova 等人，2021 年）来自磁星 SGR1935+2154 的脉冲进行了检查。 在 LPA 收到的数据以两种模式并行记录：低时间和高频率-时间分辨率模式；6 个通道，每个通道宽度为 415 kHz，时间分辨率 \Delta t = 100 ms；32 个通道，每个通道宽度为 78 kHz，时间分辨率 \Delta t = 12.5 ms。 原始搜索使用了低时间-频率分辨率的数据。 由于散射与频率的四次方成正比以及脉冲在频率信道中的色散展宽与频率的二次方成正比，在米波长范围内的色散信号搜索比在分米波长范围内更困难。 为了收集展宽的脉冲信号并获得最佳的信噪比（S/N），搜索采用了基于多通道数据与展宽脉冲模板卷积算法的方法。 模板的形状对应于具有色散度量（DM）为 375 pc/cm³ 的展宽脉冲的形状。 为了重复验证，使用了相同的探测到磁星脉冲的数据。 还使用了更高频率-时间分辨率的数据对已发布的脉冲进行了额外检查。 由于在 32 通道数据中频率信道的色散展宽是 6 通道数据的五分之一，因此预计 S/N 脉冲大约会增加两倍。 在 32 通道或 6 通道数据中，没有检测到来自 SGR1935+2154 的脉冲峰值位移依赖于 DM 的信噪比 S/N > 4 的脉冲辐射。 显示英文摘要

摘要： J1935+2154 is known as a source of soft gamma radiation. Hyperflares from magnetar were detected at a frequency of 1.25 GHz on the FAST telescope in May 2020. The magnetar enters the survey conducted on LPA radio telescope at 111 MHz. A check of the previously published (Fedorova et al. 2021) pulse from the magnetar SGR1935+2154 was carried out. The data received on the LPA is recorded in parallel in two modes having low and high frequency-time resolution: 6 channels with a channel width of 415 kHz and a time resolution of \Delta t = 100 ms; 32 channels with a channel width of 78 kHz and a time resolution of \Delta t = 12.5 ms. The original search was carried out using data with low time-frequency resolution. The search for dispersed signals in the meter wavelength range is difficult, compared with the search in the decimeter range, due to scattering proportional to the fourth power of frequency and dispersion smearing of the pulse in frequency channels proportional to the second power of frequency. In order to collect a broadened pulse signal and obtain the best value of S/N, the search was carried out using an algorithm based on the convolution of multichannel data with a scattered pulse pattern. The shape of the template corresponds to the shape of a scattered pulse with a dispersion measure (DM) of 375 pc/cm3. For repeated verification, the same data was used in which the pulse from the magnetar was detected. An additional check of the published pulse was also carried out using data with a higher frequency-time resolution. Since the dispersion smearing in the frequency channel in the 32-channel data is 5 times less than in the 6-channel data, an increase approximately 2 times in the S/N pulse could be expected. Pulse radiation with S/N>4 having a pulse peak shift depending on DM from SGR1935+2154 was not detected in either 32-channel or 6-channel data.