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Design and Application of an S-band Fast Radio Bursts Search Pipeline for the Nanshan 26 m Radio Telescope

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Research in Astronomy and Astrophysics 2024年第7期24卷 114-120页

作者： Yan-Ling Liu Mao-Zheng Chen Jian Li Jian-Ping Yuan rai yuen Zhi-Yong Liu Hao Yan Wen-Long Du Nan-Nan Zhai Xinjiang Astronomical Observatory Chinese Academy of Sciences Xinjiang Key Laboratory of Microwave Technology University of Chinese Academy of Sciences

Fast radio bursts(FRBs) are among the most studied radio transients in astrophysics, but their origin and radiation mechanism are still unknown. It is a challenge to search for FRB events in a huge amount of observational data with high speed and high accuracy. With the rapid advancement of the FRB research process, FRB searching has changed from archive data mining to either long-term monitoring of the repeating FRBs or all-sky surveys with specialized equipments. Therefore, establishing a highly efficient and high quality FRB search pipeline is the primary task in FRB research. Deep learning techniques provide new ideas for FRB search processing. We have detected radio bursts from FRB 20201124A in the L-band observational data of the Nanshan 26 m radio telescope(NSRT-26m) using the constructed deep learning based search pipeline named dispersed dynamic spectra search(DDSS). Afterwards, we further retrained the deep learning model and applied the DDSS framework to S-band observations. In this paper, we present the FRB observation system and search pipeline using the S-band *** carried out search experiments, and successfully detected the radio bursts from the magnetar SGR J1935+2145and FRB 20220912A. The experimental results show that the search pipeline can complete the search efficiently and output the search results with high accuracy.

关键词： methods: data analysis methods: observational radio continuum: general

The Bright Single Pulse Emission from PSR B1133+16

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Research in Astronomy and Astrophysics 2024年第4期24卷 253-261页

作者： Jun Tan Zhi-Gang Wen Zhen Wang Xue-Feng Duan Hong-Guang Wang Na Wang Vishal Gajjar Jian-Ping Yuan rai yuen Wen-Ming Yan Jian-Ling Chen Wei Han Hui Wang Cheng-Bing Lyu Ai-Jun Dong Maths and Information Technology School Yuncheng UniversityYuncheng 044000China Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Xinjiang Key Laboratory of Radio Astrophysics Urumqi 830011China School of Physics and Materials Science Guangzhou UniversityGuangzhou 510006China Space Science Laboratory University of CaliforniaBerkeley 94710USA Department of Physics and Electronic Engineering Yuncheng UniversityYuncheng 044000China School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550025China

We have conducted a comprehensive investigation into the bright single pulse emission from PSR B1133+16using the Giant Metrewave Radio *** time resolution data(61μs)were obtained at a center frequency of 322 MHz with a bandwidth of 32 MHz over a continuous observation period of 7.45 hr.A total of 1082 bright pulses were sporadically detected with peak flux densities ranging from 10 to 23 times stronger than the average pulse ***,no giant pulse-like emission with a relative pulse energy larger than 10 and extremely short duration was detected,indicating that these bright pulses cannot be categorized as giant pulse *** majority of these bright pulses are concentrated in pulse phases at both the leading and trailing windows of the average pulse profile,with an occurrence ratio of approximately *** pulse energy distribution for all individual pulses can be described by a combination of two Gaussian components and a cutoff power-law with an index of α=-*** updated nulling fraction of 15.35%±0.45% was determined from the energy *** emission of individual pulses follows a log-normal distribution in peak flux density *** is imperative that regular phase drifting in bright pulse sequence is identified in both the leading and trailing components for the first *** physical mechanisms are discussed in detail to provide insights into these observations.

关键词： (stars:)pulsars:general (stars:)pulsars:individual(PSR B1133+16) methods:observational methods:data analysis

脉冲星J2313+4253的周期性消零和奇偶调制特性的研究

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中国科学：物理学、力学、天文学 2024年第4期54卷 185-198页

作者：陈建玲温志刚王洪光王娜袁建平 rai yuen 闫文明韩伟李永宏王金鹏项斌斌运城学院物理与电子工程系运城044000 中国科学院新疆天文台乌鲁木齐830011 广州大学天体物理中心广州510006 新疆大学机电工程学院乌鲁木齐830017

脉冲星子脉冲的强度调制特征对揭示脉冲星辐射过程和磁层几何具有重要意义.前人研究表明,PSR J2313+4253的单脉冲序列具有44倍和2倍自转周期的强度调制.其中2倍周期的调制周期被称为奇偶性调制,其物理起源并不清晰.本文利用佳木斯66 m... 详细信息

脉冲星子脉冲的强度调制特征对揭示脉冲星辐射过程和磁层几何具有重要意义.前人研究表明,PSR J2313+4253的单脉冲序列具有44倍和2倍自转周期的强度调制.其中2倍周期的调制周期被称为奇偶性调制,其物理起源并不清晰.本文利用佳木斯66 m射电望远镜的观测数据,对脉冲星J2313+4253在2250 MHz的单脉冲辐射特性进行了详细研究.通过相位分离涨落谱(LRFS)、谐频分离的涨落谱(HRFS)和二维涨落谱(2DFS)的分析方法,发现PSR J2313+4253的奇偶性调制来自于其短周期子脉冲漂移,并且调制现象展现出了时间依赖性.分析表明,旋转木马模型下,奇偶性调制可能起源于脉冲星火花放电过程中,辐射区子辐射束间边界不清晰而发生的混叠效应.

关键词：脉冲星单脉冲消零

A Search Technique Based on Deep Learning for Fast Radio Bursts and Initial Results for FRB 20201124A with the NSRT

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Research in Astronomy and Astrophysics 2022年第10期22卷 77-85页

作者： Yan-Ling Liu Jian Li Zhi-Yong Liu Mao-Zheng Chen Jian-Ping Yuan Na Wang rai yuen Hao Yan Xinjiang Astronomical observatory Chinese Academy of SciencesUrumqi 830011China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Radio Astronomy Chinese Academy of SciencesNanjing 210033China Xinjiang Key Laboratory of Microwave Technology Urumqi 830011China

The origin and phenomenology of Fast Radio Bursts(FRBs) remain unknown. Fast and efficient search technology for FRBs is critical for triggering immediate multi-wavelength follow-up and voltage data dump. This paper proposes a dispersed dynamic spectra search(DDSS) pipeline for FRB searching based on deep learning, which performs the search directly from observational raw data, rather than relying on generated FRB candidates from single-pulse search algorithms that are based on de-dispersion. We train our deep learning network model using simulated FRBs as positive and negative samples extracted from the observational data of the Nanshan 26 m radio telescope(NSRT)at Xinjiang Astronomical Observatory. The observational data of PSR J1935+1616 are fed into the pipeline to verify the validity and performance of the pipeline. Results of the experiment show that our pipeline can efficiently search single-pulse events with a precision above 99.6%, which satisfies the desired precision for selective voltage data dump. In March 2022, we successfully detected the FRBs emanating from the repeating case of FRB 20201124A with the DDSS pipeline in L-band observations using the NSRT. The DDSS pipeline shows excellent sensitivity in identifying weak single pulses, and its high precision greatly reduces the need for manual review.

关键词： radio continuum general-methods data analysis-methods observational

Frequency dependence in the emission from subpulse drifting pulsars

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Research in Astronomy and Astrophysics 2021年第9期21卷 153-162页

作者：韩晓红 rai yuen Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Key Laboratory of Radio Astronomy Chinese Academy of SciencesUrumqi 830011China SIfA School of PhysicsUniversity of SydneySydneyNSW 2006Australia

We investigate relations in the emission properties as revealed by drifting subpulses detected at different observing frequencies based on the method that incorporates the rotating carousels in pulsar magnetospheres of multiple emission *** emission state is associated with particular emission properties as determined by the drifting subpulses at a particular frequency,and different emission states obtained at different frequencies reveal the variation of emission properties across the emission *** method allows the determination of the essential radio emission properties such as the relative emission height,subpulse number,charge density and the plasma flow relative to corotation in an emission region for a particular *** apply the method to seven pulsars that exhibit subpulse drifting along single drift-band at 326 MHz and 1429 *** results show that drifting subpulses observed at different frequencies correspond to particular emission states suggesting that the pulsar emission properties are frequency *** show that emission follows the frequency-to-radius mapping for pulsars with obliquity angle?30°regardless of the sign and magnitude of the *** pulsars with long rotation periods in our sample,the circulation time for the plasma to revolve once around the magnetosphere relative to corotation increases as the rotation period increases at both frequencies,but exhibits irregularity for pulsars with short rotation *** results suggest that evolution of the obliquity angles in subpulse drifting pulsars is from large to small,and the emission region tends to be’thicker’in younger pulsars.

关键词： radiation mechanisms:non-thermal pulsar:general

脉冲星射电轮廓中高斯成分在主脉冲和中间脉冲的不同分布

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天文学报 2022年第3期63卷 41-55页

作者：韩晓红 yuen rai 中国科学院新疆天文台乌鲁木齐830011 中国科学院射电天文重点实验室南京210023 悉尼大学物理学院悉尼NSW 2006

研究了高斯辐射成分在可视点所画出轨迹上的分布,这个可视点因脉冲星的转动而作非匀速度运动.通过假设辐射区域围绕磁轴均匀分布,一个高斯辐射成分便对应于可视轨迹划过的一个辐射区域.因为演示辐射区域在可视轨迹上是不均匀的分布,因... 详细信息

研究了高斯辐射成分在可视点所画出轨迹上的分布,这个可视点因脉冲星的转动而作非匀速度运动.通过假设辐射区域围绕磁轴均匀分布,一个高斯辐射成分便对应于可视轨迹划过的一个辐射区域.因为演示辐射区域在可视轨迹上是不均匀的分布,因此高斯成分沿轨迹也是不均匀的,而高斯成分的密度在磁轴与视线距离最近时为最大.高斯成分的分布取决于脉冲星的两个角度:旋转轴和视线之间的夹角,以及磁轴和旋转轴之间的倾角.基于此模型,一个脉冲星平均轮廓中观察到的多个高斯成分便对应于可视轨迹在特定的转动相位范围内的辐射区域.演示了脉冲星旋转的近侧和远侧的相位,分别对应的主脉冲和中间脉冲,两者高斯成分的数量和分布是不同的.而且还发现,沿可视轨迹上的辐射区域总数与围绕磁轴的辐射区域的总数是不同,并且预测的辐射区域数目会因忽略可见点的运动而明显不同.拟合表明脉冲星轮廓的高斯成分的形状和数量可能与实际构成轮廓的成分的形状和数量不同.以PSR B0826-34的辐射为例,并假设辐射来自单一磁极.

关键词：辐射机制:非热脉冲星:普通方法:分析

A single pulse study of PSR J1752+2359

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Research in Astronomy and Astrophysics 2021年第9期21卷 262-268页

作者：孙盛楠闫文明王娜 rai yuen Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Radio Astronomy Chinese Academy of SciencesNanjing 210008China Xinjiang Key Laboratory of Radio Astrophysics 150 Science 1-StreetUrumqi 830011China

The single pulse observation of PSR J1752+2359 at 1250 MHz made using the Five-hundredmeter Aperture Spherical radio Telescope(FAST)is *** show that the pulsar exhibits two distinct emission states:a normal state with continuous normal pulse emission and a rotating radio transient(RRAT)-like state with sporadic *** makes PSR J1752+2359 the third pulsar that exhibits switching between RRAT-like and pulsar-like *** data show that,during the observation,20 per cent of the time for this pulsar was in the normal state and 80 per cent in the RRAT-like state.A quasiperiodic switching,with a periodicity of around 568 spin periods,between the two states was *** pulse energies for the two states both follow log-normal *** demonstrate that the polarization profiles and the linear polarization position angle(PA)swings differ significantly between the two *** is a phase offset of about 0°.35 between the pulse profile peaks of the two *** argue that the emission geometry in the magnetosphere may be different for the two states.

关键词： stars neutron-pulsars general-pulsars individual(PSR J1752+2359)

The Multiple Images of the Plasma Lensing FRB

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Research in Astronomy and Astrophysics 2022年第6期22卷 190-203页

作者： Yu-Bin Wang Zhi-Gang Wen rai yuen Na Wang Jian-Ping Yuan Xia Zhou Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Radio Astronomy Chinese Academy of SciencesNanjing 210008China Xinjiang Key Laboratory of Radio Astrophysics Urumqi 830011China

We investigate the formation of multiple images as the radio signals from fast radio bursts(FRBs)pass through the plane of a plasma *** exponential model for the plasma clump is adopted to analyze the properties of the multiple *** comparing with the classical dispersion relations,we find that one image has exhibited specific inverse properties to others,such as their delay times at high frequency is higher than that at low frequency,owing to the lensing effects of the plasma *** demonstrate that these inverse effects should be observable in some repeating *** results predict deviation in the estimated dispersion measure(DM)across multiple images,consistent with the observations of FRB 121102 and FRB 180916.J0158+*** other plasma lenses have effects similar to an exponential lens,we find that they should also give rise to a similar dispersion relation in the multiple *** some repeating FRBs,analysis of the differences in time delay and in DM between multiple images at different frequencies can serve as a method to reveal the plasma distribution.

关键词： galaxies distances and redshifts galaxies ISM gravitational lensing:strong-ISM structure-scattering

Visibility of pulsar emission:motion of the visible point

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Visibility of pulsar emission:motion of the visible point