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The fast all sky HI survey(FASHI):The first release of catalog

Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 112-133页

作者： Chuan-Peng Zhang Ming Zhu Peng Jiang Cheng Cheng Jing Wang Jie Wang Jin-Long Xu Xiao-Lan Liu Nai-Ping Yu Lei Qian Haiyang Yu Mei Ai Yingjie Jing Chen Xu Ziming Liu Xin Guan Chun Sun Qingliang Yang Menglin Huang Qiaoli Hao fast collaboration Guizhou Radio Astronomical Observatory Guizhou UniversityGuiyang 550000China National Astronomical Observatories Chinese Academy of Sciences(CAS)Beijing 100101China Chinese Academy of Sciences South America Center for Astronomy National Astronomical ObservatoriesCASBeijing 100101China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China

The fast All Sky HI survey(FASHI)was designed to cover the entire sky observable by the Five-hundred-meter Aperture Spherical radio Telescope(fast),spanning approximately 22000 square degrees of declination between-14°and+66°,and in the frequency range of 1050-1450 MHz,with the expectation of eventually detecting more than 100000 HI *** August 2020 and June 2023,FASHI had covered more than 7600 square degrees,which is approximately 35%of the total sky observable by *** has a median detection sensitivity of around 0.76 m Jy beam-1and a spectral line velocity resolution of~6.4 km s-1at a frequency of~1.4 *** of now,a total of 41741 extragalactic HI sources have been detected in the frequency range 1305.5-1419.5 MHz,corresponding to a redshift limit of z■*** cross-matching FASHI sources with the Siena Galaxy Atlas(SGA)and the Sloan Digital Sky Survey(SDSS)catalogs,we found that 16972(40.7%)sources have spectroscopic redshifts and 10975(26.3%)sources have only photometric *** of the remaining 13794(33.0%)HI sources are located in the direction of the Galactic plane,making their optical counterparts difficult to identify due to high extinction or high contamination of Galactic stellar *** on current survey results,the FASHI survey is an unprecedented blind extragalactic H I *** has higher spectral and spatial resolution and broader coverage than the Arecibo Legacy fast ALFA Survey(ALFALFA).When completed,FASHI will provide the largest extragalactic HI catalog and an objective view of HI content and large-scale structure in the local universe.

关键词： surveys redshifts galaxies telescope radio lines HI line

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fast ultra-wideband observation of abnormal emission-shift events of PSR B0919+06

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Science China(Physics,Mechanics & Astronomy) 2019年第5期62卷 32-37页

作者： Ye-Zhao Yu Bo Peng Kuo Liu ChengMin Zhang Lin Wang FeiFei Kou JiGuang Lu Meng Yu fast collaboration CAS Key Laboratory of fast National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Astronomy and Space Sciences University of Chinese Academy of SciencesBeijing 100049China Max-Planck-Institut fur Radioastronomie Auf dem Hugel 69Bonn 53121Gennany 不详

PSR B0919+06 is known for its abnormal emission phenomenon, where the pulse emission window occasionally shifts progressively in longitude and returns afterwards. The physical mechanism behind this phenomenon is still under investigation. In this paper, we present our ultra-wideband observation of this pulsar using the Five-hundred-meter Aperture Spherical radio Telescope(fast), with simultaneous measurements in the frequency ranges 280-780 and 1250-1550 MHz. We have identified three abnormal events, each of which becomes less apparent as the frequency decreases. At 1400 MHz, the averaged profile slightly shifted after the first and third abnormal events, implying a relationship between abnormal event and profile variation. We also found a linear trend in the left-edge position of the averaged profiles between the first and third events as well as after the third event, suggesting the existence of a slow-drifting mode between the two major events. The second event has a comparatively small shift in phase and is thus categorized as a "small flare state". During the third event, a sequence of approximately nine pulses was seen to significantly weaken in all frequency bands, likely associated with the pseudo-nulling observed at 150 MHz.A three-component de-composition analysis of the normal averaged profiles shows that the trailing component is dominant at our observing frequencies, while the centre component has a comparatively steeper spectrum. We found the overall flux density in an abnormal event to slightly differ from that in an ordinary state, and the difference shows a frequency dependence. A comparison of the normal, abnormal and dimmed averaged profile indicates that the leading component is likely to be stable in all states.

关键词： pulsar B0919+06 radio

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Study of three rotating radio transients with fast

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Science China(Physics,Mechanics & Astronomy) 2019年第5期62卷 25-31页

作者： JiGuang Lu Bo Peng Kuo Liu Peng Jiang YouLing Yue Meng Yu Ye-Zhao Yu FeiFei Kou Lin Wang fast collaboration CAS Key Laboratory of fast National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Guizhou Radio Astronomy Observatory Chinese Academy of SciencesGuiyang 550025China Max-Planck-lnstitut fiir Radioastronomie Bonn D-53121Germany College of Astronomy and Space Sciences University of Chinese Academy of SciencesBeijing 100049China 不详

Rotating radio transients(RRATs) are peculiar astronomical objects whose emission mechanism remains under *** this paper, we present observations of three RRATs, J1538+2345, J1854+0306 and J1913+1330, carried out with the Fivehundred-meter Aperture Spherical radio Telescope(fast). Specifically, we analyze the mean pulse profiles and temporal flux density evolutions of the RRATs. Owing to the high sensitivity of fast, the derived burst rates of the three RRATs are higher than those in previous reports. RRAT J1854+0306 exhibited a time-dynamic mean pulse profile, whereas RRAT J1913+1330 showed distinct radiation and nulling segments on its pulse intensity trains. The mean pulse profile variation with frequency is also studied for RRAT J1538+2345 and RRAT J1913+1330, and the profiles at different frequencies could be well fitted with a cone-core model and a conal-beam model, respectively.

关键词： radiation mechanisms radio pulsars

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The radiation structure of PSR B2016+28 observed with fast

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Science China(Physics,Mechanics & Astronomy) 2019年第5期62卷 38-51页

作者： JiGuang Lu Bo Peng RenXin Xu Meng Yu Shi Dai WeiWei Zhu Ye-Zhao Yu Peng Jiang YouLing Yue Lin Wang fast collaboration CAS Key Laboratory of fast National Astronomical Obserx'atoriesChinese Academy of SciencesBeijing 100101China Guizhou Radio Astronomy Observatory Chinese Academy of SciencesGuiyang 550025China School of Physics and Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China CSIRO Astronomy and Space Science Australia Telescope National Facility Epping NSW 1710Australia College of Astronomy and Space Sciences University of Chinese Academy of SciencesBeijing 100049China 不详

With the largest dish Five-hundred-meter Aperture Spherical radio Telescope(fast), both the mean and single pulses of PSR B2016+28, especially including the single-pulse structure, are investigated in detail in this study. The mean pulse profiles at different frequencies can be well fitted in a conal model, and the peak separation of intensity-dependent pulse profiles increases with intensity. The integrated pulses are obviously frequency dependent(pulse width decreases by ～20% as frequency increases from 300 to 750 MHz), but the structure of single pulses changes slightly(the corresponding correlation scale decreases by only～1%). This disparity between mean and single pulses provides independent evidence for the existence of the RS-type vacuum inner gap, indicating a strong bond between particles on the pulsar surface. Diffused drifting sub-pulses are analyzed. The results show that the modulation period along pulse series(P_3) is positively correlated to the separation between two adjacent sub-pulses(P_2). This correlation may hint a rough surface on the pulsar, eventually resulting in the irregular drift of sparks. All the observational results may have significant implications in the dynamics of pulsar magnetosphere and are discussed extensively in this paper.

关键词： radiation mechanisms mathematical procedures and computer techniques radio pulsars

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fast interstellar scintillation observation of PSR B1929+10 and PSR B1842+14

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Research in Astronomy and Astrophysics 2020年第5期20卷 175-180页

作者： Ju-Mei Yao Wei-Wei Zhu Pei Wang Di Li Ji-Guang Lu Fei-Fei Kou Ye-Zhao Yu Bo Peng fast collaboration CAS Key Laboratory of fast National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Xinjiang Astronomical Observatories Chinese Academy of SciencesUrumqi 830011China School of Physics and Electronics Qiannan Normal University for NationalitiesDuyun 558000China

In this paper,we present the Five-hundred-meter Aperture Spherical radio Telescope(fast)observations of PSRs B1929+10 and B1842+*** analysis of the pulsars’scintillation pattern,we detected the known scintillation arc from PSR B1929+10 and two previously undetected scintillation arcs from B1842+*** find that the B1929+10 arc’s curvature scales with observing frequency asη-∝ν-2.1±0.1 andη+∝ν-1.8±0.2,consistent with Arecibo results and the theoretical expectations ofη∝ν-*** the arc curvature,we infer the scattering screen to be located at 0.20±0.02 kpc from the Earth,close to what was measured by RadioAstron at 324 *** B1842+14,we find two scintillation arcs for the first *** arcs’curvatures imply that they are caused by two scattering screens located at a distance of 0.3±0.2 kpc and 1.6±0.6 kpc from the Earth,*** screen distance uncertainties mainly come from the uncertainty in pulsar’s dispersion measure(DM)-derived *** present these fast scintillation observations and discuss the future prospect of fast pulsar scintillation study.

关键词： fast pulsars:general ISM:structure

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RFI measurements and mitigation for fast

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Research in Astronomy and Astrophysics 2020年第5期20卷 171-174页

作者： Hai-Yan Zhang Ming-Chang Wu You-Ling Yue Heng-Qian Gan Hao Hu Shi-Jie Huang Xin-Xin Zhang Jin-Hai Sun Bo Peng Ren-Dong Nan fast collaboration National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China CAS Key Laboratory of fast National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China

Radio Frequency Interference(RFI)mitigation is essential for supporting the science output of Five-hundred-meter Aperture Spherical radio Telescope(fast)due to its high *** order to protect fast from RFI,an Electromagnetic Compatibility(EMC)study has been carried out and the operation of a Radio Quiet Zone(RQZ)is *** measurements of the telescope instruments and monitoring of the active radio services outside the site have revealed the radiation properties of the RFI *** on the measurement results and theoretical analysis,various EMC methods have been implemented for the telescope to decrease the ***,the main RFI sources in the fast RQZ,such as mobile stations,broadcast stations and navigation instruments,have been identified,and the technical measures have been adopted to protect the quiet radio environment around the *** early science outputs of fast have demonstrated the efficiency of RFI mitigation methods.

关键词： radio telescope:fast radio frequency interference measurement mitigation

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Pulsar candidate selection using ensemble networks for fast drift-scan survey

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Science China(Physics,Mechanics & Astronomy) 2019年第5期62卷 61-70页

作者： HongFeng Wang WeiWei Zhu Ping Guo Di Li SiBo Feng Qian Yin ChenChen Miao ZhenZhao Tao ZhiChen Pan Pei Wang Xin Zheng XiaoDan Deng ZhiJie Liu XiaoYao Xie XuHong Yu ShanPing You Hui Zhang fast collaboration Image Processing and Pattern Recognition Laboratory College of Information Science and TechnologyBeijing Normal UniversityBeijing 100875China CAS Key Laboratory of fast Chinese Academy of SciencesBeijing 100101China School of Information Management Dezhou UniversityDezhou 253023China Image Processing and Pattern Recognition Laboratory School of Systems ScienceBeijing Normal UniversityBeijing 100875China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Information and Computing Science Guizhou Province Guizhou Normal UniversityGuiyang 550001China School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550001China 不详

The Commensal Radio Astronomy Five-hundred-meter Aperture Spherical radio Telescope(fast) Survey(CRAFTS) utilizes the novel drift-scan commensal survey mode of fast and can generate billions of pulsar candidate signals. The human experts are not likely to thoroughly examine these signals, and various machine sorting methods are used to aid the classification of the fast candidates. In this study, we propose a new ensemble classification system for pulsar candidates. This system denotes the further development of the pulsar image-based classification system(PICS), which was used in the Arecibo Telescope pulsar survey, and has been retrained and customized for the fast drift-scan survey. In this study, we designed a residual network model comprising 15 layers to replace the convolutional neural networks(CNNs) in PICS. The results of this study demonstrate that the new model can sort >96% of real pulsars to belong the top 1% of all candidates and classify >1.6 million candidates per day using a dual-GPU and 24-core computer. This increased speed and efficiency can help to facilitate real-time or quasi-real-time processing of the pulsar-search data stream obtained from CRAFTS. In addition, we have published the labeled fast data used in this study online, which can aid in the development of new deep learning techniques for performing pulsar searches.

关键词： pulsars neural networks data analysis

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fast VLBI: current status and future plans

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Research in Astronomy and Astrophysics 2020年第5期20卷 165-170页

作者： Ru-Rong Chen Hai-Yan Zhang Cheng-Jin Jin Zhi-Shen Gao Yan Zhu Kai Zhu Peng Jiang You-Ling Yue Ji-Guang Lu Bo Zhang Wu Jiang Ren-Jie Zhu Shao-Guang Guo Bo Xia Rong-Bing Zhao fast collaboration National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China CAS Key Laboratory of fast National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China

The Five-hundred-meter Aperture Spherical radio Telescope(fast)is the largest single-dish radio telescope in the world,and is now being commissioned after the first light in September *** long baseline interferometry(VLBI)is among the key science topics according to the original *** fast VLBI system has been established,and the first VLBI fringe has been successfully *** will significantly improve the sensitivity of the existing VLBI networks in the future,and some science projects in need of high sensitivity will benefit from its participation.

关键词： instrumentation:interferometers telescopes site testing

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Performance of fast with an Ultra-Wide Bandwidth Receiver at 500–3300 MHz

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Research in Astronomy and Astrophysics 2023年第7期23卷 197-205页

作者： Chuan-Peng Zhang Peng Jiang Ming Zhu Jun Pan Cheng Cheng Hong-Fei Liu Yan Zhu Chun Sun fast collaboration National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Guizhou Radio Astronomical Observatory Guizhou UniversityGuiyang 550000China College of Earth Sciences Guilin University of TechnologyGuilin 541004China

The Five-hundred-meter Aperture Spherical radio Telescope(fast)has been running for several years.A new ultra-wide bandwidth(UWB)receiver,simultaneously covering 500-3300 MHz,has been mounted in the fast feed cabin and has passed a series of observational *** whole UWB band is separated into four independent *** band has 1,048,576 channels in total,resulting in a spectral resolution of 1 *** 500-3300 MHz,the antenna gain is around 14.3-7.7 K Jy^(-1),the aperture efficiency is around 0.56-0.30,the system temperature is around 88-130 K,and the half-power beamwidth is around 7.6'-1.6'.The measured standard deviation of pointing accuracy is better than~7.9"when zenith angle is within 26.4°.The sensitivity and stability of the UWB receiver are confirmed to satisfy expectations through spectral observations,e.g.,HI and *** fast UWB receiver has already demonstrated good performance in capturing sensitive observations for various scientific goals.

关键词： instrumentation:detectors telescopes line:profiles

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The first pulsar discovered by fast

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Science China(Physics,Mechanics & Astronomy) 2019年第5期62卷 71-74页

作者： Lei Qian ZhiChen Pan Di Li George Hobbs WeiWei Zhu Pei Wang ZhiJie Liu YouLing Yue Yan Zhu HongFei Liu DongJun Yu JingHai Sun Peng Jiang GaoFeng Pan Hui Li HengQian Gan Rui Yao XiaoYao Xie Fernando Camilo Andrew Cameron Lei Zhang Shen Wang fast collaboration CAS Key Laboratory of fast National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China Commonwealth Scientific and Industrial Research Organization Australia Telescope National FacilitySydney 2122Australia Key Laboratory of Information and Computing Science Guizhou Normal UniversityGuiyang 550001China South African Radio Astronomy Observatory Observatory 7925South Africa 不详

To assist with the commissioning [1] of the Five-hundredmeter Aperture Spherical radio Telescope (fast), we performed a pulsar search, with the primary goal of developing and testing the pulsar data acquisition and processing pipelines. We tested and used three pipelines, two (Pl and P2 hereafter) searched for the periodic signature of pulsars whereas the other one was used to search for bright single pulses (P3 hereafter).

关键词： pulsar Telescope

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