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Commissioning progress of the FAST
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作者 Peng Jiang YouLing Yue +15 位作者 HengQian Gan Rui Yao Hui Li GaoFeng Pan JingHai Sun DongJun Yu HongFei Liu NingYu Tang Lei Qian JiGuang Lu Jun Yan Bo Peng ShuXin Zhang QiMing Wang Qi Li Di Li 《中国科学:物理学、力学、天文学英文版》 SCIE EI CAS CSCD 2019年第5期3-24,共22页
The Five-hundred-meter Aperture Spherical radio Telescope(FAST) was completed with its main structure installed on September 25, 2016, after which it entered the commissioning phase. This paper aims to introduce the c... The Five-hundred-meter Aperture Spherical radio Telescope(FAST) was completed with its main structure installed on September 25, 2016, after which it entered the commissioning phase. This paper aims to introduce the commissioning progress of the FAST over the past two years. To improve its operational reliability and ensure effective observation time, FAST has been equipped with a real-time information system for the active reflector system and hierarchical commissioning scheme for the feed support system, which ultimately achieves safe operation of the two systems. For meeting the high-performance indices, a highprecision measurement system was set up based on the effective control methods that were implemented for the active reflector system and feed support system. Since the commissioning of the FAST, a low-frequency ultra-wideband receiver and 19-beam1.05-1.45 GHz receiver have been mainly used. Telescope efficiency, pointing accuracy, and system noise temperature were completely tested and ultimately achieved the acceptance indices of the telescope. The FAST has been in the process of national acceptance preparations and has begun to search for pulsars. In the future, it will still strive to improve its capabilities and expand its application prospects. 展开更多
关键词 RADIO telescopes and INSTRUMENTATION astronomical OBSERVATIONS RADIO wave RECEIVERS ALGORITHMS and implementation control systems
Study of three rotating radio transients with FAST
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作者 JiGuang Lu Bo Peng +7 位作者 Kuo Liu Peng Jiang YouLing Yue Meng Yu Ye-Zhao Yu FeiFei Kou Lin Wang FAST Collaboration 《中国科学:物理学、力学、天文学英文版》 SCIE EI CAS CSCD 2019年第5期25-31,共7页
Rotating radio transients(RRATs) are peculiar astronomical objects whose emission mechanism remains under investigation.In this paper, we present observations of three RRATs, J1538+2345, J1854+0306 and J1913+1330, car... Rotating radio transients(RRATs) are peculiar astronomical objects whose emission mechanism remains under investigation.In 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. 展开更多
关键词 RADIATION MECHANISMS RADIO PULSARS
The radiation structure of PSR B2016+28 observed with FAST
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作者 JiGuang Lu Bo Peng +8 位作者 RenXin Xu Meng Yu Shi Dai WeiWei Zhu Ye-Zhao Yu Peng Jiang YouLing Yue Lin Wang FAST Collaboration 《中国科学:物理学、力学、天文学英文版》 SCIE EI CAS CSCD 2019年第5期38-51,共14页
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 s... 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(P3) is positively correlated to the separation between two adjacent sub-pulses(P2). 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. 展开更多
关键词 radiation mechanisms MATHEMATICAL procedures and COMPUTER techniques radio PULSARS
Status and perspectives of the CRAFTS extra-galactic HI survey
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作者 Kai Zhang JingWen Wu +16 位作者 Di Li Marko Krco Lister Staveley-Smith NingYu Tang Lei Qian MengTing Liu ChengJin Jin YouLing Yue Yan Zhu HongFei Liu DongJun Yu JingHai Sun GaoFeng Pan Hui Li HengQian Gan Rui Yao FAST Collaboration 《中国科学:物理学、力学、天文学英文版》 SCIE EI CAS CSCD 2019年第5期52-60,共9页
The Five-hundred-meter Aperture Spherical radio Telescope(FAST) is expected to complete its commissioning in 2019. FAST will soon begin the Commensal Radio Astronomy FasT Survey(CRAFTS), a novel and unprecedented comm... The Five-hundred-meter Aperture Spherical radio Telescope(FAST) is expected to complete its commissioning in 2019. FAST will soon begin the Commensal Radio Astronomy FasT Survey(CRAFTS), a novel and unprecedented commensal drift scan survey of the entire sky visible from FAST. The goal of CRAFTS is to cover more than 20000 deg2 and reach redshift up to about 0.35. We provide empirical measurements of the beam size and sensitivity of FAST across the 1.05 to 1.45 GHz frequency range of the FAST L-band array of 19-beams(FLAN). Using a simulated HI-galaxy catalogue based on the HI Mass Function(HIMF), we estimate the number of galaxies that CRAFTS may detect. At redshifts below 0.35, over 6 × 105 HI galaxies may be detected. Below the redshift of 0.07, the CRAFTS HIMF will be complete above a mass threshold of 109.5 M⊙. FAST will be able to investigate the environmental and redshift dependence of the HIMF to an unprecedented depth, shedding light onto the missing baryon and missing satellite problems. 展开更多
关键词 HI REGIONS and 21-cm lines radio telescopes and INSTRUMENTATION statistical and correlative studies of properties
The first pulsar discovered by FAST
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作者 Lei Qian ZhiChen Pan +20 位作者 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 《中国科学:物理学、力学、天文学英文版》 SCIE EI CAS CSCD 2019年第5期71-74,共4页
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 pr... 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). 展开更多
关键词 pulsar TELESCOPE
云南野生稻资源及其保护 被引量:2
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作者 肖素勤 殷富有 +18 位作者 张绍松 余腾琼 陈玲 柯学 付坚 张敦宇 钟巧芳 李定琴 陈越 孙治旭 岳英 郭顺云 王玲仙 黄兴奇 杨雅云 王波 曾民 李娥贤 程在全 《植物遗传资源学报》 CSCD 北大核心 2017年第3期494-502,共9页
云南野生稻生态类型丰富,且具有抗白叶枯病、抗稻瘟病、耐旱、耐寒等栽培稻不具有或已经消失的遗传基因,是水稻品种改良的优良基因库。然而,随着人类社会经济活动对生态环境影响的加剧,这一宝贵的战略性生物资源正面临着快速消失的危险... 云南野生稻生态类型丰富,且具有抗白叶枯病、抗稻瘟病、耐旱、耐寒等栽培稻不具有或已经消失的遗传基因,是水稻品种改良的优良基因库。然而,随着人类社会经济活动对生态环境影响的加剧,这一宝贵的战略性生物资源正面临着快速消失的危险。为了加强云南野生稻资源的保护,近年来,我们对云南野生稻资源开展了原生境保护(物理隔离方式和主流化方式)及非原生境保护(种质库、种质圃、细胞库和DNA库)等保护技术研究,明确了各种保护方法的优缺点和适用性,保护了云南野生稻的多样性和丰富度,为改良栽培稻储备了丰富的基因源。 展开更多
关键词 野生稻资源 居群 原生境保护 非原生境保护
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