We present Arecibo 327 MHz confirmation and follow-up studies of seven new pulsars discovered by the Five-hundred-meter Aperture Spherical radio Telescope(FAST).These pulsars are discovered in a pilot program of the C...We present Arecibo 327 MHz confirmation and follow-up studies of seven new pulsars discovered by the Five-hundred-meter Aperture Spherical radio Telescope(FAST).These pulsars are discovered in a pilot program of the Commensal Radio Astronomy FAST Survey(CRAFTS)with the ultra-widebandwidth commissioning receiver.Five of them are normal pulsars and two are extreme nulling slow pulsars.PSR J2111+2132’s dispersion measure(DM:78.5 pc cm^(-3))is above the upper limits of the two Galactic free electron density models,NE2001 and YMW16,and PSR J2057+2133’s position is out of the Scutum-Crux Arm,making them uniquely useful for improving the Galactic free electron density model in their directions.We present a detailed single pulse analysis for the slow nulling pulsars.We show evidence that PSR J2323+1214’s main pulse component follows a non-Poisson distribution and marginal evidence for a sub-pulse-drift or recurrent period of 32.3±0.4 rotations from PSR J0539+0013.We discuss the implication of our finding to the pulsar radiation mechanism.展开更多
The origin of fast radio bursts(FRBs),the brightest cosmic explosion in radio bands,remains unknown.We introduce here a novel method for a comprehensive analysis of active FRBs’behaviors in the timeenergy domain.Usin...The origin of fast radio bursts(FRBs),the brightest cosmic explosion in radio bands,remains unknown.We introduce here a novel method for a comprehensive analysis of active FRBs’behaviors in the timeenergy domain.Using"Pincus Index"and"Maximum Lyapunov Exponent",we were able to quantify the randomness and chaoticity,respectively,of the bursting events and put FRBs in the context of common transient physical phenomena,such as pulsar,earthquakes,and solar flares.In the bivariate timeenergy domain,repeated FRB bursts’behaviors deviate significantly(more random,less chaotic)from pulsars,earthquakes,and solar flares.The waiting times between FRB bursts and the corresponding energy changes exhibit no correlation and remain unpredictable,suggesting that the emission of FRBs does not exhibit the time and energy clustering observed in seismic events.The pronounced stochasticity may arise from a singular source with high entropy or the combination of diverse emission mechanisms/sites.Consequently,our methodology serves as a pragmatic tool for illustrating the congruities and distinctions among diverse physical processes.展开更多
快速射电暴(fast radio burst;FRB)是宇宙中在无线电波段最为剧烈的爆发现象,其起源未知,是当今天文学领域最大的新热点前沿之一.快速射电暴的偏振性质包含了快速射电暴本征特性与形成环境丰富的信息,对快速射电暴偏振性质的精确测量将...快速射电暴(fast radio burst;FRB)是宇宙中在无线电波段最为剧烈的爆发现象,其起源未知,是当今天文学领域最大的新热点前沿之一.快速射电暴的偏振性质包含了快速射电暴本征特性与形成环境丰富的信息,对快速射电暴偏振性质的精确测量将极大地推进快速射电暴环境及其起源的理解进程.现今已有数百个快速射电暴被探测到,其中,大部分只被探测到单次的爆发,仅有约4%呈现出重复爆发的现象.本文利用“中国天眼”500米口径球面射电望远镜FAST对两个活跃重复快速射电暴——FRB 20121102A和20190520B进行观测,首次探测到FRB 20121102A和20190520B中的圆偏振,使得有圆偏振探测的重复暴数量从原来仅1例增加到3.在FRB 20121102A和20190520B中,圆偏振度最高可达64%.作者论证了这两个活跃重复暴中的圆偏振不太可能是由多路径传播引起的,更可能由法拉第转换的机制或FRB源本征的辐射机制产生.上述两个重复暴的上千次爆发中有圆偏振比例只有百分之几,表明在这两个重复快速射电暴中产生圆偏振的条件应该是苛刻的.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11988101,U2031117,11725313,12041303,11873067,U1831131 and U1631132)the China Scholarship Council(No.201704910686)+4 种基金the CASMPG LEGACY projectthe Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB23000000)the National SKA Program of China(No.2020SKA0120200)the Foundation of Guizhou Provincial Education Department(No.KY(2020)003)the Cultivation Project for FAST Scientific Payoff and the Research Achievement of CAMS-CAS。
文摘We present Arecibo 327 MHz confirmation and follow-up studies of seven new pulsars discovered by the Five-hundred-meter Aperture Spherical radio Telescope(FAST).These pulsars are discovered in a pilot program of the Commensal Radio Astronomy FAST Survey(CRAFTS)with the ultra-widebandwidth commissioning receiver.Five of them are normal pulsars and two are extreme nulling slow pulsars.PSR J2111+2132’s dispersion measure(DM:78.5 pc cm^(-3))is above the upper limits of the two Galactic free electron density models,NE2001 and YMW16,and PSR J2057+2133’s position is out of the Scutum-Crux Arm,making them uniquely useful for improving the Galactic free electron density model in their directions.We present a detailed single pulse analysis for the slow nulling pulsars.We show evidence that PSR J2323+1214’s main pulse component follows a non-Poisson distribution and marginal evidence for a sub-pulse-drift or recurrent period of 32.3±0.4 rotations from PSR J0539+0013.We discuss the implication of our finding to the pulsar radiation mechanism.
基金supported by the Open Project Program of the Key Laboratory of FAST,Chinese Academy of Sciencessupported by the National Natural Science Foundation of China(NSFC)(11988101,11725313,11690024,and12203045)+11 种基金the Key Research Project of Zhejiang Lab(2021PE0AC03)supported by NSFC(fU2031117)the Youth Innovation Promotion Association CAS(ID.2021055)the Cultivation Project for FAST Scientific Payoff and Research Achievement of CAMS-CASsupported by NSFC(12203069)the National SKA Program of China(2022SKA0130100)the Office Leading Group for Cyberspace Affairs,CAS(CAS-WX2023PY-0102)funded by the Australian Governmentsupported by the National Science Foundation of Xinjiang Uygur Autonomous Region(2022D01D85)the Major Science and Technology Program of Xinjiang Uygur Autonomous Region(2022A03013-2)the Tianchi Talent projectthe CAS Project for Young Scientists in Basic Research(YSBR-063)。
文摘The origin of fast radio bursts(FRBs),the brightest cosmic explosion in radio bands,remains unknown.We introduce here a novel method for a comprehensive analysis of active FRBs’behaviors in the timeenergy domain.Using"Pincus Index"and"Maximum Lyapunov Exponent",we were able to quantify the randomness and chaoticity,respectively,of the bursting events and put FRBs in the context of common transient physical phenomena,such as pulsar,earthquakes,and solar flares.In the bivariate timeenergy domain,repeated FRB bursts’behaviors deviate significantly(more random,less chaotic)from pulsars,earthquakes,and solar flares.The waiting times between FRB bursts and the corresponding energy changes exhibit no correlation and remain unpredictable,suggesting that the emission of FRBs does not exhibit the time and energy clustering observed in seismic events.The pronounced stochasticity may arise from a singular source with high entropy or the combination of diverse emission mechanisms/sites.Consequently,our methodology serves as a pragmatic tool for illustrating the congruities and distinctions among diverse physical processes.
基金supported by the National Natural Science Foundation of China (11988101, 12203045, and 11725313)the Key Research Project of Zhejiang Laboratory (2021PE0AC03)+8 种基金the National Key R&D Program of China (2017YFA0402600)supported by the National Natural Science Foundation of China (12003028)the China Manned Spaced Project (CMSCSST-2021-B11)the National Key Research and Development Program of China (2022SKA0130101)the recipient of an Australian Research Council Discovery Early Career Award (DE210101738) funded by the Australian Governmentsupport from the National Natural Science Foundation of China (U2031117)the Youth Innovation Promotion Association CAS (2021055)CAS Project for Young Scientists in Basic Reasearch (grant YSBR-006)the Cultivation Project for FAST Scientific Payoff and Research Achievement of CAMS-CAS。
文摘快速射电暴(fast radio burst;FRB)是宇宙中在无线电波段最为剧烈的爆发现象,其起源未知,是当今天文学领域最大的新热点前沿之一.快速射电暴的偏振性质包含了快速射电暴本征特性与形成环境丰富的信息,对快速射电暴偏振性质的精确测量将极大地推进快速射电暴环境及其起源的理解进程.现今已有数百个快速射电暴被探测到,其中,大部分只被探测到单次的爆发,仅有约4%呈现出重复爆发的现象.本文利用“中国天眼”500米口径球面射电望远镜FAST对两个活跃重复快速射电暴——FRB 20121102A和20190520B进行观测,首次探测到FRB 20121102A和20190520B中的圆偏振,使得有圆偏振探测的重复暴数量从原来仅1例增加到3.在FRB 20121102A和20190520B中,圆偏振度最高可达64%.作者论证了这两个活跃重复暴中的圆偏振不太可能是由多路径传播引起的,更可能由法拉第转换的机制或FRB源本征的辐射机制产生.上述两个重复暴的上千次爆发中有圆偏振比例只有百分之几,表明在这两个重复快速射电暴中产生圆偏振的条件应该是苛刻的.
