Fast Radio Bursts(FRBs) are enigmatic millisecond-duration radio transients of extra-galactic origin, whose underlying mechanisms and progenitors remain poorly understood. FRBs are broadly classified into two categori...Fast Radio Bursts(FRBs) are enigmatic millisecond-duration radio transients of extra-galactic origin, whose underlying mechanisms and progenitors remain poorly understood. FRBs are broadly classified into two categories: repeating FRBs, which emit multiple bursts over time, and one-off FRBs, which are detected as single events. A central question in FRB research is whether these two classes share a common origin. In this study, we present observations of FRB 20240114A, a repeating FRB that entered a hyperactive phase in 2024 January. We conducted a 318 hr monitoring campaign using the Kunming 40-Meter Radio Telescope(KM40M) in the S-band(2.187–2.311 GHz), during which we detected eight radio bursts. We analyzed their properties, including dispersion measure, bandwidth, pulse width, flux, fluence, and energy. Additionally, we searched for counterparts in overlapping data from the Five-hundred-meter Aperture Spherical Telescope(FAST) in the L-band(1.0–1.5 GHz). While no bursts were temporally aligned between the two telescopes, we identified one FAST burst that arrived approximately 6 ms after one of the KM40M bursts. The absence of FAST counterparts for the KM40M bursts suggests that individual bursts from FRB 20240114A are likely narrow-band, with fractional bandwidths less than 10%. By comparing the cumulative event rates from KM40M and FAST observations, we found that the two measurements are compatible, indicating a possible flattening of the event rate at higher energies. This feature aligns with observations of one-off FRBs, supporting the hypothesis that repeating and oneoff FRBs may share a common origin.展开更多
Scheduled for launch in 2030,the enhanced X-ray Timing and Polarization(eXTP)telescope is a Chinese space-based mission aimed at studying extreme conditions and phenomena in astrophysics.eXTP will feature three main p...Scheduled for launch in 2030,the enhanced X-ray Timing and Polarization(eXTP)telescope is a Chinese space-based mission aimed at studying extreme conditions and phenomena in astrophysics.eXTP will feature three main payloads:Spectroscopy Focusing Array(SFA),Polarimetry Focusing Array(PFA),and a Wide-field Camera(W2C).This white paper outlines observatory science,incorporating key scientific advances and instrumental changes since the publication of the previous white paper.We will discuss perspectives of eXTP on the research domains of flare stars,supernova remnants,pulsar wind nebulae,cataclysmic variables,X-ray binaries,ultraluminous X-ray sources,active galactic nucleus(AGN),and pulsar-based positioning and timekeeping.展开更多
In this new era of time-domain and multi-messenger astronomy,various new transients and new phenomena are constantly being discovered thanks to the rapid advances in observations,which provide the excellent opportunit...In this new era of time-domain and multi-messenger astronomy,various new transients and new phenomena are constantly being discovered thanks to the rapid advances in observations,which provide the excellent opportunity to study the physics in the extreme environments.The enhanced X-ray Timing and Polarimetry mission(eXTP),planned to be launched in 2030,has several key advantages,including advanced polarimetry,high sensitivity&large effective area,and wide energy range coverage,which make it a groundbreaking project in high-energy astrophysics.In this article,we briefly introduce the potential time-domain and multi-messenger targets for eXTP,including gravitational-wave(GW)counterparts,gamma-ray bursts(GRBs),magnetars and fast radio bursts(FRBs),tidal disruption events(TDEs),supernovae,high energy neutrinos and TeV active galactic nucleus(AGNs),and so on.We discuss the advantages of future eXTP observations for detecting these sources,their detection capabilities,the abilities to distinguish theoretical models,and their applications in gravity and cosmology.展开更多
Fast radio bursts(FRBs)are bright,millisecond-duration radio emissions originating from cosmological distances.In this study,we report multi-year polarization measurements of four repeating FRBs initially discovered b...Fast radio bursts(FRBs)are bright,millisecond-duration radio emissions originating from cosmological distances.In this study,we report multi-year polarization measurements of four repeating FRBs initially discovered by the Canadian Hydrogen Intensity Mapping Experiment(CHIME):FRBs 20190117A,20190208A,20190303A,and 20190417A.We observed the four repeating FRBs with the Five-hundred-meter Aperture Spherical Radio Telescope(FAST),detecting a total of 66 bursts.Two bursts from FRB 20190417A exhibit a circular polarization signal-to-noise ratio greater than 7,with the highest circular polarization fraction recorded at 35.7%.While the bursts from FRBs 20190208A and 20190303A are highly linearly polarized,those from FRBs 20190117A and 20190417A show depolarization due to multi-path propagation,with σ_(RM)=2.78±0.05and 5.19±0.09 rad m^(-2),respectively.The linear polarization distributions among five repeating FRBs—FRBs 20190208A,20190303A,20201124A,20220912A,and 20240114A—are nearly identical but show distinct differences from those of nonrepeating FRBs.FRBs 20190117A,20190303A,and 20190417A exhibit substantial rotation measure(RM)variations between bursts,joining other repeating FRBs in this behavior.Combining these findings with published results,64% of repeating FRBs show RM variations greater than 50 rad m^(-2),and 21% exhibit RM reversals.A significant proportion of repeating FRBs reside in a dynamic magneto-ionic environment.The structure function of RM variations shows a power-law index of γ~(0-0.8),corresponding to a shallow power spectrum α=-(γ+2)~-(2.0-2.8)of turbulence,if the RM variations are attributed to turbulence.This suggests that the variations are dominated by small-scale RM density fluctuations.We perform K-S tests to compare the RMs of repeating and non-repeating FRBs,which reveal a marginal dichotomy in the distribution of their RMs.We caution that the observed dichotomy may be due to the small sample size and selection biases.展开更多
In 2007, a very bright radio pulse was identified in the archival data of the Parkes Telescope in Australia, marking the beginning of a new research branch in astrophysics. In 2013, this kind of millisecond bursts wit...In 2007, a very bright radio pulse was identified in the archival data of the Parkes Telescope in Australia, marking the beginning of a new research branch in astrophysics. In 2013, this kind of millisecond bursts with extremely high brightness temperature takes a unified name, fast radio burst(FRB). Over the first few years, FRBs seemed very mysterious because the sample of known events was limited. With the improvement of instruments over the last five years, hundreds of new FRBs have been discovered.The field is now undergoing a revolution and understanding of FRB has rapidly increased as new observational data increasingly accumulate. In this review, we will summarize the basic physics of FRBs and discuss the current research progress in this area.We have tried to cover a wide range of FRB topics, including the observational property, propagation effect, population study,radiation mechanism, source model, and application in cosmology. A framework based on the latest observational facts is now under construction. In the near future, this exciting field is expected to make significant breakthroughs.展开更多
Possible periodic features in fast radio bursts(FRBs)may provide insights into their astrophysical origins.Using extensive observations from the five-hundred-meter aperture spherical radio telescope(FAST),we conduct a...Possible periodic features in fast radio bursts(FRBs)may provide insights into their astrophysical origins.Using extensive observations from the five-hundred-meter aperture spherical radio telescope(FAST),we conduct a multi-timescale periodicity search for the exceptionally active repeater FRB 20240114A.Our analysis is based on different datasets for different timescales:for short-timescale periodicity in time of arrivals(TOAs),we use 57 observations from January to August 2024;for long-timescale periodicity,we employ an extended TOA dataset comprising 111 observations spanning from January 2024 to October 2025;and for burst time series analysis,we utilize individual burst data from the 57 FAST observations.We identify three candidate short-timescale periodic signals(0.673,0.635,and 0.536 s)with significances of 3.2σ-6σ,each detected in two independent observations.On longer timescales,we detect a significant(143.40±7.19)-d periodicity with 5.2σsignificance,establishing FRB 20240114A as a periodic repeater.In burst time series,we find quasi-periodic oscillations in the few hundred Hz range(3.4σand 3.7σ)and periodic burst trains with periods of several to tens of milliseconds(3σ-3.9σ),though these periodic features appear transient and short-lived.The detection of periodic signals at these different timescales indicates that FRB 20240114A exhibits intriguing periodic self-similar characteristics.Despite the comprehensive dataset,no definitive periodicity linked to the source's rotation is confirmed,placing stringent constraints on the intrinsic source properties and the modulation mechanisms.All data are available via the Science Data Bank.This paper is organized as follows.In sect.2,we search for periodic signals in the time-of-arrival(TOA)data of FRB 20240114A to explore possible links to magnetar rotation,binary orbits,and precession scenarios.In sect.3,we mainly investigate QPOs in the burst time series,which provide crucial insights into the underlying radiation mechanisms.Sect.4 discusses the implications of our findings,and sect.5 summarizes the main conclusions of this study.展开更多
基金supported by the National SKA Program of China (grant No. 2020SKA0120100)the Special Project of Foreign Science and Technology Cooperation, Yunnan Provincial Science and Technology Department (grant No. 202003AD150010)+4 种基金the National Key R&D Program of China (grant No. 2022YFC2205203)the National Natural Science Foundation of China (NSFC, grant Nos. 12073076, 12173087, 12041303, and 12063003)the CAS “Western Light Youth Project,” Yunnan Fundamental Research Projects (grant Nos. 202401AT070144 and 202505AO120021)funding from the Max-Planck Partner Groupsupport from the XPLORER PRIZE
文摘Fast Radio Bursts(FRBs) are enigmatic millisecond-duration radio transients of extra-galactic origin, whose underlying mechanisms and progenitors remain poorly understood. FRBs are broadly classified into two categories: repeating FRBs, which emit multiple bursts over time, and one-off FRBs, which are detected as single events. A central question in FRB research is whether these two classes share a common origin. In this study, we present observations of FRB 20240114A, a repeating FRB that entered a hyperactive phase in 2024 January. We conducted a 318 hr monitoring campaign using the Kunming 40-Meter Radio Telescope(KM40M) in the S-band(2.187–2.311 GHz), during which we detected eight radio bursts. We analyzed their properties, including dispersion measure, bandwidth, pulse width, flux, fluence, and energy. Additionally, we searched for counterparts in overlapping data from the Five-hundred-meter Aperture Spherical Telescope(FAST) in the L-band(1.0–1.5 GHz). While no bursts were temporally aligned between the two telescopes, we identified one FAST burst that arrived approximately 6 ms after one of the KM40M bursts. The absence of FAST counterparts for the KM40M bursts suggests that individual bursts from FRB 20240114A are likely narrow-band, with fractional bandwidths less than 10%. By comparing the cumulative event rates from KM40M and FAST observations, we found that the two measurements are compatible, indicating a possible flattening of the event rate at higher energies. This feature aligns with observations of one-off FRBs, supporting the hypothesis that repeating and oneoff FRBs may share a common origin.
基金supported by the China’s Space Origins Exploration Program,the National Natural Science Foundation of China(Grant Nos.12273010,12333007,12433004,12233002,12373041,and 12422306)the International Partnership Program of Chinese Academy of Sciences(Grant No.113111KYSB20190020)+9 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA15020100)the Spanish MICIU(Grant Nos.PID2021-124581OB-I0,PID2024-155316NB-I00,and 2021SGR00426)the Ramon y Cajal Fellowship(Grant Nos.RYC2021-032718-I,and RYC2018-025950-I)the European Union NextGenerationEU/PRTR,the Spanish MINECO(Grant Nos.PID2022-136828NB-C44,and PID2023-148661NB-I00)the E.U.FEDER Funds,the AGAUR/Generalitat de Catalunya(Grant No.SGR-386/2021)the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)-Projektnummer(Grant No.549824807)the Programma di Ricerca Fondamentale INAF 2023,the National SKA Program of China(Grant No.2020SKA0120300)the National Key R&D Program of China(Grant No.2021YFA0718500)the Xinjiang Tianchi Program,the Hong Kong Government under HKU(Grant No.17304524)the Bagui Scholars Program.
文摘Scheduled for launch in 2030,the enhanced X-ray Timing and Polarization(eXTP)telescope is a Chinese space-based mission aimed at studying extreme conditions and phenomena in astrophysics.eXTP will feature three main payloads:Spectroscopy Focusing Array(SFA),Polarimetry Focusing Array(PFA),and a Wide-field Camera(W2C).This white paper outlines observatory science,incorporating key scientific advances and instrumental changes since the publication of the previous white paper.We will discuss perspectives of eXTP on the research domains of flare stars,supernova remnants,pulsar wind nebulae,cataclysmic variables,X-ray binaries,ultraluminous X-ray sources,active galactic nucleus(AGN),and pulsar-based positioning and timekeeping.
基金supported by China’s Space Origins Exploration Programsupport from the Chinese Academy of Sciences (Grant No.E32983U810)+13 种基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No.XDB0550300)the National Natural Science Foundation of China (Grant No.12325301)supported by the National Natural Science Foundation of China (Grant Nos.12233002,and 12041306)the National SKA Program of China (Grant No.2020SKA0120300)the National Key R&D Program of China (Grant No.2021YFA0718500)the support from the Xinjiang Tianchi Programsupported by the National Natural Science Foundation of China (Grant No.12333007)the International Partnership Program of the Chinese Academy of Sciences (Grant No.113111KYSB20190020)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No.XDA15020100)supported by the Beijing Municipal Natural Science Foundation (Grant No.1242032)the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant No.2022056)supported by the National Key Research and Development Program of China (Grant Nos.2022YFC2205201,and 2020YFC2201400)funding by the European Union-Next Generation EU RFF M4C2 1.1 PRIN 2022 project “2022RJLWHN URKA”INAF 2023 Theory Grant Ob Fu 1.05.23.06.06 “Understanding R-process & Kilonovae Aspects (URKA)”.
文摘In this new era of time-domain and multi-messenger astronomy,various new transients and new phenomena are constantly being discovered thanks to the rapid advances in observations,which provide the excellent opportunity to study the physics in the extreme environments.The enhanced X-ray Timing and Polarimetry mission(eXTP),planned to be launched in 2030,has several key advantages,including advanced polarimetry,high sensitivity&large effective area,and wide energy range coverage,which make it a groundbreaking project in high-energy astrophysics.In this article,we briefly introduce the potential time-domain and multi-messenger targets for eXTP,including gravitational-wave(GW)counterparts,gamma-ray bursts(GRBs),magnetars and fast radio bursts(FRBs),tidal disruption events(TDEs),supernovae,high energy neutrinos and TeV active galactic nucleus(AGNs),and so on.We discuss the advantages of future eXTP observations for detecting these sources,their detection capabilities,the abilities to distinguish theoretical models,and their applications in gravity and cosmology.
基金supported by the National Natural Science Foundation of China(Grant Nos.12588202,12203045,12233002,12403100,12103069,and 12403042)the Leading Innovation and Entrepreneurship Team of Zhejiang Province of China(Grant No.2023R01008)+3 种基金the Key R&D Program of Zhejiang(Grant No.2024SSYS0012)supported by the National Natural Science Foundation of China(Grant No.12473047)the National SKA Program of China(Grant No.2022SKA0130100)the support from the Xinjiang Tianchi Program。
文摘Fast radio bursts(FRBs)are bright,millisecond-duration radio emissions originating from cosmological distances.In this study,we report multi-year polarization measurements of four repeating FRBs initially discovered by the Canadian Hydrogen Intensity Mapping Experiment(CHIME):FRBs 20190117A,20190208A,20190303A,and 20190417A.We observed the four repeating FRBs with the Five-hundred-meter Aperture Spherical Radio Telescope(FAST),detecting a total of 66 bursts.Two bursts from FRB 20190417A exhibit a circular polarization signal-to-noise ratio greater than 7,with the highest circular polarization fraction recorded at 35.7%.While the bursts from FRBs 20190208A and 20190303A are highly linearly polarized,those from FRBs 20190117A and 20190417A show depolarization due to multi-path propagation,with σ_(RM)=2.78±0.05and 5.19±0.09 rad m^(-2),respectively.The linear polarization distributions among five repeating FRBs—FRBs 20190208A,20190303A,20201124A,20220912A,and 20240114A—are nearly identical but show distinct differences from those of nonrepeating FRBs.FRBs 20190117A,20190303A,and 20190417A exhibit substantial rotation measure(RM)variations between bursts,joining other repeating FRBs in this behavior.Combining these findings with published results,64% of repeating FRBs show RM variations greater than 50 rad m^(-2),and 21% exhibit RM reversals.A significant proportion of repeating FRBs reside in a dynamic magneto-ionic environment.The structure function of RM variations shows a power-law index of γ~(0-0.8),corresponding to a shallow power spectrum α=-(γ+2)~-(2.0-2.8)of turbulence,if the RM variations are attributed to turbulence.This suggests that the variations are dominated by small-scale RM density fluctuations.We perform K-S tests to compare the RMs of repeating and non-repeating FRBs,which reveal a marginal dichotomy in the distribution of their RMs.We caution that the observed dichotomy may be due to the small sample size and selection biases.
基金supported by the National Key Research and Development Program of China (Grant No.2017YFA0402600)the National Natural Science Foundation of China (Grant Nos.11833003,U1831207,11903018,and 11851305)supported by the Natural Science Foundation for the Youth of Jiangsu Province (Grant No.BK20180324)。
文摘In 2007, a very bright radio pulse was identified in the archival data of the Parkes Telescope in Australia, marking the beginning of a new research branch in astrophysics. In 2013, this kind of millisecond bursts with extremely high brightness temperature takes a unified name, fast radio burst(FRB). Over the first few years, FRBs seemed very mysterious because the sample of known events was limited. With the improvement of instruments over the last five years, hundreds of new FRBs have been discovered.The field is now undergoing a revolution and understanding of FRB has rapidly increased as new observational data increasingly accumulate. In this review, we will summarize the basic physics of FRBs and discuss the current research progress in this area.We have tried to cover a wide range of FRB topics, including the observational property, propagation effect, population study,radiation mechanism, source model, and application in cosmology. A framework based on the latest observational facts is now under construction. In the near future, this exciting field is expected to make significant breakthroughs.
基金supported by the National Natural Science Foundation of China(Grant Nos.12588202,12303042,12041303,12421003,12233002,12041306,12403100,W2442001,12203045,12447115,U2031117,and 12503050)supported by the International Partnership Program of Chinese Academy of Sciences(Grant No.114A11KYSB20210010)+10 种基金the National SKA Program of China(Grant Nos.2020SKA0120100,2020SKA0120200,and 2022SKA0130104)supported by the Youth Innovation Promotion Association CAS(Grant No.2021055)the CAS Youth Interdisciplinary Teamsupported by the National Key R&D Program of China(Grant Nos.2023YFE0110500 and QN2023061004L)supported by the Leading Innovation and Entrepreneurship Team of Zhejiang Province of China(Grant No.2023R01008)the support from the Xinjiang Tianchi Programsupported by the China Postdoctoral Science Foundation(Grant Nos.GZB20240308,2025T180875,and 2025M773199)supported by CAS Project(Grant No.JZHKYPT-2021-06)supported by the National Natural Science Foundation of China(Grant No.12503055)the Postdoctoral Fellowship Program of CPSF(Grant No.GZB2025073)supported by the CAS Project for Young Scientists in Basic Research(Grant No.YSBR-063)。
文摘Possible periodic features in fast radio bursts(FRBs)may provide insights into their astrophysical origins.Using extensive observations from the five-hundred-meter aperture spherical radio telescope(FAST),we conduct a multi-timescale periodicity search for the exceptionally active repeater FRB 20240114A.Our analysis is based on different datasets for different timescales:for short-timescale periodicity in time of arrivals(TOAs),we use 57 observations from January to August 2024;for long-timescale periodicity,we employ an extended TOA dataset comprising 111 observations spanning from January 2024 to October 2025;and for burst time series analysis,we utilize individual burst data from the 57 FAST observations.We identify three candidate short-timescale periodic signals(0.673,0.635,and 0.536 s)with significances of 3.2σ-6σ,each detected in two independent observations.On longer timescales,we detect a significant(143.40±7.19)-d periodicity with 5.2σsignificance,establishing FRB 20240114A as a periodic repeater.In burst time series,we find quasi-periodic oscillations in the few hundred Hz range(3.4σand 3.7σ)and periodic burst trains with periods of several to tens of milliseconds(3σ-3.9σ),though these periodic features appear transient and short-lived.The detection of periodic signals at these different timescales indicates that FRB 20240114A exhibits intriguing periodic self-similar characteristics.Despite the comprehensive dataset,no definitive periodicity linked to the source's rotation is confirmed,placing stringent constraints on the intrinsic source properties and the modulation mechanisms.All data are available via the Science Data Bank.This paper is organized as follows.In sect.2,we search for periodic signals in the time-of-arrival(TOA)data of FRB 20240114A to explore possible links to magnetar rotation,binary orbits,and precession scenarios.In sect.3,we mainly investigate QPOs in the burst time series,which provide crucial insights into the underlying radiation mechanisms.Sect.4 discusses the implications of our findings,and sect.5 summarizes the main conclusions of this study.
