Fast radio bursts(FRBs)are short-duration radio transients with mysterious origins.Since their uncertainty,there are very few FRBs observed by different instruments simultaneously.This study presents a detailed analys...Fast radio bursts(FRBs)are short-duration radio transients with mysterious origins.Since their uncertainty,there are very few FRBs observed by different instruments simultaneously.This study presents a detailed analysis of a burst from FRB 20190520B observed by FAST and Parkes at the same time.The spectrum of this individual burst ended at the upper limit of the FAST frequency band and was simultaneously detected by the Parkes telescope in the 1.5–1.8GHz range.By employing spectral energy distribution(SED)and spectral sharpness methods,we confirmed the presence of narrow-band radiation in FRB 20190520B,which is crucial for understanding its radiation mechanisms.Our findings support the narrow-band characteristics that most repeaters exhibit.This work also highlights the necessity of continued multiband observations to explore its periodicity and frequency-dependent properties,contributing to an in-depth understanding of FRB phenomena.展开更多
LIGO-Virgo has observed the gravitational waves(GWs)from the coalescence of binary black hole(BBH)and binary neutron star(BNS)during O1 and O2,and the ones from NS-BH are expected to be hunted in the operating O3 run....LIGO-Virgo has observed the gravitational waves(GWs)from the coalescence of binary black hole(BBH)and binary neutron star(BNS)during O1 and O2,and the ones from NS-BH are expected to be hunted in the operating O3 run.The population properties and mass distribution of NS-BH mergers are poorly understood now,thus researchers simulated their chirp mass(M)distribution by a synthetic model,in which the BHs and NSs were inferred by LIGO-Virgo(O1/O2),and obtained the values in the range of 2.1 M_(⊙)<M<7.3 M_(⊙).In this paper,we further simulate the GW frequency(fGW)distribution of NS-BH mergers by the above-stated synthetic model,with a basic binary system model through the Monte Carlo method.Our results predict that the median with 90%credible intervals is 165+475-64 Hz in the case of Schwarzschild BH when the system just before merger,and this GW frequency is expected to increase several times in the merger stage,which is lying in the frequency band of LIGO-Virgo,i.e.,about 15 Hz to a few kHz.Our results provide an important reference for hunting the NS-BH mergers by the on-going O3 run of LIGO-Virgo.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11988101,12203069,12041302,and 12203045)the National SKA Program of China(Grant No.2022SKA0130100)+8 种基金the Office of the Leading Group for Cyberspace Affairs,CAS(Grant No.CAS-WX2023PY0102)the CAS Youth Interdisciplinary Team and the Foundation of Guizhou Provincial Education Department(Grant No.KY(2023)059)support from the National Natural Science Foundation of China(Grant Nos.11988101 and 12041303)the CAS Youth Interdisciplinary Team,the Youth Innovation Promotion Association CAS(Grant No.2021055)the Cultivation Project for FAST Scientific Payoff and Research Achievement of CAMS-CASsupported by the National Natural Science Foundation of China(Grant No.12203045)the Leading Innovation and Entrepreneurship Team of Zhejiang Province of China(Grant No.2023R01008)the Key R&D Program of Zhejiang(Grant No.2024SSYS0012)supported by the China Scholarship Council(Grant No.202304910441)。
文摘Fast radio bursts(FRBs)are short-duration radio transients with mysterious origins.Since their uncertainty,there are very few FRBs observed by different instruments simultaneously.This study presents a detailed analysis of a burst from FRB 20190520B observed by FAST and Parkes at the same time.The spectrum of this individual burst ended at the upper limit of the FAST frequency band and was simultaneously detected by the Parkes telescope in the 1.5–1.8GHz range.By employing spectral energy distribution(SED)and spectral sharpness methods,we confirmed the presence of narrow-band radiation in FRB 20190520B,which is crucial for understanding its radiation mechanisms.Our findings support the narrow-band characteristics that most repeaters exhibit.This work also highlights the necessity of continued multiband observations to explore its periodicity and frequency-dependent properties,contributing to an in-depth understanding of FRB phenomena.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11988101,11773005,U2031203,U1631236,11703001,U1731238,U1938117,11725313,and 11721303)the International Partnership Program of Chinese Academy of Sciences(Grant No.114A11KYSB20160008)+1 种基金the National Key R&D Program of China(Grant No.2016YFA0400702)the Subsidy Project of the National Natural Science Foundation of China(Grant No.2021GZJ006)。
文摘LIGO-Virgo has observed the gravitational waves(GWs)from the coalescence of binary black hole(BBH)and binary neutron star(BNS)during O1 and O2,and the ones from NS-BH are expected to be hunted in the operating O3 run.The population properties and mass distribution of NS-BH mergers are poorly understood now,thus researchers simulated their chirp mass(M)distribution by a synthetic model,in which the BHs and NSs were inferred by LIGO-Virgo(O1/O2),and obtained the values in the range of 2.1 M_(⊙)<M<7.3 M_(⊙).In this paper,we further simulate the GW frequency(fGW)distribution of NS-BH mergers by the above-stated synthetic model,with a basic binary system model through the Monte Carlo method.Our results predict that the median with 90%credible intervals is 165+475-64 Hz in the case of Schwarzschild BH when the system just before merger,and this GW frequency is expected to increase several times in the merger stage,which is lying in the frequency band of LIGO-Virgo,i.e.,about 15 Hz to a few kHz.Our results provide an important reference for hunting the NS-BH mergers by the on-going O3 run of LIGO-Virgo.
