We analyzed the optical monitoring data in the R band of Te V blazar 1ES 1959+650 from 2002 to 2018,and provided evidence of a quasi-periodic oscillation in this object.The light curve shows a stable and persistent pe...We analyzed the optical monitoring data in the R band of Te V blazar 1ES 1959+650 from 2002 to 2018,and provided evidence of a quasi-periodic oscillation in this object.The light curve shows a stable and persistent periodicity at~540 days,detected by the Lomb–Scargle periodogram,Jurkevich and weighted wavelet z-transform techniques.The red noise power spectrum was estimated using the PSRESP method,and this period was found to be at>3σsignificance level.There are also two possible periodicities at~268 and~1100 days detected by all three methods.However,their significance levels are relatively low,and thus these two periods cannot be verified by the present data.We discuss several possible physical models that could explain the periodic variability in this object.展开更多
A novel fine spectral structure in solar radio bursts has been discovered using the Chashan broadband solar radio spectrometer at meter wavelengths(CBSm),an instrument of the Chinese Meridian Project-PhaseⅡ(CMP-Ⅱ).T...A novel fine spectral structure in solar radio bursts has been discovered using the Chashan broadband solar radio spectrometer at meter wavelengths(CBSm),an instrument of the Chinese Meridian Project-PhaseⅡ(CMP-Ⅱ).The structure features periodic narrow-band stripes with a typical recurrence time<1 s(occasionally reaching 8 s),often drifting from high to low frequencies and accompanied by absorptions,with trailing stripes appearing at the end of preceding ones.Some stripes exhibit periodic beaded(or pearl-like)enhancements with a periodicity of~0.1 s.The beaded stripes are reported for the first time ever.Data from the DAocheng Radio Telescope(DART)indicate a radio emission brightness temperature exceeding 10^(9)K,originating above brightening loops in active region AR 13664.We proposed a novel generation mechanism of the periodic stripes on the basis of the double plasma resonance(DPR)instability,and explained the beaded substructure in terms of modulation by low-frequency magnetohydrodynamic(MHD)waves.The study highlights the CBSm's capability to detect high-resolution fine spectral structures and offers novel insights into the emission mechanism and source characteristics of solar radio bursts.展开更多
基金supported by National Natural Science Foundation of China(Grant No.U1931106)Shandong Provincial Natural Science Foundation of China(Grant No.ZR2019YQ03)Project of Shandong Qing Chuang Science and Technology Plan(Grant No.2019KJJ006)。
文摘We analyzed the optical monitoring data in the R band of Te V blazar 1ES 1959+650 from 2002 to 2018,and provided evidence of a quasi-periodic oscillation in this object.The light curve shows a stable and persistent periodicity at~540 days,detected by the Lomb–Scargle periodogram,Jurkevich and weighted wavelet z-transform techniques.The red noise power spectrum was estimated using the PSRESP method,and this period was found to be at>3σsignificance level.There are also two possible periodicities at~268 and~1100 days detected by all three methods.However,their significance levels are relatively low,and thus these two periods cannot be verified by the present data.We discuss several possible physical models that could explain the periodic variability in this object.
基金supported by the National Natural Science Foundation of China(NNSFC)(Grant Nos.12103029,12303061,and 12203031)the Natural Science Foundation of Shandong Province(NSFSP)(Grant Nos.ZR2023QA074,and ZR2021QA033)the National Key R&D Program of China(Grant Nos.2022YFF0503002,and 2022YFF0503000)。
文摘A novel fine spectral structure in solar radio bursts has been discovered using the Chashan broadband solar radio spectrometer at meter wavelengths(CBSm),an instrument of the Chinese Meridian Project-PhaseⅡ(CMP-Ⅱ).The structure features periodic narrow-band stripes with a typical recurrence time<1 s(occasionally reaching 8 s),often drifting from high to low frequencies and accompanied by absorptions,with trailing stripes appearing at the end of preceding ones.Some stripes exhibit periodic beaded(or pearl-like)enhancements with a periodicity of~0.1 s.The beaded stripes are reported for the first time ever.Data from the DAocheng Radio Telescope(DART)indicate a radio emission brightness temperature exceeding 10^(9)K,originating above brightening loops in active region AR 13664.We proposed a novel generation mechanism of the periodic stripes on the basis of the double plasma resonance(DPR)instability,and explained the beaded substructure in terms of modulation by low-frequency magnetohydrodynamic(MHD)waves.The study highlights the CBSm's capability to detect high-resolution fine spectral structures and offers novel insights into the emission mechanism and source characteristics of solar radio bursts.
