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	Synchronous X-ray/Optical QPOs from the Black Hole LMXB MAXI J1820+070 期刊论文 OAI收割 Monthly Notices of the Royal Astronomical Society, 2021 作者: HXMT \| 收藏 \| 浏览/下载：52/0 \| 提交时间：2022/02/08 black hole physics Low Mass X-ray Binaries accretion accretion discs stars: individual (MAXI J1820+070) Astrophysics - High Energy Astrophysical Phenomena Abstract: We present high-speed optical photometry from SAAO and SALT on the black hole LMXB MAXI J1820+070 (ASSASN-18ey), some of it simultaneous with NICER, Swift and Insight-HXMT X-ray coverage. We detect optical Quasi-Periodic Oscillations (QPOs) that move to higher frequencies as the outburst progresses, tracking both the frequency and evolution of similar X-ray QPOs previously reported. Correlated X-ray/optical data reveal a complex pattern of lags, including an anti-correlation and a sub-second lag that evolve over the first few weeks of outburst. They also show correlated components separated by a lag equal to the QPO period roughly centered on zero lag, implying that the inter-band variability is strongly and consistently affected by these QPOs at a constant phase lag of roughly ±Ю The synchronisation of X-ray and optical QPOs indicates that they must be produced in regions physically very close to each other we thus propose that they can be explained by a precessing jet model, based on analogies with V404 Cyg and MAXI J1348-630.
	An underlying clock in the extreme flip-flop state transitions of the black hole transient Swift J1658.2-4242 期刊论文 OAI收割 Astronomy and Astrophysics, 2020, 卷号: 641, 页码: A101 作者: HXMT \| 收藏 \| 浏览/下载：58/0 \| 提交时间：2022/02/08 accretion accretion disks black hole physics X-rays: binaries time Astrophysics - High Energy Astrophysical Phenomena Abstract: Aims: Flip-flops are top-hat-like X-ray flux variations, which have been observed in some transient accreting black hole binary systems, and feature simultaneous changes in the spectral hardness and the power density spectrum (PDS). They occur at a crucial time in the evolution of these systems, when the accretion disc emission starts to dominate over coronal emission. Flip-flops remain a poorly understood phenomenon, so we aim to thoroughly investigate them in a system featuring several such transitions. Methods: Within the multitude of observations of Swift J1658.2-4242 during its outburst in early 2018, we detected 15 flip-flops, enabling a detailed analysis of their individual properties and the differences between them. We present observations by XMM-Newton, NuSTAR, Astrosat, Swift, Insight-HXMT, INTEGRAL, and ATCA. We analysed their light curves, searched for periodicities, computed their PDSs, and fitted their X-ray spectra, to investigate the source behaviour during flip-flop transitions and how the interval featuring flip-flops differs from the rest of the outburst. Results: The flip-flops of Swift J1658.2-4242 are of an extreme variety, exhibiting flux differences of up to 77% within 100 s, which is much larger than what has been seen previously. We observed radical changes in the PDS simultaneous with the sharp flux variations, featuring transitions between the quasi-periodic oscillation types C and A, which have never been observed before. Changes in the PDS are delayed, but more rapid than changes in the light curve. Flip-flops occur in two intervals within the outburst, separated by about two weeks in which these phenomena were not seen. Transitions between the two flip-flop states occurred at random integer multiples of a fundamental period of 2.761 ks in the first interval and 2.61 ks in the second. Spectral analysis reveals the high and low flux flip-flop states to be very similar, but distinct from intervals lacking flip-flops. A change of the inner temperature of the accretion disc is responsible for most of the flux difference in the flip-flops. We also highlight the importance of correcting for the influence of the dust scattering halo on the X-ray spectra.
	Attribution of variations in the quasi-biennial oscillation period from the duration of easterly and westerly phases 期刊论文 iSwitch采集 Climate dynamics, 2016, 卷号: 47, 期号: 5-6, 页码: 1943-1959 作者: Yang, Mengmiao; Yu, Yueyue 收藏 \| 浏览/下载：44/0 \| 提交时间：2019/05/09 Quasi-biennial oscillation period Wavelet analysis Multi-variance-eof analysis Westerly and easterly phases
	长周期潮汐与全球地震能量释放期刊论文 OAI收割地球物理学报(CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION), 2013, 卷号: 56, 期号: 10, 页码: 3425-3433 作者: 解朝娣; 吴小平; 雷兴林; 冒蔚; 孙楠收藏 \| 浏览/下载：28/0 \| 提交时间：2016/04/11 起潮力(Tidal force) 潮汐周期(Astronomical tidal period) 地震能量释放准周期(Quasi cycle of seismic energy release) 小波变换(Wavelet transform)
	Quasi-periodicity of temperature changes on the millennial scale 期刊论文 OAI收割 PROGRESS IN NATURAL SCIENCE, 2003, 卷号: 13, 期号: 8, 页码: 601-606 作者: Ge, QS(葛全胜); Zheng, JY 收藏 \| 浏览/下载：131/31 \| 提交时间：2011/05/24 quasi-periodicity temperature change millennial scale the period of 1350a
	Quasi-periodicity of temperature changes on the millennial scale SCI/SSCI论文 OAI收割 2003 Ge Q. S.; Fang X. Q.; Zheng J. Y. 收藏 \| 浏览/下载：20/0 \| 提交时间：2012/06/08 quasi-periodicity temperature change millennial scale the period of 1350a climates
	The quasi-periodic pulsations in solar microwave bursts on May 3, 1989 期刊论文 OAI收割 CHINESE SCIENCE BULLETIN, 1992, 卷号: 37, 期号: 6, 页码: 473-478 作者: Zhang H(张衡); Gong YF(龚元芳); Shang QZ(尚琼珍); Hu HM(胡汉明); Lv SQ(吕松泉) 收藏 \| 浏览/下载：23/0 \| 提交时间：2016/03/30 MICROWAVE BURSTS AND FINE STRUCTURE QUASI-PERIOD FFT AND EPOCH-FOLDING PROBABILITY STATISTICS