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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：59/0 \| 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.
	GDAL/OGR and Geospatial Data IO Libraries 专著章节 OAI收割出自: Geographic Information Science & Technology Body of Knowledge, Online:John P. Wilson, 2020 作者: Qin, Cheng-Zhi; Zhu, Liang-Jun \| 收藏 \| 浏览/下载：26/0 \| 提交时间：2022/10/21 Geospatial Data Abstract Data Model Raster Data Vector Data Geoprocessing Format Conversion Coordinate Transformation Free And Open Source Software Programming Languages And Libraries
	The braking index of PSR B0540-69 and the associated pulsar wind nebula emission after spin-down rate transition 期刊论文 OAI收割 Monthly Notices of the Royal Astronomical Society, 2020, 卷号: 494, 页码: 1865-1870 作者: HXMT \| 收藏 \| 浏览/下载：66/0 \| 提交时间：2022/02/08 stars: magnetic field stars: neutron pulsars: general Astrophysics - High Energy Astrophysical Phenomena Abstract: In 2011 December, PSR B054-69 experienced a spin-down rate transition (SRT), after which the spin-down power of the pulsar increased by $\sim 36{{\ \rm per\ cent}}$. About 1000 d after the SRT, the X-ray luminosity of the associated pulsar wind nebula (PWN) was found to brighten by $32\pm 8{{\ \rm per\ cent}}$. After the SRT, the braking index n of PSR B0540-69 changes from n = 2.12 to 0.03 and then keeps this value for about five years before rising to n = 0.9 in the following years. We find that most of the current models have difficulties in explaining the measured braking index. One exceptive model of the braking index evolution is the increasing dipole magnetic field of PSR B0540-69. We suggest that the field increase may result from some instabilities within the pulsar core that enhance the poloidal component at the price of toroidal component of the magnetic field. The increasing dipole magnetic field will result in the X-ray brightening of the PWN. We fit the PWN X-ray light curve by two models: one assumes a constant magnetic field within the PWN during the brightening and the other assumes an enhanced magnetic field proportional to the energy density of the PWN. It appears that the two models fit the data well, though the later model seems to fit the data a bit better. This provides marginal observational evidence that magnetic field in the PWN is generated by the termination shock. Future high-quality and high-cadence data are required to draw a solid conclusion.
	GRB 200415A: A Short Gamma-Ray Burst from a Magnetar Giant Flare? 期刊论文 OAI收割 The Astrophysical Journal, 2020, 卷号: 899, 页码: 106 作者: HXMT \| 收藏 \| 浏览/下载：41/0 \| 提交时间：2022/02/08 Gamma-ray bursts Soft gamma-ray repeaters Magnetars Gamma-ray transient sources 629 1441 992 1853 Astrophysics - High Energy Astrophysical Phenomena Abstract: The giant flares of soft gamma-ray repeaters (SGRs) have long been proposed to contribute to at least a subsample of the observed short gamma-ray bursts (GRBs). In this paper, we perform a comprehensive analysis of the high-energy data of the recent bright short GRB 200415A, which was located close to the Sculptor galaxy. Our results suggest that a magnetar giant flare provides the most natural explanation for most observational properties of GRB 200415A, including its location, temporal and spectral features, energy, statistical correlations, and high-energy emissions. On the other hand, the compact star merger GRB model is found to have difficulty reproducing such an event in a nearby distance. Future detections and follow-up observations of similar events are essential to firmly establish the connection between SGR giant flares and a subsample of nearby short GRBs.
	The research for missile bullets' multiple targets of opto-electronic theodolites (EI CONFERENCE) 会议论文 OAI收割 2010 International Conference on Computer, Mechatronics, Control and Electronic Engineering, CMCE 2010, August 24, 2010 - August 26, 2010, Changchun, China Wei Z.; Liu Y.-H. 收藏 \| 浏览/下载：47/0 \| 提交时间：2013/03/25 The system of opto-electronic theodolites for measuring missile bullet provides parameter of missile bullet trajectory and affords primacy scientific data for completing campaign assign and obtaining ideal result of destroy. This article researches extraction arithmetic for missile bullet' multiple targets. Above all enactment threshold of area acquire middle axes of target by adopting Hough transforming and approximating and calculate obliquity angles of targets. In course of matching accomplish missile bullet's multiple targets data association of serial images by making use of improving eigenfunction and achieve extraction of missile bullet's multiple targets after obtaining center position of targets adopting OSTU method change numeral image into binary image according to area of target forecast searching region of target matching by using Kalman filter area of targets and abstract separately center position of targets and area of targets judge conglutination and obstruct then separate targets in term of wave crest and trough's variety of grey histogram of conglutination region grey average of target and obliquity angles of targets. The experimental result shows that right ratio of the extraction targets reach to 90%. The article use correct mathematical model and reasonable arithmetic and obtain effectively parameter of missile bullet' multiple targets. 2010 IEEE. at the same time obtain grey average of target mark target region
	computing invariants for parameter abstraction 会议论文 OAI收割 ACM/IEEE International Conference on Formal Methods and Models for Co-Design, Nice, FRANCE, MAY 30-JUN Lv Yi; Lin Huimin; Pan Hong \| 收藏 \| 浏览/下载：20/0 \| 提交时间：2011/06/29 cache coherence protocols combining invariants computing data consistency error guard strengthening methods parameter abstraction parameterized model checking transition rules abstract data types cache storage data integrity program verification