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Non-thermal emissions from accreting X-ray binary pulsars

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Research in Astronomy and Astrophysics 2014年第3期14卷 285-298页

作者： Jian-Fu Zhang Hui Jin ai-jun dong Department of Physics Tongren University School of Physics Huazhong University of Science and Technology

We study non-thermal emissions from cascade processes in accreting X-raybinary pulsars. In the framework of the magnetospheric gap model, we consider threephoton fields, which are respectively from the polar cap of a pulsar, its surroundingaccretion disk and a massive companion star with a circumstellar disk, to shield thegap. The gap-accelerated ultra-relativistic electrons emit high-energy photons via cur-vature radiation and an inverse Compton scattering process, in which part of thesehigh-energy photons absorbed by interactions with the surrounding photon fields canfacilitate the following electromagnetic cascades. We first carry out numerical calcula-tions of the cascade processes in order to obtain the predicted emission spectra. As anexample, we subsequently apply this model to reproduce observations of LS I ＋61~303. We find that the results can fit observations ranging from hard X-ray to γ-raybands, In particular, they can explain the spectral cutoff feature at a few GeV. Finally,we suggest that the emissions detected by the Fermi Large Area Telescope from X-raybinary pulsars originate in the magnetosphere region of the pulsar.

关键词： stars:binaries—stars:individual(LS I + 61°303)—radiation mechanisms:non-thermal—gamma rays:theory

CSS J075415.6+191052 and NW Leo: Two Contact Binaries at Different Evolutionary Stages

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Research in Astronomy and Astrophysics 2022年第2期22卷 118-127页

作者： Xu-dong Zhang Sheng-Bang Qian Er-Gang Zhao Qi-jun Zhi ai-jun dong Bin Zhang School of Physics and Electronic Science Guizhou Normal University550025 GuiyangChina Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang 550025 GuiyangChina Yunnan Observatories Chinese Academy of Sciences(CAS)650216 KunmingChina University of Chinese Academy of Sciences(UCAS) 100049 BeijingChina

Multi-color light curves of CSS J075415.6+191052 and NW Leo are presented and the photometric solutions suggest that CSS J075415.6+191052 is an A-subtype contact binary with low mass ratio(q = 0.178) while NW Leo has a high mass ratio(q = 0.707). For CSS J075415.6+191052, the RI light curves show weakening around the left shoulder of the secondary minimum, which indicates that there may be a dark spot on the secondary component. However, the light curves of BV bands are totally symmetric. It is unreasonable if the dark spot is caused by magnetic activity or mass transfer between the two components. Therefore, weakening of the light curves in this contact binary is caused by something else. A possible explanation is mass transferring from the primary component to the common convective envelope through the inner Lagrangian point, and this part of the mass, for some reason, weakens the RI bands of light from the secondary component. O-C analysis of NW Leo reveals a cyclic period change with a modulation period of 4.7 yr, which may be caused by the light travel time effect of a third body. The positions of CSS J075415.6+191052 and NW Leo in the P–J′_(orb)diagram indicate that CSS J075415.6+191052 mainly abides by the angular momentum loss theory while NW Leo is dominated by the thermal relaxation oscillation theory.

关键词： (stars:)binaries:eclipsing stars:evolution stars:individual(CSS J075415.6+191052 NW Leo)

Effects of the momentum dependence of nuclear symmetry potential on pion observables in Sn+Sn collisions at 270 MeV/nucleon

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Nuclear Science and Techniques 2022年第12期33卷 147-158页

作者： Gao‑Feng Wei Xin Huang Qi‑jun Zhi ai‑jun dong Chang‑Gen Peng Zheng‑Wen Long School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550025China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang 550025China Guizhou Provincial Key Laboratory of Public Big Data Guizhou UniversityGuiyang 550025China College of Physics Guizhou UniversityGuiyang 550025China

Within a transport model,we investigated the effects of the momentum dependence of the nuclear symmetry potential on the pion observables in central Sn+Sn collisions at 270 MeV/*** this end,the quantity U^(∞)_(sym)(ρ_(0))(i.e.,the value of the nuclear symmetry potential at the saturation densityρ_(0) and infinitely large nucleon momentum)was used to characterize the momentum dependence of the nuclear symmetry *** a certain L(i.e.,the slope of the nuclear symmetry energy at(ρ_(0))),the characteristic parameter U^(∞)_(sym)(ρ_(0))of the symmetry potential significantly affects the production of−and+and their pion ***,by comparing the charged pion yields,pion ratios,and spectral pion ratios of the theoretical simulations for the reactions ^(108) Sn+^(112) Sn and ^(132)Sn+^(124)Sn with the corresponding data in the SRIT experiments,we found that our results favor a constraint on U^(∞)_(sym)(ρ_(0))(i.e.,−160_(−9)^(+18) MeV),and L is also suggested within a range of 62.7 MeV

关键词： Nuclear symmetry potential Momentum dependence Symmetry energy

Time-resolved Spectral Properties of Fermi-GBM Bright Long Gamma-Ray Bursts

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Research in Astronomy and Astrophysics 2024年第2期24卷 58-73页

作者： Wan-Kai Wang Wei Xie Zhi-Fu Gao Shuo Xiao ai-jun dong Bin Zhang Qi-jun Zhi Department of Astronomy School of Physics and Electronic ScienceGuizhou Normal UniversityGuiyang 550001China Guizhou Provincial Key Laboratory of Radio Astronomy Data Processing Guizhou Normal UniversityGuiyang 550001China Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China

The prompt emission mechanism of gamma-ray bursts(GRBs)is still unclear,and the time-resolved spectral analysis of GRBs is a powerful tool for studying their underlying physical *** performed a detailed time-resolved spectral analysis of 78 bright long GRB samples detected by Fermi/Gamma-ray Burst Monitor.A total of 1490 spectra were obtained and their properties were studied using a typical Band-shape ***,the parameter distributions of the time-resolved spectrum are given as follows:the low-energy spectral indexα~-0.72,high-energy spectral indexβ~2.42,the peak energy E_(p)~221.69 keV,and the energy flux F~7.49×10^(-6)erg cm^(-2)s^(-1).More than 80%of the bursts exhibit the hardest low-energy spectral indexα_(max),exceeding the synchrotron limit(-2/3).Second,the evolution patterns of a and E_(p)were statistically *** results show that for multi-pulse GRBs the intensity-tracking pattern is more common than the hard-to-soft pattern in the evolution of both E_(p)andα.The hard-to-soft pattern is generally shown in single-pulse GRBs or in the initial pulse of multi-pulse ***,we found a significant positive correlation between F and E_(p),with half of the samples exhibiting a positive correlation between F andα.We discussed the spectral evolution of different radiation *** diversity of spectral evolution patterns indicates that there may be more than one radiation mechanism occurring in the GRB radiation process,including photo spheric radiation and synchrotron ***,it may also involve only one radiation mechanism,but more complicated physical details need to be considered.

关键词： (stars:)gamma-ray burst general-methods statistical-methods data analysis

NSVS 01286630:a detached binary with a close-in companion

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Research in Astronomy and Astrophysics 2018年第9期18卷 123-132页

作者： Bin Zhang Sheng-Bang Qian Nian-Ping Liu Wen-Ping Liao Li-Ying Zhu ai-jun dong Qi-jun Zhi Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550001China

New photometric observations of NS VS 01286630 were performed and two sets of fourcolor（B, V, Rc, Ic） light curves（LCs） were obtained. Using the 2013 version of the Wilson-Devinney（W-D） code, we analyzed these data. The photometric solutions reveal that NS VS 01286630 is an active detached eclipsing binary（EB） with a high orbital inclination（nearly 90°）. Remarkably, the temperature of the primary component（the hotter star） is higher than the secondary one, but the value of mass ratio q（M2/M1）for NS VS 0128663 is more than 1, which can be explained in that the surface of the secondary component of NSVS 01286630 is covered with big cool starspots. Based on our new CCD mid-eclipse times and the data published until now, variations in the mid-eclipse times were reanalyzed in detail using a weighted least-squares method. It is discovered that the（O-C） diagram of the system shows a cyclic oscillation with a period of 3.61 yr and an amplitude of 0.001 d. The cyclic variation may be caused by the light-travel time effect（LTTE） due to the presence of a third companion, whose mass we calculated as M3 sin（i3） =0.11 M（⊙）. The third body may affect the orbital evolution of the central binary system by transferring angular momentum.

关键词： stars binaries close- stars binaries eclipsing-stars individual (NSVS 01286630)

1SWASP J034439.97+030425.5:a short-period eclipsing binary system with a close-in stellar companion

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Research in Astronomy and Astrophysics 2020年第4期20卷 31-38页

作者： Bin Zhang Sheng-Bang Qian Jing-Jing Wang Qi-jun Zhi ai-jun dong Wei Xie Li-Ying Zhu Lin-Qiao Jiang School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550001China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang 550001China Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China Center for Astronomical Mega-Science Chinese Academy of SciencesBeijing 100101China China University of Petroleum-Beijing at Karamay Karamay 834000China School of Physics and Electronic Engineering Sichuan University of Science and EngineeringZigong 643000China

First multi-wavelength photometric light curves(LCs)of the short-period eclipsing binary(EB)1 SWASP J034439.97+030425.5(hereafter J0344)are presented and analyzed by using the 2013 version of the Wilson-Devinney(W-D)*** explain the asymmetric LCs of J0344,a cool star-spot on the less massive component was *** photometric solutions suggest that J0344 is a W-subtype shallow contact EB with a contact degree of f=4.9%±3.0%and a mass ratio of q=2.456±***,an obvious third light was detected in our *** calculated the average luminosity contribution of the third light to the total light,and that value reaches up to 49.78%.Based on the O-C method,the variations of the orbital period were studied for the first *** O-C diagram reveals a secular decrease superimposed on a cyclic *** orbital period decreases at a rate of d P/dt=-6.07×10-7 d yr-1,which can be explained by the mass transfer from the more massive component to the less massive ***,its O-C diagram also shows a cyclic oscillation with an amplitude of 0.0030 d and a period about 7.08 yr,which can be explained by the presence of a third body with a minimum mass of M3 min=0.15±0.02 M⊙.The third component may play an important role in the formation and evolution of J0344 by drawing angular momentum from the central system.

关键词： stars:binaries:close stars:binaries:eclipsing stars:individual(1SWASP J034439.97+030425.5)

Effects of low potassium dextran glucose solution on oleic acid-induced acute lung injury in juvenile piglets

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Chinese Medical Journal 2011年第14期124卷 2196-2202页

作者： LING Feng LIU Ying-long LIU ai-jun WANG dong WANG Qiang Department of Pediatric Cardiac Surgery Center Fuwai Hospital Chinese Academy of Medical Sciences & Peking Union Medical College Beijing 100037 China

Background Epithelial dysfunction in lungs plays a key role in the pathogenesis of acute lung injury. The beneficial effects of low potassium dextran glucose solution （LPD） have been reported in lung preservation, and LPD enables injured alveolar pneumocytes to recover. So we hypothesized that systemic administration of LPD may have benefits in treating acute lung injury. We investigated the effects of LPD on arterial blood gas and levels of some cytokines in oleic acid-induced acute lung injury in juvenile *** Oleic acid （0.1 ml/kg） was intrapulmonarily administered to healthy anesthetized juvenile piglets. Ten animals were randomly assigned to two groups （n=5 each）： oleic acid-induced group （control group） with intravenous infusion of 12.5 ml/kg of lactated Ringer＇s solution 30 minutes before administration of oleic acid and LPD group with systemic administration of LPD （12.5 ml/kg） 30 minutes before injecting oleic acid. Blood gas variables and concentrations of tumor necrosis factor alpha, endothelin 1 and interleukin 10 were measured before and every 1 hour for 6 hours after initial lung *** Compared with control group, blood pH, partial pressure of arterial oxygen to fraction of inspired oxygen ratio,partial pressure of arterial carbon dioxide, and mean pulmonary arterial pressure in LPD group were improved （P＜0.05or 0.01）. Six hours after lung injury, concentration of tumor necrosis factor alpha in lung tissue was lower in LPD group than control group （P＜0.05）. Plasmic concentration of endothelin 1 showed lower in LPD group while plasmic concentration of interleukin 10 showed higher in LPD group （P＜0.05）.Conclusions Before lung injury, systemic administration of LPD can improve gas exchange, attenuate pulmonary hypertension, decrease plasmic levels of endothelin 1, increase interleukin 10 and decrease concentration of tumor necrosis factor alpha in lung tissue in oleic acid-induced acute lung injury in juvenile piglets.

关键词： acute lung injury low potassium dextran cytokine piglet oleic acid

Applying Hybrid Clustering in Pulsar Candidate Sifting with Multi-modality for FAST Survey

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Research in Astronomy and Astrophysics 2024年第3期24卷 283-296页

作者： Zi-Yi You Yun-Rong Pan Zhi Ma Li Zhang Shuo Xiao Dan-Dan Zhang Shi-jun Dang Ru-Shuang Zhao Pei Wang ai-jun dong Jia-Tao Jiang Ji-Bing Leng Wei-An Li Si-Yao Li School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550025China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang 550025China College of Big Data and Information Engineering Guizhou UniversityGuiyang 550025China CAS Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Key Laboratory of Information and Computing Guizhou Province Guizhou Normal UniversityGuiyang 550001China School of Big data and Computer Science Guizhou Normal UniversityGuiyang 550025China Guizhou Software Engineering Research Center Guiyang 550000China

Pulsar search is always the basis of pulsar navigation,gravitational wave detection and other research ***,the volume of pulsar candidates collected by the Five-hundred-meter Aperture Spherical radio Telescope(FAST)shows an explosive growth rate that has brought challenges for its pulsar candidate filtering ***,the multi-view heterogeneous data and class imbalance between true pulsars and non-pulsar candidates have negative effects on traditional single-modal supervised classification *** this study,a multi-modal and semi-supervised learning based on a pulsar candidate sifting algorithm is presented,which adopts a hybrid ensemble clustering scheme of density-based and partition-based methods combined with a feature-level fusion strategy for input data and a data partition strategy for *** on both High Time Resolution Universe SurveyⅡ(HTRU2)and actual FAST observation data demonstrate that the proposed algorithm could excellently identify pulsars:On HTRU2,the precision and recall rates of its parallel mode reach0.981 and 0.988 *** FAST data,those of its parallel mode reach 0.891 and 0.961,meanwhile,the running time also significantly decreases with the increment of parallel nodes within ***,we can conclude that our algorithm could be a feasible idea for large scale pulsar candidate sifting for FAST drift scan observation.

关键词： methods data analysis-surveys-methods numerical

The Bright Single Pulse Emission from PSR B1133+16

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Research in Astronomy and Astrophysics 2024年第4期24卷 253-261页

作者： jun Tan Zhi-Gang Wen Zhen Wang Xue-Feng Duan Hong-Guang Wang Na Wang Vishal Gajjar Jian-Ping Yuan Rai Yuen Wen-Ming Yan Jian-Ling Chen Wei Han Hui Wang Cheng-Bing Lyu ai-jun dong Maths and Information Technology School Yuncheng UniversityYuncheng 044000China Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Xinjiang Key Laboratory of Radio Astrophysics Urumqi 830011China School of Physics and Materials Science Guangzhou UniversityGuangzhou 510006China Space Science Laboratory University of CaliforniaBerkeley 94710USA Department of Physics and Electronic Engineering Yuncheng UniversityYuncheng 044000China School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550025China

We have conducted a comprehensive investigation into the bright single pulse emission from PSR B1133+16using the Giant Metrewave Radio *** time resolution data(61μs)were obtained at a center frequency of 322 MHz with a bandwidth of 32 MHz over a continuous observation period of 7.45 hr.A total of 1082 bright pulses were sporadically detected with peak flux densities ranging from 10 to 23 times stronger than the average pulse ***,no giant pulse-like emission with a relative pulse energy larger than 10 and extremely short duration was detected,indicating that these bright pulses cannot be categorized as giant pulse *** majority of these bright pulses are concentrated in pulse phases at both the leading and trailing windows of the average pulse profile,with an occurrence ratio of approximately *** pulse energy distribution for all individual pulses can be described by a combination of two Gaussian components and a cutoff power-law with an index of α=-*** updated nulling fraction of 15.35%±0.45% was determined from the energy *** emission of individual pulses follows a log-normal distribution in peak flux density *** is imperative that regular phase drifting in bright pulse sequence is identified in both the leading and trailing components for the first *** physical mechanisms are discussed in detail to provide insights into these observations.

关键词： (stars:)pulsars:general (stars:)pulsars:individual(PSR B1133+16) methods:observational methods:data analysis