检索结果-南通市图书馆

The Optical Variability Properties of TeV Blazars

Research in astronomy and Astrophysics 2024年第9期24卷 68-77页

作者： Zi-An Su Wen-Xin Yang Xiang-Tao Zeng Le-Jian Ou Ze-Lin Li Jiang-He Yang Jun-Hui Fan department of physics School of Physics and Electronics Hunan Normal University Center for Astrophysics Guangzhou University Greater Bay Brand Center of the National Astronomical Data Center astronomy Science and Technology Research Laboratory of department of Education of Guangdong Province College of Microelectronics Feicuihu Campus of Hefei University of Technology College of Mathematics and physics Science Hunan University of Arts and Science

Variability is one of the typical observational properties of blazars and the spectral changes are usually associated with variability,although this kind of association is unclear *** this work,we used data from the Steward Observatory blazar monitoring program to investigate the optical variability properties including the short-term timescale,the brightness-dependent spectral property,the correlation between the the brightness variation and the polarization,and then estimate the Doppler factors based on the obtained short timescale to study the polarization property for a sample of 20 TeV *** analyses arrive at the following results:（1） The largest variation amplitude in R-band,ΔRM,covers a range fromΔRM=0.29 mag （1ES 2344+514） toΔRM=4.66 mag （3C 279）.（2） Intra-day variability was found from five sources with timescales from 0.14 day for S5 0716+714 to 0.98 day for PKS 2155–*** sources show spectra that are bluer when they become brighter,suggesting a common bluer-when-brighter property.（3） The plot of the polarization versus estimated Doppler factor is consistent with the Doppler factor dependent formula of polarization.（4） The largest polarization is correlated with the largest optical variation,suggesting that the high polarization and high amplitude variation are both the indicator of beaming effect.

关键词： galaxies: active galaxies: jets radiation mechanisms: non-thermal

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

BSN:Photometric Light Curve Analysis of Two Contact Binary Systems LS Del and V997 Cyg

引用

Research in astronomy and Astrophysics 2024年第4期24卷 192-213页

作者： Atila Poro Mehmet Tanriver Elham Sarvari Shayan Zavvarei Hossein Azarara Laurent Corp Sabrina Baudart Asma Ababafi Nazanin Kahali Poor Fariba Zare Ahmet Bulut Ahmet Keskin astronomy department of the Raderon AI Lab. BurnabyBC.Canada department of astronomy and Space Science Faculty of ScienceErciyes UniversityKayseri TR-38039Turkiye Erciyes University Astronomy and Space Science Observatory Application and Research CenterKayseri TR-38039Turkiye Independent Astrophysics Researcher TehranIran department of physics Shahid Beheshti UniversityTehranIran Faculty of physics Shahid Bahonar University of KermanP.O.Box 76175KermanIran Double Stars Committee SociétéAstronomique de FranceParisFrance Dez Astronomical Association Khouzestan ProvinceDezfulIran department of physics Amirkabir University of TechnologyTehranIran department of physics Faculty of SciencesCanakkale Onsekiz Mart UniversityTerzioglu KampusuTR-17020CanakkaleTurkiye Astrophysics Research Center and Observatory Canakkale Onsekiz Mart UniversityTerzioğlu KampusuTR-17020CanakkaleTürkiye

The light curve analyses and orbital period variations for two contact binary stars,LS Del and V997 Cyg,are presented in this work which was conducted in the frame of the Binary Systems of South and North project Ground-based photometric observations were performed at two observatories in *** used the Transiting Exoplanet Survey Satellite(TESS)data for extracting times of minima and light curve analysis of the targe *** O-C diagram for both systems displays a parabolic *** Del and V997 Cyg’s orbital periods are increasing at rates of dP/dt=7.20×10^(-08)days yr^(-1)and dP/dt=2.54×10^(-08)days yr^(-1),respectively Therefore,it can be concluded that mass is being transferred from the less massive star to the more massive component with a rate of dM/dt=-1.96×10^(-7)M_(⊙)yr^(-1)for the LS Del system,and dM/dt=-3.83×10^(-7)M_(⊙)yr-1for V997 *** parameters of a third possible object in the system are also *** physics Of Eclipsing BinariEs Python code was used to analyze the light *** light curve solutions needed a cold starspot due to the asymmetry in the LS Del system’s light curve *** mass ratio fill-out factor,and star temperature all indicate that both systems are contact binary types in this *** methods were applied to estimate the absolute parameters of the systems:one method relied on the parallax of Gaia DR3,and the other used a P-M *** positions of the systems are also depicted on the M-L,M-R q-L_(ratio),and logM_(tot)-logJ_(0)*** recommend that further observations and investigations be done on the existence of a fourth body in this system.

关键词： (stars:)binaries:eclipsing methods:observational stars:individual(LS Del and V997 Cyg)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Production and test of sPHENIX W/SciFiber electromagnetic calorimeter blocks in China

引用

Nuclear Science and Techniques 2024年第8期35卷 167-176页

作者： Xiao‑Zhou Yu Xi‑Yang Wang Wei‑Hu Ma Shi‑Hong Fu Peng‑Fei Sun Jin‑Xing Song Wan‑Bing He Yang Shen Long Ma Jin‑Hui Chen Huan‑Zhong Huang Si‑Guang Wang Jing Zhou Xiao‑Mei Li Institute of Modern physics Fudan UniversityShanghai 200433China Key Laboratory of Nuclear physics and Ion‑Beam Application(MOE) Fudan UniversityShanghai 200433China Science and Technology on Nuclear Data Laboratory China Institute of Atomic EnergyBeijing 102413China department of physics and astronomy University of CaliforniaLos AngelesCA 90095USA State Key Laboratory of Nuclear physics and Technology School of PhysicsPeking UniversityBeijing 100871China

The sPHENIX experiment is a new generation of large acceptance detectors at the relativistic heavy ion collider at Brookhaven National Laboratory,with scientific goals focusing on probing the strongly interacting Quark–Gluon plasma with hard probes of jets,open heavy flavor particles,andγ*** EMCal detector,which covers the pseudo-rapidity region of|η|≤1.1,is an essential subsystem of *** this study,we focused on producing and testing EMCal blocks covering a pseudo-rapidity of|η|∈[0.8,1.1].These,in conjunction with the central pseudo-rapidity EMCal blocks,significantly enhance the sPHENIX physics capability of the jet andγparticle *** this paper,the detector module production and testing of sPHENIX W-powder/scintillating fiber(W/ScFi)electromagnetic calorimeter blocks are *** selection of the tungsten powder,mold fabrication,QA procedures,and cosmic ray test results are discussed.

关键词： sPHENIX Tungsten/scintillating fiber electromagnetic calorimeter Cosmic ray test

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

First Light Curve Analysis of NSVS 8294044,V1023 Her,and V1397 Her Contact Binary Systems

引用

Research in astronomy and Astrophysics 2024年第5期24卷 1-12页

作者： Atila Poro Sabrina Baudart Mahshid Nourmohammad Zahra Sabaghpour Arani Fatemeh Farhadi Selda Ranjbar Salehian Ahmad Sarostad Saeideh Ranjbaryan Iri Olya Maryam Hadizadeh AmirHossein Khodaei astronomy department of the Raderon AI Lab. BurnabyBCCanada Double Stars Committee SociétéAstronomique de FranceParisFrance Independent Astrophysics Researcher IsfahanIran Akhtaran Astronomical Society Isfahan ProvinceAran and BidgolIran department of physics Faculty of ScienceZanjan UniversityZanjanIran astronomy Students'Scientific Association University of TabrizEast Azerbaijan ProvinceTabrizIran Yazd Desert Night Sky astronomy Institute Yazd ProvinceYazdIran Ayaz Astronomical Association East Azerbaijan ProvinceTabrizIran Khayyam astronomy Association FarsFasaIran

The first photometric light curve investigation of the NSVS 8294044,V1023 Her,and V1397 Her binary systems is *** used ground-based observations for the NSVS 8294044 system and Transiting Exoplanet Survey Satellite data for V1023 Her and V1397 *** primary and secondary times of minima were extracted from al the data,and,by collecting the literature,a new ephemeris was computed for each *** fits for the O-C diagrams were conducted using the Markov Chain Monte Carlo (MCMC) *** curve solutions were performed using the physics Of Eclipsing BinariEs Python code and the MCMC *** systems were found to be contact binary stars based on the fillout factor and mass ratio.V1023 Her showed the O’Connell effect and a cold starspot on the secondary component was required for the light curve *** absolute parameters of the system were estimated based on an empirical relationship between orbital period and *** presented a new T–M equation based on a sample of 428 contact binary systems and found that our three target systems were in good agreement with the *** positions of the systems were also depicted on the M–L,M–R,q–L_(ratio),and M_(tot)–J_(0)diagrams in the logarithmic scales.

关键词： (stars:)binaries eclipsing-techniques photometric-stars individual(NSVS 8294044)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

An improved bound on accelerated light dark matter

引用

Science China(physics,Mechanics & astronomy) 2024年第2期67卷 105-118页

作者： Liangliang Su Lei Wu Bin Zhu department of physics and Institute of Theoretical physics Nanjing Normal UniversityNanjing 210023China School of physics Yantai UniversityYantai 264005China

Light(sub-GeV)dark matter has gained increasing interest in terms of direct *** dark matter is a promising candidate that can generate detectable nuclear recoil energy within the sub-GeV *** of the large kinetic energy,its interactions with the nucleus are predominantly governed by inelastic scattering,including quasi-elastic and deep inelastic *** this work,we calculated the inelastic effects in dark matter-Earth scattering mediated by a vector *** analysis revealed that the impact of inelastic scattering relies on the mediator mass and the kinetic energy spectrum of dark *** results exhibited considerable disparity:the upper bounds of the exclusion limit for the spin-independent cross-section between accelerated dark matter and nuclei via a heavy mediator differ by several tens of times when inelastic scattering is considered.

关键词： accelerated dark matter inelastic scattering direct detection experiment

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Ion-acoustic waves with non-planar wavefronts

引用

Plasma Science and Technology 2024年第1期26卷 1-7页

作者： Shujaht BUKHARI Muhammad SHAHID Ata-ur RAHMAN department of physics The University of Azad Jummu and KashmirMuzaffarabad 13100Azad Kashmir department of physics Women University of Azad Jammu&KashmirBagh 12500Pakistan department of physics Islamia College PeshawerPeshawar 25120Pakistan

The ion-acoustic(IA) mode exhibiting various orbital angular momentum(OAM) states is examined in a plasma with drifting *** constituent plasma species are modeled with a non-gyrotropic Maxwellian distribution and discussion of dispersion relation and growth rate of twisted IA waves under various conditions is *** the domain of kinetic model,the twisted IA waves are characterized by Laguerre-Gaussian(LG) solutions,where plasma distribution function and electric field are decomposed into axial and azimuthal *** plasma response function is obtained under paraxial approximations and investigated for threshold condition of instability growth rate with helical electric field *** impact of an extra electron specie on the instability is demonstrated through a comparison of twisted waves for single and double electron species.

关键词： instability twist parameter wave excitation orbital angular momentum threshold limit

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Massless Dirac perturbations of black holes in f(Q) gravity: quasinormal modes and a weak deflection angle

引用

Communications in Theoretical physics 2024年第9期76卷 75-84页

作者： Ahmad Al-Badawi Sohan Kumar Jha department of physics Al-Hussein Bin Talal University department of physics Chandernagore College

This article considers a static and spherical black hole（BH） in f（Q） gravity. f（Q） gravity is the extension of symmetric teleparallel general relativity, where both curvature and torsion are vanishing and gravity is described by nonmetricity. In this study, we investigate the possible implications of quasinormal mode（QNM） modified Hawking spectra and deflection angles generated by the model. The Wentzel–Kramers–Brillouin method is used to solve the equations of motion for massless Dirac perturbation fields and explore the impact of the nonmetricity parameter（Q0）. Based on the QNM computation, we can ensure that the BH is stable against massless Dirac perturbations and as Q0increases the oscillatory frequency of the mode decreases. We then discuss the weak deflection angle in the weak field limit approximation. We compute the deflection angle up to the fourth order of approximation and show how the nonmetricity parameter affects it. We find that the Q0parameter reduces the deflection angle.

关键词： black holes in f(Q) gravity deflection angle massless Dirac perturbations quasinormal modes

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Molecular Chaperone-Dependent Polymer Translocation through Nanopores: The Effects of Chaperone Concentration and Chaperone-Polymer Interaction

引用

Chinese Journal of Polymer Science 2024年第1期42卷 125-132,I0011页

作者： Chang-Sheng Zuo Kang Wang Li-Zhen Sun Ting-Ting Sun department of physics Zhejiang University of Science and TechnologyHangzhou 310023China department of Applied physics Zhejiang University of TechnologyHangzhou 310014China

The polymer translocation through a nanopore from a donor space(or named cis side) to a receiver space(trans side) in the chaperone-induced crowded environment has attracted increasing attention in recent years due to its significance in biological systems and technological applications. In this work, we mainly focus on the effects of chaperone concentration and chaperone-polymer interaction on the polymer translocation. By assuming the polymer translocation to be a quasi-equilibrium process, the free energy F of the polymer can be estimated by Rosenbluth-Rosenbluth method and then the translocation time τ can be calculated by Fokker-Plank equation based on the obtained free energy landscape. Our calculation results show that the translocation time can be controlled by independently tuning the chaperone concentration and chaperone-polymer interaction at the cis side or the trans side. There exists a critical chaperone-polymer attraction ε~*=-0.2 at which the volume exclusion and interaction effects of the chaperone can balance each other. Additionally, we also find that at large chaperone-polymer attraction, the translocation time is mainly governed by the diffusion coefficient of the polymer.

关键词： Polymer translocation Rosenbluth-Rosenbluth method Fokker-Plank equation Free energy landscapes

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Probing turbulence in galaxies with fast radio burst scintillation

引用

Science China(physics,Mechanics & astronomy) 2024年第1期67卷 177-178页

作者： James M.Cordes department of astronomy the Cornell Center for Astrophysics and Planetary ScienceCornell UniversityIthaca NY 14853USA

Interstellar scintillation(ISS)is a well-known phenomenon observed from pulsars in the Milky *** comprises intensity variations *** and frequency caused by constructive and destructive interference from multipath propagation,which is due to diffraction from fluctuations in electron density in the interstellar medium(ISM)on scales as small as~100 *** density fluctuations appear to be part of a turbulence process combined with discrete structures in electron density from other astrophysical processes;together these fluctuations extend to scales of pc or larger.

关键词： scales galaxies turbulence

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Microlensing bias on the detection of strong lensing gravitational wave

引用

Science China(physics,Mechanics & astronomy) 2024年第6期67卷 156-165页

作者： Xikai Shan Xuechun Chen Bin Hu Guoliang Li Institute for Frontier in astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China department of astronomy Beijing Normal UniversityBeijing 100875China Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China

Identifying strong lensing gravitational wave(SLGW)events is of utmost importance in astrophysics as we approach the historic first detection of SLGW amidst the growing number of gravitational wave(GW)***,one crucial method for identifying SLGW signals involves assessing the overlap of parameters between two ***,the distribution of discrete matter,such as stars and sub-halos,within the strong lensing galaxy can imprint a wave optical(WO)effect on the SLGW *** frequency dependent imprints introduce biases in parameter estimation and impact SLGW *** this study,we assess the influence of the stellar microlensing field embedded in a strong lensing *** findings demonstrate that the WO effect reduces the detection efficiency of SLGW by 5%-50%for various false alarm probabilities per pair(FAPper pair).Specifically,at an FAPper pairof 10^(-5),the detection efficiency decreases from~10%to~5%.Consequently,the presence of the microlensing field can result in missing half of the strong lensing ***,the microlensing WO effect introduces a noticeable bias in intrinsic parameters,particularly for chirp mass and mass ***,it has tiny influence on extrinsic *** all parameters,~30%of events exhibit a 1σparameter bias,~12%exhibit a 2σparameter bias,and~5%exhibit a 3σparameter bias.

关键词： gravitational wave gravitational strong lensing gravitational micro lensing wave optical effect

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：