Astrophysics and Space Science最新文献_第4页

Time-lag in hadronic channel: to explore delayed VHE-flare of 3C 279

IF 1.8 4区物理与天体物理

Astrophysics and Space Science Pub Date : 2025-01-27 DOI: 10.1007/s10509-025-04398-8

Sunanda, Reetanjali Moharana

引用次数: 0

EFT calculations of (S_{34}(E)) for the (^{3}H(alpha ,gamma )^{7}Li) radiative capture reaction

IF 1.8 4区物理与天体物理

Astrophysics and Space Science Pub Date : 2025-01-24 DOI: 10.1007/s10509-024-04385-5

H. Sadeghi, M. Khoddam

引用次数: 0

The shape of magnetic hole in affecting electron distribution function and wave properties 磁孔的形状影响电子分布函数和波的性质

IF 1.8 4区物理与天体物理

Astrophysics and Space Science Pub Date : 2025-01-21 DOI: 10.1007/s10509-025-04397-9

Z. Y. Xu, H. S. Fu, Y. Yu, Z. Wang, W. D. Fu, W. Z. Zhang, J. B. Cao

{"title":"The shape of magnetic hole in affecting electron distribution function and wave properties","authors":"Z. Y. Xu, H. S. Fu, Y. Yu, Z. Wang, W. D. Fu, W. Z. Zhang, J. B. Cao","doi":"10.1007/s10509-025-04397-9","DOIUrl":"10.1007/s10509-025-04397-9","url":null,"abstract":"<div><p>Magnetic holes (MHs) have been widely observed in astrophysical and space plasmas. However, due to the lack of reconstruction method, the effects of MH shape on electron distribution function and wave properties are still unclear. In this study, we report a series of MHs in Earth’s magnetotail. We particularly focus on two of them with the clearest data features, reconstruct their topologies using the Second-Order Taylor Expansion (SOTE) method, and find their shapes to be bulging and deflated. Comparatively, the bulging MH exhibits a donut electron distribution, which may be attributed to the combined effects of internal expansion-induced betatron cooling and boundary contraction-induced betatron acceleration, while the deflated MH presents a pancake electron distribution. The beam instability and temperature anisotropy inside the bulging MH also excite electron cyclotron waves and whistler waves, respectively, while the deflated MH does not exhibit these types of waves. All these findings help us understand the geometric properties and evolutions of MHs.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"370 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142994907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Dispersion relations of relativistic radiation hydrodynamics 相对论辐射流体力学的色散关系

IF 1.8 4区物理与天体物理

Astrophysics and Space Science Pub Date : 2025-01-15 DOI: 10.1007/s10509-025-04395-x

Lorenzo Gavassino

引用次数: 0

Dust acoustic soliton and shock structures with consequence of head-on collision in multi-component unmagnetized plasmas 多分量非磁化等离子体中正面碰撞产生的尘埃声孤子和激波结构

IF 1.8 4区物理与天体物理

Astrophysics and Space Science Pub Date : 2025-01-13 DOI: 10.1007/s10509-024-04392-6

Umma Imon, Mohammad Shah Alam

{"title":"Dust acoustic soliton and shock structures with consequence of head-on collision in multi-component unmagnetized plasmas","authors":"Umma Imon, Mohammad Shah Alam","doi":"10.1007/s10509-024-04392-6","DOIUrl":"10.1007/s10509-024-04392-6","url":null,"abstract":"<div><p>An unmagnetized plasma system comprising Maxwellian electrons, nonthermal ions, and variable negative charged dust grains is considered to investigate the consequence of head-on collision (such as interaction processes, and phase shifts) and the formation of dust acoustic soliton as well as shock structures in the Halley’s Comet (HC), Interstellar Clouds (IC), Noctilucent Clouds (NC), and Saturn’s Spokes (SS) environments. The two-sided Korteweg de Vries Burger (KdVB) and Korteweg de Vries (KdV) equations and corresponding phase shifts are derived employing the extended Poincaré-Lighthill-Kuo (ePLK) reductive perturbation technique (ePLKRPT). The coefficient of nonlinearities vanishes in each environment at the critical value of the plasma parameters. Consequently, the nonlinearity-coupled modified KdVB (mKdVB) and modified KdV (mKdV) equations, and the associated phase shifts have been derived. The concerned parameters play a crucial role in forming soliton and shock structures, phase shifts, and the interaction process of solitons and shocks in each environment. The compressive hump-shaped structures for mKdV solitons, as well as only positive phase shifts, are produced due to the influences of concerned parameters in each environment. In the collision processes, both the KdV and mKdV dust acoustic solitons follow the principle of superposition, but the shocks do not follow the principle of superposition.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"370 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142976555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Comparative study of linear & non-linear (f(T)) gravity models in Bianchi type-III space-time Bianchi iii型时空中线性与非线性(f(T))引力模型的比较研究

IF 1.8 4区物理与天体物理

Astrophysics and Space Science Pub Date : 2025-01-10 DOI: 10.1007/s10509-025-04394-y

R. K. Mishra, Rahul Sharma

{"title":"Comparative study of linear & non-linear (f(T)) gravity models in Bianchi type-III space-time","authors":"R. K. Mishra, Rahul Sharma","doi":"10.1007/s10509-025-04394-y","DOIUrl":"10.1007/s10509-025-04394-y","url":null,"abstract":"<div><p>In this study, we explore the dynamics of Bianchi type-III space-time within the framework of <span>(f(T))</span> gravity, focusing on both linear and non-linear forms of <span>(f(T))</span> function. We analyze the behavior of cosmological parameters by assuming the deceleration parameter (DP) as a simple linear function of the Hubble parameter. Key cosmological parameters such as the scale factor, Hubble parameter, DP, spatial volume, shear scalar, expansion scalar, energy density, pressure, and the equation of state (EoS) parameter are expressed in terms of the redshift parameter. Their dynamic behaviors are graphically presented for both linear and non-linear forms of <span>(f(T))</span> gravity. Our results align with recent cosmological observations, with the non-linear form of <span>(f(T))</span> exhibiting a stronger tendency toward accelerated cosmic expansion compared to the linear model. The EoS parameter indicates a quintessence phase, driving the universe’s accelerated expansion, as recently investigated by Varshney et al. (Can. J. Phys. 102(3):199–209, 2023). Additionally, we examine the violation of the strong energy conditions, a crucial aspect in modified gravity theories. The model parameter <span>(xi )</span> and the current value of the Hubble parameter <span>(H_{0})</span> are estimated using the Hubble data set and Pantheon+ SHOES data set, further validating our theoretical model.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"370 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142941176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Resolved spectroscopic binaries: orbital elements and parallaxes 已分辨的光谱双星：轨道元素和视差

IF 1.8 4区物理与天体物理

Astrophysics and Space Science Pub Date : 2025-01-08 DOI: 10.1007/s10509-024-04393-5

Dugasa Belay Zeleke, Arseniy M. Sachkov, Oleg Y. Malkov, Seblu Humne Negu, Solomon Belay Tessema, Alyona D. Grinenko

引用次数: 0

Title: proton acceleration by kinetic turbulence across various magnetization levels in astrophysical plasmas 题目：天体物理等离子体中不同磁化水平的动力学湍流对质子的加速

IF 1.8 4区物理与天体物理

Astrophysics and Space Science Pub Date : 2024-12-20 DOI: 10.1007/s10509-024-04391-7

Ji-Hoon Ha

{"title":"Title: proton acceleration by kinetic turbulence across various magnetization levels in astrophysical plasmas","authors":"Ji-Hoon Ha","doi":"10.1007/s10509-024-04391-7","DOIUrl":"10.1007/s10509-024-04391-7","url":null,"abstract":"<div><p>Turbulence in astrophysical plasma transfers energy to kinetic scales, leading to proton acceleration or heating, yet the formation of suprathermal protons from such turbulence is not fully understood. While proton acceleration modeling based on the Fokker-Planck equation with diffusion through kinetic Alfvén waves (KAW) has been proposed to understand in-situ measurements of suprathermal protons in the interplanetary medium, more investigations using such modeling could help clarify the nature of particle acceleration in various astrophysical media beyond the interplanetary medium. Since the characteristics of KAW turbulence depend on the magnetization of the plasma system and the temperature anisotropy of the proton distribution function, proton acceleration mediated by KAW turbulence could also be influenced by these factors. By solving the Fokker-Planck equation, this study examines proton acceleration through KAW turbulence across strongly to weakly magnetized astrophysical plasmas, parameterized by plasma beta (<span>(beta =0.01-10)</span>), and the effects of proton temperature anisotropy. Particularly, our findings indicate that KAW turbulence significantly influences the presence of suprathermal protons in low-beta plasmas, such as the interplanetary medium, but is less impactful in high-beta environments, like the intergalactic and intracluster medium. Additionally, the proton temperature anisotropy significantly modulates the efficiency of proton diffusion in velocity space in low-beta environments.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"369 12","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142859463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Recycled pulsars - a historical perspective 回收脉冲星--历史视角

IF 1.8 4区物理与天体物理

Astrophysics and Space Science Pub Date : 2024-12-17 DOI: 10.1007/s10509-024-04389-1

G. Srinivasan

引用次数: 0

Perturbation effect of solar radiation pressure on the Sun-Earth co-orbital motion 太阳辐射压力对日地同轨道运动的扰动效应

IF 1.8 4区物理与天体物理

Astrophysics and Space Science Pub Date : 2024-12-16 DOI: 10.1007/s10509-024-04387-3

Mingxu Zhao, Yi Qi, Dong Qiao

引用次数: 0