Physics of the Dark Universe最新文献

{"title":"Physical viability of f(Q) gravity corrected charged anisotropic solutions","authors":"Shamaila Rani ,&nbsp;Muhammad Adeel ,&nbsp;M. Zeeshan Gul ,&nbsp;Abdul Jawad ,&nbsp;Sanjar Shaymatov","doi":"10.1016/j.dark.2024.101754","DOIUrl":"10.1016/j.dark.2024.101754","url":null,"abstract":"<div><div>This article explores the impact of charge on the properties of relativistic compact star candidates exhibiting anisotropic distribution in <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></math></span> gravity, where <span><math><mi>Q</mi></math></span> represents a nonmetricity. A specific model of this gravitational theory is considered to simplify the system and establish the precise field equations that regulate the interaction between matter and geometry. Analysis of the static spherical symmetric structures is conducted by considering the non-singular feasible solutions. The Darmois constraints are used to determine the unknown constants in the metric coefficients. We explore different physical characteristics in the interior of charged compact stars to check their viability. Sound velocity and adiabatic index techniques are employed for stability state analysis. Proposed charged stars are determined to be both viable and stable in this theoretical framework.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101754"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}

{"title":"Probing dark energy properties with Barrow Holographic Model in f(Q,C) gravity","authors":"N. Myrzakulov ,&nbsp;S.H. Shekh ,&nbsp;Anirudh Pradhan","doi":"10.1016/j.dark.2024.101790","DOIUrl":"10.1016/j.dark.2024.101790","url":null,"abstract":"<div><div>Understanding the accelerating expansion of the universe remains one of the foremost challenges in modern cosmology. This study investigates Barrow Holographic Dark Energy (BHDE), a model inspired by quantum gravitational corrections, within the framework of <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow></mrow></math></span> gravity. This extension of symmetric teleparallel gravity incorporates the non-metricity scalar <span><math><mi>Q</mi></math></span> and the boundary term <span><math><mi>C</mi></math></span>, enabling a deeper exploration of cosmic dynamics without relying on a cosmological constant or exotic matter. The BHDE model is analyzed under a flat Friedmann–Robertson–Walker (FRW) metric, focusing on key cosmological parameters such as energy density, isotropic pressure, the equation of state (EoS) parameter, stability conditions and the energy conditions. The results demonstrate that the EoS parameter transitions from matter-like behavior (<span><math><mrow><mi>z</mi><mo>&gt;</mo><mn>0</mn></mrow></math></span>) to negative values at <span><math><mrow><mi>z</mi><mo>=</mo><mn>0</mn></mrow></math></span>, indicating the dominance of dark energy and its role in the universe’s accelerated expansion. As <span><math><mi>z</mi></math></span> approaches <span><math><mrow><mo>−</mo><mn>1</mn></mrow></math></span>, the EoS parameter asymptotically converges to <span><math><mrow><mo>−</mo><mn>1</mn></mrow></math></span>, aligning with the <span><math><mi>Λ</mi></math></span>CDM model. This work underscores the potential of the BHDE model in <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow></mrow></math></span> gravity as a comprehensive framework for studying cosmic acceleration. By incorporating Barrow entropy and addressing the interplay between non-metricity and boundary terms, the model provides a dynamic approach to explaining dark energy. Its predictions align well with observational datasets, including Type Ia supernovae, cosmic microwave background (CMB) radiation, and baryon acoustic oscillations (BAO). Future investigations could refine the constraints on free parameters and explore deeper connections between quantum gravitational effects and the observed behavior of dark energy. Overall, the BHDE model within <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow></mrow></math></span> gravity offers a robust alternative to static dark energy models, capturing the universe’s complex evolution from the past to the distant future.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101790"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}

{"title":"Observational constraints on a generalized equation of state model","authors":"M. Koussour ,&nbsp;S. Bekov ,&nbsp;A. Syzdykova ,&nbsp;S. Muminov ,&nbsp;I. Ibragimov ,&nbsp;J. Rayimbaev","doi":"10.1016/j.dark.2024.101799","DOIUrl":"10.1016/j.dark.2024.101799","url":null,"abstract":"<div><div>We investigate the cosmological implications of a generalized total equation of state (EoS) model by constraining its parameters using observational datasets to effectively characterize the universe’s expansion history and its dynamic properties. We introduce three parameters: <span><math><mi>α</mi></math></span>, <span><math><mi>β</mi></math></span>, and <span><math><mi>n</mi></math></span> to capture the EoS behavior across different evolutionary phases. Our analysis indicates that at high redshifts (<span><math><mrow><mi>z</mi><mo>≫</mo><mn>1</mn></mrow></math></span>), the EoS approaches a matter- or radiation-dominated regime, transitioning to a dark energy-dominated phase as <span><math><mrow><mi>z</mi><mo>→</mo><mo>−</mo><mn>1</mn></mrow></math></span>, where it tends toward a constant value <span><math><mi>α</mi></math></span>. Using a Markov Chain Monte Carlo (MCMC) method, we analyze a combined dataset that includes 31 data points from <span><math><mrow><mi>H</mi><mrow><mo>(</mo><mi>z</mi><mo>)</mo></mrow></mrow></math></span> and 1701 data points from the Pantheon+ dataset. The results reveal a smooth transition from deceleration to acceleration in the universe’s expansion, with current EoS values suggesting quintessence-like behavior. The model aligns with observations and indicates that dark energy is dynamically evolving rather than acting as a cosmological constant. Furthermore, energy conditions and stability analyses highlight the nature and future of dark energy. This parametrized EoS model thus offers a robust framework for understanding the complexities of dark energy and the evolution of the cosmos.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101799"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}

{"title":"Thermal fluctuations, particle collision, QPOs, and emission energy around a Schwarzschild black hole immersed in Dehnen-type dark matter halo","authors":"Asifa Ashraf ,&nbsp;Allah Ditta ,&nbsp;Abdelmalek Bouzenada ,&nbsp;Assmaa Abd-Elmonem ,&nbsp;Nesreen Sirelkhtam Elmki Abdalla ,&nbsp;Farruh Atamurotov","doi":"10.1016/j.dark.2025.101823","DOIUrl":"10.1016/j.dark.2025.101823","url":null,"abstract":"<div><div>This article investigates the properties of test particles near a Schwarzschild black hole embedded in a Dehnen-type dark matter halo, focusing on how the model’s parameters influence particle dynamics. The model is defined by three key parameters: the black hole’s mass <span><math><mi>M</mi></math></span>, the central halo’s radius <span><math><msub><mrow><mi>R</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span>, and the central halo density <span><math><mi>ρ</mi></math></span>. Explicit expressions for the energy and angular momentum of test particles are derived based on these parameters. The study also explores the effective potential, the innermost stable circular orbits (ISCO), and the forces acting on the particles. Additionally, we analyze the epicyclic oscillations of particles near the equatorial plane, providing analytical formulas for the radial, vertical, and orbital frequencies as functions of the model’s parameters. The research further examines the frequency of periastron precession for these particles. Moreover, we probe particle collisions near the black hole’s horizon and compute the center-of-mass energy. The results emphasize the significant influence of the black hole model’s parameters on particle motion.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101823"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}

{"title":"Perturbed f(R) gravity coupled with neutrinos: Exploring cosmological implications","authors":"Muhammad Yarahmadi ,&nbsp;Amin Salehi ,&nbsp;Kazuharu Bamba ,&nbsp;H. Farajollahi","doi":"10.1016/j.dark.2025.101824","DOIUrl":"10.1016/j.dark.2025.101824","url":null,"abstract":"<div><div>We conduct a thorough examination of cosmological parameters within the context of perturbed <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> gravity coupled with neutrinos, using a diverse array of observational datasets, including Cosmic Microwave Background (CMB), Cosmic Chronometers (CC), Baryon Acoustic Oscillations (BAO), and Pantheon supernova and Lensing data. Our analysis unveils compelling constraints on cosmological parameters such as the sum of neutrino masses (<span><math><mrow><mo>∑</mo><msub><mrow><mi>m</mi></mrow><mrow><mi>ν</mi></mrow></msub></mrow></math></span>), sound speed (<span><math><msub><mrow><mi>c</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span>), Jean’s wavenumbers (<span><math><msub><mrow><mi>k</mi></mrow><mrow><mi>J</mi></mrow></msub></math></span>), redshift of non-relativistic matter (<span><math><msub><mrow><mi>z</mi></mrow><mrow><mi>nr</mi></mrow></msub></math></span>) and redshift of Deceleration-Acceleration phase transition (<span><math><msub><mrow><mi>z</mi></mrow><mrow><mi>DA</mi></mrow></msub></math></span>). In our model the interaction strength parameter (<span><math><mi>Γ</mi></math></span>) coming from incorporation of neutrinos with the perturbed <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> gravity as a key factor significantly influencing cosmic evolution, shaping the formation of large-scale structures and the dynamics of cosmic expansion. Our study also addresses the Hubble tension problem by providing <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span> measurements that are in agreement with the existing research.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101824"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}

{"title":"Dynamics of the universe in f(G,τ2) gravity via well-known cosmological bouncing","authors":"Shamaila Rani ,&nbsp;Nadeem Azhar ,&nbsp;Amna Mir ,&nbsp;Abdul Jawad ,&nbsp;Yousef Mohammed Alanazi ,&nbsp;Abdulrahman Bin Jumah ,&nbsp;Hafiz Haseeb Nawaz","doi":"10.1016/j.dark.2025.101832","DOIUrl":"10.1016/j.dark.2025.101832","url":null,"abstract":"<div><div>In this manuscript, we consider the newly proposed modified theory in which topological invariant Gauss–Bonnet <span><math><mi>G</mi></math></span> is coupled with the energy–momentum squared <span><math><mrow><mo>(</mo><msup><mrow><mi>τ</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>=</mo><msub><mrow><mi>τ</mi></mrow><mrow><mi>μ</mi><mi>ν</mi></mrow></msub><msup><mrow><mi>τ</mi></mrow><mrow><mi>μ</mi><mi>ν</mi></mrow></msup><mo>)</mo></mrow></math></span>. For this matter-geometric coupling, we consider <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>G</mi><mo>,</mo><msup><mrow><mi>τ</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>)</mo></mrow><mo>=</mo><mi>f</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow><mo>+</mo><mi>g</mi><mrow><mo>(</mo><msup><mrow><mi>τ</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>)</mo></mrow></mrow></math></span> model for flat FriedmannRobertsonWalker (FRW) universe. The dynamics of bouncing cosmology are thoroughly examined within the framework of underlying viable model which can overcome the singularity’s challenge in standard Big-Bang cosmology. We study a power law scale factor and some cosmological bouncing scale factors such as symmetric, super, oscillatory and matter. These cosmological bouncing scale factors are essential for exploring the universe’s origins while bypassing the concept of an initial singularity, thus presenting alternative approaches that address the limitations of the Big Bang model. In this scenario, we determine the equation of state parameter, <span><math><mi>ω</mi></math></span>, along with the squared sound speed parameter. Additionally, we investigate the behavior of the <span><math><mrow><mi>ω</mi><mo>−</mo><msup><mrow><mi>ω</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></math></span> plane for underlying framework. Interestingly, it should be noted that every outcome favors recent observational data.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"48 ","pages":"Article 101832"},"PeriodicalIF":5.0,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}

{"title":"Plasma lensing, epicyclic oscillations, particle collision, and thermal fluctuations around a short-hairy black hole","authors":"Asifa Ashraf ,&nbsp;Allah Ditta ,&nbsp;Abdelmalek Bouzenada ,&nbsp;S.K. Maurya ,&nbsp;Assmaa Abd-Elmonem ,&nbsp;Nagat A.A. Suoliman ,&nbsp;Phongpichit Channuie","doi":"10.1016/j.dark.2025.101836","DOIUrl":"10.1016/j.dark.2025.101836","url":null,"abstract":"<div><div>We explore the behavior of test particles in the vicinity of a spherically symmetric black hole with short-hair characteristics, emphasizing the impact of the model’s parameters on various phenomena such as particle trajectories, plasma-induced gravitational lensing, epicyclic oscillations, and thermal variations. The black hole is defined by three key parameters: mass <span><math><mi>M</mi></math></span>, the short-hairy parameter <span><math><mi>Q</mi></math></span>, and an additional parameter <span><math><mi>α</mi></math></span>. We derive analytical formulas for the energy and angular momentum of test particles, expressed in terms of these black hole parameters. Additionally, we investigate the effective potential, the innermost stable circular orbits, and the forces influencing particle motion. The study also delves into the epicyclic oscillations of particles close to the equatorial plane, providing analytical expressions for radial, vertical, and orbital frequencies, along with the periastron precession frequency. In the context of weak gravitational lensing with plasma, we observe that the parameter <span><math><mi>α</mi></math></span> does not affect the deflection angle, whereas the other parameters play a significant role. Moreover, we analyze thermal fluctuations in these short-hairy black holes, which are linked to the Hawking temperature and entropy. Our findings underscore the profound influence of the black hole’s parameters on particle dynamics, revealing fascinating aspects of their behavior.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"48 ","pages":"Article 101836"},"PeriodicalIF":5.0,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143312477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}

{"title":"Possible existence of traversable wormholes within stellar galactic halos in modified f(R) gravity: A class 1 embedding approach","authors":"Hammad Nazar ,&nbsp;Ghulam Abbas ,&nbsp;M.R. Shahzad ,&nbsp;Asifa Ashraf ,&nbsp;Imed Boukhris ,&nbsp;Abdulaziz Abdullah Alanazi ,&nbsp;Farruh Atamurotov","doi":"10.1016/j.dark.2025.101837","DOIUrl":"10.1016/j.dark.2025.101837","url":null,"abstract":"<div><div>The present manuscript explores the novel implications of the potential existence of static, anisotropic, and spherically symmetric wormhole spheres within the dark-matter halos of elliptical galaxies in the framework of modified <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> gravity theory. To achieve this objective, we first derived the spacetime solution employing the Tolman-V ansatz as the solution for the gravitational redshift function. In addition to this, we applied the well-known Class 1 Karmarkar condition to determine the wormhole shape function as another metric potential. Subsequently, these solutions were combined with a dark-matter galactic density profile resembling the de Vaucouleur’s model to derive the matter components of the modified field equations. We focus on three popular and cosmologically viable <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> gravity models: <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow><mo>=</mo><mi>R</mi><mo>+</mo><mi>β</mi><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></math></span>, <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow><mo>=</mo><msup><mrow><mi>e</mi></mrow><mrow><mi>β</mi><mi>R</mi></mrow></msup></mrow></math></span>, and <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow><mo>=</mo><mi>R</mi><mo>+</mo><mi>β</mi><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup><mrow><mo>(</mo><mrow><mn>1</mn><mo>+</mo><mi>α</mi><mo>ln</mo><mfenced><mrow><mfrac><mrow><mi>R</mi></mrow><mrow><msup><mrow><mi>χ</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></mfrac></mrow></mfenced></mrow><mo>)</mo></mrow></mrow></math></span>. To validate the physical acceptability of our wormhole space–time solutions, we performed a graphical analysis for these <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> gravity models. This analysis examined various constraints, such as the viability of energy conditions, stability via pressure anisotropy and the modified TOV equation, consistency through the volume integral quantifier, and credibility via total gravitational energy. In particular, for minimal values of the free parameter <span><math><mi>γ</mi></math></span> and fixed values of other constants, we observed a small amount of exotic matter near the throat of the wormhole, evidenced by limited violations of the energy conditions. This suggests that the modified gravity framework serves as a promising alternative to support wormhole structures with negligible exotic matter. In conclusion, our proposed solutions satisfy the essential requirements for configuring wormhole structures within the dark-matter halo regions of elliptical galaxies, providing new insights into the potential interplay between modified gravity and galactic dark-matter distributions.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"48 ","pages":"Article 101837"},"PeriodicalIF":5.0,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}

{"title":"Investigating the effects of particle motion and gravitational lensing of black hole in string-inspired Euler–Heisenberg theory","authors":"Muhammad Yasir ,&nbsp;Farzan Mushtaq ,&nbsp;Xia Tiecheng ,&nbsp;Faisal Javed","doi":"10.1016/j.dark.2025.101838","DOIUrl":"10.1016/j.dark.2025.101838","url":null,"abstract":"<div><div>This paper is motivated by a study that discovered the properties of black holes with string-inspired Euler–Heisenberg theory in terms of particle dynamics and weak gravitational plasma lensing. We analyze particle dynamics using the effective potential and innermost stable circular orbits for massive particle and photon motion. This study examines the interaction of test particles with a black hole under various physical parameters, focusing on the behavior of the innermost stable circular orbit radius. Notably, we discover that particles with radii less than the innermost stable circular orbit converge towards the black hole singularity, whereas those beyond the innermost stable circular orbit advance towards infinity, demonstrating the dynamic influence of the black hole parameters on particle trajectories. To examine gravitational lensed photons, we consider a weak gravitational field. This objective of lensing is served by considering three plasma fields: uniform plasma, singular isothermal sphere, and non-singular isothermal sphere. We also investigate the deflection angles for non-plasma and plasma mediums. The bending angle under weak field limitations is calculated using optical geometry and the Gibbons–Werner technique. We found that the influence of these mediums enhances the black hole’s bending angle. We analyze the deflection angle of light based on the impact parameter and its graphical impact on the angle for both cases.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"48 ","pages":"Article 101838"},"PeriodicalIF":5.0,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}

{"title":"Gravitational wave from extreme mass-ratio inspirals around a Kerr–Taub–NUT black hole","authors":"Tieguang Zi ,&nbsp;Changqing Ye","doi":"10.1016/j.dark.2025.101809","DOIUrl":"10.1016/j.dark.2025.101809","url":null,"abstract":"<div><div>We have computed the gravitational waves emitted from extreme mass-ratio inspirals (EMRIs) around the Kerr–Taub–NUT black hole using a hybrid method. Firstly, we derive the analytic expressions of the orbital energy, angular momentum and Carter constant for the generic geodesic orbits, and compute the orbital frequencies numerically. To evolve the orbital parameters adiabatically, we adopt the hybrid fluxes based on the radial motion period in the Kerr–Taub–NUT black hole and the Kerr fluxes in the numerical kludge model. Using the inspiraling trajectories, we compute EMRI waveform to assess the difference of waveforms from the Kerr and Kerr–Taub–NUT BHs. We find that, LISA can distinguish the EMRIs waveform from the Kerr–Taub–NUT black hole with a NUT charge as smaller as <span><math><mrow><msub><mrow><mi>N</mi></mrow><mrow><mtext>min</mtext></mrow></msub><mo>∼</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>6</mn></mrow></msup></mrow></math></span>. After one year observation of EMRI signal, the constraint on NUT charge by LISA can be measured within an error of <span><math><mrow><mi>Δ</mi><mi>N</mi><mo>∼</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>6</mn></mrow></msup></mrow></math></span>, which is correlated with the measurement errors of the other intrinsic parameters.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"48 ","pages":"Article 101809"},"PeriodicalIF":5.0,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}