Physics of the Dark Universe最新文献

{"title":"Epicyclic oscillations around slowly rotating charged black hole in Bumblebee gravity","authors":"G. Mustafa ,&nbsp;S.K. Maurya ,&nbsp;Phongpichit Channuie ,&nbsp;Abdelmalek Bouzenada ,&nbsp;Assmaa Abd-Elmonem ,&nbsp;Neissrien Alhubieshi","doi":"10.1016/j.dark.2024.101753","DOIUrl":"10.1016/j.dark.2024.101753","url":null,"abstract":"<div><div>We investigate the behavior of test particles orbiting a slowly rotating, axially symmetric, charged black hole within the context of Bumblebee gravity theory, with an emphasis on how the parameters of the model impact particle dynamics. This black hole solution is defined by four primary parameters: the mass <span><math><mi>M</mi></math></span>, the spin parameter <span><math><mi>a</mi></math></span>, the charge <span><math><mi>Q</mi></math></span>, and the Lorentz-violating parameter <span><math><mi>α</mi></math></span>. We give analytical expressions for the radial profiles of specific energy and specific angular momentum associated with stable circular orbits in the equatorial plane. Also, we utilize the effective potential method to analyze the stability of these orbits and the forces acting on the particles. We compute and discuss the radial and latitudinal harmonic oscillation frequencies where the parameters are the mass <span><math><mi>M</mi></math></span>, charge <span><math><mi>Q</mi></math></span>, parameter <span><math><mi>a</mi></math></span>, and the Lorentz-violating parameter <span><math><mi>α</mi></math></span>. We also explore the key characteristics of quasi-periodic oscillations of test particles near stable circular orbits, especially in the equatorial plane. Moreover, we investigate precession effects, including periastron precession and the Lense-Thirring effect. Our results indicate that the motion of particles around the black hole is notably affected by the parameters of the model.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101753"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100055","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":"Shadow and weak gravitational lensing of RN-like BH in plasma","authors":"Asalkhon Alimova ,&nbsp;Ziyodulla Turakhonov ,&nbsp;Farruh Atamurotov ,&nbsp;Ahmadjon Abdujabbarov","doi":"10.1016/j.dark.2024.101749","DOIUrl":"10.1016/j.dark.2024.101749","url":null,"abstract":"<div><div>In this paper, we investigate weak gravitational lensing and shadow radius in the Kalb–Ramond (KR) gravity for an Reissner–Nordström-like (RN-like) black hole (BH). The examination is carried out in three distinct frameworks: uniform plasma, singular isothermal sphere(SIS), and non-singular isothermal sphere (NSIS). When a gravitating object is surrounded by plasma, the lensing angle is determined by the frequency of the electromagnetic wave, plasma dispersion, plasma inhomogeneity, and gravity. Even in uniform plasma, the gravitational photon deflection angle differs from that in a vacuum and depends on photon frequency due to the second effect. We consider both effects and calculate the lensing angle for a significantly non-uniform plasma in the existence of KR gravity. Utilizing observational data from the Event Horizon Telescope (EHT) project for Sgr A*, we have obtained that which range of RN-like black hole’s parameters <span><math><mi>Q</mi></math></span> and <span><math><mi>l</mi></math></span> correspond observations as well as when the Lorentz-violating parameter <span><math><mi>l</mi></math></span> rise, radius of black hole shadow decrease. To connect a relationship with observations data, we examine the magnification and positioning of images produced by lensing, as well as the weak deflection angle and magnification for sources located near various galaxies.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101749"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100056","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":"Heat engine efficiency, particle dynamics and thermodynamic properties of Hayward–Letelier-AdS Black Hole","authors":"Ghulam Fatima ,&nbsp;Faisal Javed ,&nbsp;Arfa Waseem ,&nbsp;Bander Almutairi ,&nbsp;G. Mustafa ,&nbsp;Farruh Atamurotov ,&nbsp;Ertan Güdekli","doi":"10.1016/j.dark.2025.101820","DOIUrl":"10.1016/j.dark.2025.101820","url":null,"abstract":"<div><div>This study investigates the thermodynamic properties and Joule–Thomson effects of Hayward–Letelier-AdS black holes, providing insights into how various physical parameters influence their behavior. A detailed analysis of the lapse function reveals that increasing the cloud of string parameter results in a significant outward movement of the horizon radius, indicating an expansion of the black hole structure. The examination of Joule–Thomson coefficients demonstrates areas of both cooling and heating in the gas surrounding these BHs, with positive values of <span><math><msub><mrow><mi>μ</mi></mrow><mrow><mi>J</mi></mrow></msub></math></span> indicating cooling upon gas expansion and negative values signaling heating. The study also employs isenthalpic and inversion curves to clarify the energy dynamics involved in these processes, illustrating the influences of physical factors on the thermodynamic interactions around black holes. Additionally, the investigation into effective potential aids in understanding the stability of particle orbits around black holes, highlighting the influence of angular momentum and revealing two ISCO radii for considered black holes. The analysis of corrected entropy accounts for quantum effects near the event horizon, indicating that smaller black holes exhibit greater corrected entropy, which reflects notable fluctuations in their thermodynamic behavior. Helmholtz’s free energy and internal energy illustrate the stability of black hole structures, showing a decline in free energy and energy content with an increasing horizon radius. Ultimately, this research enhances the understanding of thermodynamic behavior and particle dynamics in Hayward–Letelier-AdS black holes, laying a robust foundation for future studies on black hole thermodynamics and their cosmological implications.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101820"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100229","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":"Circular motion of test particles, trajectories and QPOs around the non-rotating black hole in the background of the Symmergent gravity","authors":"S.K. Maurya ,&nbsp;G. Mustafa ,&nbsp;Allah Ditta ,&nbsp;Assmaa Abd-Elmonem ,&nbsp;Neissrien Alhubieshi ,&nbsp;Aylin Caliskan ,&nbsp;Ertan Güdekli","doi":"10.1016/j.dark.2025.101806","DOIUrl":"10.1016/j.dark.2025.101806","url":null,"abstract":"<div><div>We explore the circular motion of test particles around the non-rotating black hole in the background of the Symmergent gravity, focusing on how the parameters of the underlying model influence particle motion. The black hole is fully characterized by four parameters, namely, the mass <span><math><mi>M</mi></math></span> of the black hole, the charge <span><math><mi>q</mi></math></span> of the black hole, and two parameters <span><math><mi>η</mi></math></span> and <span><math><mi>α</mi></math></span>, with <span><math><mrow><mi>η</mi><mo>&gt;</mo><mn>1</mn></mrow></math></span> (<span><math><mrow><mi>η</mi><mo>&lt;</mo><mn>1</mn></mrow></math></span>) corresponding to Ads (ds) spacetime. We derive the analytical solution of the energy and angular momentum of test particles as a function of parameters of the underlying model and discuss the stability of circular orbits through an effective potential approach. The innermost stable circular orbits and the effective force exerted on particles are examined. By numerical integration of the equations of motion, we plot the trajectories to investigate the motion of particles orbiting the black hole. Furthermore, we study the epicyclic oscillation of test particles that encircle the black hole near the equatorial plane and derive analytical equations for radial, orbital, and latitudinal frequencies as a function of the parameters of the model. The frequency of periastron precession of particles has also been discussed. Lastly, we consider the collision of particles near the event horizon and examine the center of mass-energy. Our findings reveal that the model parameters influence the motion of the test particles.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101806"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100681","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":"Impact of gravitational collapse exhibiting loop quantum black holes on thermodynamical features and weak gravitational lensing","authors":"Allah Ditta ,&nbsp;Abdelmalek Bouzenada ,&nbsp;G. Mustafa ,&nbsp;Faisal Javed ,&nbsp;Fakhranda Afandi ,&nbsp;Asif Mahmood","doi":"10.1016/j.dark.2025.101818","DOIUrl":"10.1016/j.dark.2025.101818","url":null,"abstract":"<div><div>This paper investigates the loop quantum black hole (LQBH) model, focusing on its thermodynamic stability and gravitational lensing properties. We further examine the thermodynamic characteristics of these black holes, specifically their stability, by analyzing potential phase transitions and energy emissions. In the context of thermodynamic analysis, we discuss the temperature, specific heat, and Gibbs free energy. We also study the effects of weak gravitational lensing within these black holes under different conditions: uniform plasma, non-uniform plasma, and a non-singular isothermal gas with spherical symmetry, calculating the deflection angle and analyzing the influence of black hole parameters on the deflection angle. Additionally, we discuss the magnification of gravitationally lensed images, addressing the distinct lensing effects resulting from uniform and non-uniform plasma by analyzing the total deflection angle in the plasma field.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101818"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100687","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":"Orbital motion and epicyclic oscillations around a black hole with magnetic charge","authors":"G. Mustafa ,&nbsp;Phongpichit Channuie ,&nbsp;Faisal Javed ,&nbsp;Abdelmalek Bouzenada ,&nbsp;S.K. Maurya ,&nbsp;Arzu Cilli ,&nbsp;Ertan Güdekli","doi":"10.1016/j.dark.2024.101765","DOIUrl":"10.1016/j.dark.2024.101765","url":null,"abstract":"<div><div>This paper studies the orbital and epicyclic movements of test particles orbiting a black hole with magnetic charge but no rotation. We generate analytical solutions to explain the radial distributions of particular energy, and angular momentum, for steady circular orbits on the equatorial plane. By utilizing the effective potential technique, we evaluate the stability of these trajectories and the forces that influence particles within the magnetically charged black hole. Our results show how magnetic charge affects the innermost stable circular orbits. Additionally, we calculate the frequencies of radial and latitudinal harmonic oscillations using the parameters of the black hole, taking into account observers who are both nearby and far away. The research involves examining quasi-periodic oscillations around stable equatorial orbits, the precession of the periastron, and assessing particle collisions with a focus on the center of mass energy of the colliding particles.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101765"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143156653","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":"Generalized scale factor duality symmetry in symmetric teleparallel scalar–tensor FLRW cosmology","authors":"Andronikos Paliathanasis","doi":"10.1016/j.dark.2025.101830","DOIUrl":"10.1016/j.dark.2025.101830","url":null,"abstract":"<div><div>We review the Gasperini–Veneziano scale factor duality symmetry for the dilaton field in scalar–tensor theory and its extension in teleparallelism. Within the framework of symmetric teleparallel scalar–tensor theory, we consider a spatially flat Friedmann–Lemaître–Robertson–Walker metric cosmology. For the three possible connections, we write the corresponding point-like Lagrangians for the gravitational field equations, and we construct discrete transformations which generalize the Gasperini–Veneziano scale factor duality symmetry. The discrete transformations depend on the parameter which defines the coupling between the scalar field and the nonmetricity scalar. The Gasperini–Veneziano duality symmetry is recovered for a specific limit of this free parameter. Furthermore, we derive the conservation laws for the classical field equations for these models, and we present the origin of the discrete transformations. Finally, we discuss the integrability properties of the model, and exact solutions are determined.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101830"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143156716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Toward gravitational lensing in modified theories of gravity","authors":"Ali Tizfahm ,&nbsp;Saeed Fakhry ,&nbsp;Javad T. Firouzjaee ,&nbsp;Antonino Del Popolo","doi":"10.1016/j.dark.2024.101795","DOIUrl":"10.1016/j.dark.2024.101795","url":null,"abstract":"<div><div>In this study, we investigate gravitational lensing within modified gravity frameworks, focusing on the Hu–Sawicki <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> and normal branch Dvali–Gabadadze–Porrati (nDGP) models, and we compare these results with those obtained from general relativity (GR). Our results reveal that both modified gravity models consistently enhance key lensing parameters relative to GR, including the Einstein radius, lensing optical depth, and time delays. Notably, we find that the Hu–Sawicki <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> and nDGP models yield significantly larger Einstein radii and higher lensing probabilities, especially at greater redshifts, indicating an increased likelihood of lensing events under modified gravity. Our analysis of time delays further shows that the broader mass distributions in these frameworks lead to pronounced differences in high-mass lens systems, providing potential observational markers of modified gravity. Additionally, we observe amplified magnification factors in wave optics regimes, highlighting the potential for gravitational wave (GW) lensing to differentiate modified gravity effects from GR predictions. Through these findings, we propose modified gravity theories as compelling alternatives to GR in explaining cosmic phenomena, with promising implications for future high-precision gravitational lensing surveys.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101795"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143156654","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":"Spacetime-curvature induced uncertainty principle: Linking the large-structure global effects to the local black hole physics","authors":"Reggie C. Pantig ,&nbsp;Gaetano Lambiase ,&nbsp;Ali Övgün ,&nbsp;Nikko John Leo S. Lobos","doi":"10.1016/j.dark.2025.101817","DOIUrl":"10.1016/j.dark.2025.101817","url":null,"abstract":"<div><div>This paper links the advanced formulation of the Generalized Uncertainty Principle, termed the Asymptotic Generalized Extended Uncertainty Principle (AGEUP) to the corpuscular framework to derive the AGEUP-inspired black hole metric. The former incorporates spacetime curvature effects to explore black hole dynamics under quantum gravitational corrections, while the latter is a view that black holes are Bose–Einstein condensates of weakly interacting gravitons. AGEUP refines the traditional uncertainty relation by introducing curvature-based modifications that integrate the Ricci scalar and Cartan invariant, addressing the possible connection of the quantum uncertainties and gravitational influences in curved spacetimes. In particular, the phenomenological union between the AGEUP with cosmological constant <span><math><mi>Λ</mi></math></span> to the corpuscular framework enabled a black hole metric that has a scaled mass, which depends on <span><math><mi>Λ</mi></math></span> and the Planck length <span><math><msub><mrow><mi>l</mi></mrow><mrow><mi>Pl</mi></mrow></msub></math></span>. Interesting implications occur, such as the maximum limit for mass <span><math><mi>M</mi></math></span> where <span><math><mi>Λ</mi></math></span> ceases to influence the black hole. Another is the derived value of the modulation factor of the EUP term, <span><math><mi>α</mi></math></span>, if the large-scale fundamental length is defined solely as the cosmological horizon. We further analyze the black hole metric through the shadow and deflection angle phenomena, deriving constraints on the quantum gravity modulation parameter <span><math><mi>β</mi></math></span> that may be experimentally tested in future observations. Constraints from the Event Horizon Telescope (EHT) and Very Long Baseline Interferometry (VLBI) are discussed as avenues for verifying AGEUP-related deviations in black hole shadow radius and deflection angles, offering potential observational evidence of quantum gravitational effects at astrophysical scales. The findings suggest that AGEUP could be instrumental in providing hints on the quantum gravity nature of black holes, particularly in high-energy astrophysical contexts. By linking local black hole physics with large-scale curvature effects, AGEUP paves the way for further research at the intersection of quantum gravity and cosmology, with implications for observational astrophysics and the fundamental structure of spacetime.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101817"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143156801","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 the expansion scalar and shear relation in the Locally rotationally symmetric Bianchi I model","authors":"A. Singh ,&nbsp;S. Mandal ,&nbsp;R. Chaubey ,&nbsp;R. Raushan","doi":"10.1016/j.dark.2024.101798","DOIUrl":"10.1016/j.dark.2024.101798","url":null,"abstract":"<div><div>We consider the universe composed of radiation, matter, and vacuum energy in the axially symmetric Bianchi I spacetime background. In this framework, the assumption ‘shear scalar proportional to the expansion scalar’ leading to a relation between directional scale factors has been probed for its observational compatibility with the data of different origins. The phase space of the model parameters is determined through the Bayesian Monte Carlo method. The precise observational bounds on parameters including <span><math><mi>n</mi></math></span> have been obtained with the cosmic chronometer, baryonic acoustic oscillations, cosmic microwave background, and the Supernovae Ia Pantheon data. The results are then compared with the results obtained by using the Pantheon+SH0ES data and the combined data sets. The deviations of <span><math><mi>n</mi></math></span> from unity change the cosmic dynamics during the early and late time universe also, as compared to the <span><math><mi>Λ</mi></math></span> cold dark matter model. We also discuss the information criterion in the model.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101798"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143155700","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}