Pub Date : 2025-04-01Epub Date: 2024-12-12DOI: 10.1016/j.astropartphys.2024.103073
Tayyab Naseer
Three different exact solutions to the gravitational equations are formulated in this paper in the context of Rastall theory using the gravitational decoupling strategy. For doing so, the anisotropic spherical interior fluid distribution is assumed as a seed source characterized by the corresponding Lagrangian. I then modify the field equations by introducing an additional source which is gravitationally coupled with the former fluid setup. Since this approach makes the Rastall equations more complex, I use the MGD scheme to tackle this, dividing these equations into two systems. The Krori–Barua and Tolman IV spacetimes are taken into account to solve the first system, describing an initial anisotropic fluid. The metric potentials associated with these solutions contain multiple constants which are determined with the help of boundary conditions. Furthermore, I work out the solution for the second system through different well-known constraints. Afterwards, the estimated data of a compact star is considered to explore the feasibility of the developed solutions through graphical interpretation. It is concluded that all the resulting models show physically existing profiles under the variation of certain parameters.
{"title":"Isotropization and complexity based extended Krori–Barua and Tolman IV Rastall models under the effect of electromagnetic field","authors":"Tayyab Naseer","doi":"10.1016/j.astropartphys.2024.103073","DOIUrl":"10.1016/j.astropartphys.2024.103073","url":null,"abstract":"<div><div>Three different exact solutions to the gravitational equations are formulated in this paper in the context of Rastall theory using the gravitational decoupling strategy. For doing so, the anisotropic spherical interior fluid distribution is assumed as a seed source characterized by the corresponding Lagrangian. I then modify the field equations by introducing an additional source which is gravitationally coupled with the former fluid setup. Since this approach makes the Rastall equations more complex, I use the MGD scheme to tackle this, dividing these equations into two systems. The Krori–Barua and Tolman IV spacetimes are taken into account to solve the first system, describing an initial anisotropic fluid. The metric potentials associated with these solutions contain multiple constants which are determined with the help of boundary conditions. Furthermore, I work out the solution for the second system through different well-known constraints. Afterwards, the estimated data of a compact star <span><math><mrow><mi>L</mi><mi>M</mi><mi>C</mi><mspace></mspace><mi>X</mi><mo>−</mo><mn>4</mn></mrow></math></span> is considered to explore the feasibility of the developed solutions through graphical interpretation. It is concluded that all the resulting models show physically existing profiles under the variation of certain parameters.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"166 ","pages":"Article 103073"},"PeriodicalIF":4.2,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-04-01Epub Date: 2024-12-05DOI: 10.1016/j.astropartphys.2024.103064
Chavis Srichan , Pobporn Danvirutai , Adrian David Cheok , Jun Cai , Ying Yan
{"title":"Retraction Notice to “On the same origin of quantum physics and general relativity from Riemannian geometry and Planck scale formalism” [Astroparticle Physics, 164C (2025) - ASTPHY_103036]","authors":"Chavis Srichan , Pobporn Danvirutai , Adrian David Cheok , Jun Cai , Ying Yan","doi":"10.1016/j.astropartphys.2024.103064","DOIUrl":"10.1016/j.astropartphys.2024.103064","url":null,"abstract":"","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"166 ","pages":"Article 103064"},"PeriodicalIF":4.2,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-04-01Epub Date: 2024-12-19DOI: 10.1016/j.astropartphys.2024.103075
Haiyuan Feng , Rong-Jia Yang , Wei-Qiang Chen
We investigate the thin disk and shadow of Kerr–Sen black hole in Einstein–Maxwell-dilaton–axion gravity. The results reveal that as the dilaton parameter increase, the energy flux, the radiation temperature, the spectra luminosity, and the radiative efficiency of the disk all increase. By narrowing down the dilaton parameter range to , we discover that in the high-frequency region, the Kerr–Sen black hole demonstrates higher energy output compared to the Kerr black hole. We also investigated the shadow of Kerr–Sen black hole in a uniform plasma environment. For fixed inclination angle, dilaton, and spin parameters, the shadow increases as the homogeneous plasma parameter increases. Conversely, when and are fixed, an increase in leads to a decrease in the shadow. Finally, we constrain the model parameters with observational data from M87* and Sgr A*.
{"title":"Thin accretion disk and shadow of Kerr–Sen black hole in Einstein–Maxwell-dilaton–axion gravity","authors":"Haiyuan Feng , Rong-Jia Yang , Wei-Qiang Chen","doi":"10.1016/j.astropartphys.2024.103075","DOIUrl":"10.1016/j.astropartphys.2024.103075","url":null,"abstract":"<div><div>We investigate the thin disk and shadow of Kerr–Sen black hole in Einstein–Maxwell-dilaton–axion gravity. The results reveal that as the dilaton parameter <span><math><msub><mrow><mi>r</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> increase, the energy flux, the radiation temperature, the spectra luminosity, and the radiative efficiency of the disk all increase. By narrowing down the dilaton parameter range to <span><math><mrow><mn>0</mn><mo>⩽</mo><mfrac><mrow><msub><mrow><mi>r</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow><mrow><mi>M</mi></mrow></mfrac><mo>⩽</mo><mn>0</mn><mo>.</mo><mn>4</mn></mrow></math></span>, we discover that in the high-frequency region, the Kerr–Sen black hole demonstrates higher energy output compared to the Kerr black hole. We also investigated the shadow of Kerr–Sen black hole in a uniform plasma environment. For fixed inclination angle, dilaton, and spin parameters, the shadow increases as the homogeneous plasma parameter <span><math><mi>k</mi></math></span> increases. Conversely, when <span><math><mi>k</mi></math></span> and <span><math><mi>a</mi></math></span> are fixed, an increase in <span><math><msub><mrow><mi>r</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> leads to a decrease in the shadow. Finally, we constrain the model parameters with observational data from M87* and Sgr A*.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"166 ","pages":"Article 103075"},"PeriodicalIF":4.2,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-04-01Epub Date: 2024-12-08DOI: 10.1016/j.astropartphys.2024.103072
J.M. Alameddine , J. Albrecht , J. Ammerman-Yebra , L. Arrabito , A.A. Alves Jr. , D. Baack , A. Coleman , H. Dembinski , D. Elsässer , R. Engel , A. Faure , A. Ferrari , C. Gaudu , C. Glaser , M. Gottowik , D. Heck , T. Huege , K.H. Kampert , N. Karastathis , L. Nellen , R. Ulrich
CORSIKA 8 is a new framework for simulations of particle cascades in air and dense media implemented in modern C++17, based on past experience with existing codes, in particular CORSIKA 7. The flexible and modular structure of the project allows the development of independent modules that can produce a fully customizable particle shower simulation. The radio module in particular is designed to treat the electric field calculation and its propagation through complex media to each observer location in an autonomous and flexible way. It already allows for the simultaneous simulation of the radio emission calculated with two independent time-domain formalisms, the “Endpoint formalism” as previously implemented in CoREAS and the “ZHS” algorithm as ported from ZHAireS. The design acts as the baseline interface for current and future development for the simulation of radio emission from particle showers in standard and complex scenarios, such as cross-media showers penetrating from air into ice. In this work, we present the design and implementation of the radio module in CORSIKA 8, along with validation studies and a direct comparison of the radio emission from air showers simulated with CORSIKA 8, CORSIKA 7, and ZHAireS. We also present the impact of simulation details such as the step size of simulated particle tracks on radio-emission simulations and perform a direct comparison of the “Endpoints” and “ZHS” formalisms for the same underlying air showers. Finally, we present an in-depth comparison of CORSIKA 8 and CORSIKA 7 for optimum simulation settings and discuss the relevance of observed differences in light of reconstruction efforts for the energy and mass of cosmic rays.
{"title":"Simulating radio emission from particle cascades with CORSIKA 8","authors":"J.M. Alameddine , J. Albrecht , J. Ammerman-Yebra , L. Arrabito , A.A. Alves Jr. , D. Baack , A. Coleman , H. Dembinski , D. Elsässer , R. Engel , A. Faure , A. Ferrari , C. Gaudu , C. Glaser , M. Gottowik , D. Heck , T. Huege , K.H. Kampert , N. Karastathis , L. Nellen , R. Ulrich","doi":"10.1016/j.astropartphys.2024.103072","DOIUrl":"10.1016/j.astropartphys.2024.103072","url":null,"abstract":"<div><div>CORSIKA 8 is a new framework for simulations of particle cascades in air and dense media implemented in modern C++17, based on past experience with existing codes, in particular CORSIKA 7. The flexible and modular structure of the project allows the development of independent modules that can produce a fully customizable particle shower simulation. The radio module in particular is designed to treat the electric field calculation and its propagation through complex media to each observer location in an autonomous and flexible way. It already allows for the simultaneous simulation of the radio emission calculated with two independent time-domain formalisms, the “Endpoint formalism” as previously implemented in CoREAS and the “ZHS” algorithm as ported from ZHAireS. The design acts as the baseline interface for current and future development for the simulation of radio emission from particle showers in standard and complex scenarios, such as cross-media showers penetrating from air into ice. In this work, we present the design and implementation of the radio module in CORSIKA 8, along with validation studies and a direct comparison of the radio emission from air showers simulated with CORSIKA 8, CORSIKA 7, and ZHAireS. We also present the impact of simulation details such as the step size of simulated particle tracks on radio-emission simulations and perform a direct comparison of the “Endpoints” and “ZHS” formalisms for the same underlying air showers. Finally, we present an in-depth comparison of CORSIKA 8 and CORSIKA 7 for optimum simulation settings and discuss the relevance of observed differences in light of reconstruction efforts for the energy and mass of cosmic rays.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"166 ","pages":"Article 103072"},"PeriodicalIF":4.2,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-02-01Epub Date: 2024-10-21DOI: 10.1016/j.astropartphys.2024.103059
Arijit Panda , Debashis Gangopadhyay , Goutam Manna
<div><div>In this work, we develop the Raychaudhuri equation in <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mover><mrow><mi>R</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>,</mo><mover><mrow><mi>T</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>)</mo></mrow></mrow></math></span> gravity in the setting of a non-canonical theory, namely K-essence theory. We solve the modified Raychaudhuri equation for the additive form of <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mover><mrow><mi>R</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>,</mo><mover><mrow><mi>T</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>)</mo></mrow></mrow></math></span>, which is <span><math><mrow><msub><mrow><mi>f</mi></mrow><mrow><mn>1</mn></mrow></msub><mrow><mo>(</mo><mover><mrow><mi>R</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>)</mo></mrow><mo>+</mo><msub><mrow><mi>f</mi></mrow><mrow><mn>2</mn></mrow></msub><mrow><mo>(</mo><mover><mrow><mi>T</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>)</mo></mrow></mrow></math></span>. For this solution, we employ two different scale factors to give two types of <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mover><mrow><mi>R</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>,</mo><mover><mrow><mi>T</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>)</mo></mrow></mrow></math></span> solutions. The ongoing debate between Fisher et al. and Harko et al. in 2020 regarding the additive form of <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mover><mrow><mi>R</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>,</mo><mover><mrow><mi>T</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>)</mo></mrow></mrow></math></span> may provide a resolution within the modified <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mover><mrow><mi>R</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>,</mo><mover><mrow><mi>T</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>)</mo></mrow></mrow></math></span> gravity theory. By conducting a viability test and analyzing energy conditions, we have determined that in the first scenario, the null energy condition (NEC) is violated between two regions where the NEC is satisfied. Additionally, we have observed that this violation of the NEC exhibits a symmetric property during the phase transition. These observations indicate that bouncing events may occur as a result of the symmetrical violation of the NEC during the expansion of the universe. Moreover, this model indicates that resonant-type quantum tunneling may take place during the period when the NEC is violated. The findings of NEC violation through the power law of scale factor may have empirical relevance in contemporary observations. In the second scenario, our model indicates that the strong energy condition is violated, but the NEC and weak energy conditions are satisfied. The effective energy density decreases and is positive, while the effective pressure and equation of state parameters are negative. This suggests that the universe is expanding with acceleration and is dominated by dark energy.</div
在这项研究中，我们在非经典理论（即 K-essence 理论）的背景下发展了 f(R̄,T̄) 引力中的雷乔杜里方程。我们求解了 f(R̄,T̄)的加法形式的修正雷乔杜里方程，即 f1(R̄)+f2(T̄) 。对于这种解法，我们采用了两种不同的比例因子，给出了两种类型的 f(R̄,T̄) 解法。费舍尔等人和哈科等人在 2020 年就 f(R̄,T̄)的加法形式正在进行的争论，可能会为修正的 f(R̄,T̄) 引力理论提供一个解决方案。通过进行可行性测试和分析能量条件，我们确定在第一种情况下，在满足空能量条件（NEC）的两个区域之间违反了空能量条件。此外，我们还观察到，这种对 NEC 的违反在相变过程中表现出对称性。这些观测结果表明，在宇宙膨胀过程中，反弹事件可能是对称违反 NEC 的结果。此外，该模型还表明，共振型量子隧穿可能会在违反 NEC 期间发生。通过尺度因子幂律违反 NEC 的发现在当代观测中可能具有经验意义。在第二种情况下，我们的模型表明强能量条件被违反，但 NEC 和弱能量条件得到满足。有效能量密度减小并呈正值，而有效压力和状态方程参数呈负值。这表明宇宙正在加速膨胀，并由暗能量主导。
{"title":"NEC violation in f(R̄,T̄) gravity in the context of a non-canonical theory via modified Raychaudhuri equation","authors":"Arijit Panda , Debashis Gangopadhyay , Goutam Manna","doi":"10.1016/j.astropartphys.2024.103059","DOIUrl":"10.1016/j.astropartphys.2024.103059","url":null,"abstract":"<div><div>In this work, we develop the Raychaudhuri equation in <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mover><mrow><mi>R</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>,</mo><mover><mrow><mi>T</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>)</mo></mrow></mrow></math></span> gravity in the setting of a non-canonical theory, namely K-essence theory. We solve the modified Raychaudhuri equation for the additive form of <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mover><mrow><mi>R</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>,</mo><mover><mrow><mi>T</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>)</mo></mrow></mrow></math></span>, which is <span><math><mrow><msub><mrow><mi>f</mi></mrow><mrow><mn>1</mn></mrow></msub><mrow><mo>(</mo><mover><mrow><mi>R</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>)</mo></mrow><mo>+</mo><msub><mrow><mi>f</mi></mrow><mrow><mn>2</mn></mrow></msub><mrow><mo>(</mo><mover><mrow><mi>T</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>)</mo></mrow></mrow></math></span>. For this solution, we employ two different scale factors to give two types of <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mover><mrow><mi>R</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>,</mo><mover><mrow><mi>T</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>)</mo></mrow></mrow></math></span> solutions. The ongoing debate between Fisher et al. and Harko et al. in 2020 regarding the additive form of <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mover><mrow><mi>R</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>,</mo><mover><mrow><mi>T</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>)</mo></mrow></mrow></math></span> may provide a resolution within the modified <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mover><mrow><mi>R</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>,</mo><mover><mrow><mi>T</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>)</mo></mrow></mrow></math></span> gravity theory. By conducting a viability test and analyzing energy conditions, we have determined that in the first scenario, the null energy condition (NEC) is violated between two regions where the NEC is satisfied. Additionally, we have observed that this violation of the NEC exhibits a symmetric property during the phase transition. These observations indicate that bouncing events may occur as a result of the symmetrical violation of the NEC during the expansion of the universe. Moreover, this model indicates that resonant-type quantum tunneling may take place during the period when the NEC is violated. The findings of NEC violation through the power law of scale factor may have empirical relevance in contemporary observations. In the second scenario, our model indicates that the strong energy condition is violated, but the NEC and weak energy conditions are satisfied. The effective energy density decreases and is positive, while the effective pressure and equation of state parameters are negative. This suggests that the universe is expanding with acceleration and is dominated by dark energy.</div","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"165 ","pages":"Article 103059"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142526867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-02-01Epub Date: 2024-09-13DOI: 10.1016/j.astropartphys.2024.103047
Antonio Condorelli , Sergio Petrera
Interactions of ultra-high energy cosmic-rays (UHECRs) accelerated in astrophysical environments have been shown to shape the energy production rate of nuclei escaping from the confinement zone. To address the influence of hadronic interactions, Hadronic Interaction Models (HIMs) come into play. In this context, we present a parameterization capable of capturing the outcomes of two distinct HIMs, namely EPOS-LHC and Sibyll2.3d, in terms of secondary fluxes, including escaping nuclei, nucleons, neutrinos, photons, and electrons. Our parameterization is systematically evaluated against the source codes, both at fixed energy and mass, as well as in a physical case scenario. The comparison demonstrates that our parameterization aligns well with the source codes, establishing its reliability as a viable alternative for analytical or fast Monte Carlo approaches dedicated to the study of UHECR propagation within source environments. This suggests the potential for utilizing our parameterization as a practical substitute in studies focused on the intricate dynamics of ultra-high energy cosmic rays.
{"title":"Modeling hadronic interactions in ultra-high-energy cosmic rays within astrophysical environments: A parametric approach","authors":"Antonio Condorelli , Sergio Petrera","doi":"10.1016/j.astropartphys.2024.103047","DOIUrl":"10.1016/j.astropartphys.2024.103047","url":null,"abstract":"<div><p>Interactions of ultra-high energy cosmic-rays (UHECRs) accelerated in astrophysical environments have been shown to shape the energy production rate of nuclei escaping from the confinement zone. To address the influence of hadronic interactions, Hadronic Interaction Models (HIMs) come into play. In this context, we present a parameterization capable of capturing the outcomes of two distinct HIMs, namely EPOS-LHC and Sibyll2.3d, in terms of secondary fluxes, including escaping nuclei, nucleons, neutrinos, photons, and electrons. Our parameterization is systematically evaluated against the source codes, both at fixed energy and mass, as well as in a physical case scenario. The comparison demonstrates that our parameterization aligns well with the source codes, establishing its reliability as a viable alternative for analytical or fast Monte Carlo approaches dedicated to the study of UHECR propagation within source environments. This suggests the potential for utilizing our parameterization as a practical substitute in studies focused on the intricate dynamics of ultra-high energy cosmic rays.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"165 ","pages":"Article 103047"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142240344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-02-01Epub Date: 2024-10-28DOI: 10.1016/j.astropartphys.2024.103060
Sobhan Kazempour , Amin Rezaei Akbarieh
This study explores the cosmological implications of the Myrzakulov quasi-dilaton massive gravity theory, a modification of the de Rham–Gabadadze–Tolley (dRGT) massive gravity theory. Our analysis focuses on the self-accelerating solution of the background equations of motion, which are shown to exist in the theory. Notably, we find that the theory features an effective cosmological constant corresponding to the massive graviton, which has important implications for our understanding of the universe’s accelerated expansion. To assess the validity of the Myrzakulov quasi-dilaton massive gravity theory, we employ two datasets: the Union2 Type Ia Supernovae (SNIa) dataset, consisting of 557 observations, and the Pantheon SNIa data, which includes 1048 SNe I-a events gathered from diverse SN I-a samples. Our results demonstrate that the theory is capable of explaining the accelerated expansion of the universe without requiring the presence of dark energy. This finding supports the potential of the Myrzakulov quasi-dilaton massive gravity theory as an alternative explanation for the observed cosmic acceleration. Moreover, we investigate the properties of tensor perturbations within the framework of this theory and derive a novel expression for the dispersion relation of gravitational waves. Our analysis reveals interesting features of the modified dispersion relation in the Friedmann–Lemaître–Robertson–Walker (FLRW) cosmology, providing new insights into the nature of gravitational waves in the context of the Myrzakulov quasi-dilaton massive gravity theory.
{"title":"Cosmological study in Myrzakulov F(R,T) quasi-dilaton massive gravity","authors":"Sobhan Kazempour , Amin Rezaei Akbarieh","doi":"10.1016/j.astropartphys.2024.103060","DOIUrl":"10.1016/j.astropartphys.2024.103060","url":null,"abstract":"<div><div>This study explores the cosmological implications of the Myrzakulov <span><math><mrow><mi>F</mi><mrow><mo>(</mo><mi>R</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> quasi-dilaton massive gravity theory, a modification of the de Rham–Gabadadze–Tolley (dRGT) massive gravity theory. Our analysis focuses on the self-accelerating solution of the background equations of motion, which are shown to exist in the theory. Notably, we find that the theory features an effective cosmological constant corresponding to the massive graviton, which has important implications for our understanding of the universe’s accelerated expansion. To assess the validity of the Myrzakulov <span><math><mrow><mi>F</mi><mrow><mo>(</mo><mi>R</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> quasi-dilaton massive gravity theory, we employ two datasets: the Union2 Type Ia Supernovae (SNIa) dataset, consisting of 557 observations, and the Pantheon SNIa data, which includes 1048 SNe I-a events gathered from diverse SN I-a samples. Our results demonstrate that the theory is capable of explaining the accelerated expansion of the universe without requiring the presence of dark energy. This finding supports the potential of the Myrzakulov <span><math><mrow><mi>F</mi><mrow><mo>(</mo><mi>R</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> quasi-dilaton massive gravity theory as an alternative explanation for the observed cosmic acceleration. Moreover, we investigate the properties of tensor perturbations within the framework of this theory and derive a novel expression for the dispersion relation of gravitational waves. Our analysis reveals interesting features of the modified dispersion relation in the Friedmann–Lemaître–Robertson–Walker (FLRW) cosmology, providing new insights into the nature of gravitational waves in the context of the Myrzakulov <span><math><mrow><mi>F</mi><mrow><mo>(</mo><mi>R</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> quasi-dilaton massive gravity theory.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"165 ","pages":"Article 103060"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-02-01Epub Date: 2024-10-09DOI: 10.1016/j.astropartphys.2024.103053
Samprity Das , Surajit Chattopadhyay
This work analyzes and evaluates a few realistic compact objects in the presence of a gravitational interaction between two particles with a nonmetricity . In the gravity framework, we have selected the anisotropic equation of motion and have determined to be a linear function of nonmetricity . To evaluate the field equations in our work, we have opted to employ the Krori–Barua metric. We calculated the anisotropic factor for each of the four compact objects and found that the anisotropic component is positive and increases monotonically and interpreted that the nuclear force can oppose the gravitational attraction. At last, the relationship between mass and radius has been determined and illustrated visually. We have noted that the compactness of the pulsars LMC X-4, SMC X-4, Cen X-3, and Vela X-1 is inside the Buchdahl’s limit for varying values of . This has led to the interpretation that these pulsars are neutron stars in a modified gravity background of . In addition, we calculated the model mass and, using thirty distinct choices of , ran the Chi-Square test to see if there was a noticeable difference between the observed and model-generated masses. We have also looked at how the surface redshift has changed over time and whether the compact objects in our model that were previously described are compact.
在f(Q)引力框架中，我们选择了各向异性运动方程，并确定f(Q)是非度量Q的线性函数。为了评估我们工作中的场方程，我们选择使用Krori-Barua度量。我们分别计算了四个紧凑天体的各向异性因子，发现各向异性分量为正且单调增加，从而解释了核力可以对抗引力。最后，我们确定了质量与半径之间的关系，并以直观的方式进行了说明。我们注意到，脉冲星 LMC X-4、SMC X-4、Cen X-3 和 Vela X-1 在不同的 a 值下，其紧凑程度都在布赫达尔极限之内。此外，我们还计算了模型质量，并使用 30 种不同的 a 值进行了 Chi-Square 检验，以确定观测质量和模型质量之间是否存在明显差异。我们还研究了表面红移随时间的变化情况，以及模型中先前描述的紧凑天体是否紧凑。
{"title":"Evolution of realistic neutron star in the framework of f(Q) gravity","authors":"Samprity Das , Surajit Chattopadhyay","doi":"10.1016/j.astropartphys.2024.103053","DOIUrl":"10.1016/j.astropartphys.2024.103053","url":null,"abstract":"<div><div>This work analyzes and evaluates a few realistic compact objects in the presence of a gravitational interaction between two particles with a nonmetricity <span><math><mi>Q</mi></math></span>. In the <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></math></span> gravity framework, we have selected the anisotropic equation of motion and have determined <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></math></span> to be a linear function of nonmetricity <span><math><mi>Q</mi></math></span>. To evaluate the field equations in our work, we have opted to employ the Krori–Barua metric. We calculated the anisotropic factor for each of the four compact objects and found that the anisotropic component is positive and increases monotonically and interpreted that the nuclear force can oppose the gravitational attraction. At last, the relationship between mass and radius has been determined and illustrated visually. We have noted that the compactness of the pulsars LMC X-4, SMC X-4, Cen X-3, and Vela X-1 is inside the Buchdahl’s limit for varying values of <span><math><mi>a</mi></math></span>. This has led to the interpretation that these pulsars are neutron stars in a modified gravity background of <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></math></span>. In addition, we calculated the model mass and, using thirty distinct choices of <span><math><mi>a</mi></math></span>, ran the Chi-Square test to see if there was a noticeable difference between the observed and model-generated masses. We have also looked at how the surface redshift has changed over time and whether the compact objects in our model that were previously described are compact.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"165 ","pages":"Article 103053"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-02-01Epub Date: 2024-11-07DOI: 10.1016/j.astropartphys.2024.103062
F. Nozzoli
Long gamma-ray bursts (GRBs) can be generated by the collapse of a rapidly rotating massive star into a black hole and are the brightest known explosive events in the Universe. GRB221009A is the most energetic gamma-ray burst ever recorded, providing delayed detection of very high energy photons that challenge the standard propagation mechanisms, possibly suggesting exotic physics phenomena. An excess, synchronous with the ignition of GRB221009A, is detected in the rate of the Yangbajing muon telescope. A preliminary assessment of the significance of this excess limits the probability of a chance coincidence to less than 10−3. The hypothetical mechanisms for producing a muon excess induced by the GRB are exotic/puzzling. If confirmed by further investigations, this excess would add another feature to the many anomalies observed in this extreme astrophysical event.
{"title":"Candidate detection of GRB221009A by Yangbajing muon telescope","authors":"F. Nozzoli","doi":"10.1016/j.astropartphys.2024.103062","DOIUrl":"10.1016/j.astropartphys.2024.103062","url":null,"abstract":"<div><div>Long gamma-ray bursts (GRBs) can be generated by the collapse of a rapidly rotating massive star into a black hole and are the brightest known explosive events in the Universe. GRB221009A is the most energetic gamma-ray burst ever recorded, providing delayed detection of very high energy photons that challenge the standard propagation mechanisms, possibly suggesting exotic physics phenomena. An excess, synchronous with the ignition of GRB221009A, is detected in the rate of the Yangbajing muon telescope. A preliminary assessment of the significance of this excess limits the probability of a chance coincidence to less than 10<sup>−3</sup>. The hypothetical mechanisms for producing a muon excess induced by the GRB are exotic/puzzling. If confirmed by further investigations, this excess would add another feature to the many anomalies observed in this extreme astrophysical event.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"165 ","pages":"Article 103062"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
In this work, we have worked out dynamical aspects for the particles moving around the GUP-corrected-Schwarzschild (S-GUP) black hole. We have calculated the innermost stable circular orbit (ISCO) around black hole and explored its implications for different microquasars. Additionally, we have shown that the Kerr black hole mimics S-GUP black hole after some tuning of parameters. Finally, considering the S-GUP black hole as a microquasar source, we have studied quasi-periodic oscillation (QPO). Further utilizing the available observational data of few microquasars, we have obtained constrains on the GUP parameter as well.
{"title":"Particle dynamics and quasi-periodic oscillations in the GUP-modified Schwarzschild spacetime: Constraint using micro-quasars data","authors":"Husanboy Hoshimov , Odil Yunusov , Farruh Atamurotov , Mubasher Jamil , Ahmadjon Abdujabbarov","doi":"10.1016/j.astropartphys.2024.103056","DOIUrl":"10.1016/j.astropartphys.2024.103056","url":null,"abstract":"<div><div>In this work, we have worked out dynamical aspects for the particles moving around the GUP-corrected-Schwarzschild (S-GUP) black hole. We have calculated the innermost stable circular orbit (ISCO) around black hole and explored its implications for different microquasars. Additionally, we have shown that the Kerr black hole mimics S-GUP black hole after some tuning of parameters. Finally, considering the S-GUP black hole as a microquasar source, we have studied quasi-periodic oscillation (QPO). Further utilizing the available observational data of few microquasars, we have obtained constrains on the GUP parameter <span><math><mi>ϵ</mi></math></span> as well.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"165 ","pages":"Article 103056"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142526865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
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