Pub Date : 2026-04-01Epub Date: 2026-02-06DOI: 10.1016/j.jheap.2026.100576
Yu Wang , Remo Ruffini
Quasars hosting ≳ 109M⊙ black holes at z > 6 challenge growth scenarios that start from light seeds and assume accretion within already formed galaxies. Motivated by the James Webb Space Telescope (JWST) discovery of Little Red Dots (LRDs), which suggests that ∼ 106M⊙ black holes can be active in compact, pre-galactic environments, we revisit early black hole growth with a minimal cosmology-based framework. We model the accretion history as the smaller of the Bondi inflow rate and the Eddington-limited rate, where the Bondi rate is set by the supply of overdense primordial gas whose density declines with cosmic expansion, and the Eddington rate captures regulation by radiative feedback. By fitting the observed masses and luminosities of J0313–1806 () and J0100+2802 () with Bayesian inference, we infer initial conditions that favor massive seed black holes with initial mass M0 ∼ 106M⊙, formed at in environments with baryonic overdensity factors fρ ≳ 50 relative to the cosmic mean. The resulting growth histories include a prolonged supply-limited stage, and they reproduce the observed quasar masses without requiring sustained Eddington accretion or any super-Eddington episodes. The inferred seed mass scale is consistent with black holes produced by the collapse of quantum-degenerate fermion dark matter cores, providing a physically defined pathway to massive seeds at the redshifts implied by LRD phenomenology.
{"title":"Growth of high-redshift quasars from fermion dark matter seeds","authors":"Yu Wang , Remo Ruffini","doi":"10.1016/j.jheap.2026.100576","DOIUrl":"10.1016/j.jheap.2026.100576","url":null,"abstract":"<div><div>Quasars hosting ≳ 10<sup>9</sup> <em>M</em><sub>⊙</sub> black holes at <em>z</em> > 6 challenge growth scenarios that start from light seeds and assume accretion within already formed galaxies. Motivated by the James Webb Space Telescope (JWST) discovery of Little Red Dots (LRDs), which suggests that ∼ 10<sup>6</sup> <em>M</em><sub>⊙</sub> black holes can be active in compact, pre-galactic environments, we revisit early black hole growth with a minimal cosmology-based framework. We model the accretion history as the smaller of the Bondi inflow rate and the Eddington-limited rate, where the Bondi rate is set by the supply of overdense primordial gas whose density declines with cosmic expansion, and the Eddington rate captures regulation by radiative feedback. By fitting the observed masses and luminosities of J0313–1806 (<span><math><mrow><mi>z</mi><mo>=</mo><mn>7.64</mn></mrow></math></span>) and J0100+2802 (<span><math><mrow><mi>z</mi><mo>=</mo><mn>6.30</mn></mrow></math></span>) with Bayesian inference, we infer initial conditions that favor massive seed black holes with initial mass <em>M</em><sub>0</sub> ∼ 10<sup>6</sup> <em>M</em><sub>⊙</sub>, formed at <span><math><mrow><mi>z</mi><mo>∼</mo><mn>20</mn><mo>−</mo><mn>30</mn></mrow></math></span> in environments with baryonic overdensity factors <em>f<sub>ρ</sub></em> ≳ 50 relative to the cosmic mean. The resulting growth histories include a prolonged supply-limited stage, and they reproduce the observed quasar masses without requiring sustained Eddington accretion or any super-Eddington episodes. The inferred seed mass scale is consistent with black holes produced by the collapse of quantum-degenerate fermion dark matter cores, providing a physically defined pathway to massive seeds at the redshifts implied by LRD phenomenology.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"52 ","pages":"Article 100576"},"PeriodicalIF":10.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174573","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}
Pub Date : 2026-04-01Epub Date: 2026-01-25DOI: 10.1016/j.jheap.2026.100561
Andrea Addazi , Salvatore Capozziello , Qingyu Gan
We explore novel classes of exotic astrophysical sources capable of producing ultra-high-energy gamma rays extending beyond the PeV scale, motivated by quantum gravity scenarios and dark matter phenomenology. These sources include: ultra-spinning black hole vortex-string systems; exotic compact objects such as boson star, axion star and Q-ball. Such Exotica generate powerful magnetic fields through interactions with millicharged dark matter, enabling particle acceleration mechanisms that surpass the energy limits of conventional astrophysical sources like pulsar wind nebulae and supernova remnants. We demonstrate that such exotic PeVatrons could be distributed throughout our Galaxy and may be detectable by current (LHAASO, HAWC) and next-generation (CTA) gamma-ray observatories.
{"title":"Exotic PeVatrons as sources of ultra-high-energy gamma rays","authors":"Andrea Addazi , Salvatore Capozziello , Qingyu Gan","doi":"10.1016/j.jheap.2026.100561","DOIUrl":"10.1016/j.jheap.2026.100561","url":null,"abstract":"<div><div>We explore novel classes of exotic astrophysical sources capable of producing ultra-high-energy gamma rays extending beyond the PeV scale, motivated by quantum gravity scenarios and dark matter phenomenology. These sources include: ultra-spinning black hole vortex-string systems; exotic compact objects such as boson star, axion star and Q-ball. Such <em>Exotica</em> generate powerful magnetic fields through interactions with millicharged dark matter, enabling particle acceleration mechanisms that surpass the energy limits of conventional astrophysical sources like pulsar wind nebulae and supernova remnants. We demonstrate that such exotic PeVatrons could be distributed throughout our Galaxy and may be detectable by current (LHAASO, HAWC) and next-generation (CTA) gamma-ray observatories.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"52 ","pages":"Article 100561"},"PeriodicalIF":10.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081843","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}
Pub Date : 2026-04-01Epub Date: 2026-02-04DOI: 10.1016/j.jheap.2026.100567
L. West-Ocampo , F.A. Fogantini , E.A. Saavedra , J.A. Combi , F. García , P.L. Luque-Escamilla , J. Martí , S. Chaty , J.F. Albacete-Colombo
4U 1700–37 is a wind-fed high-mass X-ray binary comprising a compact object, most likely a neutron star, accreting from the O6.5 Iaf supergiant HD 153919. Coherent pulsations have not been firmly detected and the magnetic field strength remains uncertain, with previous NuSTAR studies reporting only marginal candidate cyclotron resonant scattering features (CRSFs). We analyses all available NuSTAR observations of 4U 1700–37 to characterize its hard X-ray timing and broadband spectral properties, test the robustness of candidate CRSFs against different continuum models and epochs, and constrain the magnetic field and accretion regime of the compact object. We perform a homogeneous timing and spectral analysis of two NuSTAR observations, modeling time-averaged and intensity-resolved spectra with several continua commonly used for accreting pulsars, and use spectral simulations to quantify the significance and model dependence of putative CRSFs. No coherent pulsations are detected and we constrain the pulsed fraction to be <1.5%. The spectra are well described by an absorbed blackbody plus cut-off power-law continuum, but show shallow absorption-like residuals around ∼ 20 keV and at higher energies ( ∼ 40–50 keV). These features improve the fits and can reach high formal significances for some continua, yet do not constitute firm, model-independent CRSF detections in our baseline analysis. Intensity-resolved spectroscopy hints at shifts of the apparent line centroid with flux. Interpreted as cyclotron features, these results favour a neutron-star magnetic field B ∼ (1.7–4.4) × 1012 G and a quasi-spherical subsonic accretion regime with an equilibrium spin period Peq ∼ 1.9 ks. Even without a secure CRSF detection, the homogeneous multi-epoch analysis provides quantitative constraints on the magnetic field and accretion physics of 4U 1700–37 and helps reconcile previously discrepant line-energy measurements.
{"title":"Constraints on cyclotron features and accretion regime in the high-mass X-ray binary 4U 1700–37 from NuSTAR","authors":"L. West-Ocampo , F.A. Fogantini , E.A. Saavedra , J.A. Combi , F. García , P.L. Luque-Escamilla , J. Martí , S. Chaty , J.F. Albacete-Colombo","doi":"10.1016/j.jheap.2026.100567","DOIUrl":"10.1016/j.jheap.2026.100567","url":null,"abstract":"<div><div>4U 1700–37 is a wind-fed high-mass X-ray binary comprising a compact object, most likely a neutron star, accreting from the O6.5 Iaf<span><math><msup><mrow></mrow><mo>+</mo></msup></math></span> supergiant HD 153919. Coherent pulsations have not been firmly detected and the magnetic field strength remains uncertain, with previous <em>NuSTAR</em> studies reporting only marginal candidate cyclotron resonant scattering features (CRSFs). We analyses all available <em>NuSTAR</em> observations of 4U 1700–37 to characterize its hard X-ray timing and broadband spectral properties, test the robustness of candidate CRSFs against different continuum models and epochs, and constrain the magnetic field and accretion regime of the compact object. We perform a homogeneous timing and spectral analysis of two <em>NuSTAR</em> observations, modeling time-averaged and intensity-resolved spectra with several continua commonly used for accreting pulsars, and use spectral simulations to quantify the significance and model dependence of putative CRSFs. No coherent pulsations are detected and we constrain the pulsed fraction to be <1.5%. The spectra are well described by an absorbed blackbody plus cut-off power-law continuum, but show shallow absorption-like residuals around ∼ 20 keV and at higher energies ( ∼ 40–50 keV). These features improve the fits and can reach high formal significances for some continua, yet do not constitute firm, model-independent CRSF detections in our baseline analysis. Intensity-resolved spectroscopy hints at shifts of the apparent line centroid with flux. Interpreted as cyclotron features, these results favour a neutron-star magnetic field <em>B</em> ∼ (1.7–4.4) × 10<sup>12</sup> G and a quasi-spherical subsonic accretion regime with an equilibrium spin period <em>P</em><sub>eq</sub> ∼ 1.9 ks. Even without a secure CRSF detection, the homogeneous multi-epoch analysis provides quantitative constraints on the magnetic field and accretion physics of 4U 1700–37 and helps reconcile previously discrepant line-energy measurements.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"52 ","pages":"Article 100567"},"PeriodicalIF":10.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174572","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}
Pub Date : 2026-04-01Epub Date: 2026-01-29DOI: 10.1016/j.jheap.2026.100564
Sajal Mandal
This study presents an extensive study of a class of time-evolving dark energy models defined by parametrized equations of state (EoS) parameter in the context of a spatially homogeneous yet anisotropic Bianchi type-I universe. In particular, we employ two distinct parametrization of the EoS parameter and thoroughly investigate their impact on the cosmic expansion history in the model. We utilize a diverse dataset composed of the cosmic chronometers, baryon acoustic oscillations (BAO), the cosmic microwave background (CMB), and the Pantheon+SH0ES supernova type Ia sample to impose constraints on the model parameters through the Bayesian analysis with the Markov Chain Monte Carlo (MCMC) approach. We also examine the crucial cosmological quantities such as the Hubble parameter, deceleration parameter, jerk parameter, and the effective EoS parameter to provide a comprehensive understanding of the cosmic evolution in the models. Moreover, we utilize the diagnostic parameters Om(z) and the statefinder (r, s) to examine the difference between the studied models and the ΛCDM model. To further strengthen the study, we assess the statistical performance of the models using the Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC). The isotropic models and their anisotropic extensions exhibit the accelerating universe expansion, and we demonstrate different aspects of these models with reference to the ΛCDM model and CPL parametrization based dark energy model.
本文在空间均匀但各向异性的Bianchi - i型宇宙背景下，对一类由参数化状态方程（EoS）参数定义的时间演化暗能量模型进行了广泛的研究。特别地，我们采用了两个不同的参数化EoS参数，并深入研究了它们对模型中宇宙膨胀历史的影响。我们利用由宇宙天文钟、重子声学振荡（BAO）、宇宙微波背景（CMB）和Pantheon+SH0ES Ia型超新星样本组成的多样化数据集，通过贝叶斯分析和马尔可夫链蒙特卡罗（MCMC）方法对模型参数施加约束。我们还研究了关键的宇宙学量，如哈勃参数、减速参数、激振参数和有效的EoS参数，以提供对模型中宇宙演化的全面理解。此外，我们利用诊断参数Om(z)和状态查找器（r, s）来检查所研究模型与ΛCDM模型之间的差异。为了进一步加强研究，我们使用赤池信息准则（Akaike Information Criterion， AIC）和贝叶斯信息准则（Bayesian Information Criterion， BIC）来评估模型的统计性能。各向同性模型及其各向异性扩展显示了宇宙的加速膨胀，我们通过ΛCDM模型和基于CPL参数化的暗能量模型来论证这些模型的不同方面。
{"title":"Observational constraints on new class dark energy parameterized EoS in Bianchi type-I universe","authors":"Sajal Mandal","doi":"10.1016/j.jheap.2026.100564","DOIUrl":"10.1016/j.jheap.2026.100564","url":null,"abstract":"<div><div>This study presents an extensive study of a class of time-evolving dark energy models defined by parametrized equations of state (EoS) parameter in the context of a spatially homogeneous yet anisotropic Bianchi type-I universe. In particular, we employ two distinct parametrization of the EoS parameter and thoroughly investigate their impact on the cosmic expansion history in the model. We utilize a diverse dataset composed of the cosmic chronometers, baryon acoustic oscillations (BAO), the cosmic microwave background (CMB), and the Pantheon+SH0ES supernova type Ia sample to impose constraints on the model parameters through the Bayesian analysis with the Markov Chain Monte Carlo (MCMC) approach. We also examine the crucial cosmological quantities such as the Hubble parameter, deceleration parameter, jerk parameter, and the effective EoS parameter to provide a comprehensive understanding of the cosmic evolution in the models. Moreover, we utilize the diagnostic parameters <em>Om</em>(<em>z</em>) and the statefinder (<em>r, s</em>) to examine the difference between the studied models and the ΛCDM model. To further strengthen the study, we assess the statistical performance of the models using the Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC). The isotropic models and their anisotropic extensions exhibit the accelerating universe expansion, and we demonstrate different aspects of these models with reference to the ΛCDM model and CPL parametrization based dark energy model.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"52 ","pages":"Article 100564"},"PeriodicalIF":10.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174568","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}
PeVatrons are the extreme galactic accelerators capable of producing PeV particles. Recent observation of Large High Altitude Air Shower Observatory have detected UHE photons ( ≥ 100 TeV) from 43 galactic sources. Detection of UHE photons demands the presence of at least PeV particles in the acceleration site. Although the exact nature of most of the sources are still unknown, a large fraction of these sources have spatial association with pulsar wind nebula. In this work we investigate the acceleration mechanism in pulsar wind nebula by following a magnetohydrodynamics approach. Current study relates the MHD flow solution in immediate downstream with the particle spectrum and spectral energy distribution of photons. Our study shows that MHD description in the PWN environment reduces the parameter space and most of the parameters can be constrained in terms of a single parameter, the magnetization parameter σ only. Considering the effect of σ, we show that in low σ environment pulsar wind nebula can produce PeV particles. We have also investigate the role of turbulence in the nebular region in acceleration of particle to PeV energy. Current study shows that both low σ environment and turbulence environment is favorable for acceleration of particles up to PeV energy. We have also tested our model in two different LHAASO detected PeVatron 1LHAASO J1848-000u and 1LHAASO J1929+1846u.
{"title":"Particle acceleration to PeV energies in pulsar wind nebula: A two zone model","authors":"Gunindra Krishna Mahanta , Nilay Bhatt , Bitan Ghosal , Subir Bhattacharyya","doi":"10.1016/j.jheap.2026.100562","DOIUrl":"10.1016/j.jheap.2026.100562","url":null,"abstract":"<div><div><em>PeVatrons</em> are the extreme galactic accelerators capable of producing PeV particles. Recent observation of Large High Altitude Air Shower Observatory have detected UHE photons ( ≥ 100 TeV) from 43 galactic sources. Detection of UHE photons demands the presence of at least PeV particles in the acceleration site. Although the exact nature of most of the sources are still unknown, a large fraction of these sources have spatial association with pulsar wind nebula. In this work we investigate the acceleration mechanism in pulsar wind nebula by following a magnetohydrodynamics approach. Current study relates the MHD flow solution in immediate downstream with the particle spectrum and spectral energy distribution of photons. Our study shows that MHD description in the PWN environment reduces the parameter space and most of the parameters can be constrained in terms of a single parameter, <em>the magnetization parameter σ</em> only. Considering the effect of <em>σ</em>, we show that in low <em>σ</em> environment pulsar wind nebula can produce PeV particles. We have also investigate the role of turbulence in the nebular region in acceleration of particle to PeV energy. Current study shows that both low <em>σ</em> environment and turbulence environment is favorable for acceleration of particles up to PeV energy. We have also tested our model in two different LHAASO detected PeVatron 1LHAASO J1848-000u and 1LHAASO J1929+1846u.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"52 ","pages":"Article 100562"},"PeriodicalIF":10.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174569","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}
Pub Date : 2026-04-01Epub Date: 2026-02-07DOI: 10.1016/j.jheap.2026.100578
M. Koussour , Alnadhief H.A. Alfedeel , S. Muminov , J. Rayimbaev
We investigate the late-time cosmic acceleration within the framework of viscous f(T, Lm) gravity, where the gravitational action depends on both the torsion scalar T and the matter Lagrangian Lm. In this context, the Universe is modeled as a bulk viscous fluid, allowing for dissipative effects that generate an effective negative pressure capable of driving acceleration without invoking a cosmological constant. We adopt a simple linear model and assume a constant bulk viscosity coefficient . The model parameters are constrained using a joint analysis of recent observational datasets, including 31 Hubble parameter measurements, the Pantheon+ sample of 1701 Type Ia Supernovae, and the latest baryon acoustic oscillation data from DESI, employing a Markov Chain Monte Carlo (MCMC) approach. The best-fit results, , , , and , are consistent with current cosmological observations and indicate that bulk viscosity plays a significant role in the late-time dynamics. The deceleration parameter confirms the current accelerated expansion, while the effective equation of state (EoS) evolves from a matter-like regime at high redshift toward a quintessence phase at late times. The Om(z) diagnostic further supports this behavior, suggesting a mild deviation from ΛCDM toward a dynamical dark energy component. Although information criteria (, ) slightly favor the simpler ΛCDM model, the viscous f(T, Lm) framework remains a viable and physically motivated alternative capable of explaining cosmic acceleration through the combined effects of torsion-matter coupling and viscosity.
{"title":"Observational constraints on viscous cosmology in f(T, Lm) gravity","authors":"M. Koussour , Alnadhief H.A. Alfedeel , S. Muminov , J. Rayimbaev","doi":"10.1016/j.jheap.2026.100578","DOIUrl":"10.1016/j.jheap.2026.100578","url":null,"abstract":"<div><div>We investigate the late-time cosmic acceleration within the framework of viscous <em>f</em>(<em>T, L<sub>m</sub></em>) gravity, where the gravitational action depends on both the torsion scalar <em>T</em> and the matter Lagrangian <em>L<sub>m</sub></em>. In this context, the Universe is modeled as a bulk viscous fluid, allowing for dissipative effects that generate an effective negative pressure capable of driving acceleration without invoking a cosmological constant. We adopt a simple linear model <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>T</mi><mo>,</mo><msub><mi>L</mi><mi>m</mi></msub><mo>)</mo></mrow><mo>=</mo><mi>α</mi><mi>T</mi><mo>+</mo><mi>β</mi><msub><mi>L</mi><mi>m</mi></msub></mrow></math></span> and assume a constant bulk viscosity coefficient <span><math><mrow><mi>ζ</mi><mo>=</mo><msub><mi>ζ</mi><mn>0</mn></msub><mo>></mo><mn>0</mn></mrow></math></span>. The model parameters are constrained using a joint analysis of recent observational datasets, including 31 Hubble parameter measurements, the Pantheon+ sample of 1701 Type Ia Supernovae, and the latest baryon acoustic oscillation data from DESI, employing a Markov Chain Monte Carlo (MCMC) approach. The best-fit results, <span><math><mrow><msub><mi>H</mi><mn>0</mn></msub><mo>=</mo><mn>68.16</mn><mo>±</mo><mn>0.65</mn></mrow></math></span>, <span><math><mrow><mi>α</mi><mo>=</mo><mn>1</mn><mo>.</mo><msubsup><mn>53</mn><mrow><mo>−</mo><mn>0.61</mn></mrow><mrow><mo>+</mo><mn>0.49</mn></mrow></msubsup></mrow></math></span>, <span><math><mrow><mi>β</mi><mo>=</mo><mn>0.40</mn><mo>±</mo><mn>0.96</mn></mrow></math></span>, and <span><math><mrow><msub><mi>ζ</mi><mn>0</mn></msub><mo>=</mo><mn>2</mn><mo>.</mo><msubsup><mn>15</mn><mrow><mo>−</mo><mn>0.81</mn></mrow><mrow><mo>+</mo><mn>0.69</mn></mrow></msubsup></mrow></math></span>, are consistent with current cosmological observations and indicate that bulk viscosity plays a significant role in the late-time dynamics. The deceleration parameter <span><math><mrow><msub><mi>q</mi><mn>0</mn></msub><mo>=</mo><mo>−</mo><mn>0.33</mn><mo>±</mo><mn>0.41</mn></mrow></math></span> confirms the current accelerated expansion, while the effective equation of state (EoS) evolves from a matter-like regime at high redshift toward a quintessence phase at late times. The <em>Om</em>(<em>z</em>) diagnostic further supports this behavior, suggesting a mild deviation from ΛCDM toward a dynamical dark energy component. Although information criteria (<span><math><mrow><mstyle><mi>Δ</mi></mstyle><mtext>AIC</mtext><mo>=</mo><mn>2.2</mn></mrow></math></span>, <span><math><mrow><mstyle><mi>Δ</mi></mstyle><mtext>BIC</mtext><mo>=</mo><mn>13.13</mn></mrow></math></span>) slightly favor the simpler ΛCDM model, the viscous <em>f</em>(<em>T, L<sub>m</sub></em>) framework remains a viable and physically motivated alternative capable of explaining cosmic acceleration through the combined effects of torsion-matter coupling and viscosity.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"52 ","pages":"Article 100578"},"PeriodicalIF":10.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174988","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}
Pub Date : 2026-04-01Epub Date: 2026-02-01DOI: 10.1016/j.jheap.2026.100568
J.H. Zhang , L.Y. Li , Y.W. Yao , K.X. Cheng , L. Yang
Utilizing the full pitch angle () measurements by the Relativistic Electron-Proton Telescope (REPT) onboard Van Allen Probe A, we analyzed the pitch angle distribution and storm-time variation mechanism of high-energy protons (< 30MeV) near the second peak (L* = 1.84 – 1.98) of Earth’s inner radiation belt (L*≤ 2.5). We found that the fluxes of the to protons decrease during the main phase of storms and then gradually increase during the recovery phase, whereas those fluxes at smaller or larger pitch angles ( or > ) remain relatively stable during the whole storms. Theoretic calculations indicate that the bounce latitude ( > 26°) of the quasi-parallel or anti-parallel moving protons ( or > ) exceeds the influence range (≤ 20°) of storm-time ring currents in the inner belt region (L*≤ 2.5), but those of the oblique and quasi-perpendicular protons () overlap with the low-latitude ring currents. During the main/recovery phase of storms, the oblique and quasi-perpendicular protons are transported outwards/inwards and thus experience Fermi and Betatron decelerations/accelerations. The adiabatic decelerations/accelerations modify the pancake-like pitch angle distributions of the tens of MeV protons in the outer half part (L* = 1.6 – 2.5) of the inner radiation belt, whereas field line curvature scatterings become effective outside the proton radiation belt (L* > 2.5).
{"title":"Van Allen Probe observations of the pitch angle evolutions of high-energy protons near the second peak of inner radiation belt","authors":"J.H. Zhang , L.Y. Li , Y.W. Yao , K.X. Cheng , L. Yang","doi":"10.1016/j.jheap.2026.100568","DOIUrl":"10.1016/j.jheap.2026.100568","url":null,"abstract":"<div><div>Utilizing the full pitch angle (<span><math><mi>α</mi></math></span>) measurements by the Relativistic Electron-Proton Telescope (REPT) onboard Van Allen Probe A, we analyzed the pitch angle distribution and storm-time variation mechanism of high-energy protons (< 30MeV) near the second peak (<em>L</em>* = 1.84 – 1.98) of Earth’s inner radiation belt (<em>L</em>*≤ 2.5). We found that the fluxes of the <span><math><msup><mn>40</mn><mo>∘</mo></msup></math></span> to <span><math><msup><mn>140</mn><mo>∘</mo></msup></math></span> protons decrease during the main phase of storms and then gradually increase during the recovery phase, whereas those fluxes at smaller or larger pitch angles (<span><math><mrow><mi>α</mi><mo><</mo><msup><mn>40</mn><mo>∘</mo></msup></mrow></math></span> or > <span><math><msup><mn>140</mn><mo>∘</mo></msup></math></span>) remain relatively stable during the whole storms. Theoretic calculations indicate that the bounce latitude (<span><math><mi>λ</mi></math></span> > 26°) of the quasi-parallel or anti-parallel moving protons (<span><math><mrow><mi>α</mi><mo><</mo><msup><mn>40</mn><mo>∘</mo></msup></mrow></math></span> or > <span><math><msup><mn>140</mn><mo>∘</mo></msup></math></span>) exceeds the influence range (<span><math><mrow><mi>λ</mi><mspace></mspace></mrow></math></span>≤ 20°) of storm-time ring currents in the inner belt region (<em>L</em>*≤ 2.5), but those of the oblique and quasi-perpendicular protons (<span><math><mrow><msup><mn>40</mn><mo>∘</mo></msup><mo><</mo><mi>α</mi><mo><</mo><msup><mn>140</mn><mo>∘</mo></msup></mrow></math></span>) overlap with the low-latitude ring currents. During the main/recovery phase of storms, the oblique and quasi-perpendicular protons are transported outwards/inwards and thus experience Fermi and Betatron decelerations/accelerations. The adiabatic decelerations/accelerations modify the pancake-like pitch angle distributions of the tens of MeV protons in the outer half part (<em>L</em>* = 1.6 – 2.5) of the inner radiation belt, whereas field line curvature scatterings become effective outside the proton radiation belt (<em>L</em>* > 2.5).</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"52 ","pages":"Article 100568"},"PeriodicalIF":10.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174570","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}
Within the framework of loop quantum cosmology (LQC), we investigate the effect of inverse volume corrections on the low scale spontaneously broken supersymmetric (SB SUSY) and exponential inflationary potentials. The LQC modifications to the Friedmann equations and cosmological perturbation parameters are employed to assess the observational viability of these models against recent data from the Atacama Cosmology Telescope (ACT). Our results indicate that in contrast to the standard model of inflation, in the presence of inverse volume corrections in LQC, the predictions of SB SUSY and exponential potentials in the plane lie inside the 68% confidence level interval of the ACT data.
{"title":"Loop quantum inflation with inverse volume corrections in light of ACT data","authors":"Farough Parvizi , Soma Heydari , Milad Solbi , Kayoomars Karami","doi":"10.1016/j.jheap.2026.100563","DOIUrl":"10.1016/j.jheap.2026.100563","url":null,"abstract":"<div><div>Within the framework of loop quantum cosmology (LQC), we investigate the effect of inverse volume corrections on the low scale spontaneously broken supersymmetric (SB SUSY) and exponential inflationary potentials. The LQC modifications to the Friedmann equations and cosmological perturbation parameters are employed to assess the observational viability of these models against recent data from the Atacama Cosmology Telescope (ACT). Our results indicate that in contrast to the standard model of inflation, in the presence of inverse volume corrections in LQC, the predictions of SB SUSY and exponential potentials in the <span><math><mrow><mi>r</mi><mo>−</mo><msub><mi>n</mi><mrow><mi>s</mi></mrow></msub></mrow></math></span> plane lie inside the 68% confidence level interval of the ACT data.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"52 ","pages":"Article 100563"},"PeriodicalIF":10.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174571","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}
Pub Date : 2026-04-01Epub Date: 2026-02-08DOI: 10.1016/j.jheap.2026.100579
S.D. Odintsov , V.K. Oikonomou , G.S. Sharov
Two F(R) gravity models are tested on the basis of their viability during all stages of cosmological evolution. It is shown that these models can describe both the early-time inflationary epoch and the dark energy epoch. The models are confronted with the latest observational data, including the Pantheon+ catalogue with Type Ia supernovae, the Dark Energy Spectroscopic Instrument measurements of baryon acoustic oscillations, the Hubble parameter estimations and data from cosmic microwave background radiation. Investigation of the viability conditions for these models, in particular, the condition required a deep analysis. Both models appeared to be viable during the early-time era, but for the late-time evolution the viability conditions are not fulfilled in definite domains in the parameter spaces of these models. However the best fitted parameters, determined in confrontation with the mentioned observational data, lie far from the forbidden domains for both models. These F(R) gravity models describe the observations with the large advantage over the Λ-Cold-Dark-Matter model, not only in χ2 statistics, but also with Akaike and Bayesian information criteria. This success of the two F(R) gravity scenarios is connected with their capability to mimic dynamical dark energy, similarly to models with variable equation of state, that is necessary for describing the latest Pantheon+ and DESI observational data.
{"title":"Viable F(R) scenarios unifying inflation with realistic dynamical dark energy","authors":"S.D. Odintsov , V.K. Oikonomou , G.S. Sharov","doi":"10.1016/j.jheap.2026.100579","DOIUrl":"10.1016/j.jheap.2026.100579","url":null,"abstract":"<div><div>Two <em>F</em>(<em>R</em>) gravity models are tested on the basis of their viability during all stages of cosmological evolution. It is shown that these models can describe both the early-time inflationary epoch and the dark energy epoch. The models are confronted with the latest observational data, including the Pantheon+ catalogue with Type Ia supernovae, the Dark Energy Spectroscopic Instrument measurements of baryon acoustic oscillations, the Hubble parameter estimations and data from cosmic microwave background radiation. Investigation of the viability conditions for these models, in particular, the condition <span><math><mrow><mfrac><mrow><mi>d</mi><mi>F</mi></mrow><mrow><mi>d</mi><mi>R</mi></mrow></mfrac><mo>></mo><mn>0</mn></mrow></math></span> required a deep analysis. Both models appeared to be viable during the early-time era, but for the late-time evolution the viability conditions are not fulfilled in definite domains in the parameter spaces of these models. However the best fitted parameters, determined in confrontation with the mentioned observational data, lie far from the forbidden domains for both models. These <em>F</em>(<em>R</em>) gravity models describe the observations with the large advantage over the Λ-Cold-Dark-Matter model, not only in <em>χ</em><sup>2</sup> statistics, but also with Akaike and Bayesian information criteria. This success of the two <em>F</em>(<em>R</em>) gravity scenarios is connected with their capability to mimic dynamical dark energy, similarly to models with variable equation of state, that is necessary for describing the latest Pantheon+ and DESI observational data.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"52 ","pages":"Article 100579"},"PeriodicalIF":10.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174961","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}
Pub Date : 2026-03-01Epub Date: 2025-12-22DOI: 10.1016/j.jheap.2025.100538
Jose A. Carpio, Ali Kheirandish, Bing Zhang
Microquasars, compact binary systems with an accreting stellar-mass black hole or neutron star, are promising candidates for high-energy particle acceleration. Recently, the LHAASO collaboration reported on the detection of > 100 TeV γ-ray emission from five microquasars, suggesting that these sources are efficient particle accelerators. In microquasars, high-energy γ-rays can be produced in large-scale jets or winds. In this work, we explore the X-ray, γ-ray and neutrino emission from SS 433, V4641 Sgr and GRS 1905+105. We consider leptonic and hadronic scenarios to explain the spectra observed by LHAASO and other high-energy γ-ray detectors. We estimate the neutrino flux associated with the hadronic component and investigate the detectability of neutrinos from these sources in current and future neutrino telescopes. We find that among the three sources, V4641 Sgr has the best prospects of observation with a combined next-generation neutrino telescopes.
微类星体是一种紧凑的双星系统，有一个吸积的恒星质量黑洞或中子星，是高能粒子加速的有希望的候选者。最近，LHAASO合作报告了从5个微类星体中探测到 >； 100 TeV γ射线发射，这表明这些源是有效的粒子加速器。在微类星体中，高能γ射线可以在大规模喷流或风中产生。在这项工作中，我们研究了SS 433， V4641 Sgr和GRS 1905+105的x射线，γ射线和中微子发射。我们考虑了轻子和强子场景来解释LHAASO和其他高能γ射线探测器观测到的光谱。我们估计了与强子分量相关的中微子通量，并在当前和未来的中微子望远镜中研究了这些源的中微子的可探测性。我们发现，在三个源中，Sgr V4641具有最好的观测前景。
{"title":"Multimessenger emission from very-high-energy black hole-jet systems in the milky way","authors":"Jose A. Carpio, Ali Kheirandish, Bing Zhang","doi":"10.1016/j.jheap.2025.100538","DOIUrl":"10.1016/j.jheap.2025.100538","url":null,"abstract":"<div><div>Microquasars, compact binary systems with an accreting stellar-mass black hole or neutron star, are promising candidates for high-energy particle acceleration. Recently, the LHAASO collaboration reported on the detection of > 100 TeV <em>γ</em>-ray emission from five microquasars, suggesting that these sources are efficient particle accelerators. In microquasars, high-energy <em>γ</em>-rays can be produced in large-scale jets or winds. In this work, we explore the X-ray, <em>γ</em>-ray and neutrino emission from SS 433, V4641 Sgr and GRS 1905+105. We consider leptonic and hadronic scenarios to explain the spectra observed by LHAASO and other high-energy <em>γ</em>-ray detectors. We estimate the neutrino flux associated with the hadronic component and investigate the detectability of neutrinos from these sources in current and future neutrino telescopes. We find that among the three sources, V4641 Sgr has the best prospects of observation with a combined next-generation neutrino telescopes.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100538"},"PeriodicalIF":10.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884295","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号