Pub Date : 2026-03-01Epub Date: 2025-12-04DOI: 10.1016/j.jheap.2025.100530
D. Pugliese , Z. Stuchlík
A Ringed Accretion disk (RAD) is a cluster of axially symmetric, mixed co–rotating and counter–rotating co–planar tori, orbiting on the equatorial plane of a central Kerr black hole (BH). In this work we focus on the red-shift and spectral lines emission from the RAD. Our analysis of the emissions maps, giving appearance of the RAD, envisages the possibility that the presence of a possible disk internal ringed structure could be observable from a density radial discrete structure, and a composite radial distribution of angular momentum in the disk. The co–rotating and counter–rotating bands, in the disk internal structure, are found distinguished in red-shift, in dependence on the view angle, and the BH spin. We frame our investigation, using different source corona models, and emissivity profiles for the disk. Lines emission turns affected by the knobby surface of the disk. The results of this analysis have been compared with the results for the infinite disk and the correspondent unstructured disks.
{"title":"The red-shift and spectral lines of the Kerr black hole ringed accretion disks","authors":"D. Pugliese , Z. Stuchlík","doi":"10.1016/j.jheap.2025.100530","DOIUrl":"10.1016/j.jheap.2025.100530","url":null,"abstract":"<div><div>A Ringed Accretion disk (<strong>RAD</strong>) is a cluster of axially symmetric, mixed co–rotating and counter–rotating co–planar tori, orbiting on the equatorial plane of a central Kerr black hole (<strong>BH</strong>). In this work we focus on the red-shift and spectral lines emission from the <strong>RAD</strong>. Our analysis of the emissions maps, giving appearance of the <strong>RAD</strong>, envisages the possibility that the presence of a possible disk internal ringed structure could be observable from a density radial discrete structure, and a composite radial distribution of angular momentum in the disk. The co–rotating and counter–rotating bands, in the disk internal structure, are found distinguished in red-shift, in dependence on the view angle, and the <strong>BH</strong> spin. We frame our investigation, using different source corona models, and emissivity profiles for the disk. Lines emission turns affected by the knobby surface of the disk. The results of this analysis have been compared with the results for the infinite disk and the correspondent unstructured disks.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100530"},"PeriodicalIF":10.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748542","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: 2025-11-29DOI: 10.1016/j.jheap.2025.100519
A. Kaushal , A. Manchanda , M.G. Dainotti , K. Gupta , Z. Nogala , A. Madhan , S. Naqi , Ritik Kumar , V. Oad , N. Indoriya , Krishnanjan Sil , D.H. Hartmann , M. Bogdan , A. Pollo , J.X. Prochaska , N. Fraija
Mitigating data gaps in Gamma-ray bursts (GRBs) light curves (LCs) is crucial for cosmological research, enhancing the precision of parameters, assuming perfect satellite conditions for complete LC coverage with no gaps. This analysis improves the applicability of the two-dimensional Dainotti relation, which connects the rest-frame end time of the plateau emission (Ta) and its luminosity (La), derived from the fluxes (Fa). The study expands on a previous 521 GRB sample by incorporating seven models: Deep Gaussian Process (DGP), Temporal Convolutional Network (TCN), Hybrid CNN with Bidirectional Long Short-Term Memory (CNN-BiLSTM), Bayesian Neural Network (BNN), Polynomial Curve Fitting, Isotonic Regression, and Quartic Smoothing Spline (QSS). Results indicate that QSS significantly reduces uncertainty across parameters–43.5 % for log Ta, 43.2 % for log Fa, and 48.3 % for α, outperforming the other models where α denotes the slope post-plateau based on Willingale’s 2007 functional form. The Polynomial Curve Fitting model demonstrates moderate uncertainty reduction across parameters, while CNN-BiLSTM has the lowest outlier rate for α at 0.77 %. These models broaden the application of machine-learning techniques in GRB LC analysis, enhancing uncertainty estimation and parameter recovery, and complement traditional methods like the Attention U-Net and Multilayer Perceptron (MLP). These advancements highlight the potential of GRBs as cosmological probes, supporting their role in theoretical model discrimination via LC parameters, serving as standard candles, and facilitating GRB redshift predictions through advanced machine-learning approaches.
{"title":"Multi-model framework for reconstructing gamma-Ray burst light curves","authors":"A. Kaushal , A. Manchanda , M.G. Dainotti , K. Gupta , Z. Nogala , A. Madhan , S. Naqi , Ritik Kumar , V. Oad , N. Indoriya , Krishnanjan Sil , D.H. Hartmann , M. Bogdan , A. Pollo , J.X. Prochaska , N. Fraija","doi":"10.1016/j.jheap.2025.100519","DOIUrl":"10.1016/j.jheap.2025.100519","url":null,"abstract":"<div><div>Mitigating data gaps in Gamma-ray bursts (GRBs) light curves (LCs) is crucial for cosmological research, enhancing the precision of parameters, assuming perfect satellite conditions for complete LC coverage with no gaps. This analysis improves the applicability of the two-dimensional Dainotti relation, which connects the rest-frame end time of the plateau emission (<em>T<sub>a</sub></em>) and its luminosity (<em>L<sub>a</sub></em>), derived from the fluxes (<em>F<sub>a</sub></em>). The study expands on a previous 521 GRB sample by incorporating seven models: Deep Gaussian Process (DGP), Temporal Convolutional Network (TCN), Hybrid CNN with Bidirectional Long Short-Term Memory (CNN-BiLSTM), Bayesian Neural Network (BNN), Polynomial Curve Fitting, Isotonic Regression, and Quartic Smoothing Spline (QSS). Results indicate that QSS significantly reduces uncertainty across parameters–43.5 % for log <em>T<sub>a</sub></em>, 43.2 % for log <em>F<sub>a</sub></em>, and 48.3 % for <em>α</em>, outperforming the other models where <em>α</em> denotes the slope post-plateau based on Willingale’s 2007 functional form. The Polynomial Curve Fitting model demonstrates moderate uncertainty reduction across parameters, while CNN-BiLSTM has the lowest outlier rate for <em>α</em> at 0.77 %. These models broaden the application of machine-learning techniques in GRB LC analysis, enhancing uncertainty estimation and parameter recovery, and complement traditional methods like the Attention U-Net and Multilayer Perceptron (MLP). These advancements highlight the potential of GRBs as cosmological probes, supporting their role in theoretical model discrimination via LC parameters, serving as standard candles, and facilitating GRB redshift predictions through advanced machine-learning approaches.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100519"},"PeriodicalIF":10.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748545","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: 2025-12-27DOI: 10.1016/j.jheap.2025.100544
Ribhu Pal , Arnab Roy
In this article, we report the numerical results of two-dimensional axis-symmetric relativistic jet issuing from AGN, performed using a high-order finite-volume scheme within the PLUTO code, focusing on favorable conditions for star formation within jet-inflated cocoons. A localized square subdomain of the cocoon was statistically analyzed for velocity divergence (∇ · v), current density (J), density fluctuations (), and log-normalized density () under varying jet magnetizations (σϕ, σz). Enhanced toroidal magnetization (σϕ) was found to amplify magnetic hoop stresses, producing compact, filamentary overdense clumps and strongly non-Gaussian current density and density fluctuation PDFs with pronounced skewness and kurtosis. Concurrently, the variance of the log-normal density decreased with increasing σϕ, indicating reduced large-scale density contrast despite intense local overdensities. Moderate toroidal magnetization (σϕ ∼ 0.5) yielded both numerous overdense clumps and high global density variance, providing the most favorable conditions for star formation. These results establish a direct link between jet magnetization, cocoon compression, and pre-favorable conditions for star-forming potential inside jet-induced cocoon ISM during active phase of AGN-jet. While onset of star formation is expected to occur during episodic jet-off phases, can be the future scope of current research work.
{"title":"Magnetized relativistic jet-induced cocoon as a cradle of star formation","authors":"Ribhu Pal , Arnab Roy","doi":"10.1016/j.jheap.2025.100544","DOIUrl":"10.1016/j.jheap.2025.100544","url":null,"abstract":"<div><div>In this article, we report the numerical results of two-dimensional axis-symmetric relativistic jet issuing from AGN, performed using a high-order finite-volume scheme within the PLUTO code, focusing on favorable conditions for star formation within jet-inflated cocoons. A localized square subdomain of the cocoon was statistically analyzed for velocity divergence (∇ · <strong>v</strong>), current density (J), density fluctuations (<span><math><mrow><msup><mi>ρ</mi><mo>′</mo></msup><mo>=</mo><mi>ρ</mi><mo>−</mo><mrow><mo>〈</mo><mi>ρ</mi><mo>〉</mo></mrow></mrow></math></span>), and log-normalized density (<span><math><mrow><mi>s</mi><mo>=</mo><mi>ln</mi><mo>(</mo><mi>ρ</mi><mo>/</mo><mo>〈</mo><mi>ρ</mi><mo>〉</mo><mo>)</mo></mrow></math></span>) under varying jet magnetizations (<em>σ<sub>ϕ</sub>, σ<sub>z</sub></em>). Enhanced toroidal magnetization (<em>σ<sub>ϕ</sub></em>) was found to amplify magnetic hoop stresses, producing compact, filamentary overdense clumps and strongly non-Gaussian current density and density fluctuation PDFs with pronounced skewness and kurtosis. Concurrently, the variance of the log-normal density decreased with increasing <em>σ<sub>ϕ</sub></em>, indicating reduced large-scale density contrast despite intense local overdensities. Moderate toroidal magnetization (<em>σ<sub>ϕ</sub></em> ∼ 0.5) yielded both numerous overdense clumps and high global density variance, providing the most favorable conditions for star formation. These results establish a direct link between jet magnetization, cocoon compression, and pre-favorable conditions for star-forming potential inside jet-induced cocoon ISM during active phase of AGN-jet. While onset of star formation is expected to occur during episodic jet-off phases, can be the future scope of current research work.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100544"},"PeriodicalIF":10.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938337","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: 2026-01-01DOI: 10.1016/j.jheap.2025.100546
André LeClair
<div><div>We explore the idea that quantum vacuum energy <em>ρ</em><sub>vac</sub>, as computed in flat Minkowski space, is at the origin of Gravity. We formulate a gravitational version of the electromagnetic Casimir effect, and provide an argument for how gravity can arise from <em>ρ</em><sub>vac</sub> by showing how Einstein’s field equations emerge in the form of Friedmann’s equations. This leads to the idea that Newton’s constant <em>G<sub>N</sub></em> is environmental, namely it depends on the total mass-energy of the universe <span><math><msub><mrow><mi>M</mi></mrow><mstyle><mi>∞</mi></mstyle></msub></math></span> and its size <span><math><msub><mrow><mi>R</mi></mrow><mstyle><mi>∞</mi></mstyle></msub></math></span>, with <span><math><mrow><msub><mi>G</mi><mi>N</mi></msub><mo>=</mo><msup><mi>c</mi><mn>2</mn></msup><msub><mrow><mi>R</mi></mrow><mstyle><mi>∞</mi></mstyle></msub><mo>/</mo><mn>2</mn><msub><mrow><mi>M</mi></mrow><mstyle><mi>∞</mi></mstyle></msub></mrow></math></span>. This leads to a new interpretation of the Gibbons-Hawking entropy of de Sitter space, and also the Bekenstein-Hawking entropy for black holes, wherein the quantum information “bits” are simply quantized massless particles at the horizon with wavelength <span><math><mrow><mi>λ</mi><mo>=</mo><mn>2</mn><mi>π</mi><msub><mrow><mi>R</mi></mrow><mstyle><mi>∞</mi></mstyle></msub></mrow></math></span>. We assume a recently proposed and well-motivated formula for <span><math><mrow><msub><mi>ρ</mi><mrow><mrow><mi>v</mi></mrow><mi>a</mi><mi>c</mi></mrow></msub><mo>∝</mo><msubsup><mi>m</mi><mrow><mrow><mi>z</mi></mrow></mrow><mn>4</mn></msubsup><mo>/</mo><mi>g</mi></mrow></math></span>, where <em>m</em><sub>z</sub> is the mass of the lightest particle, and <span><math><mi>g</mi></math></span> is a marginally irrelevant coupling. This leads to an effective, induced RG flow for Newton’s constant <em>G<sub>N</sub></em> as a function of an energy scale, which indicates that <em>G<sub>N</sub> decreases</em> at higher energies until it reaches a Landau pole at a minimal value of the cosmological scale factor <em>a</em>(<em>t</em>) > <em>a</em><sub>min</sub>, thus avoiding the usual geometric curvature singularity at <span><math><mrow><mi>a</mi><mo>=</mo><mn>0</mn></mrow></math></span>. The solution to the scale factor satisfies an interesting symmetry between the far past and far future due to <span><math><mrow><mi>a</mi><mrow><mo>(</mo><mi>t</mi><mo>)</mo></mrow><mo>=</mo><mi>a</mi><mrow><mo>(</mo><mo>−</mo><mi>t</mi><mo>+</mo><mn>2</mn><msub><mi>t</mi><mrow><mrow><mi>m</mi></mrow><mi>i</mi><mi>n</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span>, where <span><math><mrow><mi>a</mi><mrow><mo>(</mo><msub><mi>t</mi><mrow><mrow><mi>m</mi></mrow><mi>i</mi><mi>n</mi></mrow></msub><mo>)</mo></mrow><mo>=</mo><msub><mi>a</mi><mrow><mrow><mi>m</mi></mrow><mi>i</mi><mi>n</mi></mrow></msub></mrow></math></span>. We propose that this energy scale dependent <em>G<sub>N</sub></em> can expl
{"title":"Quantum vacuum energy as the origin of gravity","authors":"André LeClair","doi":"10.1016/j.jheap.2025.100546","DOIUrl":"10.1016/j.jheap.2025.100546","url":null,"abstract":"<div><div>We explore the idea that quantum vacuum energy <em>ρ</em><sub>vac</sub>, as computed in flat Minkowski space, is at the origin of Gravity. We formulate a gravitational version of the electromagnetic Casimir effect, and provide an argument for how gravity can arise from <em>ρ</em><sub>vac</sub> by showing how Einstein’s field equations emerge in the form of Friedmann’s equations. This leads to the idea that Newton’s constant <em>G<sub>N</sub></em> is environmental, namely it depends on the total mass-energy of the universe <span><math><msub><mrow><mi>M</mi></mrow><mstyle><mi>∞</mi></mstyle></msub></math></span> and its size <span><math><msub><mrow><mi>R</mi></mrow><mstyle><mi>∞</mi></mstyle></msub></math></span>, with <span><math><mrow><msub><mi>G</mi><mi>N</mi></msub><mo>=</mo><msup><mi>c</mi><mn>2</mn></msup><msub><mrow><mi>R</mi></mrow><mstyle><mi>∞</mi></mstyle></msub><mo>/</mo><mn>2</mn><msub><mrow><mi>M</mi></mrow><mstyle><mi>∞</mi></mstyle></msub></mrow></math></span>. This leads to a new interpretation of the Gibbons-Hawking entropy of de Sitter space, and also the Bekenstein-Hawking entropy for black holes, wherein the quantum information “bits” are simply quantized massless particles at the horizon with wavelength <span><math><mrow><mi>λ</mi><mo>=</mo><mn>2</mn><mi>π</mi><msub><mrow><mi>R</mi></mrow><mstyle><mi>∞</mi></mstyle></msub></mrow></math></span>. We assume a recently proposed and well-motivated formula for <span><math><mrow><msub><mi>ρ</mi><mrow><mrow><mi>v</mi></mrow><mi>a</mi><mi>c</mi></mrow></msub><mo>∝</mo><msubsup><mi>m</mi><mrow><mrow><mi>z</mi></mrow></mrow><mn>4</mn></msubsup><mo>/</mo><mi>g</mi></mrow></math></span>, where <em>m</em><sub>z</sub> is the mass of the lightest particle, and <span><math><mi>g</mi></math></span> is a marginally irrelevant coupling. This leads to an effective, induced RG flow for Newton’s constant <em>G<sub>N</sub></em> as a function of an energy scale, which indicates that <em>G<sub>N</sub> decreases</em> at higher energies until it reaches a Landau pole at a minimal value of the cosmological scale factor <em>a</em>(<em>t</em>) > <em>a</em><sub>min</sub>, thus avoiding the usual geometric curvature singularity at <span><math><mrow><mi>a</mi><mo>=</mo><mn>0</mn></mrow></math></span>. The solution to the scale factor satisfies an interesting symmetry between the far past and far future due to <span><math><mrow><mi>a</mi><mrow><mo>(</mo><mi>t</mi><mo>)</mo></mrow><mo>=</mo><mi>a</mi><mrow><mo>(</mo><mo>−</mo><mi>t</mi><mo>+</mo><mn>2</mn><msub><mi>t</mi><mrow><mrow><mi>m</mi></mrow><mi>i</mi><mi>n</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span>, where <span><math><mrow><mi>a</mi><mrow><mo>(</mo><msub><mi>t</mi><mrow><mrow><mi>m</mi></mrow><mi>i</mi><mi>n</mi></mrow></msub><mo>)</mo></mrow><mo>=</mo><msub><mi>a</mi><mrow><mrow><mi>m</mi></mrow><mi>i</mi><mi>n</mi></mrow></msub></mrow></math></span>. We propose that this energy scale dependent <em>G<sub>N</sub></em> can expl","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100546"},"PeriodicalIF":10.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976541","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: 2025-11-21DOI: 10.1016/j.jheap.2025.100515
Dorian Araya , Cristian Castillo , Genly Leon , Juan Magaña , Angie Barr Domínguez , Miguel A. García-Aspeitia
We revisit a cosmological model where dark matter (DM) and dark energy (DE) follow barotropic equations of state, allowing deviations from the standard ΛCDM framework (i.e. wdm ≠ 0, ), considering both flat and non-flat curvature. Using a dynamical system approach, we identify equilibrium states that govern stability, expansion, and contraction. Expansion occurs when H > 0, while contraction is linked to H < 0. Accelerated expansion arises from DE dominance, whereas radiation- and matter-dominated phases lead to deceleration. Some solutions are unphysical due to density constraints, but viable cases offer insights into cosmic transitions, including the Einstein static universe, which allows for shifts between accelerating and decelerating phases. We perform a Bayesian analysis with updated datasets, including observational Hubble data, Pantheon+ Type Ia supernovae, strong lensing systems, baryon acoustic oscillations and cosmic microwave background, to constrain the parameters wdm and wde. Our results from the data joint analysis show consistency with ΛCDM within 3σ, but none of the cases reproduce and . Nevertheless, the comparison with the standard model using the Akaike and Bayesian information criteria indicates that only the non-flat scenario has the potential to be competitive. This suggests that a non-dust-like DM may impact structure formation, while DE could shift toward quintessence fluid. While ΛCDM remains a strong model, our findings indicate that alternative dark sector models with non-standard EoS could be viable and offer new insights into cosmic evolution.
{"title":"wdm−wde cosmological model with new data samples of cosmological observations","authors":"Dorian Araya , Cristian Castillo , Genly Leon , Juan Magaña , Angie Barr Domínguez , Miguel A. García-Aspeitia","doi":"10.1016/j.jheap.2025.100515","DOIUrl":"10.1016/j.jheap.2025.100515","url":null,"abstract":"<div><div>We revisit a cosmological model where dark matter (DM) and dark energy (DE) follow barotropic equations of state, allowing deviations from the standard ΛCDM framework (i.e. <em>w<sub>dm</sub></em> ≠ 0, <span><math><mrow><msub><mi>w</mi><mrow><mi>d</mi><mi>e</mi></mrow></msub><mo>≠</mo><mo>−</mo><mn>1</mn></mrow></math></span>), considering both flat and non-flat curvature. Using a dynamical system approach, we identify equilibrium states that govern stability, expansion, and contraction. Expansion occurs when <em>H</em> > 0, while contraction is linked to <em>H</em> < 0. Accelerated expansion arises from DE dominance, whereas radiation- and matter-dominated phases lead to deceleration. Some solutions are unphysical due to density constraints, but viable cases offer insights into cosmic transitions, including the Einstein static universe, which allows for shifts between accelerating and decelerating phases. We perform a Bayesian analysis with updated datasets, including observational Hubble data, Pantheon+ Type Ia supernovae, strong lensing systems, baryon acoustic oscillations and cosmic microwave background, to constrain the parameters <em>w<sub>dm</sub></em> and <em>w<sub>de</sub></em>. Our results from the data joint analysis show consistency with ΛCDM within 3<em>σ</em>, but none of the cases reproduce <span><math><mrow><msub><mi>w</mi><mrow><mi>d</mi><mi>m</mi></mrow></msub><mo>=</mo><mn>0</mn></mrow></math></span> and <span><math><mrow><msub><mi>w</mi><mrow><mi>d</mi><mi>e</mi></mrow></msub><mo>=</mo><mo>−</mo><mn>1</mn></mrow></math></span>. Nevertheless, the comparison with the standard model using the Akaike and Bayesian information criteria indicates that only the non-flat scenario has the potential to be competitive. This suggests that a non-dust-like DM may impact structure formation, while DE could shift toward quintessence fluid. While ΛCDM remains a strong model, our findings indicate that alternative dark sector models with non-standard EoS could be viable and offer new insights into cosmic evolution.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100515"},"PeriodicalIF":10.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694269","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: 2025-12-16DOI: 10.1016/j.jheap.2025.100534
Ziyan Zhu , Qingquan Jiang , Yu Liu , Puxun Wu , Nan Liang
In this work, we constrain the phenomenological interacting dark energy (IDE) model using Fermi gamma-ray burst (GRB) dataset and the latest baryon acoustic oscillation (BAO) data from the Dark Energy Spectroscopic Instrument (DESI) Data Release 2 (DR2). Through a joint Bayesian analysis, we perform a cosmological comparative assessment of the ΛCDM, wCDM, and CPL models with the phenomenological IDE model. For the phenomenological IDE model in a flat universe with Fermi samples and DESI DR2, we obtain: , with the GOLD sample (1.4 ≤ z ≤ 5.6) and , with the FULL sample (1.4 ≤ z ≤ 8.2), respectively. Our analysis shows that the ΛCDM model without interaction (, ) is consistent with the latest Fermi sample and DESI DR2 at 1σ confidence level. We find no significant deviations from the standard model using AIC and BIC criterias.
在这项工作中，我们使用费米伽玛射线暴（GRB）数据集和暗能量光谱仪器（DESI）数据发布2 （DR2）最新的重子声学振荡（BAO）数据来约束现象相互作用暗能量（IDE）模型。通过联合贝叶斯分析，我们对ΛCDM、wCDM和CPL模型与现象学IDE模型进行了宇宙学比较评估。对于Fermi样本和DESI DR2在平坦宇宙中的现象学IDE模型，我们得到：对于GOLD样本（1.4 ≤ z ≤ 5.6），ξ=2.63−0.52+0.63,ξ+3wX=−0.98−2.07+1.90；对于FULL样本（1.4 ≤ z ≤ 8.2），ξ=2.83−0.58+0.63,ξ+3wX=0.03−1.33+1.35。我们的分析表明，无相互作用（ξ=3, ξ+3wX=0）的ΛCDM模型与最新费米样本和DESI DR2在1σ置信水平上是一致的。我们发现使用AIC和BIC标准模型没有明显的偏差。
{"title":"Cosmological constraints on the phenomenological interacting dark energy model with Fermi gamma-ray bursts and DESI DR2","authors":"Ziyan Zhu , Qingquan Jiang , Yu Liu , Puxun Wu , Nan Liang","doi":"10.1016/j.jheap.2025.100534","DOIUrl":"10.1016/j.jheap.2025.100534","url":null,"abstract":"<div><div>In this work, we constrain the phenomenological interacting dark energy (IDE) model using <em>Fermi</em> gamma-ray burst (GRB) dataset and the latest baryon acoustic oscillation (BAO) data from the Dark Energy Spectroscopic Instrument (DESI) Data Release 2 (DR2). Through a joint Bayesian analysis, we perform a cosmological comparative assessment of the ΛCDM, <em>w</em>CDM, and CPL models with the phenomenological IDE model. For the phenomenological IDE model in a flat universe with <em>Fermi</em> samples and DESI DR2, we obtain: <span><math><mrow><mi>ξ</mi><mo>=</mo><mn>2</mn><mo>.</mo><msubsup><mn>63</mn><mrow><mo>−</mo><mn>0.52</mn></mrow><mrow><mo>+</mo><mn>0.63</mn></mrow></msubsup></mrow></math></span>, <span><math><mrow><mi>ξ</mi><mo>+</mo><mn>3</mn><msub><mi>w</mi><mi>X</mi></msub><mo>=</mo><mo>−</mo><mn>0</mn><mo>.</mo><msubsup><mn>98</mn><mrow><mo>−</mo><mn>2.07</mn></mrow><mrow><mo>+</mo><mn>1.90</mn></mrow></msubsup></mrow></math></span> with the GOLD sample (1.4 ≤ <em>z</em> ≤ 5.6) and <span><math><mrow><mi>ξ</mi><mo>=</mo><mn>2</mn><mo>.</mo><msubsup><mn>83</mn><mrow><mo>−</mo><mn>0.58</mn></mrow><mrow><mo>+</mo><mn>0.63</mn></mrow></msubsup></mrow></math></span>, <span><math><mrow><mi>ξ</mi><mo>+</mo><mn>3</mn><msub><mi>w</mi><mi>X</mi></msub><mo>=</mo><mn>0</mn><mo>.</mo><msubsup><mn>03</mn><mrow><mo>−</mo><mn>1.33</mn></mrow><mrow><mo>+</mo><mn>1.35</mn></mrow></msubsup></mrow></math></span> with the FULL sample (1.4 ≤ <em>z</em> ≤ 8.2), respectively. Our analysis shows that the ΛCDM model without interaction (<span><math><mrow><mi>ξ</mi><mo>=</mo><mn>3</mn></mrow></math></span>, <span><math><mrow><mi>ξ</mi><mo>+</mo><mn>3</mn><msub><mi>w</mi><mi>X</mi></msub><mo>=</mo><mn>0</mn></mrow></math></span>) is consistent with the latest <em>Fermi</em> sample and DESI DR2 at 1<em>σ</em> confidence level. We find no significant deviations from the standard model using AIC and BIC criterias.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100534"},"PeriodicalIF":10.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797357","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: 2025-12-20DOI: 10.1016/j.jheap.2025.100535
Aromal P , Unnati Kashyap , Manoneeta Chakraborty , Sudip Bhattacharyya , Thomas J. Maccarone , Vijay Choudhary
We present a detailed analysis of the Type-I (thermonuclear) X-ray bursts and eclipses observed from the neutron star low-mass X-ray binary EXO 0748–676 with AstroSat during the second known outburst of the source following a 16-year-long quiescence period. We detect three thermonuclear X-ray bursts, with two displaying simultaneous coverage in the soft X-rays. Simultaneous UV observations show evidence of reprocessed burst emissions in the far-ultraviolet band. The time-resolved spectral analysis reveals the photospheric radius expansion (PRE) nature for two bursts. We estimate the distance to the source to be 7.42 ± 0.53 kpc using the peak flux of PRE. Notably, one of the bursts exhibited a secondary peak, ∼ 30 s after the primary, particularly dominating in the softer X-rays, which reveals a correlation with the evolution of burst hotspot radius with no temperature dependence. The burst properties and corresponding flux values suggest that mixed H/He burning may have fueled the bursts. We also detect evidence of a soft excess during one burst, likely arising from the interaction of the burst photons with the surroundings. We also probe the temporal evolution and the energy dependence of the eclipses, which offer insights into the binary environment. Our study helps gain deeper insight into the physics of burst ignition, flame propagation, the burst-accretion interaction, and the evolution of LMXBs.
{"title":"The 2024 outburst of the neutron star LMXB EXO 0748–676: An investigation of bursts and eclipses with astrosat","authors":"Aromal P , Unnati Kashyap , Manoneeta Chakraborty , Sudip Bhattacharyya , Thomas J. Maccarone , Vijay Choudhary","doi":"10.1016/j.jheap.2025.100535","DOIUrl":"10.1016/j.jheap.2025.100535","url":null,"abstract":"<div><div>We present a detailed analysis of the Type-I (thermonuclear) X-ray bursts and eclipses observed from the neutron star low-mass X-ray binary EXO 0748–676 with AstroSat during the second known outburst of the source following a 16-year-long quiescence period. We detect three thermonuclear X-ray bursts, with two displaying simultaneous coverage in the soft X-rays. Simultaneous UV observations show evidence of reprocessed burst emissions in the far-ultraviolet band. The time-resolved spectral analysis reveals the photospheric radius expansion (PRE) nature for two bursts. We estimate the distance to the source to be 7.42 ± 0.53 kpc using the peak flux of PRE. Notably, one of the bursts exhibited a secondary peak, ∼ 30 s after the primary, particularly dominating in the softer X-rays, which reveals a correlation with the evolution of burst hotspot radius with no temperature dependence. The burst properties and corresponding flux values suggest that mixed H/He burning may have fueled the bursts. We also detect evidence of a soft excess during one burst, likely arising from the interaction of the burst photons with the surroundings. We also probe the temporal evolution and the energy dependence of the eclipses, which offer insights into the binary environment. Our study helps gain deeper insight into the physics of burst ignition, flame propagation, the burst-accretion interaction, and the evolution of LMXBs.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100535"},"PeriodicalIF":10.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884293","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: 2025-12-04DOI: 10.1016/j.jheap.2025.100529
Na Wang , Guowei Ren , Shun Zhang , Tingfeng Yi , Tong Liu , Mouyuan Sun
Based on the Zwicky Transient Facility (ZTF), we selected 10 blazars as our sample sources. Among these, we found four blazars (J 0923.5+4125, J 1221.3+3010, J 1503.5+4759, and J 1652.7+4024) showing possible indications of quasi periodic oscillations (QPOs) modulation. We conducted a detailed analysis of their optical light curves (g- and r-bands) over the past five years using the root mean square (RMS)-Flux relation, flux distribution, and QPO detection methods to investigate their variability characteristics. A linear RMS-Flux relation is present in both bands, and their flux distributions follow a log-normal form. This suggests that optical variability may arise from multiplicative, nonlinear processes across different timescales and flux states. Further QPO analysis using the weighted wavelet Z-transform (WWZ), Lomb-Scargle periodogram (LSP), and autoregressive integrated moving average (ARIMA) methods identified candidate periodic signals in four blazars. J 0923.5+4125 (period ∼ 205 days) and J 1221.3+3010 ( ∼ 630 days) show local significances of ∼ 3σ, whereas J 1503.5+4759 ( ∼ 38.5 days) and J 1652.7+4024 ( ∼ 48 days) reach ∼ 4σ. After accounting for the look-elsewhere effect, the global significances for J 1503.5+4759 in the g- and r-bands are ∼ 2.7σ, while for J 1652.7+4024 they are approximately ∼ 2.5σ in both bands. These two blazars warrant further monitoring and investigation.
{"title":"Possible quasi-periodic optical oscillations of ZTF blazars","authors":"Na Wang , Guowei Ren , Shun Zhang , Tingfeng Yi , Tong Liu , Mouyuan Sun","doi":"10.1016/j.jheap.2025.100529","DOIUrl":"10.1016/j.jheap.2025.100529","url":null,"abstract":"<div><div>Based on the Zwicky Transient Facility (ZTF), we selected 10 blazars as our sample sources. Among these, we found four blazars (J 0923.5+4125, J 1221.3+3010, J 1503.5+4759, and J 1652.7+4024) showing possible indications of quasi periodic oscillations (QPOs) modulation. We conducted a detailed analysis of their optical light curves (g- and r-bands) over the past five years using the root mean square (RMS)-Flux relation, flux distribution, and QPO detection methods to investigate their variability characteristics. A linear RMS-Flux relation is present in both bands, and their flux distributions follow a log-normal form. This suggests that optical variability may arise from multiplicative, nonlinear processes across different timescales and flux states. Further QPO analysis using the weighted wavelet Z-transform (WWZ), Lomb-Scargle periodogram (LSP), and autoregressive integrated moving average (ARIMA) methods identified candidate periodic signals in four blazars. J 0923.5+4125 (period ∼ 205 days) and J 1221.3+3010 ( ∼ 630 days) show local significances of ∼ 3<em>σ</em>, whereas J 1503.5+4759 ( ∼ 38.5 days) and J 1652.7+4024 ( ∼ 48 days) reach ∼ 4<em>σ</em>. After accounting for the look-elsewhere effect, the global significances for J 1503.5+4759 in the g- and r-bands are ∼ 2.7<em>σ</em>, while for J 1652.7+4024 they are approximately ∼ 2.5<em>σ</em> in both bands. These two blazars warrant further monitoring and investigation.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100529"},"PeriodicalIF":10.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748543","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: 2025-12-26DOI: 10.1016/j.jheap.2025.100542
Mozhdeh Bitaj, Kourosh Nozari
We study the reheating process in a non-minimal Tachyon inflation with three potentials: exponential potential , inverse power law potential and inverse Cosh potential . We constrain these models in confrontation with Planck2018 TT, TE, EE+lowE+lensing+BK14(18)+BAO+DESI2024+Union3 joint data and also the latest results from the Atacama Cosmology Telescope (ACT) dataset. In this comparison, we identify an appropriate observational range for the non-minimal coupling parameter ξ for the exponential potential parameter α ∈ [0.1, 1], inverse power law, and inverse Cosh potentials. A successful reheating stage with acceptable reheating number of e-folds, Nre, and reheating temperature, Tre, happens in the exponential potential model for α ∈ [0.2, 0.6] as well as the two models mentioned above, all with the equation of state parameter .
{"title":"Reheating in a non-minimal tachyon cosmic inflation","authors":"Mozhdeh Bitaj, Kourosh Nozari","doi":"10.1016/j.jheap.2025.100542","DOIUrl":"10.1016/j.jheap.2025.100542","url":null,"abstract":"<div><div>We study the reheating process in a non-minimal Tachyon inflation with three potentials: exponential potential <span><math><mrow><mi>V</mi><mrow><mo>(</mo><mi>ϕ</mi><mo>)</mo></mrow><mo>=</mo><msup><mi>M</mi><mn>4</mn></msup><mi>exp</mi><mrow><mo>(</mo><mo>−</mo><mfrac><mi>α</mi><msub><mi>M</mi><mrow><mi>p</mi><mi>l</mi></mrow></msub></mfrac><mi>ϕ</mi><mo>)</mo></mrow></mrow></math></span>, inverse power law potential <span><math><mrow><mi>V</mi><mrow><mo>(</mo><mi>ϕ</mi><mo>)</mo></mrow><mo>=</mo><mstyle><mfrac><mi>λ</mi><mrow><mn>1</mn><mo>+</mo><msup><mi>ϕ</mi><mn>4</mn></msup></mrow></mfrac></mstyle></mrow></math></span> and inverse Cosh potential <span><math><mrow><mi>V</mi><mrow><mo>(</mo><mi>ϕ</mi><mo>)</mo></mrow><mo>=</mo><mstyle><mfrac><mi>λ</mi><mrow><mi>cosh</mi><mi>ϕ</mi></mrow></mfrac></mstyle></mrow></math></span>. We constrain these models in confrontation with Planck2018 TT, TE, EE+lowE+lensing+BK14(18)+BAO+DESI2024+Union3 joint data and also the latest results from the Atacama Cosmology Telescope (ACT) dataset. In this comparison, we identify an appropriate observational range for the non-minimal coupling parameter <em>ξ</em> for the exponential potential parameter <em>α</em> ∈ [0.1, 1], inverse power law, and inverse Cosh potentials. A successful reheating stage with acceptable reheating number of e-folds, <em>N<sub>re</sub></em>, and reheating temperature, <em>T<sub>re</sub></em>, happens in the exponential potential model for <em>α</em> ∈ [0.2, 0.6] as well as the two models mentioned above, all with the equation of state parameter <span><math><mrow><mi>ω</mi><mo>=</mo><mn>1</mn></mrow></math></span>.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100542"},"PeriodicalIF":10.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884290","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}
We present a comprehensive study of the optical and dynamical properties of a rotating black hole immersed in a Dehnen-type (1,4,0) galactic dark matter halo, modelled by a double power-law density profile commonly used to describe realistic galactic cores. By extending our previous Schwarzschild-Dehnen solution using a modified Newman-Janis algorithm, we construct a Kerr-like axisymmetric spacetime that smoothly incorporates both black hole rotation and the influence of the surrounding dark matter halo. We systematically investigate the effects of the halo parameters-the central density and halo radius-on horizon structure, the shape and extent of the ergoregion, and the null geodesics associated with black hole shadows. Our results show that the presence of a dense or extended halo expands the event horizon and ergoregion, and significantly alters the size and distortion of the black hole shadow. Furthermore, by applying the WKB approximation to scalar field perturbations, we compute the quasinormal mode (QNM) spectra and demonstrate that the frequencies and damping times of ringdown signals are highly sensitive to the halo profile. These results open promising avenues for probing the dark matter environment of astrophysical black holes through black hole imaging and gravitational wave observations.
{"title":"Investigating optical and ring-down gravitational wave properties of a rotating black hole in a Dehnen galactic dark matter halo","authors":"Mrinnoy M. Gohain , Dhruba Jyoti Gogoi , Kalyan Bhuyan , Prabwal Phukon","doi":"10.1016/j.jheap.2025.100539","DOIUrl":"10.1016/j.jheap.2025.100539","url":null,"abstract":"<div><div>We present a comprehensive study of the optical and dynamical properties of a rotating black hole immersed in a Dehnen-type (1,4,0) galactic dark matter halo, modelled by a double power-law density profile commonly used to describe realistic galactic cores. By extending our previous Schwarzschild-Dehnen solution using a modified Newman-Janis algorithm, we construct a Kerr-like axisymmetric spacetime that smoothly incorporates both black hole rotation and the influence of the surrounding dark matter halo. We systematically investigate the effects of the halo parameters-the central density and halo radius-on horizon structure, the shape and extent of the ergoregion, and the null geodesics associated with black hole shadows. Our results show that the presence of a dense or extended halo expands the event horizon and ergoregion, and significantly alters the size and distortion of the black hole shadow. Furthermore, by applying the WKB approximation to scalar field perturbations, we compute the quasinormal mode (QNM) spectra and demonstrate that the frequencies and damping times of ringdown signals are highly sensitive to the halo profile. These results open promising avenues for probing the dark matter environment of astrophysical black holes through black hole imaging and gravitational wave observations.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100539"},"PeriodicalIF":10.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884292","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}
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