Journal of High Energy Astrophysics最新文献

{"title":"Search for γ-ray emission from dwarf spheroidal galaxies with Fermi-LAT data","authors":"Shang Li","doi":"10.1016/j.jheap.2025.100536","DOIUrl":"10.1016/j.jheap.2025.100536","url":null,"abstract":"<div><div>This study uses approximately 17 years of <em>Fermi</em>-LAT data to search for <em>γ</em>-ray emission from 45 Milky Way dwarf spheroidal galaxies (dSphs, including candidates). No significant ( &gt; 5<em>σ</em>) <em>γ</em>-ray signal is found in the scenarios of dark matter annihilations. Very weak <em>γ</em>-ray excesses ( &gt;  2 <em>σ</em>) are found in some dSphs. The most significant signal for dark matter annihilation is observed toward Willman 1, the peak TS value is  ∼  9.6 at a dark matter mass  ∼  60 GeV for the annihilation channel <span><math><mrow><mi>χ</mi><mi>χ</mi><mo>→</mo><msup><mi>τ</mi><mo>+</mo></msup><msup><mi>τ</mi><mo>−</mo></msup></mrow></math></span>. Due to the low significance of the signal, its true origin cannot be determined at the moment. The observed <em>γ</em>-ray excess in the vicinity of Reticulum II shows variation, indicating that the signal is unlikely to be attributable to dark matter annihilation. Furthermore, the <em>γ</em>-ray excesses in Eridanus II and Reticulum III are significantly offset from their centers, possibly due to contamination from astrophysical sources. Three other targets (Boötes II, Ursa Minor and Crater II) show local significance between 2 - 2.5<em>σ</em>, whereas the corresponding cross-sections are inconsistent with the stringent limits from the stacked analysis of dSphs, ruling out a dark matter annihilation origin.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100536"},"PeriodicalIF":10.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976521","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}

{"title":"Exploring the spectral characteristics of the periodic burster 4U 1323-62: Type-I X-ray burst and persistent emission","authors":"Mahasweta Bhattacharya ,&nbsp;Aditya S. Mondal ,&nbsp;Biplab Raychaudhuri ,&nbsp;Gulab C. Dewangan","doi":"10.1016/j.jheap.2025.100545","DOIUrl":"10.1016/j.jheap.2025.100545","url":null,"abstract":"<div><div>We report on the results obtained by the analysis of persistent and type-I thermonuclear X-ray burst emission observed from the periodic burster 4U 1323-62. These analyses are based on the <em>NuSTAR</em> observation performed on 2024 August 7, for a total exposure of around 90 ks. The persistent emission is well described by an absorbed thermal Comptonization model. An absorption edge is also detected at an energy of  ∼  7.42 keV, which indicates the presence of absorbing material in the vicinity of this system. Six bursts have been observed during this observation, wherein we find the burst recurrence time to be 4.52 ± 0.32 hr. All the bursts exhibit the characteristics of a sharp rise and exponential decay. We perform the time-resolved spectroscopy of the burst spectra described by a model consisting of thermal emission from the neutron star surface and a varying persistent emission component to study the evolution of burst parameters. The enhancement of the persistent emission during burst exposure is characterized by the scaling parameter <em>f</em>_a, which reflects the increasing strength of the burst-disc interaction with burst intensity, likely driven by Poynting-Robertson drag. The spectral analysis of bursts estimate the average apparent blackbody emitting radius of the neutron star to lie within 1.5-3.5 km. The ignition depths computed from the burst parameters indicate short Type-I thermonuclear bursts from a mixed hydrogen-helium fuel layer.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100545"},"PeriodicalIF":10.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938335","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}

{"title":"The red-shift and spectral lines of the Kerr black hole ringed accretion disks","authors":"D. Pugliese ,&nbsp;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}

{"title":"Multi-model framework for reconstructing gamma-Ray burst light curves","authors":"A. Kaushal ,&nbsp;A. Manchanda ,&nbsp;M.G. Dainotti ,&nbsp;K. Gupta ,&nbsp;Z. Nogala ,&nbsp;A. Madhan ,&nbsp;S. Naqi ,&nbsp;Ritik Kumar ,&nbsp;V. Oad ,&nbsp;N. Indoriya ,&nbsp;Krishnanjan Sil ,&nbsp;D.H. Hartmann ,&nbsp;M. Bogdan ,&nbsp;A. Pollo ,&nbsp;J.X. Prochaska ,&nbsp;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_a</em>) and its luminosity (<em>L_a</em>), derived from the fluxes (<em>F_a</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_a</em>, 43.2 % for log <em>F_a</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}

{"title":"Magnetized relativistic jet-induced cocoon as a cradle of star formation","authors":"Ribhu Pal ,&nbsp;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_ϕ, σ_z</em>). Enhanced toroidal magnetization (<em>σ_ϕ</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_ϕ</em>, indicating reduced large-scale density contrast despite intense local overdensities. Moderate toroidal magnetization (<em>σ_ϕ</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}

{"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":"&lt;div&gt;&lt;div&gt;We explore the idea that quantum vacuum energy &lt;em&gt;ρ&lt;/em&gt;&lt;sub&gt;vac&lt;/sub&gt;, 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 &lt;em&gt;ρ&lt;/em&gt;&lt;sub&gt;vac&lt;/sub&gt; by showing how Einstein’s field equations emerge in the form of Friedmann’s equations. This leads to the idea that Newton’s constant &lt;em&gt;G&lt;sub&gt;N&lt;/sub&gt;&lt;/em&gt; is environmental, namely it depends on the total mass-energy of the universe &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mstyle&gt;&lt;mi&gt;∞&lt;/mi&gt;&lt;/mstyle&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; and its size &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;/mrow&gt;&lt;mstyle&gt;&lt;mi&gt;∞&lt;/mi&gt;&lt;/mstyle&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, with &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;G&lt;/mi&gt;&lt;mi&gt;N&lt;/mi&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;msup&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msup&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;/mrow&gt;&lt;mstyle&gt;&lt;mi&gt;∞&lt;/mi&gt;&lt;/mstyle&gt;&lt;/msub&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mstyle&gt;&lt;mi&gt;∞&lt;/mi&gt;&lt;/mstyle&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. 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 &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;λ&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mi&gt;π&lt;/mi&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;/mrow&gt;&lt;mstyle&gt;&lt;mi&gt;∞&lt;/mi&gt;&lt;/mstyle&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. We assume a recently proposed and well-motivated formula for &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;ρ&lt;/mi&gt;&lt;mrow&gt;&lt;mrow&gt;&lt;mi&gt;v&lt;/mi&gt;&lt;/mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;∝&lt;/mo&gt;&lt;msubsup&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;mrow&gt;&lt;mrow&gt;&lt;mi&gt;z&lt;/mi&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;mn&gt;4&lt;/mn&gt;&lt;/msubsup&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, where &lt;em&gt;m&lt;/em&gt;&lt;sub&gt;z&lt;/sub&gt; is the mass of the lightest particle, and &lt;span&gt;&lt;math&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; is a marginally irrelevant coupling. This leads to an effective, induced RG flow for Newton’s constant &lt;em&gt;G&lt;sub&gt;N&lt;/sub&gt;&lt;/em&gt; as a function of an energy scale, which indicates that &lt;em&gt;G&lt;sub&gt;N&lt;/sub&gt; decreases&lt;/em&gt; at higher energies until it reaches a Landau pole at a minimal value of the cosmological scale factor &lt;em&gt;a&lt;/em&gt;(&lt;em&gt;t&lt;/em&gt;) &gt; &lt;em&gt;a&lt;/em&gt;&lt;sub&gt;min&lt;/sub&gt;, thus avoiding the usual geometric curvature singularity at &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. The solution to the scale factor satisfies an interesting symmetry between the far past and far future due to &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;msub&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;mrow&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, where &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;mrow&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mrow&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. We propose that this energy scale dependent &lt;em&gt;G&lt;sub&gt;N&lt;/sub&gt;&lt;/em&gt; 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}

{"title":"wdm−wde cosmological model with new data samples of cosmological observations","authors":"Dorian Araya ,&nbsp;Cristian Castillo ,&nbsp;Genly Leon ,&nbsp;Juan Magaña ,&nbsp;Angie Barr Domínguez ,&nbsp;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_dm</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> &gt; 0, while contraction is linked to <em>H</em> &lt; 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_dm</em> and <em>w_de</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}

{"title":"Cosmological constraints on the phenomenological interacting dark energy model with Fermi gamma-ray bursts and DESI DR2","authors":"Ziyan Zhu ,&nbsp;Qingquan Jiang ,&nbsp;Yu Liu ,&nbsp;Puxun Wu ,&nbsp;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}

{"title":"The 2024 outburst of the neutron star LMXB EXO 0748–676: An investigation of bursts and eclipses with astrosat","authors":"Aromal P ,&nbsp;Unnati Kashyap ,&nbsp;Manoneeta Chakraborty ,&nbsp;Sudip Bhattacharyya ,&nbsp;Thomas J. Maccarone ,&nbsp;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}

{"title":"Possible quasi-periodic optical oscillations of ZTF blazars","authors":"Na Wang ,&nbsp;Guowei Ren ,&nbsp;Shun Zhang ,&nbsp;Tingfeng Yi ,&nbsp;Tong Liu ,&nbsp;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}