Journal of High Energy Astrophysics最新文献

{"title":"Black holes immersed in polytropic scalar field gas","authors":"Y. Sekhmani ,&nbsp;S. Zare ,&nbsp;L.M. Nieto ,&nbsp;H. Hassanabadi ,&nbsp;K. Boshkayev","doi":"10.1016/j.jheap.2025.100389","DOIUrl":"10.1016/j.jheap.2025.100389","url":null,"abstract":"<div><div>By implementing the concept of polytropic structures as a scalar field gas with a dark energy-like behavior, we obtain a static spherically symmetric black hole solution in the framework of general relativity. In this paper, we study the quasinormal modes, the greybody bound process, the shadow behaviors, and the sparsity of black holes with a surrounding polytropic scalar field gas. Using the Wentzel-Kramers-Brillouin (WKB) approach, we evaluate the impact of a particular set of polytropic parameters <span><math><mo>(</mo><mi>ξ</mi><mo>,</mo><mi>A</mi><mo>)</mo></math></span> with a fixed setting of the polytropic index <em>n</em> on the oscillation frequency and damping rate of gravitational waves. The results show that the effect of the parameter <em>ξ</em> is much less significant than that of the parameter <em>A</em> on the gravitational waves oscillation frequency and damping rate. Furthermore, the analysis of the greybody factor bounds reveals special insight into the effect of certain parameters where the multipole moments <em>l</em> and the polytropic index <em>n</em> have similar effects, in contrast to the pair of polytropic parameters (<span><math><mi>ξ</mi><mo>,</mo><mi>A</mi></math></span>). In light of such a comparative study, we investigate, on the other hand, the third-order Padé WKB method, which results in a more accurate process for quasinormal mode frequencies compared to the third-order standard WKB method. In this way, exploring the sparsity of Hawking radiation is another task that provides a better understanding of the behavior of the black hole solution. In this respect, the results show that the black hole behaves like blackbody radiation for a sufficiently large entropy. And for <span><math><mi>ξ</mi><mo>=</mo><mi>A</mi><mo>=</mo><mn>0</mn></math></span>, the relevant sparsity acts exactly like the Schwarzschild sparsity. These results provide an insight into the dynamics of black holes with a surrounding polytropic scalar field gas from the analysis of their quasinormal modes, greybody factors, shadow behaviors, energy emission rate and sparsity process. Constraints on the associated BH parameters, derived from the Event Horizon Telescope observations of M87* and Sgr A*, indicate that this black hole model stands as a compelling candidate for representing astrophysical black holes.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"47 ","pages":"Article 100389"},"PeriodicalIF":10.2,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865168","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":"Probing thermonuclear bursts and X-ray reflection features in Aql X-1 during 2024 outburst","authors":"Manoj Mandal ,&nbsp;Sabyasachi Pal ,&nbsp;G.K. Jaisawal ,&nbsp;Anne Lohfink ,&nbsp;Sachindra Naik ,&nbsp;Jaiverdhan Chauhan","doi":"10.1016/j.jheap.2025.100387","DOIUrl":"10.1016/j.jheap.2025.100387","url":null,"abstract":"<div><div>We report the broadband timing and spectral properties of the neutron star low-mass X-ray binary Aql X-1 during the 2024 outburst with <em>NICER</em>, <em>NuSTAR</em>, and <em>Swift</em> observatories. We detected six thermonuclear X-ray bursts during the <em>NICER</em> and <em>NuSTAR</em> observations, with the observed X-ray burst profiles exhibiting a strong energy dependence. The time-resolved burst spectra indicate the presence of soft excess during the burst, which can be modeled by using a variable persistent emission method (<span><math><msub><mrow><mi>f</mi></mrow><mrow><mi>a</mi></mrow></msub></math></span> method) or the <span>relxillNS</span> reflection model. We found that the reflection model can contribute ∼20% of total emission as observed during the <em>NICER</em> burst. The reflection and blackbody component fluxes are strongly correlated, as observed during a burst. The excess emission is possible due to the enhanced mass accretion rate to the neutron star due to the Poynting-Rodertson drag, and a fraction of burst emission may be reflected from the disk. The bursts did not show photospheric radius expansion during the peak. Moreover, we examined the burst-free accretion emission in the broadband range with <em>NuSTAR</em>, <em>NICER</em>, and <em>Swift</em> at two epochs of the outburst. The persistent emission showed X-ray reflection features, which can be well modeled with the relativistic reflection model <span>relxillCp</span>. The inner disk radius (R<span><math><msub><mrow></mrow><mrow><mi>i</mi><mi>n</mi></mrow></msub></math></span>) is found to be nearly 22 and 10 times <span><math><msub><mrow><mi>R</mi></mrow><mrow><mi>g</mi></mrow></msub></math></span> for two observations, respectively. Assuming that the inner disk is truncated at the magnetospheric radius, the magnetic field strength at the poles of the neutron star is estimated to be <span><math><mo>(</mo><mn>0.6</mn><mo>−</mo><mn>1.9</mn><mo>)</mo><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mn>9</mn></mrow></msup></math></span> G.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"47 ","pages":"Article 100387"},"PeriodicalIF":10.2,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865166","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":"Constraining the initial Lorentz factor of gamma-ray bursts under different circumburst mediums","authors":"Sheng-Jin Sun ,&nbsp;Shuang-Xi Yi ,&nbsp;Yuan-Chuan Zou ,&nbsp;Yu-Peng Yang ,&nbsp;Ying Qin ,&nbsp;Qing-Wen Tang ,&nbsp;Fa-Yin Wang","doi":"10.1016/j.jheap.2025.100390","DOIUrl":"10.1016/j.jheap.2025.100390","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The initial Lorentz factor (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;Γ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;0&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;) plays a crucial role in uncovering the physical characteristics of gamma-ray bursts (GRBs). Previous studies have indicated that the ambient medium density index &lt;em&gt;k&lt;/em&gt; for GRBs falls in the range of 0 - 2, rather than exactly equal to 0 (homogeneous interstellar ambient) or 2 (typical stellar wind). In this work, we aim to constrain the &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;Γ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; of GRBs considering their distinct circumburst medium. We select a total of 33 GRBs for our analysis, comprising 7 X-ray GRBs and 26 optical GRBs. Subsequently, by utilizing the deceleration time of fireball &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, we derive the &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;Γ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; for the 33 GRBs assuming the radiation efficiency of &lt;em&gt;η&lt;/em&gt;= 0.2. The inferred initial Lorentz factor was found to be from 50 to 500, consistent with previous studies. We then investigate the correlation between the &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;Γ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; and the isotropic energy &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;E&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;γ&lt;/mi&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mrow&gt;&lt;mi&gt;iso&lt;/mi&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; (as well as the mean isotropic luminosity &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;L&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;γ&lt;/mi&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mrow&gt;&lt;mi&gt;iso&lt;/mi&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;), finding very tight correlations between them, i.e., &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;Γ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; ∝ &lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;E&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;γ&lt;/mi&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mrow&gt;&lt;mi&gt;iso&lt;/mi&gt;&lt;/mrow&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mn&gt;52&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;0.24&lt;/mn&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt; (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;Γ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; ∝ &lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;L&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;γ&lt;/mi&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mrow&gt;&lt;mi&gt;iso&lt;/mi&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;49&lt;/mn&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;0.20&lt;/mn&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt;) with &lt;em&gt;η&lt;/em&gt;=0.2. Additionally, we verify the correlation among &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;Γ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, the isotropic energy &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;E&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;γ&lt;/mi&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mrow&gt;&lt;mi&gt;iso&lt;/mi&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; (or &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;L&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;γ&lt;/mi&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mrow&gt;&lt;mi&gt;iso&lt;/mi&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;) and the peak energy &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;E&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mi&gt;z&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, i.e., &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;E&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;γ&lt;/mi&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mrow&gt;&lt;mi&gt;iso&lt;/mi&gt;&lt;/mrow&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mn&gt;52&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; ∝ &lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;Γ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;1.36&lt;/mn&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;E&lt;","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"47 ","pages":"Article 100390"},"PeriodicalIF":10.2,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865167","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":"Diagnostics of dark energy evolution using logarithmic Om(z) parameterization","authors":"Y. Myrzakulov ,&nbsp;Alnadhief H.A. Alfedeel ,&nbsp;M. Koussour ,&nbsp;E.I. Hassan ,&nbsp;S. Muminov","doi":"10.1016/j.jheap.2025.100386","DOIUrl":"10.1016/j.jheap.2025.100386","url":null,"abstract":"<div><div>In this study, we explore the logarithmic <span><math><mi>O</mi><mi>m</mi><mo>(</mo><mi>z</mi><mo>)</mo></math></span> parameterization as a tool for diagnosing the nature and evolution of dark energy. We propose the form <span><math><mi>O</mi><mi>m</mi><mo>(</mo><mi>z</mi><mo>)</mo><mo>=</mo><mi>α</mi><mi>ln</mi><mo>⁡</mo><mo>(</mo><mn>1</mn><mo>+</mo><mi>z</mi><mo>)</mo><mo>+</mo><mi>β</mi></math></span>, where <em>α</em> and <em>β</em> are free parameters, and analyze its behavior for different values of <em>α</em>. When <span><math><mi>α</mi><mo>=</mo><mn>0</mn></math></span>, the model reduces to a constant, consistent with the cosmological constant, while <span><math><mi>α</mi><mo>≠</mo><mn>0</mn></math></span> indicates dynamical dark energy, with <span><math><mi>α</mi><mo>&gt;</mo><mn>0</mn></math></span> suggesting phantom-like behavior and <span><math><mi>α</mi><mo>&lt;</mo><mn>0</mn></math></span> indicating quintessence-like dynamics. By constraining the model parameters using observational datasets such as OHD, the Pantheon+ sample, and the combined dataset (OHD+SNe+BAO), we obtain tight constraints on the cosmic evolution. Our results suggest a mild deviation from the standard ΛCDM model, with a slight preference for phantom-like behavior at low redshifts. The deceleration parameter and equation of state parameter were analyzed to understand the cosmic transition from deceleration to acceleration, with a transition redshift around <span><math><msub><mrow><mi>z</mi></mrow><mrow><mi>t</mi><mi>r</mi></mrow></msub><mo>≈</mo><mn>0.6</mn><mo>−</mo><mn>0.8</mn></math></span>. The present-day deceleration parameter was found to range from <span><math><msub><mrow><mi>q</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>=</mo><mo>−</mo><mn>0.55</mn></math></span> to <span><math><msub><mrow><mi>q</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>=</mo><mo>−</mo><mn>0.60</mn></math></span>, and the EoS parameter values varied between <span><math><msub><mrow><mi>ω</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>=</mo><mo>−</mo><mn>0.70</mn></math></span> and <span><math><msub><mrow><mi>ω</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>=</mo><mo>−</mo><mn>0.73</mn></math></span>. The inferred Hubble constant values exhibit dataset-dependent variations, highlighting the persistent Hubble tension. Our analysis suggests that the logarithmic <span><math><mi>O</mi><mi>m</mi><mo>(</mo><mi>z</mi><mo>)</mo></math></span> parameterization offers a flexible framework for studying cosmic acceleration.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"47 ","pages":"Article 100386"},"PeriodicalIF":10.2,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859606","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":"Shadows and strong gravitational lensing around black hole-like compact object in quadratic gravity","authors":"Somi Aktar ,&nbsp;Niyaz Uddin Molla ,&nbsp;Farook Rahaman ,&nbsp;G. Mustafa","doi":"10.1016/j.jheap.2025.100385","DOIUrl":"10.1016/j.jheap.2025.100385","url":null,"abstract":"<div><div>We investigate the astrophysical consequences of black holes in quadratic gravity, characterized by the parameters <span><math><msub><mrow><mi>S</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>, <span><math><msub><mrow><mi>S</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>, <span><math><msub><mrow><mi>m</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>m</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>, in addition to the black hole mass <em>M</em>. To evaluate the physical validity of the fundamental quadratic gravity black hole solutions, we analyze their gravitational lensing properties in the strong deflection limit. Specifically, we examine the shadow cast by the quadratic gravity black hole and constrain its parameters using observational data from the <span><math><mi>M</mi><msup><mrow><mn>87</mn></mrow><mrow><mo>⁎</mo></mrow></msup></math></span> and <span><math><mi>S</mi><mi>g</mi><mi>r</mi><msup><mrow><mi>A</mi></mrow><mrow><mo>⁎</mo></mrow></msup></math></span> supermassive black holes. Our analysis reveals that, within the 1<em>σ</em> confidence level, a significant portion of the parameter space for quadratic gravity black holes is consistent with the Event Horizon Telescope (EHT) observations of <span><math><mi>M</mi><msup><mrow><mn>87</mn></mrow><mrow><mo>⁎</mo></mrow></msup></math></span> and <span><math><mi>S</mi><mi>g</mi><mi>r</mi><msup><mrow><mi>A</mi></mrow><mrow><mo>⁎</mo></mrow></msup></math></span>. This suggests that these black holes are plausible candidates for describing astrophysical black holes. As an additional observational test, we perform a detailed investigation of the strong deflection limit properties of these black holes. We explore the fundamental lensing observables in detail, including the angular positions and separations of the lensed images, the relative magnifications, the radius of the outermost Einstein ring, and the relativistic time delay between images. We compare the predictions of the quadratic gravity black hole for each observable with those of the classical Schwarzschild solution using realistic astrophysical data. Our findings provide a pathway for testing quadratic gravity at the galactic and extragalactic scales, offering new insights into the observational properties of black hole solutions within this framework.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"47 ","pages":"Article 100385"},"PeriodicalIF":10.2,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143843745","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 multiwavelength correlations quest for central engines of GRB plateaus: Magnetar vs black hole spin-down","authors":"Aleksander Ł. Lenart ,&nbsp;Maria G. Dainotti ,&nbsp;Nikita Khatiya ,&nbsp;Dhruv Bal ,&nbsp;Dieter H. Hartmann ,&nbsp;Nissim Fraija ,&nbsp;Bing Zhang","doi":"10.1016/j.jheap.2025.100384","DOIUrl":"10.1016/j.jheap.2025.100384","url":null,"abstract":"<div><div>This manuscript presents a multilevel analysis of gamma-ray bursts (GRBs). We focus on the plateau phase, which is often observed in the light curves (LCs) of GRBs. We discuss its observational properties and then thoroughly examine possible theoretical models to explain them. Inspired by the limitations of many currently known models, we introduce a novel scenario of an LC powered by the kinetic energy of a rotating black hole (BH). We investigate observational correlations between the properties of GRBs across the gamma, X-ray, and optical bands during the prompt and plateau phases of their LCs. Our analysis includes all GRBs with known redshifts detected by the Neil Gehrels <em>Swift</em> Observatory (<em>Swift</em>) and the <em>Fermi</em> Gamma-ray Space Telescope (<em>Fermi</em>), as well as ground-based optical telescopes. We identify a tight correlation with the <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> coefficient of ∼0.89 for the three-dimensional Dainotti relation between the luminosity at the end of the plateau, its duration measured by <em>Swift</em>, and the peak luminosity measured by <em>Fermi</em> in the 10-1000 keV band. When accounting for redshift evolution, we achieve very small intrinsic scatter <span><math><msub><mrow><mi>σ</mi></mrow><mrow><mi>i</mi><mi>n</mi><mi>t</mi></mrow></msub><mo>=</mo><mn>0.25</mn><mo>±</mo><mn>0.04</mn></math></span> (<span><math><mo>∼</mo><mn>43</mn><mtext>%</mtext></math></span> reduction compared to the previous results). Additionally, we explore correlations involving the optical luminosity at the end of the plateau, yielding promising results. We investigate the clustering of different classes of GRBs in the investigated parameter space and discuss its impact on the aforementioned correlations as well as <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>i</mi><mi>s</mi><mi>o</mi></mrow></msub></math></span>-<span><math><msubsup><mrow><mi>E</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow><mrow><mo>⁎</mo></mrow></msubsup></math></span> correlation. Notably, we demonstrate how to use the correlations as a powerful class discriminator. Finally, we discuss the theory supporting the evidence of the plateau emission. We present a new paradigm for the GRB plateau: energy extraction from a quickly rotating black hole (BH) via spin-down by a magnetically arrested disk (MAD). We compare this model with observations and explain multiple observed features. We predict the plateau luminosity - time anti-correlation and discuss the cosmological evolution within this proposed model. Furthermore, within this new model, we discuss the possible physical origin of the clustering of long and short GRBs in the parameter space of plateau luminosity - time - prompt luminosity.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"47 ","pages":"Article 100384"},"PeriodicalIF":10.2,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829646","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":"Non-linear fermion dynamics, Hawking radiation, and dark energy: Thermodynamic implications for black hole evolution and cosmology","authors":"André Pereira Marques Trindade Miranda","doi":"10.1016/j.jheap.2025.100382","DOIUrl":"10.1016/j.jheap.2025.100382","url":null,"abstract":"<div><div>The dynamics of fermion fields in curved spacetimes have garnered increasing attention in the context of black hole thermodynamics, particularly with respect to the generation of Hawking radiation. The present work explores the thermodynamic consequences of non-linear fermion dynamics, focusing on the role of non-Hermitian terms in the fermion field's Lagrangian. These modifications, which capture the dissipative effects inherent in black hole dynamics, are found to significantly influence the effective potential governing fermion propagation near the event horizon. The implications for the Hawking radiation spectrum, black hole evaporation, and the corresponding changes in the thermodynamic properties of the black hole are discussed. The inclusion of non-Hermitian terms is shown to accelerate the evaporation rate and modify the Hawking temperature, which has profound consequences for the black hole's long-term behavior and the stability of the quantum field.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"47 ","pages":"Article 100382"},"PeriodicalIF":10.2,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143815964","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":"Dynamics of an interacting matter − f(R) model with expansion histories approximating ΛCDM","authors":"Jianwen Liu,&nbsp;Fabao Gao,&nbsp;Ruifang Wang,&nbsp;Aqeela Razzaq","doi":"10.1016/j.jheap.2025.100383","DOIUrl":"10.1016/j.jheap.2025.100383","url":null,"abstract":"<div><div>The paper examines the cosmological dynamics of a <span><math><mi>f</mi><mo>(</mo><mi>R</mi><mo>)</mo></math></span> model that integrates interactions between matter and an effective fluid. It employs a dynamical system approach with three cosmographic parameters. The equilibrium state's physical characteristics and linear stability within the cosmological dynamical system, derived from the field equations, are examined, taking into account an interacting term <span><math><mi>Q</mi><mo>=</mo><mn>3</mn><mi>α</mi><mi>H</mi><mi>ρ</mi></math></span> and the specific relationships among cosmological parameters as per ΛCDM cosmology. It is found that the solutions of the model, while imposing a global ΛCDM alike evolution, exhibit significant sensitivity to initial conditions when evaluating cosmological parameters, primarily due to the phase-space constraints imposed by the viability conditions for <span><math><mi>f</mi><mo>(</mo><mi>R</mi><mo>)</mo></math></span> models. The presence of the interacting term alters most equilibrium points in the system and contributes to the cosmological evolution, imposing constraints on the parameter <em>α</em> of interaction strength. Additionally, by using Poincaré compactification, we conduct a global dynamics analysis for the spatially flat scenario, revealing all possible evolutions of the flat universe in the form of a Poincaré disk and a comprehensive dynamic flow chart. Several equilibrium points and the cosmological evolution within this model exhibit slight deviations from the non-interacting case, yet it successfully captures the universe's acceleration phase.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"47 ","pages":"Article 100383"},"PeriodicalIF":10.2,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143833813","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":"Low frequency radio observation of the dark PeVatron 1LHAASO J2108+5153u using uGMRT","authors":"Gunindra Krishna Mahanta ,&nbsp;Subhashis Roy ,&nbsp;Sagar Godambe ,&nbsp;Bitan Ghosal ,&nbsp;Nilay Bhatt ,&nbsp;Subir Bhattacharyya","doi":"10.1016/j.jheap.2025.100381","DOIUrl":"10.1016/j.jheap.2025.100381","url":null,"abstract":"<div><div>1LHAASO J2108+5153u, a PeVatron candidate detected by Large High Altitude Air Shower Observatory (LHAASO), has no known association in any other wavelength range. In this work we attempted to identify any possible association by observing the source region in low frequency radio band. 1LHAASO J2108+5153u was observed by upgraded Giant Metrewave Radio Telescope (uGMRT) at 650 MHz frequency. The data were analysed to map and spatially correlate the sources in the field of view with the LHAASO detected source. We identified a new extended source within the LHAASO PSF showing a distinct jet and core structure in radio band. The exact nature of the source could not be identified with the present observation. It can be a microquasar and the particles can be accelerated to PeV energies in the microquasar jet.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"47 ","pages":"Article 100381"},"PeriodicalIF":10.2,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143785910","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":"Neutron star analysis under f(R,G,Lm) gravity model","authors":"H. Aman,&nbsp;Z. Yousaf","doi":"10.1016/j.jheap.2025.100380","DOIUrl":"10.1016/j.jheap.2025.100380","url":null,"abstract":"<div><div>The modified Tolman-Oppenheimer-Volkoff (TOV) equations for compact stars in the setting of <span><math><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><mi>G</mi><mo>,</mo><msub><mrow><mi>L</mi></mrow><mrow><mi>m</mi></mrow></msub><mo>)</mo></math></span> gravity are derived and numerically solved in this paper, specifically using the functional formulation <span><math><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><mi>G</mi><mo>,</mo><msub><mrow><mi>L</mi></mrow><mrow><mi>m</mi></mrow></msub><mo>)</mo><mo>=</mo><mi>R</mi><mo>+</mo><mi>α</mi><mi>G</mi><msub><mrow><mi>L</mi></mrow><mrow><mi>m</mi></mrow></msub></math></span>. Both quark and hadronic matter, which are characterized by physically accurate equations of state, are taken into consideration while analysing different values of the free parameter <em>α</em>. The influence of <em>α</em> on the properties of these specific stars is examined. The concluding remarks encapsulate the principal discoveries, highlighting their significance and alignment with observational data derived from the neutron star in <span><math><mi>N</mi><mi>G</mi><mi>C</mi><mspace></mspace><mn>6397</mn></math></span>. To account for two different possibilities of the matter Lagrangian density, the study modifies the stellar structure equations by considering <span><math><msub><mrow><mi>L</mi></mrow><mrow><mi>m</mi></mrow></msub><mo>=</mo><mi>p</mi></math></span> (where <em>p</em> denotes the pressure) and <span><math><msub><mrow><mi>L</mi></mrow><mrow><mi>m</mi></mrow></msub><mo>=</mo><mo>−</mo><mi>ρ</mi></math></span> (where <em>ρ</em> represents the density), allowing for accurate and reliable numerical simulations and further analysis. As expected, when <span><math><mi>α</mi><mo>→</mo><mn>0</mn></math></span>, the traditional TOV equations of Einstein's gravity are recovered. The results indicate that the two distinct options, as, <span><math><msub><mrow><mi>L</mi></mrow><mrow><mi>m</mi></mrow></msub><mo>=</mo><mi>p</mi></math></span> and <span><math><msub><mrow><mi>L</mi></mrow><mrow><mi>m</mi></mrow></msub><mo>=</mo><mo>−</mo><mi>ρ</mi></math></span>, lead to markedly different outcomes on the mass-radius diagrams. In summary, this research advances our comprehension of the way <span><math><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><mi>G</mi><mo>,</mo><msub><mrow><mi>L</mi></mrow><mrow><mi>m</mi></mrow></msub><mo>)</mo></math></span> gravity affects neutron star interior structures. By providing insightful observations, it lays the groundwork for future studies and investigations in this field.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"47 ","pages":"Article 100380"},"PeriodicalIF":10.2,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792399","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}