Pub 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":"2025-12-27","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 : 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":"2025-12-26","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}
Pub Date : 2025-12-25DOI: 10.1016/j.jheap.2025.100541
Saad Eddine Baddis, Adil Belhaj, Hajar Belmahi, Maryem Jemri
With the help of CUDA high-performance numerical codes exploited in machine learning, we investigate the shadow aspect of new rotating and charged black holes using the Dunkl derivative formalism. Precisely, we first establish the corresponding metric function encoding the involved physical properties including the optical character. Exploiting such accelerated simulations, we approach the horizon radius behaviors in order to determine the regions of the moduli space providing physical solutions. Applying the Hamilton-Jacobi mechanism, we assess the shadow aspect for non-rotating and rotating solutions. Using such an aspect, we evaluate the energy rate of emission. Developing a high-performance CUDA numerical code, we derive strict constraints on the Dunkl deformation parameters in order to establish a link with the shadow observations provided by the Event Horizon Telescope collaboration.
{"title":"Constraining black hole shadows in dunkl spacetime using CUDA numerical computations","authors":"Saad Eddine Baddis, Adil Belhaj, Hajar Belmahi, Maryem Jemri","doi":"10.1016/j.jheap.2025.100541","DOIUrl":"10.1016/j.jheap.2025.100541","url":null,"abstract":"<div><div>With the help of CUDA high-performance numerical codes exploited in machine learning, we investigate the shadow aspect of new rotating and charged black holes using the Dunkl derivative formalism. Precisely, we first establish the corresponding metric function encoding the involved physical properties including the optical character. Exploiting such accelerated simulations, we approach the horizon radius behaviors in order to determine the regions of the moduli space providing physical solutions. Applying the Hamilton-Jacobi mechanism, we assess the shadow aspect for non-rotating and rotating solutions. Using such an aspect, we evaluate the energy rate of emission. Developing a high-performance CUDA numerical code, we derive strict constraints on the Dunkl deformation parameters in order to establish a link with the shadow observations provided by the Event Horizon Telescope collaboration.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100541"},"PeriodicalIF":10.5,"publicationDate":"2025-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884289","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 : 2025-12-24DOI: 10.1016/j.jheap.2025.100540
Xiao-Xiong Zeng , Chen-Yu Yang , Muhammad Israr Aslam , Rabia Saleem
In this study, we have considered the Kerr-like black hole (BH) model in Horndeski gravity and analyse the visual characteristics of shadow images under two illumination models, such as a celestial light source and a thin accretion disk. To capture the BH shadow images, we utilize a recent fisheye camera model and ray-tracing procedures. In this view, we carefully addressed the influence of the spin parameter a and the hair parameter h on the BH shadow images. The results indicate that for smaller values of h, the BH shadow contours shift noticeably towards the right side of the screen, while for larger values of h, the nearly circular shadow gradually deforms into a possible flatness profile. For a celestial light source, the larger values of h lead to a reduction in the corresponding radius of the photon ring, while the space-dragging effect becomes more pronounced with increasing a. We further discuss the distinctive characteristics of images observed in both prograde and retrograde accretion disk scenarios. The results reveal that variations in h significantly affect both the inner shadow and the resulting Einstein ring. Subsequently, we also discussed the distinct features of red-shift configurations on the disk for both direct and lensed images, which are closely related to the accretion flow and the relevant parameters. We also attempt to use the recent observational data from M87* and Sgr A* and constraint the hair parameter h, the results are consistent and promising.
{"title":"Probing Horndeski gravity via Kerr black hole: Insights from thin accretion disks and shadows with EHT observations","authors":"Xiao-Xiong Zeng , Chen-Yu Yang , Muhammad Israr Aslam , Rabia Saleem","doi":"10.1016/j.jheap.2025.100540","DOIUrl":"10.1016/j.jheap.2025.100540","url":null,"abstract":"<div><div>In this study, we have considered the Kerr-like black hole (BH) model in Horndeski gravity and analyse the visual characteristics of shadow images under two illumination models, such as a celestial light source and a thin accretion disk. To capture the BH shadow images, we utilize a recent fisheye camera model and ray-tracing procedures. In this view, we carefully addressed the influence of the spin parameter <em>a</em> and the hair parameter <em>h</em> on the BH shadow images. The results indicate that for smaller values of <em>h</em>, the BH shadow contours shift noticeably towards the right side of the screen, while for larger values of <em>h</em>, the nearly circular shadow gradually deforms into a possible flatness profile. For a celestial light source, the larger values of <em>h</em> lead to a reduction in the corresponding radius of the photon ring, while the space-dragging effect becomes more pronounced with increasing <em>a</em>. We further discuss the distinctive characteristics of images observed in both prograde and retrograde accretion disk scenarios. The results reveal that variations in <em>h</em> significantly affect both the inner shadow and the resulting Einstein ring. Subsequently, we also discussed the distinct features of red-shift configurations on the disk for both direct and lensed images, which are closely related to the accretion flow and the relevant parameters. We also attempt to use the recent observational data from M87* and Sgr <em>A</em>* and constraint the hair parameter <em>h</em>, the results are consistent and promising.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100540"},"PeriodicalIF":10.5,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884291","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 : 2025-12-23DOI: 10.1016/j.jheap.2025.100537
Guoying Zhao , Weikang Zheng , Rong-Feng Shen , Qingcang Shui , Dongyue Li , Chang Zhou , Tianci Zheng , Weimin Yuan , HeYang Liu , Junfeng Wang , Alexei V. Filippenko , Thomas G. Brink , Chong Ge , Jordan Forman , Mayra Gutierrez , Isabelle Jones , Ravjit Kaur , Naunet Leonhardes-Barboza , Petra Mengistu , Avi Patel , Michele N. Woodland
Stellar flares are an intense stellar activity that can significantly impact the atmospheric composition of the surrounding planets and even the possible existence of life. During such events, the radiative energy of the star is primarily concentrated in the optical and X-ray bands, with the X-ray flux potentially increasing by tens or even hundreds of times. Einstein Probe (EP) detected a new X-ray transient EP J2322.1–0301 on 27 September 2024. Its spatial localization shows a high positional coincidence with the nearby high proper motion K-type star PM J23221–0301. Follow-up X-ray observations confirmed the flux enhancement of the source, while optical spectroscopic monitoring revealed time-variable features, particularly the disappearance of the Hα emission line. This X-ray flare is consistent with a characteristic fast-rise-exponential-decay (FRED) light curve, with a rise timescale of 1.4 ks, a decay timescale of 5.7 ks, and a total duration of ∼ 7.1 ks. The peak luminosity in the 0.5–4.0 keV energy band reached ∼ 1.3 × 1031 erg s, with a total energy release of ∼ 9.1 × 1034 erg, consistent with the empirical energy correlations observed in magnetic-reconnection-driven stellar flares, as inferred from the multitemperature plasma structure and Hα-X-ray energy correlation. This discovery underscores EP’s capability in understanding stellar magnetic activity via observing stellar transients.
{"title":"Einstein Probe discovery of an X-ray flare from K-type star PM J23221-0301","authors":"Guoying Zhao , Weikang Zheng , Rong-Feng Shen , Qingcang Shui , Dongyue Li , Chang Zhou , Tianci Zheng , Weimin Yuan , HeYang Liu , Junfeng Wang , Alexei V. Filippenko , Thomas G. Brink , Chong Ge , Jordan Forman , Mayra Gutierrez , Isabelle Jones , Ravjit Kaur , Naunet Leonhardes-Barboza , Petra Mengistu , Avi Patel , Michele N. Woodland","doi":"10.1016/j.jheap.2025.100537","DOIUrl":"10.1016/j.jheap.2025.100537","url":null,"abstract":"<div><div>Stellar flares are an intense stellar activity that can significantly impact the atmospheric composition of the surrounding planets and even the possible existence of life. During such events, the radiative energy of the star is primarily concentrated in the optical and X-ray bands, with the X-ray flux potentially increasing by tens or even hundreds of times. Einstein Probe (EP) detected a new X-ray transient EP J2322.1–0301 on 27 September 2024. Its spatial localization shows a high positional coincidence with the nearby high proper motion K-type star PM J23221–0301. Follow-up X-ray observations confirmed the flux enhancement of the source, while optical spectroscopic monitoring revealed time-variable features, particularly the disappearance of the H<em>α</em> emission line. This X-ray flare is consistent with a characteristic fast-rise-exponential-decay (FRED) light curve, with a rise timescale of 1.4 ks, a decay timescale of 5.7 ks, and a total duration of ∼ 7.1 ks. The peak luminosity in the 0.5–4.0 keV energy band reached ∼ 1.3 × 10<sup>31</sup> erg s<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span>, with a total energy release of ∼ 9.1 × 10<sup>34</sup> erg, consistent with the empirical energy correlations observed in magnetic-reconnection-driven stellar flares, as inferred from the multitemperature plasma structure and H<em>α</em>-X-ray energy correlation. This discovery underscores EP’s capability in understanding stellar magnetic activity via observing stellar transients.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100537"},"PeriodicalIF":10.5,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938401","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":"2025-12-23","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}
Pub Date : 2025-12-22DOI: 10.1016/j.jheap.2025.100538
Jose A. Carpio, Ali Kheirandish, Bing Zhang
Microquasars, compact binary systems with an accreting stellar-mass black hole or neutron star, are promising candidates for high-energy particle acceleration. Recently, the LHAASO collaboration reported on the detection of > 100 TeV γ-ray emission from five microquasars, suggesting that these sources are efficient particle accelerators. In microquasars, high-energy γ-rays can be produced in large-scale jets or winds. In this work, we explore the X-ray, γ-ray and neutrino emission from SS 433, V4641 Sgr and GRS 1905+105. We consider leptonic and hadronic scenarios to explain the spectra observed by LHAASO and other high-energy γ-ray detectors. We estimate the neutrino flux associated with the hadronic component and investigate the detectability of neutrinos from these sources in current and future neutrino telescopes. We find that among the three sources, V4641 Sgr has the best prospects of observation with a combined next-generation neutrino telescopes.
微类星体是一种紧凑的双星系统，有一个吸积的恒星质量黑洞或中子星，是高能粒子加速的有希望的候选者。最近，LHAASO合作报告了从5个微类星体中探测到 >； 100 TeV γ射线发射，这表明这些源是有效的粒子加速器。在微类星体中，高能γ射线可以在大规模喷流或风中产生。在这项工作中，我们研究了SS 433， V4641 Sgr和GRS 1905+105的x射线，γ射线和中微子发射。我们考虑了轻子和强子场景来解释LHAASO和其他高能γ射线探测器观测到的光谱。我们估计了与强子分量相关的中微子通量，并在当前和未来的中微子望远镜中研究了这些源的中微子的可探测性。我们发现，在三个源中，Sgr V4641具有最好的观测前景。
{"title":"Multimessenger emission from very-high-energy black hole-jet systems in the milky way","authors":"Jose A. Carpio, Ali Kheirandish, Bing Zhang","doi":"10.1016/j.jheap.2025.100538","DOIUrl":"10.1016/j.jheap.2025.100538","url":null,"abstract":"<div><div>Microquasars, compact binary systems with an accreting stellar-mass black hole or neutron star, are promising candidates for high-energy particle acceleration. Recently, the LHAASO collaboration reported on the detection of > 100 TeV <em>γ</em>-ray emission from five microquasars, suggesting that these sources are efficient particle accelerators. In microquasars, high-energy <em>γ</em>-rays can be produced in large-scale jets or winds. In this work, we explore the X-ray, <em>γ</em>-ray and neutrino emission from SS 433, V4641 Sgr and GRS 1905+105. We consider leptonic and hadronic scenarios to explain the spectra observed by LHAASO and other high-energy <em>γ</em>-ray detectors. We estimate the neutrino flux associated with the hadronic component and investigate the detectability of neutrinos from these sources in current and future neutrino telescopes. We find that among the three sources, V4641 Sgr has the best prospects of observation with a combined next-generation neutrino telescopes.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100538"},"PeriodicalIF":10.5,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The AT2017gfo kilonova transient remains a unique multi-messenger event thanks to its proximity () and the possibility to investigate time-resolved spectra, thus providing evidence of r-process nucleosynthesis. The kilonova signal was extensively studied in the spectral and time domains, providing key insights into the chemical composition and physical properties of the ejecta. Here, we report the discovery of a novel correlation between two fundamental observables: the peak energy of the EFE spectrum, Ep, and the isotropic-equivalent luminosity, Liso. In particular, we show that up to about 2.5 days after the merger, the AT2017gfo spectrum evolves according to: while in the subsequent epochs, Ep remains almost constant with Liso, flattening around 1 eV. Exploiting simulations from a state-of-the-art radiative transfer code, we demonstrate that our kilonova model inherently predicts this peculiar correlation, hence suggesting a new diagnostic tool for comparing observables against simulations. Future kilonova observations will provide additional insight into the physics behind the correlation.
{"title":"The Ep−Liso correlation: A new diagnostic tool for kilonova transients","authors":"Ruben Farinelli , Fabrizio Cogato , Mattia Bulla , Paramvir Singh , Giulia Stratta , Andrea Rossi , Eliana Palazzi , Cristiano Guidorzi , Elisabetta Maiorano , Lorenzo Amati , Bing Zhang , Luciano Rezzolla , Filippo Frontera","doi":"10.1016/j.jheap.2025.100532","DOIUrl":"10.1016/j.jheap.2025.100532","url":null,"abstract":"<div><div>The AT2017gfo kilonova transient remains a unique multi-messenger event thanks to its proximity (<span><math><mrow><mi>z</mi><mo>=</mo><mn>0.00987</mn></mrow></math></span>) and the possibility to investigate time-resolved spectra, thus providing evidence of r-process nucleosynthesis. The kilonova signal was extensively studied in the spectral and time domains, providing key insights into the chemical composition and physical properties of the ejecta. Here, we report the discovery of a novel correlation between two fundamental observables: the peak energy of the <em>E</em> <em>F<sub>E</sub></em> spectrum, <em>E</em><sub>p</sub>, and the isotropic-equivalent luminosity, <em>L</em><sub>iso</sub>. In particular, we show that up to about 2.5 days after the merger, the AT2017gfo spectrum evolves according to: <span><math><mrow><msub><mtext>log</mtext><mn>10</mn></msub><mrow><mo>[</mo><msub><mi>E</mi><mrow><mi>p</mi></mrow></msub><mo>/</mo><mtext>eV</mtext><mo>]</mo></mrow><mo>=</mo><mo>−</mo><mn>0</mn><mo>.</mo><msubsup><mn>13</mn><mrow><mo>−</mo><mn>0.02</mn></mrow><mrow><mo>+</mo><mn>0.02</mn></mrow></msubsup><mo>+</mo><mn>0</mn><mo>.</mo><msubsup><mn>62</mn><mrow><mo>−</mo><mn>0.02</mn></mrow><mrow><mo>+</mo><mn>0.02</mn></mrow></msubsup><mspace></mspace><msub><mtext>log</mtext><mn>10</mn></msub><mrow><mo>[</mo><msub><mi>L</mi><mrow><mrow><mi>i</mi></mrow><mi>s</mi><mi>o</mi></mrow></msub><mo>/</mo><mrow><mo>(</mo><msup><mn>10</mn><mn>41</mn></msup><mspace></mspace><mtext>erg</mtext><mspace></mspace><msup><mtext>s</mtext><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>)</mo></mrow><mo>]</mo></mrow><mspace></mspace><mrow><mo>(</mo><mn>68</mn><mspace></mspace><mo>%</mo><mspace></mspace><mrow><mrow><mi>C</mi></mrow><mo>.</mo><mi>L</mi><mo>.</mo></mrow><mo>)</mo></mrow></mrow></math></span> while in the subsequent epochs, <em>E</em><sub>p</sub> remains almost constant with <em>L</em><sub>iso</sub>, flattening around 1 eV. Exploiting simulations from a state-of-the-art radiative transfer code, we demonstrate that our kilonova model inherently predicts this peculiar correlation, hence suggesting a new diagnostic tool for comparing observables against simulations. Future kilonova observations will provide additional insight into the physics behind the <span><math><mrow><msub><mi>E</mi><mrow><mi>p</mi></mrow></msub><mo>−</mo><msub><mi>L</mi><mrow><mrow><mi>i</mi></mrow><mi>s</mi><mi>o</mi></mrow></msub></mrow></math></span> correlation.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100532"},"PeriodicalIF":10.5,"publicationDate":"2025-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884294","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 : 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":"2025-12-20","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 : 2025-12-17DOI: 10.1016/j.jheap.2025.100533
Andronikos Paliathanasis , Genly Leon , Yoelsy Leyva , Giuseppe Gaetano Luciano , Amare Abebe
We study quantum corrections to the ΛCDM model arising from a minimum measurable length in Heisenberg’s uncertainty principle. We focus on a higher-order Generalized Uncertainty Principle, beyond the quadratic form. This generalized GUP introduces two free parameters, and we determine the modified Friedmann equation. This framework leads to a perturbative cosmological model that naturally reduces to ΛCDM in an appropriate limiting case of the deformation parameters. We construct the modified cosmological scenario, analyze its deviations from the standard case, and examine it as a mechanism for the description of dynamical dark energy. To constrain the model, we employ Cosmic Chronometers, the latest Baryon Acoustic Oscillations from the DESI DR2 release, and Supernova data from the PantheonPlus and Union3 catalogues. Our analysis indicates that the modified GUP model is statistically competitive with the ΛCDM scenario, providing comparable or even improved fits to some of the combined datasets. Moreover, the data constrain the deformation parameter of the GUP model, with the preferred value found to be negative, which corresponds to a phantom regime in the effective dynamical dark energy description.
{"title":"Challenging ΛCDM with higher-order GUP corrections","authors":"Andronikos Paliathanasis , Genly Leon , Yoelsy Leyva , Giuseppe Gaetano Luciano , Amare Abebe","doi":"10.1016/j.jheap.2025.100533","DOIUrl":"10.1016/j.jheap.2025.100533","url":null,"abstract":"<div><div>We study quantum corrections to the ΛCDM model arising from a minimum measurable length in Heisenberg’s uncertainty principle. We focus on a higher-order Generalized Uncertainty Principle, beyond the quadratic form. This generalized GUP introduces two free parameters, and we determine the modified Friedmann equation. This framework leads to a perturbative cosmological model that naturally reduces to ΛCDM in an appropriate limiting case of the deformation parameters. We construct the modified cosmological scenario, analyze its deviations from the standard case, and examine it as a mechanism for the description of dynamical dark energy. To constrain the model, we employ Cosmic Chronometers, the latest Baryon Acoustic Oscillations from the DESI DR2 release, and Supernova data from the PantheonPlus and Union3 catalogues. Our analysis indicates that the modified GUP model is statistically competitive with the ΛCDM scenario, providing comparable or even improved fits to some of the combined datasets. Moreover, the data constrain the deformation parameter of the GUP model, with the preferred value found to be negative, which corresponds to a phantom regime in the effective dynamical dark energy description.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100533"},"PeriodicalIF":10.5,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145839881","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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