Journal of High Energy Astrophysics最新文献

{"title":"Spin and spectral properties of Cygnus X-1 observed with Insight-HXMT","authors":"Yihao Zhu, Hanji Wu, Wei Wang","doi":"10.1016/j.jheap.2024.10.013","DOIUrl":"10.1016/j.jheap.2024.10.013","url":null,"abstract":"<div><div>Cygnus X-1 is a Galactic black hole X-ray binary with persistent X-ray emissions. We examine the spectral data from 2 – 22 keV gathered by Insight-HXMT observations conducted from 2020 to 2022. We use the continuum-fitting method to constrain three parameters of Cygnus X-1: the black hole spin <span><math><msup><mrow><mi>a</mi></mrow><mrow><mo>⁎</mo></mrow></msup></math></span>, the hydrogen column density <span><math><msub><mrow><mi>N</mi></mrow><mrow><mi>H</mi></mrow></msub></math></span>, and the photon index of the powerlaw component Γ. The fittings constrain <span><math><msub><mrow><mi>N</mi></mrow><mrow><mi>H</mi></mrow></msub><mo>=</mo><mo>(</mo><mn>1.1</mn><mo>±</mo><mn>0.1</mn><mo>)</mo><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mn>22</mn></mrow></msup></math></span> atom cm<sup>−2</sup>, and Γ evolving from ∼2.4 in 2020 to ∼1.9 in 2022. We find the dimensionless spin parameter <span><math><msup><mrow><mi>a</mi></mrow><mrow><mo>⁎</mo></mrow></msup><mo>></mo><mn>0.977</mn></math></span> <span><math><mo>(</mo><mn>3</mn><mi>σ</mi><mo>)</mo></math></span> assuming the distance of the source <span><math><mi>D</mi><mo>=</mo><mn>2.22</mn></math></span> kpc, the mass of the black hole <span><math><msub><mrow><mi>M</mi></mrow><mrow><mi>BH</mi></mrow></msub><mo>=</mo><mn>21.4</mn><msub><mrow><mi>M</mi></mrow><mrow><mo>⊙</mo></mrow></msub></math></span>, and the inclination of the system <span><math><mi>i</mi><mo>=</mo><msup><mrow><mn>27.47</mn></mrow><mrow><mo>∘</mo></mrow></msup></math></span>. Furthermore, considering the uncertainty of <em>D</em> from 1.22 kpc to 3.22 kpc, <span><math><mn>16</mn><msub><mrow><mi>M</mi></mrow><mrow><mo>⊙</mo></mrow></msub><mo><</mo><msub><mrow><mi>M</mi></mrow><mrow><mi>BH</mi></mrow></msub><mo><</mo><mn>25</mn><msub><mrow><mi>M</mi></mrow><mrow><mo>⊙</mo></mrow></msub></math></span>, <span><math><msup><mrow><mn>22</mn></mrow><mrow><mo>∘</mo></mrow></msup><mo><</mo><mi>i</mi><mo><</mo><msup><mrow><mn>31</mn></mrow><mrow><mo>∘</mo></mrow></msup></math></span>, the Monte Carlo analysis is performed and still confirms a large spin of the limitation <span><math><msup><mrow><mi>a</mi></mrow><mrow><mo>⁎</mo></mrow></msup><mo>></mo><mn>0.999</mn><mo>(</mo><mn>1</mn><mi>σ</mi><mo>)</mo></math></span> without the <em>D</em>, <em>i</em>, and <span><math><msub><mrow><mi>M</mi></mrow><mrow><mi>BH</mi></mrow></msub></math></span> bias for Cygnus X-1. We also try to use the limits of <span><math><msup><mrow><mi>a</mi></mrow><mrow><mo>⁎</mo></mrow></msup></math></span> to reversely constrain the range of <em>D</em>, <em>i</em>, and <span><math><msub><mrow><mi>M</mi></mrow><mrow><mi>BH</mi></mrow></msub></math></span>, and find that for the extreme situation (<span><math><msup><mrow><mi>a</mi></mrow><mrow><mo>⁎</mo></mrow></msup><mo>></mo><mn>0.99</mn></math></span>), the derived distributions prefer a low <em>i</em>, large <span><math><msub><mrow><mi>M</mi></mrow><mrow><mi>BH</mi></mrow></msub","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"44 ","pages":"Pages 381-392"},"PeriodicalIF":10.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561353","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":"Neutrino emission due to pair – annihilation in the neutron star magnetic field","authors":"Shiladittya Debnath ,&nbsp;Brajagopal Majumder","doi":"10.1016/j.jheap.2024.11.005","DOIUrl":"10.1016/j.jheap.2024.11.005","url":null,"abstract":"<div><div>In this paper, we have calculated the energy loss in terms of luminosity for neutrinos produced by the annihilation of electron–positron pair in the light of Photo – Neutrino weak interaction with an intense magnetic field. After analytical calculation, we may conclude that the neutrino luminosity increases with the magnetic field in the temperature range of 10⁸ to 10¹² Kelvins giving rise to an energy loss channel. This may provide an alternate cooling mechanism for highly magnetized neutron stars. We have also conducted a comparative study of neutrino emission from magnetized neutron stars based on both Photo–Neutrino interaction and Conventional (current – current) weak interaction. We found a remarkable similarity between the two models on temperature versus energy loss behaviour of neutron stars. However, these are found to differ from one another on the overall time scale of evolution.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"44 ","pages":"Pages 468-481"},"PeriodicalIF":10.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656500","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 equation of state parametrization in Hořava-Lifshitz gravity","authors":"Himanshu Chaudhary ,&nbsp;Ujjal Debnath ,&nbsp;S.K. Maurya ,&nbsp;G. Mustafa ,&nbsp;Farruh Atamurotov","doi":"10.1016/j.jheap.2024.11.003","DOIUrl":"10.1016/j.jheap.2024.11.003","url":null,"abstract":"<div><div>In this paper, we investigate the late-time cosmic accelerated expansion using various equations of state parametrizations within the framework of Hořava-Lifshitz gravity. We utilize Markov Chain Monte Carlo (MCMC) analysis to constrain the parameters of each proposed model, employing observational Hubble data and Type Ia supernovae. Additionally, we analyze and plot the deceleration parameters for each model. Our findings suggest that the Universe has recently transitioned from a phase of deceleration to acceleration in all the models considered. We also analyzed the behavior of the energy conditions for each proposed model within the framework of Hořava-Lifshitz gravity, specifically at the present epoch (<span><math><mi>z</mi><mo>=</mo><mn>0</mn></math></span>). To further assess the effectiveness of these models, we apply both the Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC) to compare their performance against the standard ΛCDM model. Our results provide valuable insights into how different models perform relative to ΛCDM, offering a comprehensive evaluation of their viability in describing the Universe's accelerated expansion.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"44 ","pages":"Pages 427-436"},"PeriodicalIF":10.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656499","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 supernova remnant contribution to the first LHAASO source catalog via passively illuminated interstellar clouds","authors":"Alison M.W. Mitchell ,&nbsp;Silvia Celli","doi":"10.1016/j.jheap.2024.10.011","DOIUrl":"10.1016/j.jheap.2024.10.011","url":null,"abstract":"<div><div>Supernova remnants (SNRs) are considered as the most promising source class to account for the bulk of the Galactic cosmic-ray flux. Yet amongst the population of ultra-high energy (UHE) sources that has recently emerged, due to high-altitude particle detector experiments such as LHAASO and HAWC, remarkably few are associated with known SNRs. These observations might well indicate that the highest energy particles would escape the remnant early during the shock evolution as a result of its reduced confinement capabilities. This flux of escaping particles may then encounter dense targets (gas and dust) for hadronic interactions in the form of both atomic and molecular material such as interstellar clouds, thereby generating a UHE gamma-ray flux. We explore such a scenario here, considering known SNRs in a physically driven model for particle escape, and as coupled to molecular clouds in the Galaxy. Our analysis allows the investigation of SNR-illuminated clouds in coincidence with sources detected in the first LHAASO catalogue. Indeed, the illuminated interstellar clouds may contribute to the total gamma-ray flux from several unidentified sources, as we discuss here. Yet we nevertheless find that further detailed studies will be necessary to verify or refute this scenario of passive UHE gamma-ray sources in future.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"44 ","pages":"Pages 340-355"},"PeriodicalIF":10.2,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards a new model-independent calibration of Gamma-Ray Bursts","authors":"Arianna Favale ,&nbsp;Maria Giovanna Dainotti ,&nbsp;Adrià Gómez-Valent ,&nbsp;Marina Migliaccio","doi":"10.1016/j.jheap.2024.10.010","DOIUrl":"10.1016/j.jheap.2024.10.010","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Current data on baryon acoustic oscillations and Supernovae of Type Ia (SNIa) cover up to &lt;span&gt;&lt;math&gt;&lt;mi&gt;z&lt;/mi&gt;&lt;mo&gt;∼&lt;/mo&gt;&lt;mn&gt;2.5&lt;/mn&gt;&lt;/math&gt;&lt;/span&gt;. These low-redshift observations play a very important role in the determination of cosmological parameters and have been widely used to constrain the ΛCDM and models beyond the standard, such as the ones with open curvature. To extend this investigation to higher redshifts, Gamma-Ray Bursts (GRBs) stand out as one of the most promising observables. In spite of being transient, they are extremely energetic and can be used to probe the universe up to &lt;span&gt;&lt;math&gt;&lt;mi&gt;z&lt;/mi&gt;&lt;mo&gt;∼&lt;/mo&gt;&lt;mn&gt;9.4&lt;/mn&gt;&lt;/math&gt;&lt;/span&gt;. They exhibit characteristics that suggest they are potentially standardizable candles and this allows their use to extend the distance ladder beyond SNIa. The use of GRB correlations is still a challenge due to the spread in their intrinsic properties. One of the correlations that can be employed for the standardization is the fundamental plane relation between the peak prompt luminosity, the rest-frame end time of the plateau phase, and its corresponding luminosity, also known as the &lt;em&gt;three-dimensional Dainotti correlation&lt;/em&gt;. In this work, we propose an innovative method of calibration of the Dainotti relation which is independent of cosmology. We employ state-of-the-art data on Cosmic Chronometers (CCH) at &lt;span&gt;&lt;math&gt;&lt;mi&gt;z&lt;/mi&gt;&lt;mo&gt;≲&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/math&gt;&lt;/span&gt; and use the Gaussian Processes Bayesian reconstruction tool. To match the CCH redshift range, we select 20 long GRBs in the range &lt;span&gt;&lt;math&gt;&lt;mn&gt;0.553&lt;/mn&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mi&gt;z&lt;/mi&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mn&gt;1.96&lt;/mn&gt;&lt;/math&gt;&lt;/span&gt; from the &lt;em&gt;Platinum sample&lt;/em&gt;, which consists of well-defined GRB plateau properties that obey the fundamental plane relation. To ensure the generality of our method, we verify that the choice of priors on the parameters of the Dainotti relation and the modeling of CCH uncertainties and covariance have negligible impact on our results. Moreover, we consider the case in which the redshift evolution of the physical features of the plane is accounted for. We find that the use of CCH allows us to identify a sub-sample of GRBs that adhere even more closely to the fundamental plane relation, with an intrinsic scatter of &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mn&gt;0.20&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;0.05&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mn&gt;0.03&lt;/mn&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt; obtained in this analysis when evolutionary effects are considered. In an epoch in which we strive to reduce uncertainties on the variables of the GRB correlations in order to tighten constraints on cosmological parameters, we have found a novel model-independent approach to pinpoint a sub-sample that can thus represent a valuable set of standardizable candles. This allows us to extend the cosmic distance ladder presenting a new catalog of calibrated luminosity distanc","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"44 ","pages":"Pages 323-339"},"PeriodicalIF":10.2,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A multiwavelength study of the most distant gamma-ray detected BL Lacertae object 4FGL J1219.0+3653 (z = 3.59)","authors":"Srijita Hazra ,&nbsp;Vaidehi S. Paliya ,&nbsp;A. Domínguez ,&nbsp;C. Cabello ,&nbsp;N. Cardiel ,&nbsp;J. Gallego","doi":"10.1016/j.jheap.2024.10.008","DOIUrl":"10.1016/j.jheap.2024.10.008","url":null,"abstract":"<div><div>BL Lac objects are a class of jetted active galactic nuclei that do not exhibit or have weak emission lines in their optical spectra. Recently, the first <em>γ</em>-ray emitting BL Lac beyond <span><math><mi>z</mi><mo>=</mo><mn>3</mn></math></span>, 4FGL J1219.0 +3653 (hereafter J1219), was identified, i.e., within the first two billion years of the age of the universe. Here we report the results obtained from a detailed broadband study of this peculiar source by analyzing the new ∼58 ksec <em>XMM-Newton</em> and archival observations and reproducing the multiwavelength spectral energy distribution with the conventional one-zone leptonic radiative model. The <em>XMM-Newton</em> data revealed that J1219 is a faint X-ray emitter (<span><math><msub><mrow><mi>F</mi></mrow><mrow><mn>0.3</mn><mo>−</mo><mn>10 keV</mn></mrow></msub><mo>=</mo><msubsup><mrow><mn>1.02</mn></mrow><mrow><mo>−</mo><mn>0.24</mn></mrow><mrow><mo>+</mo><mn>0.47</mn></mrow></msubsup><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>15</mn></mrow></msup></math></span> <span><math><mrow><mi>erg</mi></mrow><mspace></mspace><mspace></mspace><msup><mrow><mi>cm</mi></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup><mspace></mspace><msup><mrow><mi>s</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span>) and exhibits a soft spectrum (0.3−10 keV photon index<span><math><mo>=</mo><msubsup><mrow><mn>2.28</mn></mrow><mrow><mo>−</mo><mn>0.46</mn></mrow><mrow><mo>+</mo><mn>0.58</mn></mrow></msubsup></math></span>). By comparing the broadband physical properties of J1219 with <span><math><mi>z</mi><mo>&gt;</mo><mn>3</mn></math></span> <em>γ</em>-ray detected flat spectrum radio quasars (FSRQs), we have found that it has a relatively low jet power and, similar to FSRQs, the jet power is larger than the accretion disk luminosity. We conclude that deeper multiwavelength observations will be needed to fully explore the physical properties of this unique high-redshift BL Lac object.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"44 ","pages":"Pages 290-299"},"PeriodicalIF":10.2,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441579","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":"Matter bounce cosmology within Finsler-Randers geometry: A comprehensive study of anisotropic influences","authors":"J. Praveen,&nbsp;S.K. Narasimhamurthy","doi":"10.1016/j.jheap.2024.10.009","DOIUrl":"10.1016/j.jheap.2024.10.009","url":null,"abstract":"<div><div>In this study, we explore the dynamics of matter bounce cosmology within the framework of Finsler-Randers geometry, focusing on the role of the Finslerian correction term <span><math><mi>η</mi><mo>(</mo><mi>t</mi><mo>)</mo></math></span>. By integrating Finsler geometry into cosmological models, we introduce anisotropic effects that significantly impact the evolution of the universe, particularly during the bounce phase. The research examines various cosmological parameters, including the deceleration (<span><math><msub><mrow><mi>q</mi></mrow><mrow><mi>η</mi></mrow></msub><mo>(</mo><mi>t</mi><mo>)</mo></math></span>), jerk (<span><math><msub><mrow><mi>j</mi></mrow><mrow><mi>η</mi></mrow></msub><mo>(</mo><mi>t</mi><mo>)</mo></math></span>), and snap (<span><math><msub><mrow><mi>s</mi></mrow><mrow><mi>η</mi></mrow></msub><mo>(</mo><mi>t</mi><mo>)</mo></math></span>) parameters, highlighting the influence of the Finsler correction on these key indicators. Our results demonstrate that the Finslerian framework leads to more complex and abrupt transitions in the universe's expansion dynamics compared to traditional Riemannian models. The study also reveals that the Finslerian correction intensifies the violations of energy conditions, such as the null energy condition (NEC), which are crucial for the occurrence of a successful bounce. Furthermore, the analysis of the squared sound speed <span><math><msubsup><mrow><mi>v</mi></mrow><mrow><mi>s</mi></mrow><mrow><mn>2</mn></mrow></msubsup></math></span> indicates that the model's stability is highly sensitive to the choice of the Finslerian parameters, with certain configurations leading to instability during the bounce. Our findings underscore the unique contributions of Finsler geometry to cosmological models, offering deeper insights into the behavior of the universe under anisotropic influences and providing a potential avenue for addressing longstanding challenges in cosmology.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"44 ","pages":"Pages 300-314"},"PeriodicalIF":10.2,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441580","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":"A universal energy relation between synchrotron and synchrotron self-Compton radiation in GRBs and blazars","authors":"Tao Wen ,&nbsp;Yu-Hua Yao ,&nbsp;Song-Zhan Chen ,&nbsp;Ben-Zhong Dai ,&nbsp;Yi-Qing Guo","doi":"10.1016/j.jheap.2024.10.007","DOIUrl":"10.1016/j.jheap.2024.10.007","url":null,"abstract":"<div><div>The recent and brightest GRB 221009A observed by LHAASO marked the first detection of the onset of TeV afterglow, with a total of 7 GRBs exhibiting very high energy (VHE) afterglow radiation. However, consensus on VHE radiation of GRBs is still lacking. Multi-wavelength studies are currently a primary research method for investigating high-energy <em>γ</em>-ray astronomy. The limited sample of VHE GRBs, combined with their transient nature, hinders the progress of physical studies of GRBs. This paper aims to obtain useful information for GRB research through the properties of blazars, which share significant similarities with GRBs. By fitting high-quality and simultaneous multiwavelength spectral energy distributions with a one-zone leptonic model, the study explores the similarity of radiation properties of blazars and GRBs. A tight correlation between synchrotron and synchrotron self-Compton (SSC) emission luminosities suggests that blazars and GRBs share similar radiation mechanisms, to be specific, synchrotron radiation produces the observed X-ray photons, which also serve as targets for electrons in the SSC process. We hope that ground-based experiments can observe more GRBs in sub-TeV to confirm these findings.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"44 ","pages":"Pages 315-322"},"PeriodicalIF":10.2,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142444817","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":"Bouncing universe scenarios in an extended gravitational framework involving curvature-matter coupling","authors":"M. Zubair ,&nbsp;Quratulien Muneer ,&nbsp;Saira Waheed ,&nbsp;G. Dilara Açan Yildiz ,&nbsp;Ertan Gudekli","doi":"10.1016/j.jheap.2024.10.005","DOIUrl":"10.1016/j.jheap.2024.10.005","url":null,"abstract":"<div><div>Exploration of bouncing cosmic models in modified theories has gained much popularity in modern cosmology. This paper explores the Lagrangian function of a new theory namely <span><math><mi>F</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mrow><mi>L</mi></mrow><mrow><mi>m</mi></mrow></msub><mo>,</mo><mi>T</mi><mo>)</mo></math></span> framework by taking four renowned cosmic bouncing models, i.e., the exponential bounce, oscillatory bounce scenario, power law, and matter bouncing. Our primary objective is to fix the form of <span><math><mi>F</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mrow><mi>L</mi></mrow><mrow><mi>m</mi></mrow></msub><mo>,</mo><mi>T</mi><mo>)</mo></math></span> function for each model and investigate which kinds of reconstructed Lagrangian function have potential of regenerating bouncing scenario in terms of analytical form. It is seen that except power law model, the analytical solutions are conceivable only for certain cases of these bouncing models. For power law bounce, different cases of Lagrangian function may be rebuilt analytically while for some other bouncing scenarios, it is found that particular solutions are not always attainable and hence only the complimentary solutions can be explored. Further, we examine the behavior of energy constraints and stability of these analytically formed bouncing solutions. Additionally, we determine that the dark energy phase in <span><math><mi>F</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mrow><mi>L</mi></mrow><mrow><mi>m</mi></mrow></msub><mo>,</mo><mi>T</mi><mo>)</mo></math></span> gravity is compatible with the experimental data of BAO+Sne-Ia+CMB+H(z) and it is shown that cosmic bounce can be produced with dark energy eras in this gravity. We also present some constraints on the model parameters with Hubble parameter values and ΛCDM to determine the best-fit values of model via least square and reduced chi-squares methods. It is concluded that matter bounce model is the best fitted with the observational data set as well as ΛCDM model because it has least value of <span><math><msubsup><mrow><mi>χ</mi></mrow><mrow><mi>m</mi></mrow><mrow><mn>2</mn></mrow></msubsup></math></span>.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"44 ","pages":"Pages 243-265"},"PeriodicalIF":10.2,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433060","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":"Reconstructing inflationary potential from NANOGrav 15-year data: A robust study using Non-Bunch Davies initial condition","authors":"Sayantan Choudhury","doi":"10.1016/j.jheap.2024.10.003","DOIUrl":"10.1016/j.jheap.2024.10.003","url":null,"abstract":"<div><div>We discuss the theoretical framework behind reconstruction of a generic class of inflationary potentials for canonical single-field slow-roll inflation in a model-independent fashion. The Non-Bunch Davies (NBD) initial condition is an essential choice to determine the structure of potential and to accommodate the blue-tilted tensor power spectrum feature recently observed in NANOGrav. Using the reconstruction technique we found the favoured parameter space which supports blue tilted tensor power spectrum. The validity of the EFT prescription in inflation is also maintained through the use of a new field excursion formula while keeping the necessary and sufficient conditions on the sub-Planckian field values in check. We find that the reconstructed potential display inflection point behaviour, which has deeper connection with high energy physics.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"44 ","pages":"Pages 220-242"},"PeriodicalIF":10.2,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433059","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}