Journal of High Energy Astrophysics最新文献

{"title":"Probing the universe's expansion dynamics: The linear correction scenario perspective on dark energy","authors":"Yerlan Myrzakulov ,&nbsp;M. Koussour ,&nbsp;M. Karimov ,&nbsp;J. Rayimbaev","doi":"10.1016/j.jheap.2024.05.006","DOIUrl":"10.1016/j.jheap.2024.05.006","url":null,"abstract":"<div><p>In this study, we investigate the cosmological evolution of the universe, focusing on the KMMS models in a model-independent approach, particularly the scenario involving linear correction, given by <span><math><msup><mrow><mi>E</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>(</mo><mi>z</mi><mo>)</mo><mo>=</mo><mi>A</mi><mo>(</mo><mi>z</mi><mo>)</mo><mo>+</mo><mi>β</mi><mo>(</mo><mn>1</mn><mo>+</mo><mi>γ</mi><mi>B</mi><mo>(</mo><mi>z</mi><mo>)</mo><mo>)</mo></math></span>, where <span><math><mi>A</mi><mo>(</mo><mi>z</mi><mo>)</mo><mo>=</mo><msub><mrow><mi>Ω</mi></mrow><mrow><mi>m</mi><mn>0</mn></mrow></msub><msup><mrow><mo>(</mo><mn>1</mn><mo>+</mo><mi>z</mi><mo>)</mo></mrow><mrow><mn>3</mn></mrow></msup></math></span> and <span><math><mi>B</mi><mo>(</mo><mi>z</mi><mo>)</mo><mo>=</mo><mi>z</mi></math></span>. By analyzing recent Cosmic Chronometers (CC) and the <span><math><mi>P</mi><mi>a</mi><mi>n</mi><mi>t</mi><mi>h</mi><mi>e</mi><mi>o</mi><msup><mrow><mi>n</mi></mrow><mrow><mo>+</mo></mrow></msup></math></span> samples, we determine the best-fit values of model parameters using a Markov chain Monte Carlo analysis. Our models exhibit unique dynamics, transitioning from super-exponential to exponential expansion, with a significant shift at redshift <span><math><msub><mrow><mi>z</mi></mrow><mrow><mi>t</mi></mrow></msub><mo>=</mo><msubsup><mrow><mn>0.83</mn></mrow><mrow><mo>−</mo><mn>0.10</mn></mrow><mrow><mo>+</mo><mn>0.11</mn></mrow></msubsup></math></span> and present deceleration parameter <span><math><msub><mrow><mi>q</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>=</mo><mo>−</mo><msubsup><mrow><mn>0.69</mn></mrow><mrow><mo>−</mo><mn>0.17</mn></mrow><mrow><mo>+</mo><mn>0.17</mn></mrow></msubsup></math></span>. The jerk parameter exceeds 1, indicating a faster change in acceleration than predicted by ΛCDM. The energy density parameter is consistent with Planck observations, and the dark sector evolution follows the expected thermal history. The EoS parameter approaches <span><math><msub><mrow><mi>ω</mi></mrow><mrow><mi>d</mi><mi>e</mi></mrow></msub><mo>=</mo><mo>−</mo><mn>1</mn></math></span> over time, with a current value of <span><math><msub><mrow><mi>ω</mi></mrow><mrow><mi>d</mi><mi>e</mi><mn>0</mn></mrow></msub><mo>=</mo><mo>−</mo><mn>1.06</mn><mo>±</mo><mn>0.12</mn></math></span>, aligning with the phantom phase. Our model presents a new dark energy alternative, emphasizing the importance of considering models like KMMS in understanding cosmic evolution.</p></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"42 ","pages":"Pages 209-216"},"PeriodicalIF":3.8,"publicationDate":"2024-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141055190","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":"f(T) gravity after DESI Baryon acoustic oscillation and DES supernovae 2024 data","authors":"Celia Escamilla-Rivera,&nbsp;Rodrigo Sandoval-Orozco","doi":"10.1016/j.jheap.2024.05.005","DOIUrl":"10.1016/j.jheap.2024.05.005","url":null,"abstract":"<div><p>In this work, we investigate new constraints on <span><math><mi>f</mi><mo>(</mo><mi>T</mi><mo>)</mo></math></span> gravity using the recent Baryon Acoustic Oscillation (BAO) data released by the Dark Energy Spectroscopic Instrument (DESI) and the Type Ia supernovae (SNIa) catalog from the full 5-years of the Dark Energy Survey Supernova Program (DES-SN5YR). The <span><math><mi>f</mi><mo>(</mo><mi>T</mi><mo>)</mo></math></span> cosmological models considered are characterised by power law late-time accelerated expansion. Our results show that the combination DESI BAO +<span><math><msub><mrow><mi>r</mi></mrow><mrow><mi>d</mi></mrow></msub></math></span> CMB Planck suggests a Bayesian preference for late-time <span><math><mi>f</mi><mo>(</mo><mi>T</mi><mo>)</mo></math></span> cosmological models over ΛCDM, obtaining a value of <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>=</mo><msubsup><mrow><mn>68.3</mn></mrow><mrow><mo>−</mo><mn>3.5</mn></mrow><mrow><mo>+</mo><mn>3.0</mn></mrow></msubsup></math></span> [km/s/Mpc] in agreement with SH0ES collaboration, <strong>however, due to a bigger uncertainty</strong>.</p></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"42 ","pages":"Pages 217-221"},"PeriodicalIF":3.8,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141057036","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":"Cosmic evolution in f(Q,T) gravity with observational constraints: A comparative analysis with ΛCDM","authors":"B.K. Shukla ,&nbsp;Değer Sofuoğlu ,&nbsp;Himanshu Chaudhary ,&nbsp;Farruh Atamurotov ,&nbsp;G. Mustafa","doi":"10.1016/j.jheap.2024.05.004","DOIUrl":"10.1016/j.jheap.2024.05.004","url":null,"abstract":"<div><p>In this investigation, we explore the flat Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmological model within the framework of the <span><math><mi>f</mi><mo>(</mo><mi>Q</mi><mo>,</mo><mi>T</mi><mo>)</mo></math></span> modified gravitation theory. This theory was recently introduced to account for the late cosmic acceleration of our Universe. To address the modified field equations derived from the <span><math><mi>f</mi><mo>(</mo><mi>Q</mi><mo>,</mo><mi>T</mi><mo>)</mo><mo>=</mo><mi>α</mi><mi>Q</mi><mo>+</mo><mi>β</mi><msup><mrow><mi>Q</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>+</mo><mi>k</mi><mi>T</mi></math></span> form of the <span><math><mi>f</mi><mo>(</mo><mi>Q</mi><mo>,</mo><mi>T</mi><mo>)</mo></math></span> function, we assume a redshift-dependent deceleration parameter. Our goal is to impose observational constraints on the model parameters, ensuring its viability and alignment with the observable Universe's characteristics. The observational constraints are derived from a diverse dataset, encompassing Cosmic Chronometers (CC), type Ia supernovae (SNIa), Baryon Acoustic Oscillation (BAO), Gamma Ray Burst (GRB), and Quasar (Q) measurements. Employing the Markov Chain Monte Carlo (MCMC) technique with the CC + BAO + SNIa + GRB + Q dataset, we conduct simulations to obtain constraints on the model parameters. In the subsequent segments of the study, we delve into the evolution of the constrained model from the past to the present. We utilize metrics such as deceleration and jerk parameters, statefinder pairs, the <span><math><msub><mrow><mi>O</mi></mrow><mrow><mi>m</mi></mrow></msub></math></span> diagnostic, and various physical parameters of the model. This detailed analysis allows us to scrutinize the transition of the model from a decelerating phase in the past to the late accelerating phase, comparing its evolution with established dark energy models. To assess the model's goodness of fit, we employ statistical criteria, including the Akaike Information Criterion (AIC), Bayesian Information Criterion (BIC), P-value, and L-statistic. Remarkably, these criteria consistently indicate that the ΛCDM model is slightly favored by the observational data compared to the proposed cosmological model.</p></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"43 ","pages":"Pages 1-14"},"PeriodicalIF":3.8,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141041765","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":"Relativistic massive and massless scalar fields bound to the Bumblebee gravity's black hole","authors":"David Senjaya","doi":"10.1016/j.jheap.2024.05.003","DOIUrl":"https://doi.org/10.1016/j.jheap.2024.05.003","url":null,"abstract":"<div><p>In this letter, we examine massive and massless scalar quasibound states bound in the static spherically symmetric black hole solution of the Einstein-Bumblebee space-time. We start with constructing the governing relativistic fields' dynamical equation, i.e. the Klein-Gordon equation, component by component. With the help of the ansatz of separation of variables, we find the exact solution of the angular part in terms of Spherical Harmonics while the radial exact solution is discovered in terms of the Confluent Heun function. The quantization of the quasibound state is done by applying the polynomial condition of the Confluent Heun function that reveals a complex-valued energy levels expression for the case of massive scalar, where the real part is the scalar particle's energy and the imaginary part represents the quasibound state's decay. And for a massless scalar, a pure imaginary energy levels is obtained. The quasibound states, thus, describe decaying relativistic states bound in the black hole's gravitational potential well. At the end, we investigate the Hawking radiation of the static Bumblebee black hole's horizon by deriving and investigating the radiation distribution function.</p></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"42 ","pages":"Pages 197-204"},"PeriodicalIF":3.8,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140952266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cosmological transition epoch from gamma-ray burst correlations","authors":"Anna Chiara Alfano ,&nbsp;Salvatore Capozziello ,&nbsp;Orlando Luongo ,&nbsp;Marco Muccino","doi":"10.1016/j.jheap.2024.05.002","DOIUrl":"https://doi.org/10.1016/j.jheap.2024.05.002","url":null,"abstract":"<div><p>The redshift <span><math><msub><mrow><mi>z</mi></mrow><mrow><mi>t</mi></mrow></msub></math></span> and the jerk parameter <span><math><msub><mrow><mi>j</mi></mrow><mrow><mi>t</mi></mrow></msub></math></span> of the transition epoch are constrained by using two model-independent approaches involving the direct expansion of the Hubble rate and the expansion of the deceleration parameter around <span><math><mi>z</mi><mo>=</mo><msub><mrow><mi>z</mi></mrow><mrow><mi>t</mi></mrow></msub></math></span>. To extend our analysis to high-redshifts, we employ the <em>Amati</em>, <em>Combo</em>, <em>Yonetoku</em> and <em>Dainotti</em> gamma-ray burst correlations. The <em>circularity problem</em> is prevented by calibrating these correlations through the Bézier interpolation of the updated observational Hubble data. Each gamma-ray burst data set is jointly fit with type Ia supernovae and baryonic acoustic oscillations through a Monte Carlo analysis, based on the Metropolis-Hastings algorithm, to obtain <span><math><msub><mrow><mi>z</mi></mrow><mrow><mi>t</mi></mrow></msub></math></span>, <span><math><msub><mrow><mi>j</mi></mrow><mrow><mi>t</mi></mrow></msub></math></span> and the correlation parameters. The overall results are compatible with the concordance model with some exceptions. We also focus on the behaviors of the dark energy, verifying its compatibility with a cosmological constant, and the matter density <span><math><msub><mrow><mi>Ω</mi></mrow><mrow><mi>m</mi></mrow></msub></math></span> and compare them with the expectations of the concordance paradigm.</p></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"42 ","pages":"Pages 178-196"},"PeriodicalIF":3.8,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140948657","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":"X-ray emission from large scale jets of AGNs at high redshifts","authors":"Amal A. Rahman ,&nbsp;Sunder Sahayanathan ,&nbsp;P.A. Subha","doi":"10.1016/j.jheap.2024.05.001","DOIUrl":"https://doi.org/10.1016/j.jheap.2024.05.001","url":null,"abstract":"<div><p>The limited angular resolution of the existing telescopes, operating in radio, optical and X-ray wavebands, hinder the study on multi-spectral component (MSC) emissions from the large scale jet of AGNs. This is particularly strenuous for the sources located at high redshifts. Though a few of them were resolved in radio-optical wavebands, their X-ray counterparts have been rarely discovered. This poses a bigger challenge in understanding their emission mechanism. At high redshifts, the X-ray emission from the large scale jets are generally interpreted as inverse-Compton scattering of cosmic microwave background photons (IC/CMB), due to the increase in CMB photon density. However, recent <em>Fermi γ</em>-ray flux upper limit estimates on two high redshift (<span><math><mi>z</mi><mo>&gt;</mo><mn>3.5</mn></math></span>) AGN jets (J1510+5702 and J1421-0643), question the validity of the IC/CMB model. Here, we propose a model by considering the advection of electrons from the sites of particle acceleration (<span>Rahman et al., 2022</span>), to interpret the MSC emission from these sources. We show that observed radio/optical/X-ray emissions can be explained by the synchrotron emission from the advected and accelerated electron distribution. We also show that the IC/CMB spectrum of this composite electron distribution satisfies the constraints drawn from <em>Fermi</em> observations.</p></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"42 ","pages":"Pages 156-162"},"PeriodicalIF":3.8,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140878763","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 comparative study of embedding class one, conformally flat, vanishing complexity factor and conformally symmetric solutions and their impacts on compact star structure","authors":"Ksh. Newton Singh ,&nbsp;S.K. Maurya ,&nbsp;Satyanarayan Gedela ,&nbsp;Ravindra K. Bisht","doi":"10.1016/j.jheap.2024.04.008","DOIUrl":"https://doi.org/10.1016/j.jheap.2024.04.008","url":null,"abstract":"<div><p>For the first time, we have presented in detail the comparative studies of embedding class one (CO), conformally flat (CF), vanishing complexity factor (COM), and conformally symmetric (CS) solutions, which are the easiest way of exploring new solutions of the field equations. All these solutions simplify the two metric potentials problem to one metric potential through specific bridge equations. To compare on the same footing, we have assumed the same <span><math><msub><mrow><mi>g</mi></mrow><mrow><mi>r</mi><mi>r</mi></mrow></msub></math></span> metric function and solved the <span><math><msub><mrow><mi>g</mi></mrow><mrow><mi>t</mi><mi>t</mi></mrow></msub></math></span> metric functions via the bridge equations. We then compare all the physical quantities like density, pressure, anisotropy, adiabatic index, etc. To check which type of matter is appropriate for these solutions, we have plotted the equation of states (EoSs) and found the best-fitted functions. We have found that CO solution obeys quadratic EoS, the COM solution best fits with linear EoS, CF solution contains normal and exotic matters, while the CS solution follows a cubic polynomial, and also includes normal, stiff, and exotic matters. In the end, we have plotted the <span><math><mi>M</mi><mo>−</mo><mi>R</mi></math></span> curves and fitted them with observed masses of a few neutron stars to predict their radii.</p></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"42 ","pages":"Pages 163-177"},"PeriodicalIF":3.8,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140947079","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":"Thermal analysis of gravitational decoupling black hole solution","authors":"Allah Ditta ,&nbsp;Saadia Mumtaz ,&nbsp;G. Mustafa ,&nbsp;S.K. Maurya ,&nbsp;Farruh Atamurotov ,&nbsp;Asif Mahmood","doi":"10.1016/j.jheap.2024.04.007","DOIUrl":"https://doi.org/10.1016/j.jheap.2024.04.007","url":null,"abstract":"<div><p>In this work, we examine the thermodynamic properties of the hairy black holes that develop when the Reissner–Nordström geometry is applied to the gravitational decoupling method. Gibbs free energy and energy emission are also examined in our investigation. We compute several parameters to evaluate the local and global thermodynamic stability, including the Hawking temperature, geometric mass, and heat capacity. The first law of thermodynamics calculates the black hole's temperature and assesses the energy emission rate. We investigate the black hole's phase transition behavior by calculating the Gibbs free energy, paying particular attention to the swallowing tails.</p></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"42 ","pages":"Pages 146-155"},"PeriodicalIF":3.8,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140649926","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":"NuSTAR detection of a broad absorption line in IGR J06074+2205","authors":"Mohammed Tobrej,&nbsp;Binay Rai,&nbsp;Manoj Ghising,&nbsp;Bikash Chandra Paul","doi":"10.1016/j.jheap.2024.04.006","DOIUrl":"https://doi.org/10.1016/j.jheap.2024.04.006","url":null,"abstract":"<div><p>BeXRB pulsar IGR J06074+2205 using NuSTAR observations. The temporal and spectral characteristics of the source are investigated. We detect coherent X-ray pulsations of the source and determine the spin period evolution. Using the current spin period data of the source, we show that the source is spinning down at 0.0202(2) s<!--> <span><math><mi>d</mi><mi>a</mi><msup><mrow><mi>y</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span>. The pulse profiles are found to evolve with energy and luminosity. Another interesting feature of the source is that the pulse profiles are dual peaked. The dual-peaked pulse profile is characterized by a decreasing secondary peak amplitude with increasing energy. We also observed a proportionate increase in the primary peak amplitude as the energy increases. The pulse fraction exhibits an overall increasing trend with the energy. The X-ray continuum of the source indicates the existence of a characteristic absorption feature with a centroid energy ∼55 keV, which may be interpreted as a cyclotron line. We estimate the corresponding magnetic field strength to be <span><math><mo>∼</mo><mn>4.74</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mn>12</mn></mrow></msup></math></span> G. A peculiar ‘10 keV’ absorption feature is observed in the X-ray spectra of the second observation. The luminosity measurements predict that the source may be accreting in the sub-critical regime.</p></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"42 ","pages":"Pages 129-135"},"PeriodicalIF":3.8,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140640755","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":"Spectral and timing analysis of the frequent flares experienced by AT2019wey","authors":"Zi-Xu Yang ,&nbsp;Liang Zhang ,&nbsp;Qing-Cui Bu ,&nbsp;Rui-Can Ma ,&nbsp;Yue Huang ,&nbsp;He-Xin Liu ,&nbsp;Wei Yu ,&nbsp;Peng-Ju Wang ,&nbsp;Lian Tao ,&nbsp;Jin-Lu Qu ,&nbsp;Xiang Ma ,&nbsp;Pan-Ping Li ,&nbsp;Pei Jin ,&nbsp;Shu-Jie Zhao ,&nbsp;Qing-Chang Zhao","doi":"10.1016/j.jheap.2024.04.004","DOIUrl":"https://doi.org/10.1016/j.jheap.2024.04.004","url":null,"abstract":"<div><p>In this paper, we compare the timing and spectral properties for those frequent flares observed in AT2019wey from 2020 August to 2023 March. We conducted a comparative analysis of the evolution of timing properties, specifically the continuum fractional rms, broadband noise characteristic frequency, and spectral parameters, in relation to the hardness ratio and count rates for all 10 flares. Based on the timing and spectral properties, we have identified four flares entering high soft state and six flares not. For all flares, the continuum fractional rms decreases with increasing count rates whereas characteristic frequency of broadband noise behaves in the opposite way. Meanwhile, the disc temperature <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>in</mi></mrow></msub></math></span> and powerlaw index Γ consistently increases throughout all flares. During the 10 flares, the luminosity of accretion disc does not follow the canonical <span><math><mi>L</mi><mo>∼</mo><msup><mrow><mi>T</mi></mrow><mrow><mn>4</mn></mrow></msup></math></span> relation which implicates a moving disc inner radius.</p></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"42 ","pages":"Pages 136-145"},"PeriodicalIF":3.8,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140640756","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}