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Soft Xray observing the cosmic sources by the ESA–CAS satellite SMILE J. High Energy Astrophys. (IF 3.8) Pub Date : 20240222
Vojtěch Šimon, René Hudec, Andrew ReadThis paper describes the scientific potential of a Soft Xray Imager (SXI) onboard the ESA–CAS satellite for investigating cosmic Xray sources of various types. We show that this instrument, albeit designed for Xray imaging of solar wind Charge eXchange of the magnetosheath and the cusps, is also essential for astrophysics because it is able to provide widefield imaging of the sky in the soft Xray

Generalized wormhole models within galactic halo region in torsion and matter coupling gravity formalism J. High Energy Astrophys. (IF 3.8) Pub Date : 20240222
G. Mustafa, Abdelghani Errehymy, Faisal Javed, S.K. Maurya, Sudan Hansraj, Sobia SadiqIn the current analysis, we investigate the possible existence of generalized Wormhole models within the galactic halo region by analyzing specific dark matter models. The observational data is checked in the framework of torsion within minimal matter coupling gravity. By using the variational approach modified versions of the field equations under the anisotropic source of matter are calculated. To

Different behaviors of wavelet results for typeB and typeC QPOs of MAXI J1535571 based on NICER data J. High Energy Astrophys. (IF 3.8) Pub Date : 20240221
X. Chen, W. WangWavelet analysis, in addition to power density spectra, is another method to study the quasiperiodic signals in the light curves, but has been rarely used in black hole Xray transients. We performed wavelet analysis of Xray timing features and quasiperiodic oscillations (QPOs) based on NICER observations of the black hole candidate MAXI J1535571 in this paper. Separating the light curves by the

Reduction of ultrahigh energy neutrino flux for spacelike neutrinos from extragalactic sources J. High Energy Astrophys. (IF 3.8) Pub Date : 20240213
J. Rembieliński, J. CiborowskiAssuming that neutrinos are spacelike (tachyonic) fermions, we calculate width for the kinematically allowed, lepton number conserving, threebody decay in the Standard Model. Decays of tachyonic neutrinos over cosmological distances can lead to a reduction of the neutrino flux in the highenergy end of the spectrum. We estimate upper limits on the spacelike neutrino mass based on the PeVenergy cosmological

The challenge of identifying INTEGRAL sources on the Galactic plane J. High Energy Astrophys. (IF 3.8) Pub Date : 20240122
Raffaella Landi, Loredana Bassani, Gabriele Bruni, Manuela Molina, Nicola Masetti, Angela Malizia, Mariateresa Fiocchi, Angela Bazzano, Pietro Ubertini(INTEGRAL) has been surveying the sky above 20 keV since its launch in 2002 providing new insights into the nature of the sources that populate our Universe at soft γray energies. The latest IBIS/ISGRI survey lists 929 hard Xray sources, of which 113 are reported as unidentified, i.e. lacking a lower energy counterpart or simply not studied in other wavebands. To overcome this lack of information

Exact scalar quasibound states solutions of f(R) theory's static spherically symmetric black hole J. High Energy Astrophys. (IF 3.8) Pub Date : 20240115
David SenjayaFollowing the recent developments in black holes' quasibound states exact solutions by Senjaya, 2023b, Senjaya, 2023c, in this letter, we present a novel exact solution of quasibound states of a scalar around a static spherically symmetric black hole solution of f(R) theory of gravity. We start with the relativistic scalar field wave equation, i.e. the KleinGordon equation, isolating the radial equation

Particle correlation in the cosmic ray showers around the spectral knee J. High Energy Astrophys. (IF 3.8) Pub Date : 20240111
Tadeusz WibigIn this paper, we answer the question to what extent the particles in showers initiated by particles with energies of 1014 – 1017 eV observed at the edges of extensive air showers, where average particle densities are low (< a few per m2), are correlated. The particle number multiplicity distributions in the surface detectors of the shower arrays are affected by the existence of such a correlation

On the statistical assumption on the distance moduli of Supernovae Ia and its impact on the determination of cosmological parameters J. High Energy Astrophys. (IF 3.8) Pub Date : 20240104
M.G. Dainotti, G. Bargiacchi, M. Bogdan, S. Capozziello, S. NagatakiType Ia Supernovae (SNe Ia) are considered the most reliable standard candles and they have played an invaluable role in cosmology since the discovery of the Universe's accelerated expansion. During the last decades, the SNe Ia samples have been improved in number, redshift coverage, calibration methodology, and systematics treatment. These efforts led to the most recent “Pantheon” (2018) and “Pantheon

The BOAT GRB 221009A: A Poyntingfluxdominated narrow jet surrounded by a matterdominated structured jet wing J. High Energy Astrophys. (IF 3.8) Pub Date : 20240104
Bing Zhang, XiangYu Wang, JianHe ZhengWe argue that the broadband observations of the brightestofalltime (BOAT) GRB 221009A reveal a physical picture involving two jet components: a narrow (∼0.6 degree half opening angle) pencilbeam jet that has a Poyntingfluxdominated jet composition, and a broader matterdominated jet with an angular structure. We discuss various observational evidence that supports such a picture. To treat the

Constraints on the internal physics of neutron stars from the observational data of several young pulsars: The role of a powerlaw decaying dipole magnetic field J. High Energy Astrophys. (IF 3.8) Pub Date : 20231220
YuLong Yan, Quan Cheng, XiaoPing ZhengThe observational data (e.g., the timing data and magnetic tilt angles χ) of young pulsars can be used to probe some critical issues about the internal physics of neutron stars (NSs), for instance, the number of precession cycles ξ and the internal magnetic field configuration (IMFC) of NSs. Evolution of the dipole magnetic field Bd of NSs may play an important role in determining the final results

Studying the variations of the cyclotron line in Cen X3 using InsightHXMT J. High Energy Astrophys. (IF 3.8) Pub Date : 20231220
Qi Liu, Wei Wang, Wen Yang, Xiao Chen, Hanji WuWe investigate the cyclotron resonant scattering features (CRSFs) of the accreting Xray pulsar Cen X3 and significantly detect the 29 keV cyclotron line features in the hard Xray averaged spectroscopy studies based on the recent InsightHXMT observations in 2022, when Cen X3 has Xray luminosity LX>∼5×1037 erg s−1 in the bands of 2 – 60 keV. We do not find a harmonic line in the average spectra

GRB 080710: A narrow, structured jet showing a late, achromatic peak in the optical and infrared afterglow? J. High Energy Astrophys. (IF 3.8) Pub Date : 20231212
Kaori Obayashi, Ayumu Toriyama, Mayu Murakoshi, Yuri Sato, Shuta J. Tanaka, Takanori Sakamoto, Ryo YamazakiWe present a possible theoretical interpretation of the observed afterglow emission of long gammaray burst GRB 080710. While its prompt GRB emission properties are normal, the afterglow light curves in the optical and infrared bands are exceptional in two respects. One is that the observed light curves of different wavelengths have maximum at the same time, and that the achromatic peak time, 2.2×103


Corrigendum to “Energetic requirements of the gammaray emission from pulsars: A nonparametric analysis of the data in the FermiLAT 12Year Catalog” [J. High Energy Astrophys. 37 (2023) 62–70] J. High Energy Astrophys. (IF 3.8) Pub Date : 20231121
Houshang ArdavanAbstract not available

Anisotropic quark stars in energymomentum squared gravity J. High Energy Astrophys. (IF 3.8) Pub Date : 20231114
Takol Tangphati, Abdelghani Errehymy, Ayan Banerjee, Anirudh PradhanAt supersaturation densities, quarks in the core of neutron stars (NSs) have been a subject of intense investigation for last few decades. In particular, an intriguing conjecture has emerged suggesting that the true ground state of hadronic matter may be strange quark matter (SQM). In the present manuscript, we study internal structure and the physical properties of quark stars (QSs) in energymomentum

InsightHXMT observations on thermonuclear Xray bursts from 4U 1608–52 in 2022: The accretion rate dependent anisotropy of burst emission J. High Energy Astrophys. (IF 3.8) Pub Date : 20231114
YuPeng Chen, Shu Zhang, Long Ji, ShuangNan Zhang, PengJu Wang, LingDa Kong, Zhi Chang, JingQiang Peng, QingCang Shui, Jian Li, Lian Tao, MingYu Ge, JinLu QuThermonuclear Xray bursts occur on the surface of an accreting neutron star (NS), and their characteristics and interplay with the surrounding circumstance could be a clue to understand the nature of the NS and accretion process. For this purpose, InsightHXMT has performed high cadence observations on the bright thermonuclear Xray burster–4U 1608–52 during its outburst in July and August 2022; nine

Exact analytical quasibound states of a scalar particle around a slowly rotating black hole J. High Energy Astrophys. (IF 3.8) Pub Date : 20231023
David SenjayaIn this work, behaviour of massive and massless scalar particle around a slowly rotating black hole in 3+1 dimension is investigated. Exact solutions of the KleinGordon equation, i.e. the wave functions and energy levels are discovered. The quasibound state has complexvalued energy levels E=ER+iEI where the real part ER is directly related to the particle's energy while the imaginary part represents

The unprecedented flaring activities around Mrk 421 in 2012 and 2013: The test for neutrino and UHECR event connection J. High Energy Astrophys. (IF 3.8) Pub Date : 20231026
Nissim Fraija, Edilberto AguilarRuiz, Antonio Galván, Jose Antonio de Diego Onsurbe, Maria G. DainottiSince its mission, Fermi Collaboration reported the highest flux observed during July  September 2012 for the BL Lac Markarian 421 (Mrk 421). The integrated flux was eight times greater than the average flux reported in the second Fermi catalog. During April 2013, Mrk 421 exhibited the highest TeV γray and optical fluxes recorded. The Telescope Array (TA) collaboration reported the arrival of 72

Bayesian evidence for spectral lag transition due to Lorentz invariance violation for 32 Fermi/GBM Gammaray bursts J. High Energy Astrophys. (IF 3.8) Pub Date : 20231016
Vibhavasu Pasumarti, Shantanu DesaiWe use the spectral lag data of 32 long GRBs detected by Fermi/GBM, which has been recently collated in Liu et al. (2022) to quantify the statistical significance of a transition in the spectral lag data based on Lorentz invariance violation (LIV) (for both subluminal and superluminal propagation) using Bayesian model selection. We use two different parametric functions to model the null hypothesis

On the dynamics of a dark sector coupling J. High Energy Astrophys. (IF 3.8) Pub Date : 20230921
Weiqiang Yang, Supriya Pan, Olga Mena, Eleonora Di ValentinoInteracting dark energy models may play a crucial role in explaining several important observational issues in modern cosmology and also may provide a solution to current cosmological tensions. Since the phenomenology of the dark sector could be extremely rich, one should not restrict the interacting models to have a coupling parameter which is constant in cosmic time, rather allow for its dynamical

Intermittent behaviour in small CORSIKA showers J. High Energy Astrophys. (IF 3.8) Pub Date : 20230830
Tadeusz WibigIn this work we are concerned with the quantitative study of correlations between charged particles: electrons/positrons and muons in small Extensive Air Showers. By “small”, we mean showers that are initiated by primary protons with energies of up to ∼1 TeV. We study the strength of these correlations with the help of the CORSIKA simulation program. The results show the ‘intermittent’ behaviour of


Particle acceleration in selfdriven turbulent reconnection J. High Energy Astrophys. (IF 3.8) Pub Date : 20230821
JianFu Zhang, Siyao Xu, Alex Lazarian, Grzegorz KowalThe theoretical prediction that magnetic reconnection spontaneously drives turbulence has been supported by magnetohydrodynamic (MHD) and kinetic simulations. While reconnection with externally driven turbulence is accepted as an effective mechanism for particle acceleration, the acceleration during the reconnection with selfdriven turbulence is studied for the first time in this work. By using highresolution

Propagation of anisotropic gravitational and electromagnetic waves at very high energies J. High Energy Astrophys. (IF 3.8) Pub Date : 20230725
J. MestraPáez, Alvaro Restuccia, Francisco TelloOrtizWe analyze the dispersion relation for an anisotropic gravityelectromagnetic theory at very high energies. In particular for photons of very high energy. We start by introducing the anisotropic gravitygauge vector field model. It is invariant under spacelike diffeomorphisms, time parametrization, and U(1) gauge transformations. It includes highorder spacelike derivatives as well as polynomial expressions

Type Ia supernovae induced by primordial black holes from dark firstorder phase transition J. High Energy Astrophys. (IF 3.8) Pub Date : 20230725
PinJung Chen, PoYan TsengA primordial black hole (PBH) with mass 10−15≤MPBH/M⊙≤10−10 is currently beyond the sensitivity of both microlensing and black hole (BH) evaporation methods. A novel scenario has been proposed: When a PBH with mass 10−14≤MPBH/M⊙≤10−11 transits through a white dwarf (WD) made up of carbon and oxygen, BondiHoyleLyttleton (BHL) accretion in a reactive medium creates a shock wave, which generates direct

Inflationary interpretation of the stochastic gravitational wave background signal detected by pulsar timing array experiments J. High Energy Astrophys. (IF 3.8) Pub Date : 20230710
Sunny VagnozziVarious pulsar timing array (PTA) experiments (NANOGrav, EPTA, PPTA, CPTA, including data from InPTA) very recently reported evidence for excess red commonspectrum signals in their latest datasets, with interpulsar correlations following the HellingsDowns pattern, pointing to a stochastic gravitational wave background (SGWB) origin. Focusing for concreteness on the NANOGrav signal (given that all

The neutrino emissivity and the cooling energy resources by magnetic monopole in white dwarfs J. High Energy Astrophys. (IF 3.8) Pub Date : 20230705
JingJing Liu, DongMei LiuSome typical low mass and high mass white dwarfs (WDs) are selected and the neutrino emissivity and the cooling energy resources problems are discussed. We present three models (I, II, III) to investigate the number of magnetic monopole (MM) captured, the luminosity, and the neutrino emissivity based on the MM catalytic nuclear decay. Model (I) mainly considers the effect of compression factor on thermonuclear

New emergent observational constraints in f(Q,T) gravity model J. High Energy Astrophys. (IF 3.8) Pub Date : 20230619
S.H. Shekh, A. Bouali, Anirudh Pradhan, A. BeeshamIn the current study, we inspect the latetime acceleration of the universe in f(Q,T) gravity. In this theory, Q represents the nonmetricity term and with Tμν the energymomentum tensor, with T its trace. To explore the solutions in the theory for the FriedmannLemaitreRobertsonWalker (FLRW) model, we propose a new scale factor called the emergent scale factor, which yields the Hubble parameter

Thermal properties of the core of magnetar J. High Energy Astrophys. (IF 3.8) Pub Date : 20230609
Trisha Sarkar, Shalu Yadav, Monika SinhaDuring very early age of neutron stars, the core cools down faster compared to the crust creating a large thermal gradient in the interior of the star. During 10−100 years, a cooling wave propagates from the core to the crust causing the interior of the star to thermalize. During this duration thermal properties of the core material is of great importance to understand the dynamics of the interior

The radio monitoring of the microquasar GRS 1915+105 with FAST J. High Energy Astrophys. (IF 3.8) Pub Date : 20230608
PengFu Tian, Ping Zhang, Wei Wang, Pei Wang, Xiaohui Sun, Zheng ZhengWe report radio observations of the Galactic microquasar GRS 1915+105 with the Fivehundredmeter Aperture Spherical radio Telescope (FAST) in the band of 1.0−1.5 GHz. The observations were performed in 2020 with a total duration of ∼ 3.5 hours. In this work, we developed the pipeline to perform the calibration of the radio flux density and polarization for the persistent emitting radio source GRS

The massive black holes, high accretion rates, and nontilted jet feedback, of jetted AGN triggered by secular processes J. High Energy Astrophys. (IF 3.8) Pub Date : 20230607
Chandra B. Singh, David GarofaloThat jetted active galactic nuclei (AGN) are also hosted in spiral galaxies is now well established. Our understanding of how such objects might fit in the radio loud AGN subclass has been described by Foschini and others over the past decade in that jets in spirals are weaker than those of radio galaxies and quasars because the black holes in spirals tend to be less massive. Recent data, however,


No evidence for EDE from Planck data in extended scenarios J. High Energy Astrophys. (IF 3.8) Pub Date : 20230525
Emanuele Fondi, Alessandro Melchiorri, Luca PaganoThe latest data release from the ACT CMB experiment (in combination with previous WMAP data) shows evidence for an Early Dark Energy component at more than 3 standard deviations. The same conclusion has been recently shown to hold when temperature data from the Planck experiment limited to intermediate angular scales (l≤650) are included while it vanishes when the full Planck dataset is considered

Short Gamma rays bursts from binary black holes merger J. High Energy Astrophys. (IF 3.8) Pub Date : 20230519
Shad AliIn this paper, we introduced a model related to the astronomical events having the codetection of GW associated with Short Gamma Ray Bursts (SGRBs). Study shows that the existence of magnetized accretion disks is responsible for creating the events of GWs associated with electromagnetic (EM) counterparts from binary BHs mergers. Our model leads from spacetime instability to the emission of EM radiations

Entropy as logarithmic term of the central charge and modified Friedmann equation in AdS/CFT correspondence J. High Energy Astrophys. (IF 3.8) Pub Date : 20230518
M. Bousder, E. Salmani, H. EzZahraouyThis paper is about the extended thermodynamics of AdS black holes and its relation to CFT thermodynamics. The logarithmic term of the central charge is interpreted as black hole entropy. We have to obtain a modified Friedmann equation from the Smarr formula. We find that the AdS radius is the critical shadow radius. We obtain the HawkingBekenstein formula with logarithmic corrections, which depends

Observationally constrained accelerating cosmological model with higher power of nonmetricity and squared trace J. High Energy Astrophys. (IF 3.8) Pub Date : 20230424
A.S. Agrawal, B. Mishra, S.K. TripathyIn this paper, a cosmological model of the Universe is presented in f(Q,T) gravity and the parameters are constrained by cosmological data sets. Initially, a generalised form of f(Q,T) model is used as f(Q,T)=−λ1Qm−λ2T2, where λ1, λ2 and m are model parameters. With some algebraic manipulation, the Hubble parameter is obtained in terms of redshift. Then, using MCMC analysis, the model parameters are

Measurements of spin and orbital parameters in Cen X3 by InsightHXMT J. High Energy Astrophys. (IF 3.8) Pub Date : 20230331
Qi Liu, Wei WangWe present a detailed temporal analysis for the eclipsing highmass Xray binary system Cen X3 using the InsightHXMT data in 2018 and 2020. Three consecutive and high statistic observations among data are used for the precise timing analysis. The pulse profiles are revealed to vary with energy and time. The pulse profiles for the 2018 observations showed a double peak in the low energy bands below

Sensitivity to pointlike sources of the ALTO atmospheric particle detector array, designed for 200 GeV–50 TeV γray astronomy J. High Energy Astrophys. (IF 3.8) Pub Date : 20230331
M. Punch, M. Senniappan, Y. Becherini, G. Kukec Mezek, S. Thoudam, T. Bylund, J.P. ErnenweinIn the context of atmospheric shower arrays designed for γray astronomy and in the context of the ALTO project, we present: a study of the impact of heavier nuclei in the cosmicray background on the estimated γray detection performance on the basis of dedicated Monte Carlo simulations, a method to calculate the sensitivity to a pointlike source, and finally the required observation times to reach

Gamma rays from nebulae around recurrent novae J. High Energy Astrophys. (IF 3.8) Pub Date : 20230330
W. Bednarek, J. SitarekNovae were discovered to emit transient γ rays during the period of several days to a few weeks after initial explosion, indicating presence of acceleration processes of particles in their expanding shells. In the case of recurrent novae, electrons can be in principle accelerated in the nova shells for the whole recurrence period of nova producing delayed γ ray emission as considered in Bednarek (2022)

The reconstruction of constant jerk parameter with f(R,T) gravity J. High Energy Astrophys. (IF 3.8) Pub Date : 20230315
Anirudh Pradhan, Gopikant Goswami, Aroonkumar BeeshamIn this work, we have developed an FLRW type model of a universe which displays transition from deceleration in the past to the acceleration at the present. For this, we have considered field equations of f(R,T) gravity and have taken f(R,T)=R+2λT, λ being an arbitrary constant. We have estimated the λ parameter in such a way that the transition red shift is found similar in the deceleration parameter

Highenergy neutrino fluxes from hardTeV BL Lacs J. High Energy Astrophys. (IF 3.8) Pub Date : 20230228
E. AguilarRuiz, N. Fraija, A. GalvánGámezBlazars have been pointed out as promising highenergy (HE) neutrinos sources, although the mechanism is still under debate. The blazars with a hardTeV spectrum, which leptonic models can hardly explain, can be successfully interpreted in the hadronic scenarios. Recently, Aguilar et al. proposed a leptohadronic twozone model to explain the multiwavelength observations of the six bestknown extreme

Energetic requirements of the gammaray emission from pulsars: A nonparametric analysis of the data in the FermiLAT 12Year Catalog J. High Energy Astrophys. (IF 3.8) Pub Date : 20230121
Houshang ArdavanThe prevalent view that the radioloud gammaray pulsars have gammaray luminosities that exceed their radio luminosities by several orders of magnitude is based on the assumption that the decay with distance of their gammaray fluxes obeys the inversesquare law as does that of their radio fluxes. The results presented here, of testing the hypothesis of independence of luminosities and distances of

Synchrotron selfcompton emission in the twocomponent jet model for gammaray bursts J. High Energy Astrophys. (IF 3.8) Pub Date : 20221222
Yuri Sato, Kaori Obayashi, B. Theodre Zhang, Shuta J. Tanaka, Kohta Murase, Yutaka Ohira, Ryo YamazakiGammaray bursts (GRBs) are intense bursts of highenergy photons (prompt emissions) caused by relativistic jets. After the emissions, multiwavelength afterglows, from radio to veryhighenergy (VHE) gammaray, last for more than a few days. In the past three years, the VHE gammaray photons from four GRBs (GRBs 180720B, 190114C, 190829A and 201216C) were detected by groundbased Imaging Atmospheric

Classification of pulsar glitch amplitudes using extreme deconvolution J. High Energy Astrophys. (IF 3.8) Pub Date : 20221219
Swetha Arumugam, Shantanu DesaiWe carry out a classification of the glitch amplitudes of radio pulsars using Extreme Deconvolution technique based on the Gaussian Mixture Model, where the observed uncertainties in the glitch amplitudes (Δνν) are taken into account. Our dataset consists of 699 glitches from 238 pulsars. We then use information theory criteria such as AIC and BIC to determine the optimum number of glitch classes.

Dependency of optical/UV parameters on Xray spectral index in AGNs J. High Energy Astrophys. (IF 3.8) Pub Date : 20221215
D. Nour, K. SriramThe study of Active Galactic Nuclei (AGNs) is vital in order to understand their respective nuclei bounded activity primarily triggered by the accretion disk and the associated corona. The hard Xray emission characterised by the spectral index Γ emitted by these sources in 210 keV band ionizes the nearby physical features like disk, BLR, NLR and provides a radiative configuration. However, based

Thermodynamical aspects of Bianchi typeI Universe in quadratic form of f(Q) gravity and observational constraints J. High Energy Astrophys. (IF 3.8) Pub Date : 20221209
M. Koussour, S.H. Shekh, M. Govender, M. BennaiIn this paper, we discuss the Bianchi typeI cosmological model in the framework of symmetric teleparallel gravity say f(Q) gravity in which the nonmetricity term Q is responsible for the gravitational interaction. We consider a special form of the f(Q) function which can be cast as f(Q)=λQn, where λ and n both are the dynamical model parameters. Such a choice can be viewed as a hybrid scale factor

Accretion disk wind during the outburst of the stellarmass black hole MAXI J1348630 J. High Energy Astrophys. (IF 3.8) Pub Date : 20221212
Hanji Wu, Wei Wang, Na SaiWe analyzed two observations of the lowmass black hole Xray binary MAXI J1348630 from Nuclear Spectroscopic Telescope Array (NuSTAR) during low hard state and hard intermediate state in the 2019 outburst. The reflection components are found in the Xray spectra, and the spectral fittings give an inclination angle of ∼25∘−35∘ for the binary system, and there is an absorption line around ∼7 keV coming

Dissipative unified dark fluid: Observational constraints J. High Energy Astrophys. (IF 3.8) Pub Date : 20221201
Esraa Ali Elkhateeb, Mahmoud HashimWe adopt a standard FRW cosmology with a unified scenario, where the usual dark matter and dark energy sectors are replaced by a single dissipative unified dark fluid (DUDF). The equation of state of such fluid can asymptote between two power laws. As a result, it enables fluid to have a smooth transition from dust at early times to dark energy at late times. The dissipation is represented by a bulk

Foreword J. High Energy Astrophys. (IF 3.8) Pub Date : 20221121
Giovanni Pareschi, Patrizia CaraveoAbstract not available

Xray properties of highredshift Radio Loud and Radio Quiet Quasars observed by Chandra J. High Energy Astrophys. (IF 3.8) Pub Date : 20221031
F. Shaban, A. Siemiginowska, R.M. Suleiman, M.S. ElNawawy, A. AliWe performed a study of high redshift (z>2) quasars, looking for the main differences between Radio Loud Quasars (RLQ) and Radio Quiet Quasars (RQQ) in the Xray band. Our sample of 472 RQQ and 81 RLQ was selected by crossmatching the SDSS DR7 quasars catalog with the Chandra Source Catalog. We computed the Xray luminosity for the two samples and confirmed the Xray luminosity excess of RLQ over

Interacting dark energy in curved FLRW spacetime from Weyl Integrable Spacetime J. High Energy Astrophys. (IF 3.8) Pub Date : 20221019
S. Chatzidakis, A. Giacomini, P.G.L. Leach, G. Leon, A. Paliathanasis, Supriya PanIn the present article, we show that a simple modification to the EinsteinHilbert action can explain the possibility of mutual interaction between the cosmic fluids. That is achieved considering the Weyl Integrable Spacetime in the background of a nonflat FriedmannLemaîtreRobertsonWalker geometry for the universe. We perform the dynamical system analysis of the underlying cosmological scenario

How unique are pulsar wind nebulae models? Implementation of a multiparameter, automatic fitting for timedependent spectra J. High Energy Astrophys. (IF 3.8) Pub Date : 20220928
J. Martin, D.F. TorresDue to the computational cost of calculating a great number of variations of the parameters, detailed radiative models of pulsar wind nebulae (PWNe) do not usually contain fitting algorithms. As a consequence, most of the models in the literature are, in fact, qualitative fits based on visual inspection. This is particularly true when complex, timedependent models are considered. Motivated by improvements

Special cases of the multimeasure model – Understanding the prolonged inflation J. High Energy Astrophys. (IF 3.8) Pub Date : 20220921
Denitsa StaicovaThe multimeasure model (MMM), in which one modifies the action to include both the Riemannian measure and a nonRiemannian one, has proven to be able to produce viable Universe evolution scenarios. In this article we consider two special cases of the multimeasure model, in which we first decouple the two kinetic terms in the Lagrangian entirely and later remove the dark charge of the model. We show

An extensive analysis of Schwarzschild exterior solution J. High Energy Astrophys. (IF 3.8) Pub Date : 20220913
Devanarayanan Rajeeb Kumar, Nibedita Chowdhury, S.D. Pathak, Umang Kumar, Manabendra Sharma, Vikash Kumar OjhaWe pursue a detailed analysis of the Schwarzschild geometry around a spherically symmetric, nonrotating, uncharged source and aim to construct the Schwarzschild metric by considering trigonometric, hyperbolic and logarithmic functions of position and time and solving the Einstein field equation. We investigate whether the Schwarzschild exterior solution is indeed independent of the choice of the nature

Highenergy and ultrahighenergy neutrinos: A Snowmass white paper J. High Energy Astrophys. (IF 3.8) Pub Date : 20220808
Markus Ackermann, Mauricio Bustamante, Lu Lu, Nepomuk Otte, Mary Hall Reno, Stephanie Wissel, Markus Ackermann, Sanjib K. Agarwalla, Jaime AlvarezMuñiz, Rafael Alves Batista, Carlos A. Argüelles, Mauricio Bustamante, Brian A. Clark, Austin Cummings, Sudipta Das, Valentin Decoene, Peter B. Denton, Damien Dornic, Shiqi YuAstrophysical neutrinos are excellent probes of astroparticle physics and highenergy physics. With energies far beyond solar, supernovae, atmospheric, and accelerator neutrinos, highenergy and ultrahighenergy neutrinos probe fundamental physics from the TeV scale to the EeV scale and beyond. They are sensitive to physics both within and beyond the Standard Model through their production mechanisms

Gravitational waves with dark energy J. High Energy Astrophys. (IF 3.8) Pub Date : 20220805
Jafar KhodagholizadehIn this article, we study the tensor mode equation of perturbation in the presence of nonzero−Λ as dark energy, the dynamic nature of which depends on the Hubble parameter H and/or its time derivative. Dark energy, according to the total vacuum contribution, has a slight effect during the radiationdominated era, but it reduces the squared amplitude of gravitational waves (GWs) up to 60% for the wavelengths

Implications for the Hubble tension from the ages of the oldest astrophysical objects J. High Energy Astrophys. (IF 3.8) Pub Date : 20220802
Sunny Vagnozzi, Fabio Pacucci, Abraham LoebWe use the ages of old astrophysical objects (OAO) in the redshift range 0≲z≲8 as stringent tests of the latetime cosmic expansion history. Since the age of the Universe at any redshift is inversely proportional to H0, requiring that the Universe be older than the oldest objects it contains at any redshift, provides an upper limit on H0. Using a combination of galaxies imaged from the CANDELS program

Study of general relativistic shocks and their propagation in neutron stars J. High Energy Astrophys. (IF 3.8) Pub Date : 20220802
Ritam Mallick, Anshuman VermaAstrophysical shocks are very common and are interesting as they are responsible for particle acceleration in supernovas, blazers, and neutron stars. In this work, we study general relativistic shocks in which the shock front is at rest. We derive the jump conditions and the Taub adiabat equation for both the spacelike and timelike shocks. We solve these equations for a neutron star where the shock

Updated neutrino mass constraints from galaxy clustering and CMB lensinggalaxy crosscorrelation measurements J. High Energy Astrophys. (IF 3.8) Pub Date : 20220722
Isabelle Tanseri, Steffen Hagstotz, Sunny Vagnozzi, Elena Giusarma, Katherine FreeseWe revisit cosmological constraints on the sum of the neutrino masses Σmν from a combination of fullshape BOSS galaxy clustering [P(k)] data and measurements of the crosscorrelation between Planck Cosmic Microwave Background (CMB) lensing convergence and BOSS galaxy overdensity maps [Cℓκg], using a simple but theoretically motivated model for the scaledependent galaxy bias in auto and crosscorrelation

Northern Hemisphere UHECR data further supports CMBR photons with weak U(1) component J. High Energy Astrophys. (IF 3.8) Pub Date : 20220718
Daniel PiaseckiI further test the theory that the Cosmic Background Radiation (CBR) is made of photons with a weak U(1) component. Tipler (2005) has previously argued that the consistency of the Standard Model (SM) with the Second Law of Thermodynamics requires the early universe CBR to be composed mainly of an SU(2) gauge field. The U(1) field would be suppressed. One of the consequences of this approach is that