arXiv subjects

Jing-Ya Zhao

Publications and source records attributed to Jing-Ya Zhao.

3 recordsLinked to original sources

arXiv2026

Radiation properties of a regular black hole embedded in a Dehnen-type dark matter halo with a thin accretion disk

We investigate the shadow, timelike geodesic structure, radiation properties of thin accretion disks, and optical appearance of a static spherically symmetric regular black hole, constructed based on the Dehnen-type density profile. Using observational data from M87* and Sgr A*, we constrain the model parameter $a$ at both $1σ$ and $2σ$ confidence levels. Based on the Page--Thorne model, we calculate the local radiative flux, redshift factor distribution, and the radiation flux received by a distant observer, systematically examining the effects of the parameter $a$ and the viewing angle on the black hole image. The results show that larger $a$ will enlarge the effective radiation area of the accretion disk and significantly enhance the asymmetry and Doppler boosting effects of the direct and secondary images at large viewing angles.

gr-qc↗

arXiv2026

Observational Signatures of Accretion Disks around a Schwarzschild Black Hole in a Hernquist Dark Matter Halo

We investigate how a Hernquist type dark matter (DM) halo, parametrized by its core radius $r_{s}$ and central density $ρ_{s}$, influences both the gravitational wave (GW) emission from timelike periodic orbits and the electromagnetic appearance of a thin accretion disk around a Schwarzschild black hole (BH). By analyzing the effective potential for timelike geodesics, we show that the DM halo shifts the marginally bound orbit (MBO) and the innermost stable circular orbit (ISCO) outward, reflecting its modification of the spacetime geometry and the energy-angular momentum structure of particle motion. Employing a semi-analytical method, we compute orbital trajectories and the associated GW waveforms, revealing that the DM halo alters the characteristic zoom-whirl dynamics and induces measurable changes in waveform morphology. Furthermore, we generate direct and secondary images of the accretion disk across various observer inclinations and find that increasing $r_{s}$ or $ρ_{s}$ results in cooler, dimmer disks with modified flux distributions. Our results demonstrate that the presence of a DM halo imprints distinct signatures in both gravitational and electromagnetic observables, offering a multimessenger pathway to probe DM environments near BHs.

gr-qc↗

arXiv2025

A parameterized equation of state for dark energy and Hubble Tension

We propose a parameterized equation of state for dark energy and perform observational tests with the Hubble parameter measurements, the Pantheon supernova sample, and DESI DR2 data. We obtain the best-fit values for the parameters as: $H_0 = 73.28\pm 0.15~\mathrm{km\,s^{-1}\, Mpc^{-1}}$, $\Omega_{\rm m} = 0.316\pm 0.011$, and $\alpha = 0.00032\pm 0.00046$, demonstrating that the model exhibits a high degree of consistency with astronomical observations and provides a promising parameterized method for addressing the Hubble tension.

gr-qc↗