6 papers
Images of shadow and thin accretion disk around Bardeen black hole surrounded by perfect fluid dark matter
Haiyuan Feng, Ziqiang Cai, Hao-Peng Yan +2
We investigate the shadow and optical appearance of Bardeen black hole (BH) immersed in perfect fluid dark matter (PFDM). Using EHT observations of M87* and Sgr A*, we constrain th…
Shadow of rotating black hole surrounded by dark matter
Haiyuan Feng, Ziqiang Cai, Rong-Jia Yang +1
Dark matter (DM), a fundamental cosmic component, motivates the study of its influence on black hole (BH) shadows, especially for spinning BHs confirmed by EHT observations. This w…
Newtonian potential from scattering amplitudes in super-renormalizable gravity
Haiyuan Feng, Rong-Jia Yang, Jinjun Zhang
Based on the classical limit of relativistic scattering amplitudes, we compute the coupling between a general super-renormalizable gravity and massive scalar particles. This allows…
The stability of the de-Sitter universe in nonlocal gravity
Haiyuan Feng, Rong-Jia Yang
We constructed the ghost-free condition for nonlocal gravity using de-Sitter background field expansion and identified the structure of the nontrivial form factors. Our analysis sh…
Damping of gravitational waves in f(R) gravity
Haiyuan Feng, Laiyuan Su, Rong-Jia Yang +1
We investigate the damping of gravitational waves (GW) in gravity by matter. By applying the kinetic theory, we examine the first-order approximation of the relativistic Bol…
Thin accretion disk and shadow of Kerr-Sen black hole in Einstein-Maxwell-dilaton-axion gravity
Haiyuan Feng, Rong-Jia Yang, Wei-Qiang Chen
We investigate the thin disk and shadow of Kerr-Sen black hole in Einstein-Maxwell-dilaton-axion gravity. The results reveal that as the dilaton parameter increase, the energ…