Thin accretion disk around a four-dimensional Einstein-Gauss-Bonnet black hole

• 来源期刊: 中国物理C（英文版）
• 年，卷（期）: 2021,（1）
• 所属期刊栏目: PARTICLE AND NUCLEAR ASTROPHYSICS AND COSMOLOGY
• 页码范围: 366-374
• 页数: 9页
• 语种: 英文
• DOI: 10.1088/1674-1137/abc16c

摘要

Recently,a novel four-dimensional Einstein-Gauss-Bonnet(4EGB)theory of gravity was proposed by Glavan and Lin[D.Glavan and C.Lin,Phys.Rev.Lett.124,081301(2020)],which includes a regularized Gauss-Bonnet term using the re-scalaring of the Gauss-Bonnet coupling constant α → α/(D-4)in the limit D → 4.This theory has also been reformulated to a specific class of the Homdeski theory with an additional scalar degree of free-dom and to a spatial covariant version with a Lagrangian multiplier,which can eliminate the scalar mode.Here,we study the physical properties of the electromagnetic radiation emitted from a thin accretion disk around a static spherically symmetric black hole in 4EGB gravity.For this purpose,we assume the disk is in a steady-state and in hydrodynamic and thermodynamic equilibrium,so that the emitted electromagnetic radiation is a black body spec-trum.We study in detail the effects of the Gauss-Bonnet coupling constant α in 4EGB gravity on the energy flux,temperature distribution,and electromagnetic spectrum of the disk.With an increase in the parameter α,the energy flux,temperature distribution,and electromagnetic spectrum of the accretion disk all increase.We also show that the accretion effiiciency increases with the growth of the parameter α.Our results indicate that the thin accretion disk around a static spherically symmetric black hole in 4EGB gravity is hotter,more luminous,and more efficient than that around a Schwarzschild black hole with the same mass for positive α,while it is cooler,less luminous,and less effiicient for negative α.