Observational appearances of hairy black holes in the framework of Gravitational Decoupling

Abstract

We investigate the observation appearance of the static and spherical symmetric hairy black holes in the framework of the gravitational decoupling with the weak energy condition. Two types of thin illumination conditions are studied, named spherical accretion and disk accretion. As the hairy parameter increases, the size of the photon sphere and photon rings in both models decreases, and the overall luminosity attenuation becomes more pronounced. In spherical accretion, the luminosity of infalling accretion is significantly lower than that of stationary accretion. In disk accretion the luminosity of the black hole is contributed by direct emission, lensing ring and photon ring. With four types of astrophysical disk luminosity model employed, we investigate the appearance of halos and note that the luminosity of them do not superimpose when the source is on and beyond the innermost stable circular orbit.