Silhouette and spectral line profiles in the special modification of the Kerr black hole geometry generated by quintessential fields

TL;DR

This paper investigates how quintessential fields with a specific equation-of-state parameter modify Kerr black hole geometries, affecting their silhouettes and spectral line profiles, with implications for astrophysical observations.

Contribution

It extends previous Kerr black hole models by incorporating quintessential fields with a particular equation-of-state parameter, analyzing their effects on optical signatures.

Findings

Silhouette size increases with quintessential parameter c

Spectral lines are redshifted due to quintessence influence

Shape of spectral lines remains nearly unchanged

Abstract

We study optical effects in quintessential Kerr black hole spacetimes corresponding to the limiting case of the equation-of-state parameter $\omega_{q}=-1/3$ of the quintessence. In dependence on the dimensionless quintessential field parameter $c$, we determine the black hole silhouette and the spectral line profiles of Keplerian disks generated in this special quintessential Kerr geometry, representing an extension of the general modifications of the Kerr geometry introduced recently by Ghasemi-Nodehi and Bambi \cite{Gha-Bam:2016:EPJC:}. We demonstrate that due to the influence of the parameter $c$, the silhouette is almost homogeneously enlarged, and the spectral line profiles are redshifted with almost conserved shape.