Observational appearances of a f(R) global monopole black hole illuminated by various accretions

Abstract In this paper, we explore three simple models of accretions on a global monopole black hole in f(R) theory, and numerically study the corresponding observational appearances as seen by an observer located at the asymptotic infinity and the certain region out of black hole. For the thin-disk...

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Autores principales:	Guo-Ping Li, Ke-Jian He
Formato:	article
Lenguaje:	EN
Publicado:	SpringerOpen 2021
Materias:	Astrophysics QB460-466 Nuclear and particle physics. Atomic energy. Radioactivity QC770-798
Acceso en línea:	https://doaj.org/article/b19a561395594cf192c42064476be7a4
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spelling	oai:doaj.org-article:b19a561395594cf192c42064476be7a42021-11-28T12:12:11ZObservational appearances of a f(R) global monopole black hole illuminated by various accretions10.1140/epjc/s10052-021-09817-y1434-60441434-6052https://doaj.org/article/b19a561395594cf192c42064476be7a42021-11-01T00:00:00Zhttps://doi.org/10.1140/epjc/s10052-021-09817-yhttps://doaj.org/toc/1434-6044https://doaj.org/toc/1434-6052Abstract In this paper, we explore three simple models of accretions on a global monopole black hole in f(R) theory, and numerically study the corresponding observational appearances as seen by an observer located at the asymptotic infinity and the certain region out of black hole. For the thin-disk accretion, the results here show that the brighter lensing ring and the darker photon ring that around black hole shadow, always make a small contribution and a negligible contribution to total observed intensity respectively. While, the direct emission of disk contributes a dominant part, and the size of shadow always depends on the disk’s location. For the static and infalling spherical accretions, it turns out that the radiuses of the shadows and photon spheres are always same for both accretions, which implies that the boundary of shadow represents the signature of the spacetime geometry in this case. However, we also find that the brightness of shadow in infalling accretion is darker than that in static case since the Doppler effect is taken into account. In addition, the effect of the global monopole parameter $$\eta $$ η and f(R) parameter $$\psi _0$$ ψ 0 on observational appearances of black hole are clearly emphasized throughout of this paper. Finally, we conclude that black hole shadows and the related rings with some different observable features can be used for us to distinguish black holes from different gravity theories and set the upper limits to the f(R) parameter $$\psi _0$$ ψ 0 .Guo-Ping LiKe-Jian HeSpringerOpenarticleAstrophysicsQB460-466Nuclear and particle physics. Atomic energy. RadioactivityQC770-798ENEuropean Physical Journal C: Particles and Fields, Vol 81, Iss 11, Pp 1-15 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Astrophysics QB460-466 Nuclear and particle physics. Atomic energy. Radioactivity QC770-798
spellingShingle	Astrophysics QB460-466 Nuclear and particle physics. Atomic energy. Radioactivity QC770-798 Guo-Ping Li Ke-Jian He Observational appearances of a f(R) global monopole black hole illuminated by various accretions
description	Abstract In this paper, we explore three simple models of accretions on a global monopole black hole in f(R) theory, and numerically study the corresponding observational appearances as seen by an observer located at the asymptotic infinity and the certain region out of black hole. For the thin-disk accretion, the results here show that the brighter lensing ring and the darker photon ring that around black hole shadow, always make a small contribution and a negligible contribution to total observed intensity respectively. While, the direct emission of disk contributes a dominant part, and the size of shadow always depends on the disk’s location. For the static and infalling spherical accretions, it turns out that the radiuses of the shadows and photon spheres are always same for both accretions, which implies that the boundary of shadow represents the signature of the spacetime geometry in this case. However, we also find that the brightness of shadow in infalling accretion is darker than that in static case since the Doppler effect is taken into account. In addition, the effect of the global monopole parameter $$\eta $$ η and f(R) parameter $$\psi _0$$ ψ 0 on observational appearances of black hole are clearly emphasized throughout of this paper. Finally, we conclude that black hole shadows and the related rings with some different observable features can be used for us to distinguish black holes from different gravity theories and set the upper limits to the f(R) parameter $$\psi _0$$ ψ 0 .
format	article
author	Guo-Ping Li Ke-Jian He
author_facet	Guo-Ping Li Ke-Jian He
author_sort	Guo-Ping Li
title	Observational appearances of a f(R) global monopole black hole illuminated by various accretions
title_short	Observational appearances of a f(R) global monopole black hole illuminated by various accretions
title_full	Observational appearances of a f(R) global monopole black hole illuminated by various accretions
title_fullStr	Observational appearances of a f(R) global monopole black hole illuminated by various accretions
title_full_unstemmed	Observational appearances of a f(R) global monopole black hole illuminated by various accretions
title_sort	observational appearances of a f(r) global monopole black hole illuminated by various accretions
publisher	SpringerOpen
publishDate	2021
url	https://doaj.org/article/b19a561395594cf192c42064476be7a4
work_keys_str_mv	AT guopingli observationalappearancesofafrglobalmonopoleblackholeilluminatedbyvariousaccretions AT kejianhe observationalappearancesofafrglobalmonopoleblackholeilluminatedbyvariousaccretions
_version_	1718408161390493696

Observational appearances of a f(R) global monopole black hole illuminated by various accretions

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