Accretion disks around the Gibbons–Maeda–Garfinkle–Horowitz–Strominger charged black holes

Karimov, R. Kh.; Izmailov, R. N.; Bhattacharya, Amrita; Nandi, K. K.

doi:10.1140/epjc/s10052-018-6270-6

“…Strong gravitational lensing by GMGHS black hole was explored in [38], which showed that there are few observational differences between Schwarzchild and GMGHS black holes for strong lensing. Accretion disks around GMGHS black hole was studied in [39]. Last but not least, the (in)stability under charged scalar perturbations and the existence of scalar clouds of the GMGHS black hole were studied in [40][41][42][43][44][45][46].…”

Section: Introductionmentioning

confidence: 99%

Scattering of massless scalar field by charged dilatonic black holes

Huang

¹

,

Zhang

²

2020

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Wave propagations in the presence of black holes is a significant problem both in theoretical and observational aspects, especially after the discovery of gravitational wave and confirmation of black holes. We study the scattering of massless scalar field by a charged dilatonic black hole in frame of full wave theory. We apply partial wave method to obtain the scattering cross sections of the scalar field, and investigate how the black hole charge affects the scalar scattering cross sections. Furthermore, we investigate the Regge pole approach of the scattering cross section of the dilatonic black hole. We find that in order to obtain results at the same precision, we need more Regge poles as the black hole charge increases. We compare the results in the full wave theory and results in the classical geodesic scattering and the semi-classical glory approximations, and demonstrate the improvements and power of our approach.

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“…and going over to the EF via using (11,12), we obtain a solution that we claim to be just the everywhere regular EF EBWH describing the positive mass mouth. This is given by…”

Section: Jf Brans II ←→ Ebwhmentioning

confidence: 94%

“…There could be other categories of hypothetical objects such as naked singularity (NS) and wormholes (WH) that are not ruled out either by theory or by experiment to date. On the contrary, there has been a recent surge of interest a e-mail: izmailov.ramil@gmail.com (corresponding author) in the study of their observational signatures, which include, but not limited to, the phenomena of accretion [2][3][4][5][6][7][8][9][10][11][12][13][14][15], gravitational lensing [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31], shadow cast on the background of the thin accretion flow [32][33][34][35][36][37][38][39][40][41] and gravitational waves [42][43][44][45][46][47]…”

Section: Introductionmentioning

confidence: 99%

Can accretion properties distinguish between a naked singularity, wormhole and black hole?

Karimov¹,

Izmailov²,

Potapov

³

et al. 2020

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We first advance a mathematical novelty that the three geometrically and topologically distinct objects mentioned in the title can be exactly obtained from the Jordan frame vacuum Brans I solution by a combination of coordinate transformations, trigonometric identities and complex Wick rotation. Next, we study their respective accretion properties using the Page–Thorne model which studies accretion properties exclusively for $$r\ge r_{\text {ms}}$$ r ≥ r ms (the minimally stable radius of particle orbits), while the radii of singularity/throat/horizon $$r<r_{\text {ms}}$$ r < r ms . Also, its Page–Thorne efficiency $$\epsilon $$ ϵ is found to increase with decreasing $$r_{\text {ms}}$$ r ms and also yields $$\epsilon =0.0572$$ ϵ = 0.0572 for Schwarzschild black hole (SBH). But in the singular limit $$r\rightarrow r_{s}$$ r → r s (radius of singularity), we have $$\epsilon \rightarrow 1$$ ϵ → 1 giving rise to $$100 \%$$ 100 % efficiency in agreement with the efficiency of the naked singularity constructed in [10]. We show that the differential accretion luminosity $$\frac{d{\mathcal {L}}_{\infty }}{d\ln {r}}$$ d L ∞ d ln r of Buchdahl naked singularity (BNS) is always substantially larger than that of SBH, while Eddington luminosity at infinity $$L_{\text {Edd}}^{\infty }$$ L Edd ∞ for BNS could be arbitrarily large at $$r\rightarrow r_{s}$$ r → r s due to the scalar field $$\phi $$ ϕ that is defined in $$(r_{s}, \infty )$$ ( r s , ∞ ) . It is concluded that BNS accretion profiles can still be higher than those of regular objects in the universe.

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“…Accretion disks for other compact astrophysical objects such as neutron, boson and fermion stars and gravastars have been studied in [66][67][68][69][70][71][72][73][74]. In a recent work [75], the authors have studied thin accretion disks around electrically and magnetically charged Gibbons-Maeda-Garfinkle-Horowitz-Strominger (GMGHS) black holes. Also, k α iron line analysis and continuum-fitting method are used to distinguish different astrophysical objects through their accretion disks [76][77][78][79].…”

Section: Introductionmentioning

confidence: 99%

Thin accretion disks and charged rotating dilaton black holes

Heydari-Fard

¹

,

Sepangi

²

2020

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Einstein-Maxwell-dilaton theory is an interesting theory of gravity for studying scalar fields in the context of no-hair theorem. In this work, we consider static charged dilaton and charged, slowly rotating dilaton black holes in Einstein-Maxwell-dilaton gravity. We investigate the accretion process in thin disks around such black holes, using the Novikov-Thorne model. The electromagnetic flux, temperature distribution, energy conversion efficiency and also innermost stable circular orbits of thin disks are obtained and effects of dilaton and rotation parameters are studied. For the static and slowly rotating black holes the results are compared to that of Schwarzschild and Kerr, respectively.

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Accretion disks around the Gibbons–Maeda–Garfinkle–Horowitz–Strominger charged black holes

Cited by 27 publications

References 59 publications

Scattering of massless scalar field by charged dilatonic black holes

Scattering of massless scalar field by charged dilatonic black holes

Can accretion properties distinguish between a naked singularity, wormhole and black hole?

Thin accretion disks and charged rotating dilaton black holes

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