Accretion disks around the Gibbons\u2013Maeda\u2013Garfinkle\u2013Horowitz\u2013Strominger charged black holes

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

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

R Kh Karimov, K K Nandi + Show 2 more

Open Access

https://doi.org/10.1140/epjc/s10052-018-6270-6

Copy DOI

Abstract

It seems surprising that the emissivity properties of the accretion disk (à la Page and Thorne) surrounding the Gibbons–Maeda–Garfinkle–Horowitz–Strominger (GMGHS) black holes of heterotic string theory have not yet been studied. To fill this gap in the literature, we study the emissivity properties of the thin accretion disks around these black holes both in the Einstein and in the string frame using the Page–Thorne model. For illustration, we choose as a toy model a stellar-sized spherically symmetric black hole and find that, while the emissivity properties do not significantly differ from those of Reissner–Nordström and Schwarzschild black holes, they remarkably differ at GMGHS extreme limits corresponding to naked singularity and wormhole at higher frequencies. These differences provide a novel way to speculatively conclude about different types of objects from the observational point of view.

Highlights

String theory is a promising candidate for a consistent quantum theory of gravity and needless to say that the characteristics of black holes (BH) in string theory would be utmost interest
The thin accretion disk model further assumes that individual particles are moving on Keplerian orbits, but for this to be true the central object should have weak magnetic field, otherwise the orbits in the inner edge of the disk will be deformed
The present paper is devoted to studying the kinematic and emissivity properties of a central object represented by stringy Gibbons–Maeda–Garfinkle–Horowitz– Strominger (GMGHS) solutions in the Einstein frame (EF) and string frame (SF) using the Page–Thorne model

Summary

Introduction

String theory is a promising candidate for a consistent quantum theory of gravity and needless to say that the characteristics of black holes (BH) in string theory would be utmost interest. The work in [11], though useful in its own right, is distinct from the Page–Thorne emission model since it studied only the non-emissivity aspects of the fluid flow with the predicted mass accretion rate M 0 depending on the radius of the disk. The present paper is devoted to studying the kinematic and emissivity properties of a central object represented by stringy GMGHS solutions (not necessarily BHs) in the EF and SF using the Page–Thorne model.

GMGHS solutions

Thin accretion disk

GMGHS solutions: kinematic and accretion features

Findings

Summary