Eur. Phys. J. C (2015) 75: 553
https://doi.org/10.1140/epjc/s10052-015-3786-x

Regular Article - Theoretical Physics

Horizon structure of rotating Bardeen black hole and particle acceleration

¹ Centre for Theoretical Physics, Jamia Millia Islamia, New Delhi, 110025, India
² Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Private Bag X54001, Durban, 4000, South Africa

^* e-mail: amir@ctp-jamia.res.in
^** e-mail: amirctp12@gmail.com

Received: 6 October 2015
Accepted: 7 November 2015
Published online: 25 November 2015

Abstract

We investigate the horizon structure and ergosphere in a rotating Bardeen regular black hole, which has an additional parameter (g) due to the magnetic charge, apart from the mass (M) and the rotation parameter (a). Interestingly, for each value of the parameter g, there exists a critical rotation parameter (), which corresponds to an extremal black hole with degenerate horizons, while for it describes a non-extremal black hole with two horizons, and no black hole for . We find that the extremal value is also influenced by the parameter g, and so is the ergosphere. While the value of remarkably decreases when compared with the Kerr black hole, the ergosphere becomes thicker with the increase in g. We also study the collision of two equal mass particles near the horizon of this black hole, and explicitly show the effect of the parameter g. The center-of-mass energy () not only depend on the rotation parameter a, but also on the parameter g. It is demonstrated that the could be arbitrarily high in the extremal cases when one of the colliding particles has a critical angular momentum, thereby suggesting that the rotating Bardeen regular black hole can act as a particle accelerator.