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Amir Hadi Ziaie

Amir Hadi Ziaie

Academic rank: Assistant Professor
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Education: PhD.
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Faculty: Research Institute for Astronomy and Astrophysics
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Research

Title
Naked Singularity Formation In f(R) Gravity
Type
JournalPaper
Keywords
Gravitational Collapse, Naked Singularity, Black Hole
Year
2011
Journal GENERAL RELATIVITY AND GRAVITATION
DOI
Researchers Amir Hadi Ziaie ، Khedmat Atazadeh ، Seyed Meraj Mousavi Rasouli

Abstract

We study the gravitational collapse of a star with barotropic equation of state p=w\rho in the context of f(R) theories of gravity. Utilizing the metric formalism, we rewrite the field equations as those of Brans-Dicke theory with vanishing coupling parameter. By choosing the functionality of Ricci scalar as f(R)=\alphaR^m, we show that for an appropriate initial value of the energy density, if α and m satisfy certain conditions, the resulting singularity would be naked, violating the cosmic censorship conjecture. These conditions are the ratio of the mass function to the area radius of the collapsing ball, negativity of the effective pressure, and the time behavior of the Kretschmann scalar. Also, as long as parameter α obeys certain conditions, the satisfaction of the weak energy condition is guaranteed by the collapsing configuration.