18 citations · 74 across the 23 of their papers we have counts for
23 papers
Conformal Killing--Yano Ricci solitons: Structure, compatibility, and rigidity
Mohammadjavad Habibivostakolaei, Abbas M. Sherif, Yen-Kheng Lim
We introduce a geometric structure -- a conformal Killing--Yano Ricci soliton (CKY--RS) -- that couples conformal Ricci soliton (CRS) geometry to conformal Killing--Yano (CKY) 2--f…
Geodesic completeness of anisotropic cosmologies and the null energy condition
Sebastian Garcia-Saenz, Junjie Hua, Abbas M. Sherif
We demonstrate that a Bianchi-I spacetime in general relativity must be geodesically past-incomplete under the assumption of the null energy condition and provided there exists a t…
Conformal symmetries and MOTS stability
Abbas M. Sherif
Let be a spacelike foliation of a spacetime , and suppose each is foliated by 2-surfaces with spacelike unit normal in . We show tha…
Interior marginally outer trapped surfaces in Hayward black holes
Abbas M. Sherif, Yen-Kheng Lim
We locate interior marginally outer trapped and marginally outer trapped open surfaces (MOTS/MOTOS) in the regular Haward metric with parameter for which a critical (extremal)…
A complete correspondence between the Newman-Penrose and 1+1+2 formalisms
Abbas M Sherif, Peter K S Dunsby
We establish a correspondence between the Newman-Penrose and 1+1+2 semitetrad covariant formalisms by expressing all Newman-Penrose spin coefficients, Ricci scalars, and Weyl scala…
On conformal Komar currents in LRS spacetimes
Abbas M. Sherif
For locally rotationally symmetric (LRS) spacetimes, we construct two equivalent forms of the Komar current derived from a conformal Killing vector. One is a kinematic construction…
Instability of marginally outer trapped surfaces from initial data set symmetry
Abbas M. Sherif
Let be an initial data set and let be a symmetry vector of . Consider a MOTS in and let the symmetry vector be deco…
Causal dynamics of null horizons under linear perturbations
Peter K. S. Dunsby, Seoktae Koh, Abbas M. Sherif
We study the causal dynamics of an embedded null horizon foliated by marginally outer trapped surfaces (MOTS) for a locally rotationally symmetric background spacetime subjected to…
Gradient conformal stationarity and the CMC condition in LRS spacetimes
Gareth Amery, Peter K S Dunsby, Abbas M Sherif
We study the existence of gradient conformal Killing vectors (CKVs) in the class of locally rotationally symmetric (LRS) spacetimes which generalizes spherically symmetric spacetim…
On the existence of conformal Killing horizons in LRS spacetimes
Abbas M. Sherif
Let be a locally rotationally symmetric spacetime, and a conformal Killing vector for the metric on , lying in the subspace spanned by the unit timelike direction and…
Thermodynamics with conformal Killing vector in the charged Vaidya metric
Seoktae Koh, Miok Park, Abbas M. Sherif
We investigate the charged Vaidya spacetime with conformal symmetry by classifying the horizons and finding its connection to Hawking temperature. We find a conformal Killing vecto…
Existence of gradient CKV and gradient conformally stationary LRS spacetimes
Seoktae Koh, Abbas M Sherif, Gansukh Tumurtushaa
In this work, we study the existence of gradient (proper) CKVs in locally rotationally symmetric spacetimes (LRS), those CKVs in the space spanned by the tangent to observers' cong…
Horizon area bound and MOTS stability in locally rotationally symmetric solutions
Abbas M. Sherif, Peter K. S. Dunsby
In this paper, we study the stability of marginally outer trapped surfaces (MOTS), foliating horizons of the form , embedded in locally rotationally symmetric class II perf…
Conformal geometry on a class of embedded hypersurfaces in spacetimes
Abbas M. Sherif, Peter K. S. Dunsby
In this work, we study various properties of embedded hypersurfaces in decomposed spacetimes with a preferred spatial direction, denoted , which are orthogonal to the…
On some locally symmetric embedded spaces with non-negative scalar curvature and their characterization
Abbas M Sherif, Peter K S Dunsby, Rituparno Goswami
In this work we perform a general study of properties of a class of locally symmetric embedded hypersurfaces in spacetimes admitting a spacetime decomposition. The hypersur…
On the existence of marginally trapped tubes in spacetimes with local rotational symmetry
Abbas Sherif
Let be a locally rotationally symmetric spacetime with at least one of the rotation or spatial twist being non-zero. It is proved that cannot admit a non-minimal marginally…
On homothetic Killing vectors in stationary axisymmetric vacuum spacetimes
Abbas M. Sherif, Peter K. S. Dunsby, Rituparno Goswami +1
In this paper we consider homothetic Killing vectors in the class of stationary axisymmetric vacuum (SAV) spacetimes, where the components of the vectors are functions of the time…
Geometric properties of a certain class of compact dynamical horizons in locally rotationally symmetric class II spacetimes
Abbas M. Sherif, Peter K. S. Dunsby
In this paper we study the geometry of a certain class of compact dynamical horizons with a time-dependent induced metric in locally rotationally symmetric class II spacetimes. We…
Non-existence of expansion-free dynamical stars with rotation and spatial twist
Abbas Sherif, Rituparno Goswami, Sunil D. Maharaj
Extending a previous work by the same authors, we investigate the existence of expansion-free dynamical stars with non-zero spatial twist and rotation and show that such stars cann…
On Properties of Expansion-free Dynamical Stars
Abbas Sherif, Rituparno Goswami, Sunil D. Maharaj
We study the geometrical and dynamical features of expansion-free dynamical stars in general relativity. Such stars can exist only if particular physical and geometric conditions a…
Some Result on Cosmological and Astrophysical Horizons and Trapped Surfaces
Abbas Sherif, Rituparno Goswami, Sunil Maharaj
We study the evolution of horizons of black holes in the covariant setting and investigate various properties intrinsic to the geometry of the foliation surfaces of these h…
Relating a Geroch-like boundary and the abstract boundary constructions for spacetimes
Abbas Sherif, Gareth Amery
We construct a Geroch-like boundary (when restricted to geodesic curves, this boundary contains as a subset the Geroch's boundary), which we denote by , and establis…
Geometrical properties of trapped surfaces and apparent horizons
Abbas Sherif, Rituparno Goswami, Sunil D Maharaj
In this paper, we perform a detailed investigation on the various geometrical properties of trapped surfaces and the boundaries of trapped region in general relativity. This treatm…