J 2021

Trapping of null geodesics in slowly rotating extremely compact Tolman VII spacetimes

STUCHLÍK, Zdeněk and Jaroslav VRBA

Basic information

Original name

Trapping of null geodesics in slowly rotating extremely compact Tolman VII spacetimes

Authors

STUCHLÍK, Zdeněk (203 Czech Republic, belonging to the institution) and Jaroslav VRBA (203 Czech Republic, belonging to the institution)

Edition

European Physical Journal Plus, 2021, 2190-5444

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Field of Study

10308 Astronomy

Country of publisher

Germany

Confidentiality degree

není předmětem státního či obchodního tajemství

References:

RIV identification code

RIV/47813059:19630/21:A0000133

Organization unit

Institute of physics in Opava

UT WoS

000701060200003

Keywords in English

NEUTRON-STARS;FIELD;CONSTANT;DENSITY;SPHERES

Tags

Tags

International impact, Reviewed

Links

LTC18058, research and development project.
Změněno: 4/2/2022 14:01, Mgr. Pavlína Jalůvková

Abstract

V originále

Region of trapped null geodesics hidden inside of extremely compact objects is of astrophysical importance because of trapping of gravitational waves, or neutrinos. The trapping effect of null geodesics was extensively studied for spherically symmetric extremely compact objects. Recently, influence of rotation of the extremely compact objects on the trapping of null geodesics was treated in the simplest possible model of internal linearized Hartle-Thorne spacetime with uniform energy density distribution and uniform emissivity distribution of null geodesics. Here, we extend the study of the rotation influence on the trapping effect in the case of linearized Hartle-Thorne spacetimes based on the Tolman VII spherically symmetric solutions, where we assume the emissivity of the null geodesics proportional to the energy density of the Tolman VII object having quadratic radial profile. We demonstrate enhancement (suppression) of the trapping effect in the case of counter-rotating (co-rotating) null geodesics due to the behavior of the effective potentials and escape cones of the null geodesics in the linearized Hartle-Thorne-Tolman VII spacetimes. In dependence on the parameters of these spacetimes, we determine the "local" and "global" coefficients of efficiency of the trapping and compare the results to those related to the rotating spacetimes based on the internal Schwarzschild spacetimes. We demonstrate that in the Tolman VII spacetimes the trapping is more efficient, being allowed in objects with radii larger than those of the trapping internal Schwarzschild spacetimes, occurring even for R > 3.3 M.