Detailed Information on Publication Record
2017
Gravitational instability of polytropic spheres containing region of trapped null geodesics: a possible explanation of central supermassive black holes in galactic halos
STUCHLÍK, Zdeněk, Jan SCHEE, Bobir TOSHMATOV, Jan HLADÍK, Jan NOVOTNÝ et. al.Basic information
Original name
Gravitational instability of polytropic spheres containing region of trapped null geodesics: a possible explanation of central supermassive black holes in galactic halos
Authors
STUCHLÍK, Zdeněk (203 Czech Republic, guarantor, belonging to the institution), Jan SCHEE (203 Czech Republic, belonging to the institution), Bobir TOSHMATOV (860 Uzbekistan, belonging to the institution), Jan HLADÍK (203 Czech Republic, belonging to the institution) and Jan NOVOTNÝ (203 Czech Republic, belonging to the institution)
Edition
Journal of Cosmology and Astroparticle Physics, 2017, 1475-7516
Other information
Language
English
Type of outcome
Článek v odborném periodiku
Field of Study
10308 Astronomy
Country of publisher
United Kingdom of Great Britain and Northern Ireland
Confidentiality degree
není předmětem státního či obchodního tajemství
References:
RIV identification code
RIV/47813059:19240/17:A0000015
Organization
Filozoficko-přírodovědecká fakulta – Slezská univerzita v Opavě – Repository
UT WoS
000408310600026
Keywords in English
gravitational waves / theory; star formation; stars
Tags
Tags
International impact, Reviewed
Links
GB14-37086G, research and development project.
Změněno: 5/4/2018 17:17, Jan Hladík
Abstract
V originále
We study behaviour of gravitational waves in the recently introduced general relativistic polytropic spheres containing a region of trapped null geodesics extended around radius of the stable null circular geodesic that can exist for the polytropic index N > 2.138 and the relativistic parameter, giving ratio of the central pressure p_c to the central energy density rho_c, higher than sigma = 0.677. In the trapping zones of such polytropes, the effective potential of the axial gravitational wave perturbations resembles those related to the ultracompact uniform density objects, giving thus similar long-lived axial gravitational modes. These long-lived linear perturbations are related to the stable circular null geodesic and due to additional non-linear phenomena could lead to conversion of the trapping zone to a black hole. We give in the eikonal limit examples of the long-lived gravitational modes, their oscillatory frequencies and slow damping rates, for the trapping zones of the polytropes with N is an element of (2.138, 4). However, in the trapping polytropes the long-lived damped modes exist only for very large values of the multipole number l > 50, while for smaller values of l the numerical calculations indicate existence of fast growing unstable axial gravitational modes. We demonstrate that for polytropes with N >= 3.78, the trapping region is by many orders smaller than extension of the polytrope, and the mass contained in the trapping zone is about 10^(-3) of the total mass of the polytrope. Therefore, the gravitational instability of such trapping zones could serve as a model explaining creation of central supermassive black holes in galactic halos or galaxy clusters.