STUCHLÍK, Zdeněk, Jan SCHEE, Bobir TOSHMATOV, Jan HLADÍK a Jan NOVOTNÝ. Gravitational instability of polytropic spheres containing region of trapped null geodesics: a possible explanation of central supermassive black holes in galactic halos. Journal of Cosmology and Astroparticle Physics. 2017, neuveden, č. 6, s. „056- i, ii, 1“-„056-25“, 27 s. ISSN 1475-7516. Dostupné z: https://dx.doi.org/10.1088/1475-7516/2017/06/056. |
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Originální název | Gravitational instability of polytropic spheres containing region of trapped null geodesics: a possible explanation of central supermassive black holes in galactic halos |
Autoři | STUCHLÍK, Zdeněk (203 Česká republika, garant, domácí), Jan SCHEE (203 Česká republika, domácí), Bobir TOSHMATOV (860 Uzbekistán, domácí), Jan HLADÍK (203 Česká republika, domácí) a Jan NOVOTNÝ (203 Česká republika, domácí). |
Vydání | Journal of Cosmology and Astroparticle Physics, 2017, 1475-7516. |
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Originální jazyk | angličtina |
Typ výsledku | Článek v odborném periodiku |
Obor | 10308 Astronomy |
Stát vydavatele | Velká Británie a Severní Irsko |
Utajení | není předmětem státního či obchodního tajemství |
WWW | Journal of Cosmology and Astroparticle Physics |
Kód RIV | RIV/47813059:19240/17:A0000015 |
Organizace | Filozoficko-přírodovědecká fakulta – Slezská univerzita v Opavě – Repozitář |
Doi | http://dx.doi.org/10.1088/1475-7516/2017/06/056 |
UT WoS | 000408310600026 |
Klíčová slova anglicky | gravitational waves / theory; star formation; stars |
Štítky | CTP, GB14-37086G, SGS-14-2016, ÚF |
Příznaky | Mezinárodní význam, Recenzováno |
Návaznosti | GB14-37086G, projekt VaV. |
Změnil | Změnil: Jan Hladík, učo 1305. Změněno: 5. 4. 2018 17:17. |
Anotace |
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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. |