Dark matter halos modeled by polytropic spheres influenced by the relict cosmological constant and trapping polytropes forming supermassive black holes

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F47813059%3A19630%2F25%3AA0000411" target="_blank" >RIV/47813059:19630/25:A0000411 - isvavai.cz</a>

Result on the web

<a href="https://www.aanda.org/articles/aa/pdf/2025/10/aa54520-25.pdf" target="_blank" >https://www.aanda.org/articles/aa/pdf/2025/10/aa54520-25.pdf</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202554520" target="_blank" >10.1051/0004-6361/202554520</a>

Result language

angličtina

Original language name

Dark matter halos modeled by polytropic spheres influenced by the relict cosmological constant and trapping polytropes forming supermassive black holes

Original language description

Aims. We study dark matter halos modeled by general relativistic polytropic spheres in spacetimes with the repulsive cosmological constant representing vacuum energy density, governed by a polytropic index, n, and a relativistic (cosmological) parameter, σ (λ), determining the ratio of central pressure (vacuum energy density) and central energy density of the fluid. Methods. To give mapping of the polytrope parameters for matching the extension and mass of large dark matter halos, we study the properties of the polytropic spheres and introduce an effective potential of the geodesic motion in their internal spacetime. Circular geodesics enable us to find the limits of the trapping polytropes with central regions containing trapped null geodesics; supermassive black holes can be formed due to the instability of the central region against gravitational perturbations. The stability of the polytropic spheres relative to radial perturbations is determined. We match the extension and mass of the polytropes to the ones of dark matter halos related to large galaxies or galaxy clusters, with an extension of 100 &lt; `/kpc &lt; 5000 and gravitational mass of 1012 &lt; M/M &lt; 5 × 1015. The velocity radial profiles of circular geodesics in the polytrope spacetimes are numerically compared to the observed velocity profiles. Results. The observed velocity profiles simulated by the phenomenological dark matter halo density profiles can also be well matched by the velocity profiles of the exact polytrope spacetimes. The matching is made possible by the nonrelativistic polytropes for each value of n, with a relativistic parameter of σ ≤ 10−4 and a very low central energy density. Surprisingly, the matching works for “spread” relativistic polytropes with n &gt; 3.3 and σ ≥ 0.1 when the central density can be much larger. The trapping polytropes forming supermassive black holes must have n &gt; 3.8 and σ &gt; 0.667. We thus explain the mass and structure of large galaxies and galaxy clusters, their extension limited by the cosmic repulsion, and the existence of black holes with mass M &gt; 1010 M in very large galaxies; we suggest black holes with M ∼ 1012 M in large galaxy clusters.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

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Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2025

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

ASTRONOMY & ASTROPHYSICS

ISSN

0004-6361

e-ISSN

1432-0746

Volume of the periodical

702

Issue of the periodical within the volume

September 2025

Country of publishing house

FR - FRANCE

Number of pages

31

Pages from-to

„A2-1“-„A2-31“

UT code for WoS article

001582547500001

EID of the result in the Scopus database

2-s2.0-105017768820