Polytropic spheres modelling dark matter haloes of dwarf galaxies
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F47813059%3A19630%2F21%3AA0000127" target="_blank" >RIV/47813059:19630/21:A0000127 - isvavai.cz</a>
Result on the web
<a href="https://www.aanda.org/articles/aa/abs/2021/03/aa39338-20/aa39338-20.html" target="_blank" >https://www.aanda.org/articles/aa/abs/2021/03/aa39338-20/aa39338-20.html</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1051/0004-6361/202039338" target="_blank" >10.1051/0004-6361/202039338</a>
Alternative languages
Result language
angličtina
Original language name
Polytropic spheres modelling dark matter haloes of dwarf galaxies
Original language description
Dwarf galaxies and their dark matter (DM) haloes have velocity curves of a different character than those in large galaxies. These velocity curves are modelled by a simple pseudo-isothermal model containing only two parameters, which do not give us insight into the physics of the DM halo.Aims. We seek to obtain some insight into the physical conditions in DM haloes of dwarf galaxies by using a simple physically based model of DM haloes. To treat the diversity of the dwarf galaxy velocity profiles in a unifying framework, we applied polytropic spheres characterised by the polytropic index n and the relativistic parameter sigma as a model of dwarf-galaxy DM haloes and matched the velocity of circular geodesics of the polytropes to the velocity curves observed in the dwarf galaxies from the LITTLE THINGS ensemble. We introduce three classes of the LITTLE THINGS dwarf galaxies in relation to the polytrope models due to the different character of the velocity profile. The first class corresponds to polytropes that have n<1 with linearly increasing velocity along the whole profile, the second class has 1 < n < 2 and the velocity profile becomes flat in the external region, the third class has n > 2, and the velocity profile reaches a maximum and demonstrates a decline in the external region. The sigma parameter has to be strongly non-relativistic (sigma < 10^(-8)) for all dwarf galaxy models; this parameter varies for the models of each class, but these variations have negligible influence on the character of the velocity profile.Conclusions. Our results indicate a possibility that at least two different kinds of DM are behind the composition of DM haloes. The matches of the observational velocity curves are of the same quality as those obtained by the pseudo-isothermal, core-like models of dwarf galaxy DM haloes.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - 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)
Result continuities
Project
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Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2021
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Astronomy & Astrophysics
ISSN
0004-6361
e-ISSN
1432-0746
Volume of the periodical
467
Issue of the periodical within the volume
March
Country of publishing house
FR - FRANCE
Number of pages
16
Pages from-to
„A29-1“-„A29-16“
UT code for WoS article
000626206800001
EID of the result in the Scopus database
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