The High Fraction of Thin Disk Galaxies Continues to Challenge ?CDM Cosmology
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F22%3A10456042" target="_blank" >RIV/00216208:11320/22:10456042 - isvavai.cz</a>
Result on the web
<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=Tm49HZIOYv" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=Tm49HZIOYv</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.3847/1538-4357/ac46ac" target="_blank" >10.3847/1538-4357/ac46ac</a>
Alternative languages
Result language
angličtina
Original language name
The High Fraction of Thin Disk Galaxies Continues to Challenge ?CDM Cosmology
Original language description
Any viable cosmological framework has to match the observed proportion of early- and late-type galaxies. In this contribution, we focus on the distribution of galaxy morphological types in the standard model of cosmology (Lambda cold dark matter, ?CDM). Using the latest state-of-the-art cosmological ?CDM simulations known as Illustris, IllustrisTNG, and EAGLE, we calculate the intrinsic and sky-projected aspect ratio distribution of the stars in subhalos with stellar mass M (*) > 10(10) M (circle dot) at redshift z = 0. There is a significant deficit of intrinsically thin disk galaxies, which however comprise most of the locally observed galaxy population. Consequently, the sky-projected aspect ratio distribution produced by these ?CDM simulations disagrees with the Galaxy And Mass Assembly (GAMA) survey and Sloan Digital Sky Survey at >= 12.52 sigma (TNG50-1) and >= 14.82 sigma (EAGLE50) confidence. The deficit of intrinsically thin galaxies could be due to a much less hierarchical merger-driven build-up of observed galaxies than is given by the ?CDM framework. It might also arise from the implemented sub-grid models, or from the limited resolution of the above-mentioned hydrodynamical simulations. We estimate that an 8(5) times better mass resolution realization than TNG50-1 would reduce the tension with GAMA to the 5.58 sigma level. Finally, we show that galaxies with fewer major mergers have a somewhat thinner aspect ratio distribution. Given also the high expected frequency of minor mergers in ?CDM, the problem may be due to minor mergers. In this case, the angular momentum problem could be alleviated in Milgromian dynamics because of a reduced merger frequency arising from the absence of dynamical friction between extended dark matter halos.
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
2022
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Astrophysical Journal
ISSN
0004-637X
e-ISSN
1538-4357
Volume of the periodical
925
Issue of the periodical within the volume
2
Country of publishing house
US - UNITED STATES
Number of pages
20
Pages from-to
183
UT code for WoS article
000751072700001
EID of the result in the Scopus database
2-s2.0-85125849191