Lambda-CDM model: Difference between revisions

Revision as of 10:16, 24 July 2025

Revision as of 10:19, 24 July 2025

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==== Satellite disk problem ====

Dwarf galaxies around the [[Milky Way]] and [[Andromeda Galaxy|Andromeda]] galaxies are observed to be orbiting in thin, planar structures whereas the simulations predict that they should be distributed randomly about their parent galaxies.<ref name=Pawlowski>{{cite journal |first1=Marcel |last1=Pawlowski |display-authors=etal |title=Co-orbiting satellite galaxy structures are still in conflict with the distribution of primordial dwarf galaxies |journal=Monthly Notices of the Royal Astronomical Society |volume=442 |issue=3 |pages=2362–2380 |year=2014 |arxiv=1406.1799|doi=10.1093/mnras/stu1005 |doi-access=free |bibcode=2014MNRAS.442.2362P }}</ref> However, latest research suggests this seemingly bizarre alignment is just a quirk which will dissolve over time.<ref name="Sawala">{{cite journal |first1=Till |last1=Sawala |first2=Marius |last2=Cautun |first3=Carlos |last3=Frenk |display-authors=etal |title=The Milky Way's plane of satellites: consistent with ΛCDM|journal=Nature Astronomy |year=2022 |volume=7 |issue=4 |pages=481–491 |arxiv=2205.02860|doi=10.1038/s41550-022-01856-z |bibcode=2023NatAs...7..481S|s2cid=254920916 }}</ref>

==== High-velocity galaxy problem ====

Galaxies in the [[NGC 3109]] association are moving away too rapidly to be consistent with expectations in the ΛCDM model.<ref>{{Cite journal|last1=Banik|first1=Indranil|last2=Zhao|first2=H|date=2018-01-21|title=A plane of high velocity galaxies across the Local Group|journal=Monthly Notices of the Royal Astronomical Society|volume=473|issue=3|pages=4033–4054|doi=10.1093/mnras/stx2596|arxiv=1701.06559|bibcode=2018MNRAS.473.4033B|issn=0035-8711|doi-access=free}}</ref> In this framework, [[NGC 3109]] is too massive and distant from the [[Local Group]] for it to have been flung out in a three-body interaction involving the [[Milky Way]] or [[Andromeda Galaxy]].<ref>{{Cite journal|last1=Banik|first1=Indranil|last2=Haslbauer|first2=Moritz|last3=Pawlowski|first3=Marcel S.|last4=Famaey|first4=Benoit|last5=Kroupa|first5=Pavel|date=2021-06-21|title=On the absence of backsplash analogues to NGC 3109 in the ΛCDM framework|journal=Monthly Notices of the Royal Astronomical Society|volume=503|issue=4|pages=6170–6186|doi=10.1093/mnras/stab751|arxiv=2105.04575|bibcode=2021MNRAS.503.6170B|issn=0035-8711|doi-access=free}}</ref>

==== High redshift galaxies ====