Editing Lambda-CDM model (section)

=== El Gordo galaxy cluster collision ===
{{main|El Gordo (galaxy cluster)}}

[[El Gordo (galaxy cluster)|El Gordo]] is a massive interacting galaxy cluster in the early Universe (<math>z = 0.87</math>). The extreme properties of [[El Gordo (galaxy cluster)|El Gordo]] in terms of its redshift, mass, and the collision velocity leads to strong (<math>6.16\sigma</math>) tension with the ΛCDM model.<ref name="Asencio">{{Cite journal|last1=Asencio|first1=E|last2=Banik|first2=I|last3=Kroupa|first3=P|date=2021-02-21|title=A massive blow for ΛCDM – the high redshift, mass, and collision velocity of the interacting galaxy cluster El Gordo contradicts concordance cosmology|journal=Monthly Notices of the Royal Astronomical Society|volume=500|issue=2|pages=5249–5267|doi=10.1093/mnras/staa3441|arxiv=2012.03950|bibcode=2021MNRAS.500.5249A|issn=0035-8711|doi-access=free}}</ref><ref name="Asencio_2023">{{Cite journal|last1=Asencio|first1=E|last2=Banik|first2=I|last3=Kroupa|first3=P|date=2023-09-10|title=A massive blow for ΛCDM – the high redshift, mass, and collision velocity of the interacting galaxy cluster El Gordo contradicts concordance cosmology|journal=The Astrophysical Journal|volume=954|issue=2|pages=162|doi=10.3847/1538-4357/ace62a|doi-access=free|arxiv=2308.00744|bibcode=2023ApJ...954..162A|issn=1538-4357}}</ref> The properties of [[El Gordo (galaxy cluster)|El Gordo]] are however consistent with cosmological simulations in the framework of [[MOND]] due to more rapid structure formation.<ref name="Katz">{{Cite journal|last1=Katz|first1=H|last2=McGaugh|first2=S|last3=Teuben|first3=P|last4=Angus|first4=G. W.|date=2013-07-20|title=Galaxy Cluster Bulk Flows and Collision Velocities in QUMOND|journal = The Astrophysical Journal|volume=772|issue=1|page=10|doi=10.1088/0004-637X/772/1/10|arxiv=1305.3651|bibcode=2013ApJ...772...10K|issn=1538-4357|doi-access=free}}</ref>