nLab KBC void

Idea

In astrophysics/cosmology, the KBC void (KBC13) refers to a large neighbourhood of the Milky Way whose average matter density is considerably smaller than on average in the observable universe.

In the context of inhomogeneous cosmology, this means that the Hubble constant effectively observed inside the void appears larger than that given by the cosmological constant of a large-scale homogeneous FRW model. It has been suggested that this might explain away the need for the dark energy hypothesis, or at least help explain recent tensions in different measurements of the Hubble constant, but the issue remains debated (Wu-Huterer 17).

Related concepts

• structure formation

References

Due to

• Ryan C. Keenan, Amy J. Barger, Lennox L. Cowie, Evidence for a ~300 Mpc Scale Under-density in the Local Galaxy Distribution, 2013, ApJ, 775, 62 (arXiv:1304.2884)

Review in:

• Phillip James E. Peebles, §4 of: Anomalies in Physical Cosmology [arXiv:2208.05018]

See also:

• Wikipedia, KBC void

Discussion in view of the observed Hubble constant:

• Hao-Yi Wu, Dragan Huterer, Sample variance in the local measurements of the Hubble constant, Monthly Notices of the Royal Astronomical Society, Volume 471, Issue 4, November 2017, Pages 4946–4955 (arXiv:1706.09723)

Discussion in view of MOND:

• Moritz Haslbauer, Indranil Banik, Pavel Kroupa, The KBC void and Hubble tension contradict ΛCDM on a Gpc scale − Milgromian dynamics as a possible solution, Monthly Notices of the Royal Astronomical Society, Volume 499, Issue 2, December 2020, Pages 2845–2883 (arXiv:2009.11292)