2021/07/31 by Jonathan Wong, Jonathan H. W. Wong, T. Shanks +2 · 32 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Galaxies: Formation, Evolution, Phenomena #Galaxy #Luminosity #Physics #Redshift #Redshift survey #Sky #Stellar, planetary, and galactic studies #astro-ph.CO
paper · pdf · open access · doi:10.1093/mnras/stac396
published in Monthly Notices of the Royal Astronomical Society 511(4), 5742-5755 (Oxford University Press) · 14 pages, 12 figures, Accepted by MNRAS on 7th February, 2022, references updated for publication
openalex publication_date 2022/02/13 · openalex created_date 2022/02/24 · arxiv created 2022/03/04 · arxiv updated 2022/03/09 · openalex updated_date 2026/07/23
We investigate the `Local Hole', an anomalous under-density in the local galaxy environment, by extending our previous galaxy K-band number-redshift and number-magnitude counts to ≈ 90% of the sky. Our redshift samples are taken from the 2MASS Redshift Survey (2MRS) and the 2M++ catalogues, limited to K<11.5. We find that both surveys are in good agreement, showing an ≈ 21-22% under-density at z<0.075 when compared to our homogeneous counts model that assumes the same luminosity function and other parameters as in our earlier papers. Using the Two Micron All Sky Survey (2MASS) for n(K) galaxy counts, we measure an under-density relative to this model of 20± 2 % at K<11.5, which is consistent in both form and scale with the observed n(z) under-density. To examine further the accuracy of the counts model, we compare its prediction for the fainter n(K) counts of the Galaxy and Mass Assembly (GAMA) survey. We further compare these data with a model assuming the parameters of a previous study where little evidence for the Local Hole was found. At 13<K<16 we find a significantly better fit for our model, arguing for our higher luminosity function normalisation. Although our implied under-density of ≈ 20% means local measurements of the Hubble Constant have been over-estimated by ≈3%, such a scale of under-density is in tension with a global ΛCDM cosmology at an ≈3σ level.