The redshifts of ≈ 250000 galaxies are used to study the Local Hole and its associated peculiar velocities. The sample, compiled from 6dF Galaxy Redshift Survey (6dFGS) and Sloan Digital Sky Survey (SDSS), provides wide sky coverage to a depth of ≈ 300h −1 Mpc. We have therefore examined K and r limited galaxy redshift distributions and number counts to map the local density field. Comparing observed galaxy n(z) distributions to homogeneous models in three large regions of the high latitude sky, we find evidence for under-densities ranging from ≈4-40% in these regions to depths of ≈150h −1 Mpc with the deepest under-density being over the Southern Galactic cap. Using the Galaxy and Mass Assembly (GAMA) survey we then establish the normalisation of galaxy counts at fainter magnitudes and thus confirm that the underdensity over all three fields at K < 12.5 is ≈ 15 ± 3%. Finally, we further use redshift catalogues to map sky-averaged peculiar velocities over the same areas using the average redshift -magnitude, z(m), technique of Soneira (1979). After accounting for the direct effect of large-scale structure on z(m) we can then search for peculiar velocities. Taking all three regions into consideration the data reject at the ≈ 4σ level the idea that we have recovered the CMB rest frame in the volume probed. We therefore conclude that there is some consistent evidence from both counts and Hubble diagrams for a 'Local Hole' with a ≈ 150h −1 Mpc under-density that deeper counts and redshifts in the Northern Galactic cap suggest may extend to ≈ 300h −1 Mpc.

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The prime evidence underpinning the standard ΛCDM cosmological model is the CMB power spectrum as observed by WMAP and other microwave experiments. But Sawangwit & Shanks (2010a) have recently shown that the WMAP CMB power spectrum is highly sensitive to the beam profile of the WMAP telescope. Here, we use the source catalogue from the Planck Early Data Release to test further the WMAP beam profiles. We confirm that stacked beam profiles at Q, V and particularly at W appear wider than expected when compared to the Jupiter beam, normalised either directly to the radio source profiles or using Planck fluxes. The same result is also found based on WMAP -CMBfree source catalogues and NVSS sources. The accuracy of our beam profile measurements is supported by analysis of CMB sky simulations. However the beam profiles from WMAP 7 at the W band are narrower than previously found in WMAP 5 data and the rejection of the WMAP beam is now only at the ≈ 3σ level. We also find that the WMAP source fluxes demonstrate possible non-linearity with Planck fluxes. But including ground-based and Planck data for the bright Weiland et al. (2011) sources may suggest that the discrepancy is a linear offset rather than a non-linearity. Additionally, we find that the stacked Sunyaev-Zel'dovich (SZ) decrements of ≈ 151 galaxy clusters observed by Planck are in agreement with the WMAP data. We find that there is no evidence for a WMAP SZ deficit as has previously been reported. In the particular case of Coma we find evidence for the presence of an O(0.1mK) downwards CMB fluctuation. We conclude that beam profile systematics can have significant effects on both the amplitude and position of the acoustic peaks, with potentially important implications for cosmology parameter fitting.

We revisit our mapping of the 'Local Hole', a large underdensity in the local galaxy redshift distribution that extends out to redshift, z ≈ 0.05 and a potential source of outflows that may perturb the global expansion rate and thus help mitigate the present 'H 0 tension'. First, we compare local peculiar velocities measured via the galaxy average redshift-magnitude Hubble diagram, z(m), with a simple dynamical outflow model based on the average underdensity in the Local Hole. We find that this outflow model is in good agreement with our peculiar velocity measurements from z(m) and not significantly inconsistent with SNIa peculiar velocity measurements from at least the largest previous survey. This outflow could cause an ≈ 2 − 3% increase in the local value of Hubble's constant. Second, considering anisotropic motions, we find that the addition of the outflow model may improve the z(m) fit of a bulk flow where galaxies are otherwise at rest in the Local Group frame. We conclude that the Local Hole plus neighbouring overdensities such as the Shapley Supercluster may cause outflow and bulk motions out to ≈ 150h −1 Mpc that are cosmologically significant and that need to be taken into account in estimating Hubble's constant.

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 per cent of the sky. Our redshift samples are taken from the 2MASS Redshift Survey (2MRS) and the 2M++ catalogues, limited to K &lt; 11.5. We find that both surveys are in good agreement, showing an $\approx 21-22{{\ \rm per\ cent}}$ under-density at z &lt; 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 $20 \pm 2 {{\ \rm per\ cent}}$ at K &lt; 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 &lt; K &lt; 16 we find a significantly better fit for our galaxy counts model, arguing for our higher luminosity function normalization. Although our implied under-density of $\approx 20{{\ \rm per\ cent}}$ means local measurements of the Hubble Constant have been over-estimated by ≈3 per cent, such a scale of under-density is in tension with a global ΛCDM cosmology at an ≈3σ level.