The Sloan Digital Sky Survey Peculiar Velocity Catalogue

Abstract

We present a new catalogue of distances and peculiar velocities (PVs) of 34, 059 early-type galaxies derived from Fundamental Plane (FP) measurements using data from the Sloan Digital Sky Survey (SDSS). This 7016 deg 2 sample comprises the largest set of peculiar velocities produced to date and extends the reach of PV surveys up to a redshift limit of 𝑧 = 0.1. Alongside the data, we produce an ensemble of 2, 048 mock galaxy catalogues that reproduce the data selection function, and are used to validate our fitting pipelines and check for systematics. We uncover a significant trend between group richness and mean surface brightness within the sample, which hints at an environmental dependence within the FP and can result in biased peculiar velocities. This is removed using multiple FP fits as function of group richness, a procedure made tractable through a new analytic derivation for the integral of a 3D Gaussian over non-trivial limits. Our catalogue is calibrated to the zero-point of the CosmicFlows-III sample with an uncertainty of 0.004 dex, which is cross-validated using the independent, predicted zero-point from the 2M++ reconstruction of our local velocity field. We achieve a mean uncertainty on the PVs of ∼ 23% compared to the CMB-frame redshift. Finally, as an example of what is possible with our new catalogue, we obtain preliminary bulk flow measurements up to a depth of 135 ℎ −1 Mpc. We find a slightly larger-than-expected bulk flow, although this could be caused by the presence of the Shapley supercluster lying just beyond the bounds of our data.

Cosmology Intertwined: A Review of the Particle Physics, Astrophysics, and Cosmology Associated with the Cosmological Tensions and Anomalies

“…The first possibility is consistent with previous results in the literature, where anomalously large bulk flows exceeding the expectations of ΛCDM have been observed [1630][1631][1632][1633][1634][1635], but in contrast to Refs. [1341,1342], at smaller scales.…”

Hints of FLRW breakdown from supernovae

“…It is worth noting that any residual dipole in the Low z sample shows consistent directional dependence with reported anomalous bulk flows [57,[90][91][92], which have most recently been recovered in Ref. [93]. Since we are working at low redshift, we have fixed Ω m0 ¼ 0.3.…”

Probing the Anisotropic Universe with Gravitational Waves

“…strong lensing time delay observations [22], it is premature to assign any statistical significance to such a small sample. That being said, since anisotropy claims in a coherent direction have emerged [2,3,4,5,6,17,23,24,28,29,30,31,32,33,34,35,39], while GW technology is still in its infancy, it is worth highlighting the potential for GW events to weigh in on the debate surrounding the anisotropic Universe, provided suitably localised events can be found.…”

“…Note, the local Universe is not FLRW and it is well documented that peculiar velocities map out a bulk flow in the direction of the Shapley supercluster at a distance of ∼ 200 Mpc [1]. As an aside, such bulk flows appear anomalously large from the perspective of the flat ΛCDM model [2,3,4,5,6]. Moreover, the bulk flows may terminate at Shapley, the Vela supercluster in the Zone of Avoidance, or they may continue beyond.…”