Cosmic bulk flows on 50 {h}^{-1}Mpc scales: A Bayesian hyper-parameter method and multishells likelihood analysis

Abstract

It has been argued recently that the galaxy peculiar velocity field provides evidence of excessive power on scales of $50\hmpc$, which seems to be inconsistent with the standard $\Lambda$CDM cosmological model. We discuss several assumptions and conventions used in studies of the large-scale bulk flow to check whether this claim is robust under a variety of conditions. Rather than using a composite catalogue we select samples from the SN, ENEAR, SFI++ and A1SN catalogues, and correct for Malmquist bias in each according to the IRAS PSCz density field. We also use slightly different assumptions about the small-scale velocity dispersion and the parameterisation of the matter power spectrum when calculating the variance of the bulk flow. By combining the likelihood of individual catalogues using a Bayesian hyper-parameter method, we find that the joint likelihood of the amplitude parameter gives ${\sigma }_8=0.65_{-0.35}^{+0.47}(\pm 1\sigma )$, which is entirely consistent with the $\Lambda$CDM model. In addition, the bulk flow magnitude ($v \sim 310 \kms$) and direction, $(l,b)\sim (280^{\circ }\pm 8^{\circ },5.1^{\circ }\pm 6^{\circ })$, found by each of the catalogues are all consistent with each other, and with the bulk flow results from most previous studies. Furthermore, the bulk flow velocities in different shells of the surveys constrain ${\sigma }_8$--${\Omega }_{\mathrm{m}}$ to be ($1.01_{-0.20}^{+0.26},0.31_{-0.14}^{+0.28}$, SFI++) and ($1.04_{-0.24}^{+0.32},0.28_{-0.14}^{+0.30}$, ENEAR), which is consistent with {\it WMAP} 7-year best-fit values. We finally discuss the differences between our conclusions and those of the studies claiming the largest bulk flows.

13 pages, 13 figures, MNRAS in press

References in corpus (6)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Improved Dark Energy Constraints from ~100 New CfA Supernova Type Ia Light Curves
• Improved Distances to Type Ia Supernovae with Multicolor Light Curve Shapes: MLCS2k2
• Maximum Likelihood algorithm for parametric component separation in CMB experiments
• The peculiar velocity field: constraining the tilt of the Universe
• Current Status Of Velocity Field Surveys: A Consistency Check

Cited by in corpus (42)

• Challenges for $\Lambda$CDM: An update
• Dark energy two decades after: Observables, probes, consistency tests
• Is the Observable Universe Consistent with the Cosmological Principle?
• Testing $\Lambda$CDM at the lowest redshifts with SN Ia and galaxy velocities
• The 6dF Galaxy Velocity Survey: Cosmological constraints from the velocity power spectrum
• Are peculiar velocity surveys competitive as a cosmological probe?
• Measuring cosmic bulk flows with Type Ia Supernovae from the Nearby Supernova Factory
• The 6dF Galaxy Survey: Bulk Flows on $50-70h^{-1}$ Mpc scales
• Anomalies in Physical Cosmology
• Observational constraints on the deceleration parameter in a tilted universe
• The 6dF Galaxy Survey: Fundamental Plane Data
• The Sloan Digital Sky Survey Peculiar Velocity Catalogue
• Planck intermediate results. XIII. Constraints on peculiar velocities
• 2MTF IV. A bulk flow measurement of the local Universe
• Constrained realizations of 2MRS density and peculiar velocity fields: growth rate and local flow
• Probing bulk flow with nearby SNe Ia data
• Differential cosmic expansion and the Hubble flow anisotropy
• An estimation of local bulk flow with the maximum-likelihood method
• No evidence for bulk velocity from type Ia supernovae
• Large-scale Cosmic Flows from Cosmicflows-2 Catalog
• 2MTF - VII. 2MASS Tully-Fisher survey final data release: distances for 2,062 nearby spiral galaxies
• Studying the Peculiar Velocity Bulk Flow in a Sparse Survey of Type-Ia SNe
• Bulk flow and shear in the local Universe: 2MTF and COSMICFLOWS-3
• Bulk flow in the combined 2MTF and 6dFGSv surveys
• Bulk Flow Motion Detection in the Local Universe with Pantheon$+$ Type Ia Supernovae
• The cosmological bulk flow in QCDM model: (In)consistency with $\Lambda CDM$
• Frames of most uniform Hubble flow
• Constraining cosmology with pairwise velocity estimator
• Cosmic Flow Measurement and Mock Sampling Algorithm of Cosmicflows-4 Tully-Fisher Catalogue
• Detectability of Cosmic Dark Flow in the Type Ia Supernova Redshift-Distance Relation
• Cosmology with Peculiar Velocities: Observational Effects
• How to combine correlated data sets -- A Bayesian hyperparameter matrix method
• Uneven flows: On cosmic bulk flows, local observers, and gravity
• The bulk flow motion and the Hubble-Lema\^ıtre law in the Local Universe with the ALFALFA survey
• Planck intermediate results. LIII. Detection of velocity dispersion from the kinetic Sunyaev-Zeldovich effect
• Gaussianization of peculiar velocities and bulk flow measurement
• Velocities hasten to tell us about the Universe
• The Polarization Signature of Local Bulk Flows
• The Low Redshift survey at Calar Alto (LoRCA)
• In search for the Local Universe dynamical homogeneity scale with CF4++ peculiar velocities
• Constraints on the birth of the universe and origin of cosmic dark flow
• Squared-field cross-correlation between kinetic Sunyaev-Zel'dovich effect and 21-cm intensity mapping