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Title: An inconsistency in the standard maximum likelihood estimation of bulk flows

Maximum likelihood estimation of the bulk flow from radial peculiar motions of galaxies generally assumes a constant velocity field inside the survey volume. This assumption is inconsistent with the definition of bulk flow as the average of the peculiar velocity field over the relevant volume. This follows from a straightforward mathematical relation between the bulk flow of a sphere and the velocity potential on its surface. This inconsistency also exists for ideal data with exact radial velocities and full spatial coverage. Based on the same relation, we propose a simple modification to correct for this inconsistency.
Authors:
 [1]
  1. Physics Department and the Asher Space Science Institute, Technion, Haifa 32000 (Israel)
Publication Date:
OSTI Identifier:
22370353
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 795; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COSMOLOGY; GALAXIES; MAXIMUM-LIKELIHOOD FIT; MODIFICATIONS; NONLUMINOUS MATTER; RADIAL VELOCITY; SURFACES; UNIVERSE