Document Type

Article

Publication Date

11-10-1998

Publication Title

The Astrophysical Journal

Department

Department of Physics and Astronomy

Abstract

In order to investigate the reality of large-scale streaming motion on scales of up to 150 Mpc, we have studied the peculiar motions of ~200 early-type galaxies in three directions of the South Equatorial Strip at distances out to ~20,000 km s-1. The new Automatic Plate Measuring Facility South Equatorial Strip Catalog (-175<δ<+25) was used to select the sample of field galaxies in three directions: (1) 15h10m-16h10m; (2) 20h30m-21h50m; (3) 00h10m-01h30m. New R-band CCD photometry and spectroscopic data for the galaxies are used. The fundamental plane distance-indicator relation is calibrated with Coma cluster data, and a correction for inhomogeneous Malmquist bias is applied to the distance estimates. A linear bulk flow model is fitted to the peculiar velocities in the sample regions, and the results do not reflect the bulk flow observed by Lauer and Postman (LP). Accounting for the difference in geometry between the galaxy distribution in the three regions and the LP clusters confirms the disagreement; assuming a low-density CDM power spectrum, we find that the observed bulk flow of the galaxies in our sample excludes the LP bulk flow at the 99.8% confidence level.

DOI

10.1086/311685

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