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The Astrophysical Journal


Department of Physics and Astronomy


We use Tully-Fisher distances for a sample of field late spiral galaxies to test the Lauer & Postman result suggestive of a bulk flow with respect to the cosmic microwave background reference frame, of amplitude of +689 km s-1 in the direction l = 343°, b = +52°. A total of 432 galaxies are used, subdivided between two cones, of 30° semiaperture each and pointed toward the apex and antapex of the LP motion, respectively. The peculiar velocities in the two data sets are inconsistent with a bulk flow of the amplitude claimed by Lauer & Postman. When combined in opposition, the peculiar velocity medians in shells of constant redshift width are never larger than half the amplitude of the Lauer & Postman bulk flow. Out to 5000 km s-1 the median bulk velocity in the Lauer & Postman apex-antapex cones is about 200 km s-1 or less, dropping to a value indistinguishable from zero beyond that distance. It can be excluded that field spiral galaxies within 8000 km s-1 partake of a bulk flow of the amplitude and direction reported by Lauer & Postman.