Spectroscopy and Photometry of Elliptical Galaxies: A Large-Scale Streaming Motion in the Local Universe
Abstract
The authors present results from a study of the distances and velocities of elliptical galaxies out to ≡6000 km s-1. Distances are inferred from a new relation between central velocity dispersion and an angular diameter defined by integrated surface brightness. With this residual velocities Vobs - Vpred from a smooth Hubble flow are estimated. It is found that Vobs - Vpred, in coordinates with respect to the microwave background, exhibits a systematic variation over the celestial sphere. Interpreted as a large-scale bulk flow, this variation implies a mean motion of the ellipticals with respect to the microwave background of 599±104 km s-1 in the direction l = 312°±11°, b = 6°±10°. The data show that if the microwave dipole anisotropy is due to a motion of the Local Group of ≡600 km s-1, as conventionally interpreted, this motion is not primarily the result of gravitational acceleration by local (V < 5000 km s-1) mass concentrations.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 1987
- DOI:
- 10.1086/184827
- Bibcode:
- 1987ApJ...313L..37D
- Keywords:
-
- Astronomical Photometry;
- Astronomical Spectroscopy;
- Cosmology;
- Elliptical Galaxies;
- Local Group (Astronomy);
- Background Radiation;
- Distance;
- Microwaves;
- Red Shift;
- Velocity;
- Astrophysics;
- COSMIC BACKGROUND RADIATION;
- COSMOLOGY;
- GALAXIES: DISTANCES;
- GALAXIES: GENERAL;
- GALAXIES: REDSHIFTS