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ISRN Astronomy and Astrophysics
Volume 2011 (2011), Article ID 958973, 11 pages
http://dx.doi.org/10.5402/2011/958973
Research Article

Locations of Satellite Galaxies in the Two-Degree Field Galaxy Redshift Survey

Department of Astronomy, Boston University, 725 Commonwealth Avenue, Boston, MA, 02215, USA

Received 24 June 2011; Accepted 8 August 2011

Academic Editors: J. A. L. Aguerri, E. Benitez, A. J. R. Sanderson, and W. W. Zeilinger

Copyright © 2011 Ingólfur Ágústsson and Tereasa G. Brainerd. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We compute the locations of satellite galaxies in the Two-Degree Field Galaxy Redshift Survey using two sets of selection criteria and three sources of photometric data. Using the SuperCOSMOS 𝑟 𝐹 photometry, we find that the satellites are located preferentially near the major axes of their hosts, and the anisotropy is detected at a highly significant level (confidence levels of 99.6% to 99.9%). The locations of satellites that have high velocities relative to their hosts are statistically indistinguishable from the locations of satellites that have low velocities relative to their hosts. Additionally, satellites with passive star formation are distributed anisotropically about their hosts (99% confidence level), while the locations of star-forming satellites are consistent with an isotropic distribution. These two distributions are, however, statistically indistinguishable. Therefore it is not correct to interpret this as evidence that the locations of the star-forming satellites are intrinsically different from those of the passive satellites.