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The alignment between the distribution of satellites and the orientation of their central galaxy

Yang, Xiaohu ; Van Den Bosch, Frank C. ; Mo, H. J. ; Mao, Shude ; Kang, Xi ; Weinmann, Simone M. ; Guo, Yicheng ; Jing, Y. P.

In: Monthly Notices of the Royal Astronomical Society, 2006, vol. 369, no. 3, p. 1293-1302

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    Title
    • The alignment between the distribution of satellites and the orientation of their central galaxy
    Author
    • Yang, Xiaohu. Shanghai Astronomical Observatory, the Partner Group of MPA, Nandan Road 80, Shanghai 200030, China
    • Van Den Bosch, Frank C.. Max-Planck-Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany
    • Mo, H. J.. Department of Astronomy, University of Massachusetts, Amherst, MA 01003-9305, USA
    • Mao, Shude. University of Manchester, Jodrell Bank Observatory, Macclesfield, Cheshire SK11 9DL
    • Kang, Xi. Astrophysics Department, University of Oxford, Oxford OX1 3RH
    • Weinmann, Simone M.. Institute for Theoretical Physics, University of Zürich, CH-8057 Zürich, Switzerland
    • Guo, Yicheng. Department of Astronomy, University of Massachusetts, Amherst, MA 01003-9305, USA
    • Jing, Y. P.. Shanghai Astronomical Observatory, the Partner Group of MPA, Nandan Road 80, Shanghai 200030, China
    Document Type
    • Postprint
    OAI-PMH Identifier
    • oai:doc.rero.ch:296702
    Summary
    We use galaxy groups selected from the Sloan Digital Sky Survey to examine the alignment between the orientation of the central galaxy (defined as the brightest group member) and the distribution of satellite galaxies. By construction, we therefore only address the alignment on scales smaller than the halo virial radius. We find a highly significant alignment of satellites with the major axis of their central galaxy. This is in qualitative agreement with the recent study of Brainerd, but inconsistent with several previous studies who detected a preferential minor-axis alignment. The alignment strength in our sample is strongest between red central galaxies and red satellites. On the contrary, the satellite distribution in systems with a blue central galaxy is consistent with isotropic. We also find that the alignment strength is stronger in more massive haloes and at smaller projected radii from the central galaxy. In addition, there is a weak indication that fainter (relative to the central galaxy) satellites are more strongly aligned. We present a detailed comparison with previous studies, and discuss the implications of our findings for galaxy formation