The alignment of satellite galaxies and cosmic filaments: observations and simulations

The accretion of satellites on to central galaxies along vast cosmic filaments is an apparent outcome of the anisotropic collapse of structure in our Universe. Numerical work (based on gravitational dynamics of N-body simulations) indicates that satellites are beamed towards hosts along preferred di...

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Bibliographic Details
Published in:Monthly notices of the Royal Astronomical Society 2015-07, Vol.450 (3), p.2727-2738
Main Authors: Tempel, E., Guo, Q., Kipper, R., Libeskind, N. I.
Format: Article
Language:English
Subjects:
Accretion disks
Alignment
Astronomy
Collapse
Computer simulation
Dynamical systems
Filaments
Galaxies
Satellites
Simulation
Stars & galaxies
Three dimensional
Universe
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Summary:The accretion of satellites on to central galaxies along vast cosmic filaments is an apparent outcome of the anisotropic collapse of structure in our Universe. Numerical work (based on gravitational dynamics of N-body simulations) indicates that satellites are beamed towards hosts along preferred directions imprinted by the velocity shear field. Here, we use the Sloan Digital Sky Survey to observationally test this claim. We construct 3D filaments and sheets and examine the relative position of satellite galaxies. A statistically significant alignment between satellite galaxy position and filament axis in observations is confirmed. We find a qualitatively compatible alignments by examining satellites and filaments similarly identified in the Millennium simulation, semi-analytical galaxy catalogue. We also examine the dependence of the alignment strength on galaxy properties such as colour, magnitude and (relative) satellite magnitude, finding that the alignment is strongest for the reddest and brightest central and satellite galaxies. Our results confirm the theoretical picture and the role of the cosmic web in satellite accretion. Furthermore our results suggest that filaments identified on larger scales can be reflected in the positions of satellite galaxies that are quite close to their hosts.
ISSN:0035-8711
1365-2966
DOI:10.1093/mnras/stv919