The remnants of galaxy formation from a panoramic survey of the region around M31

Date

2009

Authors

McConnachie, Alan W
Irwin, M. J.
Ibata, Rodrigo A
Dubinski, John
Widrow, L. M.
Martin, N F
Cote, P
Dotter, Aaron
Navarro, J F
Ferguson, A. M. N.

Journal Title

Journal ISSN

Volume Title

Publisher

Macmillan Publishers Ltd

Abstract

In hierarchical cosmological models, galaxies grow in mass through the continual accretion of smaller ones. The tidal disruption of these systems is expected to result in loosely bound stars surrounding the galaxy, at distances that reach 10-100 times the radius of the central disk. The number, luminosity and morphology of the relics of this process provide significant clues to galaxy formation history, but obtaining a comprehensive survey of these components is difficult because of their intrinsic faintness and vast extent. Here we report a panoramic survey of the Andromeda galaxy (M31). We detect stars and coherent structures that are almost certainly remnants of dwarf galaxies destroyed by the tidal field of M31. An improved census of their surviving counterparts implies that three-quarters of M31?s satellites brighter than Mv =-6 await discovery. The brightest companion, Triangulum (M33), is surrounded by a stellar structure that provides persuasive evidence for a recent encounter with M31. This panorama of galaxy structure directly confirms the basic tenets of the hierarchical galaxy formation model and reveals the shared history of M31 and M33 in the unceasing build-up of galaxies.

Description

Keywords

Keywords: cosmochemistry; modeling; survey; article; astronomy; cosmological phenomena; luminance; priority journal; telecommunication; Andromeda

Citation

Source

Nature

Type

Journal article

Book Title

Entity type

Access Statement

License Rights

Restricted until

2037-12-31