Dwarf satellite galaxies are thought to be the remnants of the population of
primordial structures that coalesced to form giant galaxies like the Milky Way.
An early analysis noted that dwarf galaxies may not be isotropically
distributed around our Galaxy, as several are correlated with streams of HI
emission, and possibly form co-planar groups. These suspicions are supported by
recent analyses, and it has been claimed that the apparently planar
distribution of satellites is not predicted within standard cosmology, and
cannot simply represent a memory of past coherent accretion. However, other
studies dispute this conclusion. Here we report the existence (99.998%
significance) of a planar sub-group of satellites in the Andromeda galaxy,
comprising approximately 50% of the population. The structure is vast: at least
400 kpc in diameter, but also extremely thin, with a perpendicular scatter
<14.1 kpc (99% confidence). Radial velocity measurements reveal that the
satellites in this structure have the same sense of rotation about their host.
This finding shows conclusively that substantial numbers of dwarf satellite
galaxies share the same dynamical orbital properties and direction of angular
momentum, a new insight for our understanding of the origin of these most dark
matter dominated of galaxies. Intriguingly, the plane we identify is
approximately aligned with the pole of the Milky Way's disk and is co-planar
with the Milky Way to Andromeda position vector. The existence of such
extensive coherent kinematic structures within the halos of massive galaxies is
a fact that must be explained within the framework of galaxy formation and
cosmology.
Description
[1301.0446] A Vast Thin Plane of Co-rotating Dwarf Galaxies Orbiting the Andromeda Galaxy
cite arxiv:1301.0446Comment: Published in the 3rd Jan 2013 issue of Nature. 19 pages, 4 figures, 1 three-dimensional interactive figure. To view and manipulate the 3-D figure, an Adobe Reader browser plug-in is required; alternatively save to disk and view with Adobe Reader
%0 Generic
%1 ibata2013plane
%A Ibata, Rodrigo A.
%A Lewis, Geraint F.
%A Conn, Anthony R.
%A Irwin, Michael J.
%A McConnachie, Alan W.
%A Chapman, Scott C.
%A Collins, Michelle L.
%A Fardal, Mark
%A Ferguson, Annette M. N.
%A Ibata, Neil G.
%A Mackey, A. Dougal
%A Martin, Nicolas F.
%A Navarro, Julio
%A Rich, R. Michael
%A Valls-Gabaud, David
%A Widrow, Lawrence M.
%D 2013
%K dwarf galaxies group local m31
%R 10.1038/nature11717
%T A Vast Thin Plane of Co-rotating Dwarf Galaxies Orbiting the Andromeda
Galaxy
%U http://arxiv.org/abs/1301.0446
%X Dwarf satellite galaxies are thought to be the remnants of the population of
primordial structures that coalesced to form giant galaxies like the Milky Way.
An early analysis noted that dwarf galaxies may not be isotropically
distributed around our Galaxy, as several are correlated with streams of HI
emission, and possibly form co-planar groups. These suspicions are supported by
recent analyses, and it has been claimed that the apparently planar
distribution of satellites is not predicted within standard cosmology, and
cannot simply represent a memory of past coherent accretion. However, other
studies dispute this conclusion. Here we report the existence (99.998%
significance) of a planar sub-group of satellites in the Andromeda galaxy,
comprising approximately 50% of the population. The structure is vast: at least
400 kpc in diameter, but also extremely thin, with a perpendicular scatter
<14.1 kpc (99% confidence). Radial velocity measurements reveal that the
satellites in this structure have the same sense of rotation about their host.
This finding shows conclusively that substantial numbers of dwarf satellite
galaxies share the same dynamical orbital properties and direction of angular
momentum, a new insight for our understanding of the origin of these most dark
matter dominated of galaxies. Intriguingly, the plane we identify is
approximately aligned with the pole of the Milky Way's disk and is co-planar
with the Milky Way to Andromeda position vector. The existence of such
extensive coherent kinematic structures within the halos of massive galaxies is
a fact that must be explained within the framework of galaxy formation and
cosmology.
@misc{ibata2013plane,
abstract = {Dwarf satellite galaxies are thought to be the remnants of the population of
primordial structures that coalesced to form giant galaxies like the Milky Way.
An early analysis noted that dwarf galaxies may not be isotropically
distributed around our Galaxy, as several are correlated with streams of HI
emission, and possibly form co-planar groups. These suspicions are supported by
recent analyses, and it has been claimed that the apparently planar
distribution of satellites is not predicted within standard cosmology, and
cannot simply represent a memory of past coherent accretion. However, other
studies dispute this conclusion. Here we report the existence (99.998%
significance) of a planar sub-group of satellites in the Andromeda galaxy,
comprising approximately 50% of the population. The structure is vast: at least
400 kpc in diameter, but also extremely thin, with a perpendicular scatter
<14.1 kpc (99% confidence). Radial velocity measurements reveal that the
satellites in this structure have the same sense of rotation about their host.
This finding shows conclusively that substantial numbers of dwarf satellite
galaxies share the same dynamical orbital properties and direction of angular
momentum, a new insight for our understanding of the origin of these most dark
matter dominated of galaxies. Intriguingly, the plane we identify is
approximately aligned with the pole of the Milky Way's disk and is co-planar
with the Milky Way to Andromeda position vector. The existence of such
extensive coherent kinematic structures within the halos of massive galaxies is
a fact that must be explained within the framework of galaxy formation and
cosmology.},
added-at = {2013-01-04T14:07:46.000+0100},
author = {Ibata, Rodrigo A. and Lewis, Geraint F. and Conn, Anthony R. and Irwin, Michael J. and McConnachie, Alan W. and Chapman, Scott C. and Collins, Michelle L. and Fardal, Mark and Ferguson, Annette M. N. and Ibata, Neil G. and Mackey, A. Dougal and Martin, Nicolas F. and Navarro, Julio and Rich, R. Michael and Valls-Gabaud, David and Widrow, Lawrence M.},
biburl = {https://www.bibsonomy.org/bibtex/23e7e9539c7e876466d42fbda77657c97/miki},
description = {[1301.0446] A Vast Thin Plane of Co-rotating Dwarf Galaxies Orbiting the Andromeda Galaxy},
doi = {10.1038/nature11717},
interhash = {d56f014de6343db668010c7247a3c39b},
intrahash = {3e7e9539c7e876466d42fbda77657c97},
keywords = {dwarf galaxies group local m31},
note = {cite arxiv:1301.0446Comment: Published in the 3rd Jan 2013 issue of Nature. 19 pages, 4 figures, 1 three-dimensional interactive figure. To view and manipulate the 3-D figure, an Adobe Reader browser plug-in is required; alternatively save to disk and view with Adobe Reader},
timestamp = {2013-01-04T14:07:46.000+0100},
title = {A Vast Thin Plane of Co-rotating Dwarf Galaxies Orbiting the Andromeda
Galaxy},
url = {http://arxiv.org/abs/1301.0446},
year = 2013
}