Satellite galaxies in the Illustris-1 simulation: anisotropic locations around relatively isolated hosts. (arXiv:1811.04942v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Brainerd_T/0/1/0/all/0/1">Tereasa G. Brainerd</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yamamoto_M/0/1/0/all/0/1">Masaya Yamamoto</a>
We investigate the locations of luminous satellite galaxies in the z = 0
redshift slice of the hydrodynamical Illustris-1 simulation. As expected from
previous studies, the satellites are distributed anisotropically in the plane
of the sky, with a preference for being located near the major axes of their
hosts. Due to misalignment of mass and light within the hosts, the degree of
anisotropy is considerably less when the mean satellite location is measured
with respect to the hosts’ stellar surface mass density than when it is
measured with respect to the hosts’ dark matter surface mass density. When
measured with respect to the hosts’ dark matter surface mass density, the mean
satellite location depends strongly on host stellar mass and luminosity, with
the satellites of the faintest, least massive hosts showing the greatest
anisotropy. This is caused by a strong correlation between the degree of
anisotropy in the plane of the sky and host-satellite proximity in 3-d. The
satellites of the faintest, least massive hosts are dominated by objects that
are close to their hosts in 3-d, whereas the satellites of the brightest, most
massive hosts are dominated by objects that are far from their hosts in 3-d.
When measured with respect to the hosts’ stellar surface mass density, the mean
satellite location is essentially independent of host stellar mass and
luminosity. The satellite locations are, however, dependent upon the stellar
masses of the satellites, with the most massive satellites having the most
anisotropic distributions.
We investigate the locations of luminous satellite galaxies in the z = 0
redshift slice of the hydrodynamical Illustris-1 simulation. As expected from
previous studies, the satellites are distributed anisotropically in the plane
of the sky, with a preference for being located near the major axes of their
hosts. Due to misalignment of mass and light within the hosts, the degree of
anisotropy is considerably less when the mean satellite location is measured
with respect to the hosts’ stellar surface mass density than when it is
measured with respect to the hosts’ dark matter surface mass density. When
measured with respect to the hosts’ dark matter surface mass density, the mean
satellite location depends strongly on host stellar mass and luminosity, with
the satellites of the faintest, least massive hosts showing the greatest
anisotropy. This is caused by a strong correlation between the degree of
anisotropy in the plane of the sky and host-satellite proximity in 3-d. The
satellites of the faintest, least massive hosts are dominated by objects that
are close to their hosts in 3-d, whereas the satellites of the brightest, most
massive hosts are dominated by objects that are far from their hosts in 3-d.
When measured with respect to the hosts’ stellar surface mass density, the mean
satellite location is essentially independent of host stellar mass and
luminosity. The satellite locations are, however, dependent upon the stellar
masses of the satellites, with the most massive satellites having the most
anisotropic distributions.
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