Investigating the Stellar Mass Growth Histories of Satellite Galaxies as a Function of Infall Time using Phase-Space. (arXiv:1904.07340v1 [astro-ph.GA])

Investigating the Stellar Mass Growth Histories of Satellite Galaxies as a Function of Infall Time using Phase-Space. (arXiv:1904.07340v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Smith_R/0/1/0/all/0/1">Rory Smith</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pacifici_C/0/1/0/all/0/1">Camilla Pacifici</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pasquali_A/0/1/0/all/0/1">Anna Pasquali</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Calderon_Castillo_P/0/1/0/all/0/1">Paula Calderon-Castillo</a>

We compile a large sample of nearby galaxies that are satellites of hosts
using a well known SDSS group catalogue. From this sample, we create an
`ancient infallers’ and `recent infallers’ subsample, based on the mean infall
time predicted from cosmological simulations for galaxies with their location
in phase-space. We compare the stellar mass growth histories of the galaxies in
these two subsamples, as determined from multi-wavelength SED fitting that uses
a comprehensive library of star formation history shapes derived from
cosmological simulations. By simultaneously controlling for satellite stellar
mass and host halo mass, we can clearly see the impact of time spent in their
hosts. As we might predict, the ancient infaller population shows clear signs
of earlier quenching, especially for lower mass satellites in more massive
hosts. More importantly, we find the effects are not limited to massive hosts.
We find that hosts which might be considered low mass groups (halo masses
$sim$10$^{13}$ M$_odot$) can significantly alter their satellites, even for
massive satellites (stellar masses $sim$10$^{10}$ M$_odot$). Intriguingly, we
see changes in the mass growth history of the satellites of clusters as early
as 8 or 9 Gyr ago, when they had not yet entered the virial radius of their
current host. We propose that this could be the result of galaxies being
pre-processed in low-mass substructures in the protocluster outskirts, prior to
infall.

We compile a large sample of nearby galaxies that are satellites of hosts
using a well known SDSS group catalogue. From this sample, we create an
`ancient infallers’ and `recent infallers’ subsample, based on the mean infall
time predicted from cosmological simulations for galaxies with their location
in phase-space. We compare the stellar mass growth histories of the galaxies in
these two subsamples, as determined from multi-wavelength SED fitting that uses
a comprehensive library of star formation history shapes derived from
cosmological simulations. By simultaneously controlling for satellite stellar
mass and host halo mass, we can clearly see the impact of time spent in their
hosts. As we might predict, the ancient infaller population shows clear signs
of earlier quenching, especially for lower mass satellites in more massive
hosts. More importantly, we find the effects are not limited to massive hosts.
We find that hosts which might be considered low mass groups (halo masses
$sim$10$^{13}$ M$_odot$) can significantly alter their satellites, even for
massive satellites (stellar masses $sim$10$^{10}$ M$_odot$). Intriguingly, we
see changes in the mass growth history of the satellites of clusters as early
as 8 or 9 Gyr ago, when they had not yet entered the virial radius of their
current host. We propose that this could be the result of galaxies being
pre-processed in low-mass substructures in the protocluster outskirts, prior to
infall.

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