The Formation of Ultra-Diffuse Galaxies from Passive Evolution in the RomulusC Galaxy Cluster Simulation. (arXiv:1908.05684v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Tremmel_M/0/1/0/all/0/1">Michael Tremmel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wright_A/0/1/0/all/0/1">Anna C. Wright</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brooks_A/0/1/0/all/0/1">Alyson M. Brooks</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Munshi_F/0/1/0/all/0/1">Ferah Munshi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nagai_D/0/1/0/all/0/1">Daisuke Nagai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Quinn_T/0/1/0/all/0/1">Thomas R. Quinn</a>
We study the origins of 122 ultra-diffuse galaxies (UDGs) in the RomulusC
zoom-in cosmological simulation of a galaxy cluster (M$_{200} = 1.15 times
10^{14}$ M$_{odot}$), one of the only such simulations capable of resolving
the evolution and structure of dwarf galaxies (M$_{star} < 10^9$ M$_{odot}$).
We find broad agreement with observed cluster UDGs and predict that they are
not separate from the overall cluster dwarf population. UDGs in cluster
environments form primarily due to the quenching of star formation from ram
pressure stripping and the subsequent passive evolution of their stellar
population which results in very low surface brightness dwarf galaxies. We
predict that there is little difference between UDGs and non-UDGs in terms of
their dark matter halo masses and spins, their $z = 0$ colors, nor their
evolution over time. UDGs are typically larger dwarf galaxies well before
in-fall into the cluster and have had their star formation quenched for longer,
typically due to entering the cluster earlier. We find that in most respects
cluster UDG and non-UDGs alike are similar to isolated dwarf galaxies, although
they are typically larger in size. This is due, in part, to the fact that
cluster dwarf galaxies grow from higher angular momentum gas compared to
isolated dwarf galaxies.
We study the origins of 122 ultra-diffuse galaxies (UDGs) in the RomulusC
zoom-in cosmological simulation of a galaxy cluster (M$_{200} = 1.15 times
10^{14}$ M$_{odot}$), one of the only such simulations capable of resolving
the evolution and structure of dwarf galaxies (M$_{star} < 10^9$ M$_{odot}$).
We find broad agreement with observed cluster UDGs and predict that they are
not separate from the overall cluster dwarf population. UDGs in cluster
environments form primarily due to the quenching of star formation from ram
pressure stripping and the subsequent passive evolution of their stellar
population which results in very low surface brightness dwarf galaxies. We
predict that there is little difference between UDGs and non-UDGs in terms of
their dark matter halo masses and spins, their $z = 0$ colors, nor their
evolution over time. UDGs are typically larger dwarf galaxies well before
in-fall into the cluster and have had their star formation quenched for longer,
typically due to entering the cluster earlier. We find that in most respects
cluster UDG and non-UDGs alike are similar to isolated dwarf galaxies, although
they are typically larger in size. This is due, in part, to the fact that
cluster dwarf galaxies grow from higher angular momentum gas compared to
isolated dwarf galaxies.
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