A new method to constrain the origins of dark matter-free galaxies and their unusual globular clusters. (arXiv:1903.06717v3 [astro-ph.GA] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Leigh_N/0/1/0/all/0/1">Nathan Leigh</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fragione_G/0/1/0/all/0/1">Giacomo Fragione</a>
We present a novel method to uniquely constrain the collisional evolution of
globular cluster (GC) populations that are hypothesized to have recently
underwent an episode of violent relaxation due to a strong galaxy-galaxy
interaction. We show via analytic methods that numerical simulations combined
with observed constraints on the GC luminosity function can be used to
constrain the GC mass function immediately after the assumed episode of violent
relaxation. In order to apply our method, we first explore the observational
evidence for a collisional origin for the recently discovered dark matter
(DM)-free ultra-diffuse galaxies observed in the NGC 1052 group. We compute the
timescales for infall to the central nucleus due to dynamical friction (DF) for
the GCs in NGC 1052-DF2 and NGC 1052-DF4, using the shortest of these times to
constrain how long ago such an interaction could have occurred. We find that
two out of ten GCs in NGC 1052-DF2 and one out of seven in NGC 1052-DF4 have DF
timescales less than a Hubble time. We go on to quantify the initial GC numbers
and densities needed for significant collisional evolution to occur within the
allotted times. Finally, we apply our method to these galaxies, in order to
illustrate its efficacy in constraining their dynamical evolution post-violent
relaxation. Our results motivate more complete observations of the GC
luminosity functions in these galaxies, which can be used to constrain the
origins of the hypothesized DM-free galaxies, by combining the method presented
here with a suite of numerical simulations.
We present a novel method to uniquely constrain the collisional evolution of
globular cluster (GC) populations that are hypothesized to have recently
underwent an episode of violent relaxation due to a strong galaxy-galaxy
interaction. We show via analytic methods that numerical simulations combined
with observed constraints on the GC luminosity function can be used to
constrain the GC mass function immediately after the assumed episode of violent
relaxation. In order to apply our method, we first explore the observational
evidence for a collisional origin for the recently discovered dark matter
(DM)-free ultra-diffuse galaxies observed in the NGC 1052 group. We compute the
timescales for infall to the central nucleus due to dynamical friction (DF) for
the GCs in NGC 1052-DF2 and NGC 1052-DF4, using the shortest of these times to
constrain how long ago such an interaction could have occurred. We find that
two out of ten GCs in NGC 1052-DF2 and one out of seven in NGC 1052-DF4 have DF
timescales less than a Hubble time. We go on to quantify the initial GC numbers
and densities needed for significant collisional evolution to occur within the
allotted times. Finally, we apply our method to these galaxies, in order to
illustrate its efficacy in constraining their dynamical evolution post-violent
relaxation. Our results motivate more complete observations of the GC
luminosity functions in these galaxies, which can be used to constrain the
origins of the hypothesized DM-free galaxies, by combining the method presented
here with a suite of numerical simulations.
http://arxiv.org/icons/sfx.gif
