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Alexi M. Musick

Publications and source records attributed to Alexi M. Musick.

2 recordsLinked to original sources

Connection Between Dwarf Galaxies and Globular Clusters: Insights from the Perseus Cluster Using Subaru Imaging and Keck Spectroscopy

We present a systematic study of 189 dwarf galaxies and their globular cluster (GC) systems in the Perseus cluster, based on deep Subaru Hyper Suprime-Cam imaging and Keck spectroscopy, supplemented by literature data. This constitutes the largest sample of dwarfs in a single galaxy cluster to date with simultaneous deep imaging, spectroscopic coverage, and GC measurements, while uniquely spanning a broad and continuous range of galaxy properties. We find an anti-correlation between GC specific mass and galaxy stellar mass for dwarfs in Perseus similar to observations in other clusters. At fixed stellar mass, dwarfs with lower surface brightness or larger effective radius tend to be more GC-rich -- suggesting either high GC formation efficiency in an earlier compact-galaxy phase, or less efficient GC disruption. The correlation between GC richness and axis ratio in Perseus is weaker than in other environments. We find some connection between GC richness and infall time, but not with the clear correlations found in Virgo, Coma, and cosmological simulations. More complete observations are needed to test for cluster-to-cluster variations in galaxy and GC evolutionary histories. This work demonstrates the potential of new wide-field imaging and spectroscopy surveys for understanding GCs and dwarf galaxies, and highlights the need for further work in theoretical modeling.

astro-ph.GA

Devouring the Milky Way Satellites: Modeling Dwarf Galaxies with Galacticus

Dwarf galaxies are ubiquitous throughout the universe and are extremely sensitive to various forms of internal and external feedback. Over the last two decades, the census of dwarf galaxies in the Local Group and beyond has increased markedly. While hydrodynamic simulations (e.g. FIRE II, MINT Justice League) have reproduced the observed dwarf properties down to the ultra-faints, such simulations require extensive computational resources to run. In this work, we constrain the standard physical implementations in the semi-analytic model Galacticus to reproduce the observed properties of the Milky Way satellites down to the ultra-faint dwarfs found in SDSS. We run Galacticus on merger trees from our high-resolution N-body simulation of a Milky Way analog. We determine the best-fit parameters by matching the cumulative luminosity function and luminosity-metallicity relation from both observations and hydrodynamic simulations. With the correct parameters, the standard physics in Galacticus can reproduce the observed luminosity function and luminosity-metallicity relation of the Milky Way dwarfs. In addition, we find a multi-dimensional match with half-light radii, velocity dispersions and mass-to-light ratios at z = 0 down to M_V <= -6 (L >= 10^4 L_solar). In addition to successfully reproducing the properties of the z = 0 Milky Way satellite population, our modeled dwarfs have star formation histories which are consistent with those of the Local Group dwarfs.

astro-ph.GA