The origins of ultra diffuse galaxies: characterization of their globular cluster population.
Loading...
Date
2025
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Universidad de Concepción
Abstract
Presentamos nuestro análisis de los sistemas de cúmulos globulares (GC) de seis galaxias ultra difusas (UDG) en diferentes entornos. Estudiamos cómo los procesos dinámicos podrían haber modelado la función de luminosidad de cúmulos globulares (GCLF). Comenzamos ajustando GCLF gaussianas y gaussianas sesgadas. Obtenemos la distribución espacial de los GCs y usamos observables fotométricos para modelar los perfiles de densidad, masa y dispersión de velocidad de las UDGs. Luego calculamos las escalas temporales de fricción dinámica y de disrupción para los GCs en cada UDG. Analizamos cómo la fricción dinámica (DF) y la disrupción podrían modelar la GCLF y la distribución espacial si las escalas temporales son menores a un tiempo de Hubble. La fricción dinámica actuaria principalmente sobre los GCs masivos de la GCLF haciéndolos hundirse, potencialmente creando un cúmulo estelar nuclear. Por otro lado, la disrupción afectaría principalmente a los GCs en el extremo de baja masa, estableciendo un límite inferior para la GCLF. Nuestros resultados son consistentes con las tendencias observables de los sistemas de GCs en las UDGs, como R9c/Re < 1 y una GCLF más estrecha. Finalmente, somos capaces de restringir los escenarios de formaciones consistentes con nuestras escalas temporales estimadas y la inexistencia de cúmulos estelares nucleares observada, incluso cuando los GCs tienen tiempos de fricción dinámica bajos.
We present our analysis of the globular cluster (GC) systems in six ultra diffuse galaxies (UDG) living in different environments, with the over-arching goal to understand the origins of UDGs. We study how dynamical processes may have shaped the GC luminosity functions (GCLFs) and their spatial distributions. We begin by fitting gaussian and skew-gaussian profiles to the GCLFs in arder to evaluate if they are different from normal dwarf galaxies, for which a Gaussian profile typically matches the data. We retrieve the spatial distribution of GCs and use photometric observables to model the density, enclosed mass and velocity dispersion profiles. We then compute dynamical friction and disruption timescales for GCs in each UDG. We analyze how dynamical friction (DF) and disruption may have shaped the GCLFs and spatial distributions. DF would preferentially make the high-mass end of the GCLF sink into the center, potentially forming a nuclear star cluster anda skew Gaussian GCLF (positively skewed) profile that is depleted at the high-mass end. Disruption, on the other hand, would likely affect those GCs at the low-mass end of the GCLF, establishing a lower limit for GC mass and a negatively skew gaussian. Our results are consistent with observable trends of GC systems in UDGs, such as the distribution of Galactocentric radii, where R9c/Re < 1, and a narrower GCLF. Finally we are a ble to constrain formation scenarios consistent with our estimated timescales and the lack of nuclear star clusters, even in those galaxies with DF timescales shorter than a Hubble time.
We present our analysis of the globular cluster (GC) systems in six ultra diffuse galaxies (UDG) living in different environments, with the over-arching goal to understand the origins of UDGs. We study how dynamical processes may have shaped the GC luminosity functions (GCLFs) and their spatial distributions. We begin by fitting gaussian and skew-gaussian profiles to the GCLFs in arder to evaluate if they are different from normal dwarf galaxies, for which a Gaussian profile typically matches the data. We retrieve the spatial distribution of GCs and use photometric observables to model the density, enclosed mass and velocity dispersion profiles. We then compute dynamical friction and disruption timescales for GCs in each UDG. We analyze how dynamical friction (DF) and disruption may have shaped the GCLFs and spatial distributions. DF would preferentially make the high-mass end of the GCLF sink into the center, potentially forming a nuclear star cluster anda skew Gaussian GCLF (positively skewed) profile that is depleted at the high-mass end. Disruption, on the other hand, would likely affect those GCs at the low-mass end of the GCLF, establishing a lower limit for GC mass and a negatively skew gaussian. Our results are consistent with observable trends of GC systems in UDGs, such as the distribution of Galactocentric radii, where R9c/Re < 1, and a narrower GCLF. Finally we are a ble to constrain formation scenarios consistent with our estimated timescales and the lack of nuclear star clusters, even in those galaxies with DF timescales shorter than a Hubble time.
Description
Tesis presentada para optar al grado de Magister en Ciencias con Mención en Astronomía
Keywords
Galaxias Cúmulos, Galaxias Formación, Dinámica galáctica