CBL - Campus del Baix Llobregat

Projecte llegit

Títol: Estudio dinámico de galaxias doblemente barradas con barras asimétricas

Estudiants que han llegit aquest projecte:

Director/a: SÁNCHEZ MARTÍN, PATRICIA

Departament: MAT

Títol: Estudio dinámico de galaxias doblemente barradas con barras asimétricas

Data inici oferta: 29-01-2025     Data finalització oferta: 29-09-2025


Estudis d'assignació del projecte:
    GR ENG SIST AEROESP
Tipus: Individual
 
Lloc de realització: EETAC
 
Segon director/a (UPC): MASDEMONT SOLER, JOSEP JOAQUIM
 
Paraules clau:
Dynamical Systems, Differential Equations, Galaxies
 
Descripció del contingut i pla d'activitats:
Barred galaxies, characterized by a central stellar bar, exhibit dynamics that are strongly influenced by equilibrium points, which help structure the overall motion within the galaxy. A subset of barred galaxies contains double bars, often oriented at an angle to each other. This project focuses on analyzing the dynamical consequences of density asymmetries in one or both bars. Specifically, we will study how such asymmetries affect the location and stability of equilibrium points as well as the morphology of galactic arms.
 
Overview (resum en anglès):
Barred spiral galaxies frequently exhibit configurations in which a secondary bar is embedded within a primary bar, forming double-barred systems. Recent observations show that these galaxies may present asymmetries in the shape and brightness of their spiral arms, suggesting the possible influence of small internal perturbations in the mass distribution. The aim of this work is to investigate how a slight asymmetry in the central region of the galaxy, introduced by one of the bars, can modify the global dynamics. To this end, we analyze the effect of displacing the central bulge with respect to the galactic center along the major axis of the fixed bar (and subsequently of the rotated bar) on the structure of the potential and the dynamics in galaxies with two bars rotating together.
The study focuses on the analysis of the equilibrium points of the effective potential, since these constitute the basis of the local dynamical behavior and are directly connected to the existence of periodic orbits and, through their invariant manifolds, to the formation and morphology of spiral arms and rings. Understanding how the position and stability of these points change under an asymmetric perturbation allows us to assess their potential role in generating complex spiral structures (including the possible development of asymmetric spiral arms).
To carry out this analysis, we employ an analytical model consisting of a Miyamoto-Nagai disk, two Ferrers bars, a Plummer bulge, and a Plummer halo, where both bars share the same pattern speed in order to maintain the system as an autonomous model. From this model, we compute and analyze isopotential curves, isodensity maps, and rotation curves for different values of the angle between the bars and several bulge displacements along both bars, thereby generating controlled asymmetries in the galactic mass distribution. The results show that even a moderate displacement of the bulge leads to systematic shifts in the center of mass, alters the position and stability of the equilibrium points, and can even induce the appearance of additional equilibrium points in certain configurations. Furthermore, the analysis reveals a progressive distortion in the density distribution and a modification of the internal morphology of the bar, which may be linked to the development of asymmetric spiral arms.

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