8-14 kpc produce strongest bars in isolated models. Then, we extent this work by considering tidal effects due to interacting galaxies. We send two spirals to collide and study the bar properties of the remnant. We characterize the bar kinematical properties in terms of our parameters (λ, α).]]>
8 - 14 kpc producen barras mas pronunciadas en los modelos de galaxias aisladas. Después, extendemos este trabajo al considerar efectos de marea debido a galaxias que interaccionan. Enviamos dos galaxias espirales a colisionar para estudiar las características de la barra del remanente formado. Caracterizamos las propiedades cinemáticas de la barra en términos de nuestros parámetros (λ, α).]]>
J.L. Cervantes–Cota*, M.A. Rodríguez–Meza, R. Gabbasov, and J. Klapp
Depto. de Física, Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18–1027, México D.F. 11801, México, * e–mail: jorge@nuclear.inin.mx
Recibido el 1 de mayo de 2006
Aceptado el 1 de noviembre de 2006
Abstract
]]> We use the Newtonian limit of a general scalar–tensor theory around a background field to study astrophysical effects. The gravitational theory modifies the standard Newtonian potential by adding a Yukawa term to it, which is quantified by two theoretical parameters: A, the lenghtscale of the gravitational interaction and its strength, α. Within this formalism we firstly present a numerical study on the formation of bars in isolated galaxies. We have found for positive α. that the modified gravity destabilizes the galactic discs and leads to rapid bar formation in isolated galaxies. Values of λ in the range
8–14 kpc produce strongest bars in isolated models. Then, we extent this work by considering tidal effects due to interacting galaxies. We send two spirals to collide and study the bar properties of the remnant. We characterize the bar kinematical properties in terms of our parameters (λ, α). Keywords: Bar formation; galaxy interaction; scalar–tensor theory.
Resumen
Usamos el límite newtoniano de una teoría escalar–tensorial general alrededor de un campo del fondo para estudiar efectos astrofísicos. La teoría gravitacional modifica el potencial newtoniano estandar, agregándole un término de Yukawa, el cual se cuantifica por dos parámetros teóricos: A, la escala de longitud de la interacción gravitacional y α, su intensidad. Dentro de este formalismo primero presentamos un estudio numérico de la formación de barras en galaxias aisladas. Encontramos que para α positiva la gravedad modificada desestabiliza a los discos galácticos y lleva a una rápida formación de la barra en galaxias aisladas. Valores de λ en el rango de 8 – 14 kpc producen barras mas pronunciadas en los modelos de galaxias aisladas. Después, extendemos este trabajo al considerar efectos de marea debido a galaxias que interaccionan. Enviamos dos galaxias espirales a colisionar para estudiar las características de la barra del remanente formado. Caracterizamos las propiedades cinemáticas de la barra en términos de nuestros parámetros (λ, α).
Descriptores: Formación de la barra; interacción de galaxias; teoría escalar–tensorial.
PACS: 04.50.+h, 04.25.Nx; 98.10.+z; 98.62.Gq; 98.62. Js
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