A Headless Tadpole Galaxy: The High Gas-phase Metallicity of the Ultra-diffuse Galaxy UGC 2162

Sánchez Almeida, J.; Olmo-García, A.; Elmegreen, B. G.; Elmegreen, D. M.; Filho, M.; Muñoz-Tuñón, C.; Pérez-Montero, E.; Román, J.
Referencia bibliográfica

The Astrophysical Journal, Volume 869, Issue 1, article id. 40, 7 pp. (2018).

Fecha de publicación:
The cosmological numerical simulations tell us that accretion of external metal-poor gas drives star formation (SF) in galaxy disks. One the best pieces of observational evidence supporting this prediction is the existence of low-metallicity star-forming regions in relatively high-metallicity host galaxies. The SF is thought to be fed by metal-poor gas recently accreted. Since the gas accretion is stochastic, there should be galaxies with all the properties of a host but without the low-metallicity starburst. These galaxies have not been identified yet. The exception may be UGC 2162, a nearby ultra-diffuse galaxy (UDG) that combines low surface brightness and relatively high metallicity. We confirm the high metallicity of UGC 2162 (12+{log}({{O}}/{{H}})={8.52}-0.24+0.27) using spectra taken with the 10 m GTC telescope. UGC 2162 has the stellar mass, metallicity, and star formation rate surface density expected for a host galaxy in between outbursts. This fact suggests a physical connection between some UDGs and metal-poor galaxies, which may be the same type of object in a different phase of the SF cycle. UGC 2162 is a high-metallicity outlier of the mass–metallicity relation, a property shared by the few UDGs with known gas-phase metallicity.
Proyectos relacionados
Imagen del Proyecto
Grupo de Estudios de Formación Estelar GEFE

El proyecto interno GEFE está enmarcado en el proyecto coordinado, ESTALLIDOS, financiado por el plan nacional desde el año 2001. El ultimo proyecto aprobado es ESTALLIDOS 6.0 (AYA2016- 79724-C4-2-P). En el proyecto GEFE trabajamos en base al caso científico del proyecto ESTALLIDOS 6.0. Los estallidos de formación estelar (Starbursts o SB) son

Muñoz Tuñón