A tidal extension in the Ursa Minor dwarf spheroidal galaxy

Martinez-Delgado, D; Alonso-Garcia, J; Aparicio, A; Gomez-Flechoso, MA

Abstract

We report the detection of main-sequence and blue horizontal-branch stars of the Ursa Minor dwarf spheroidal galaxy beyond its tidal radius, indicating the existence of a possible tidal extension in this satellite of the Milky Way. This tidal extension could spread out well beyond the area covered in our survey (R > 80'), as suggested by the presence of a "break" to a shallower slope observed in its density profile. The V-band surface brightness for this possible tidal extension ranges from 29.8 to 31.5 mag arcsec(-2). The area covered in our survey (similar to1.65 deg(2)) is not enough to discriminate if this extratidal population is part of a tidal tail or an extended halo around the galaxy. The existence of this tidal extension in Ursa Minor indicates that this satellite is currently undergoing a tidal disruption process by the Milky Way. We discuss the possibility of a tidal origin for the high mass-to-light ratio observed in this galaxy on the basis of our result and recent theoretical simulations of the tidal disruption of dwarf satellites in the Galactic halo.

Más información

Título según WOS: ID WOS:000167208700015 Not found in local WOS DB
Título de la Revista: ASTROPHYSICAL JOURNAL
Volumen: 549
Número: 1
Editorial: IOP PUBLISHING LTD
Fecha de publicación: 2001
Página de inicio: L63
Página final: L66
DOI:

10.1086/319150

Notas: ISI