Bibcode
DOI
Martinez-Valpuesta, I.; Knapen, J. H.; Buta, R.
Referencia bibliográfica
The Astronomical Journal, Volume 134, Issue 5, pp. 1863-1869 (2007).
Fecha de publicación:
11
2007
Número de citas
52
Número de citas referidas
43
Descripción
Many barred galaxies show a set of symmetric enhancements at the ends of
the stellar bar, called ansae, or the "handles" of the bar. Ansa bars
have been in the literature for some decades, but their origin has still
not been specifically addressed, although they could be related to the
growth process of bars. But even though ansae have been known for a long
time, no statistical analysis of their relative frequency of occurrence
has been performed yet. Similarly, there has been no study of the
varieties in the morphology of ansae, even though significant
morphological variations are known to characterize the features. In this
paper we make a quantitative analysis of the occurrence of ansae in
barred galaxies, making use of The de Vaucouleurs Atlas of Galaxies by
Buta and coworkers. We find that ~40% of SB0's show ansae in their bars,
thus confirming that ansae are common features in barred lenticulars.
The ansa frequency decreases dramatically with later types, and hardly
any ansae are found in galaxies of type Sb or later. The bars in
galaxies with ansae are stronger in the median than those in galaxies
without ansae, but the presence of inner and outer rings is not related
to the presence of ansae. Implications of these results and theories for
the possible origin of ansae are discussed briefly.