1 research outputs found
Double-Barred Galaxies: I. A Catalog of Barred Galaxies with Stellar Secondary Bars and Inner Disks
I present a catalog of 67 barred galaxies which contain distinct, elliptical
stellar structures inside their bars. Fifty of these are double-barred
galaxies: a small-scale, "inner" or "secondary" bar is embedded within a
large-scale, "outer" or "primary" bar. I provide homogenized measurements of
the sizes, ellipticities, and orientations of both inner and outer bars, along
with with global parameters for the galaxies. The other 17 are classified as
"inner-disk" galaxies, where a large-scale bar harbors an inner elliptical
structure which is aligned with the galaxy's outer disk. Four of the
double-barred galaxies also possess inner disks, located in between the inner
and outer bars. While the inner-disk classification is ad-hoc -- and
undoubtedly includes some inner bars with chance alignments (five such probable
cases are identified) -- there is good evidence that inner disks form a
statistically distinct population, and that at least some are indeed disks
rather than bars. In addition, I list 36 galaxies which may be double-barred,
but for which current observations are ambiguous or incomplete, and another 23
galaxies which have been previously suggested as potentially being
double-barred, but which are probably *not*. False double-bar identifications
are usually due to features such as nuclear rings and spirals being
misclassified as bars; I provide some illustrated examples of how this can
happen.Comment: LaTeX, 25 pages, 6 EPS figures. Typos fixed and title slightly
altered; accepted by Astronomy & Astrophysics. Version with full-resolution
figures available at http://www.iac.es/galeria/erwin/research