Bibcode
Erwin, Peter; Pohlen, Michael; Beckman, John E.
Bibliographical reference
The Astronomical Journal, Volume 135, Issue 1, pp. 20-54 (2008).
Advertised on:
1
2008
Citations
210
Refereed citations
187
Description
We present a study of 66 barred, early-type (S0-Sb) disk galaxies,
focused on the disk surface brightness profile outside the bar region,
with the aim of throwing light on the nature of Freeman type I and II
profiles, their origins, and their possible relation to disk
truncations. This paper discusses the data and their reduction, outlines
our classification system, and presents R-band profiles for all galaxies
in the sample, along with their classifications. In subsequent papers,
we will explore the structure of outer disks as revealed by these
profiles, and investigate their possible origins.
The profiles are derived from a variety of different sources, including
the Sloan Digital Sky Survey (Data Release 5). For about half of the
galaxies, we have profiles derived from more than one telescope; this
allows us to check the stability and repeatability of our profile
extraction and classification. The vast majority of the profiles are
reliable down to levels of μ R ≈ 27 mag
arcsec-2; in exceptional cases, we can trace profiles down to
μ R > 28. We can typically follow disk profiles out to
at least 1.5 times the traditional optical radius R 25; for
some galaxies, we find light extending to ~3 × R 25.
For type I (single-exponential) profiles, this means that we can trace
the exponential disk out to 6-7 scale lengths.
We classify the profiles into three main groups: type I
(single-exponential), type II (down-bending), and type III (up-bending).
The frequencies of these types are approximately 27%, 42%, and 24%,
respectively, plus another 6% which are combinations of types II and
III. We further classify type II profiles by where the break falls in
relation to the bar length, and in terms of the postulated mechanisms
for breaks at large radii ("classical truncation" of star formation
versus the influence of the Outer Lindblad Resonance of the bar). We
also classify the type III profiles by the probable morphology of the
outer light (disk or spheroid). Illustrations are given for all cases.