2007/09/21 by Peter Erwin, Michael Pohlen, John E. Beckman · 3 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Bar (unit) #Brightness #Galaxies: Formation, Evolution, Phenomena #Galaxy #RADIUS #Sky #Surface brightness #TRACE (psycholinguistics) #Thick disk #Type (biology) #astro-ph
paper · pdf · doi:10.1088/0004-6256/135/1/20
published as Astron.J.135:20-54,2008 · 41 pages, 26 PDF figures. To appear in the Astronomical Journal. Version with full-resolution figures available at http://www.mpe.mpg.de/~erwin/research/
arxiv created 2007/09/21 · openalex publication_date 2007/11/29 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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.