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Date and Time of the Query: 2019-06-18 T02:30:26 PDT
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For refcode 2011AJ....142..145G:
Retrieve 47 NED objects in this reference.
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2011AJ....142..145G The Outer Disks of Early-type Galaxies. II. Surface-brightness Profiles of Unbarred Galaxies and Trends with Hubble Type Gutierrez, Leonel; Erwin, Peter; Aladro, Rebeca; Beckman, John E. Abstract. We present azimuthally averaged radial profiles of R-band surface brightness for a complete sample of 47 early-type, unbarred galaxies, as a complement to our previous study of early-type barred galaxies. Following very careful sky subtraction, the profiles can typically be determined down to brightness levels well below 27 mag arcsec^-2^ and in the best cases below 28 mag arcsec^-2^. We classified the profiles according to the scheme used previously for the barred sample: Type I profiles are single unbroken exponential radial declines in brightness; Type II profiles ("truncations") have an inner shallow slope (usually exponential) which changes at a well-defined break radius to a steeper exponential; and Type III profiles ("antitruncations") have an inner exponential that is steeper, giving way to a shallower outer (usually exponential) decline. By combining these profiles with previous studies, we can make the first clear statements about the trends of outer-disk-profile types along the Hubble sequence (including both barred and unbarred galaxies), and their global frequencies. We find that Type I profiles are most frequent in early-type disks, decreasing from one-third of all S0-Sa disks to barely 10% of the latest-type spirals. Conversely, Type II profiles (truncations) increase in frequency with Hubble type, from only ~25% of S0 galaxies to ~80% of Sd-Sm spirals. Overall, the fractions of Type I, II, and III profiles for all disk galaxies (Hubble types S0-Sm) are 21%, 50%, and 38%, respectively; this includes galaxies (~8% of the total) with composite Type II+III profiles (counted twice). Finally, we note the presence of bars in 10 galaxies previously classified (optically) as "unbarred." This suggests that ~20% of optically unbarred galaxies are actually barred; the bars in such cases can be weak, obscured by dust, or so large as to be mistaken for the main disk of the galaxy. Key words: galaxies: elliptical and lenticular, cD, galaxies: spiral, galaxies: structure
Retrieve 47 NED objects in this reference.
Please click here for ADS abstract

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