15,376 research outputs found
An Optimal Strategy for Accurate Bulge-to-disk Decomposition of Disk Galaxies
The development of two-dimensional (2D) bulge-to-disk decomposition
techniques has shown their advantages over traditional one-dimensional (1D)
techniques, especially for galaxies with non-axisymmetric features. However,
the full potential of 2D techniques has yet to be fully exploited. Secondary
morphological features in nearby disk galaxies, such as bars, lenses, rings,
disk breaks, and spiral arms, are seldom accounted for in 2D image
decompositions, even though some image-fitting codes, such as GALFIT, are
capable of handling them. We present detailed, 2D multi-model and
multi-component decomposition of high-quality -band images of a
representative sample of nearby disk galaxies selected from the Carnegie-Irvine
Galaxy Survey, using the latest version of GALFIT. The sample consists of five
barred and five unbarred galaxies, spanning Hubble types from S0 to Sc.
Traditional 1D decomposition is also presented for comparison. In detailed case
studies of the 10 galaxies, we successfully model the secondary morphological
features. Through a comparison of best-fit parameters obtained from different
input surface brightness models, we identify morphological features that
significantly impact bulge measurements. We show that nuclear and inner
lenses/rings and disk breaks must be properly taken into account to obtain
accurate bulge parameters, whereas outer lenses/rings and spiral arms have a
negligible effect. We provide an optimal strategy to measure bulge parameters
of typical disk galaxies, as well as prescriptions to estimate realistic
uncertainties of them, which will benefit subsequent decomposition of a larger
galaxy sample.Comment: 30 pages, 14 figures, published in ApJ; minor typos correcte
Spectra of some invertible weighted composition operators on Hardy and weighted Bergman spaces in the unit ball
In this paper, we investigate the spectra of invertible weighted composition
operators with automorphism symbols, on Hardy space and
weighted Bergman spaces , where is the
unit ball of the -dimensional complex space. By taking ,
the unit disc, we also complete the discussion about
the spectrum of a weighted composition operator when it is invertible on
or .Comment: 23 Page
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