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Surface photometry of nearby field galaxies
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Originally published as R.A. Jansen, M. Franx, D. Fabricant & N.
Caldwell, 2000a
The Astrophysical Journal Supplement Series, vol. 126, p. 271
We have obtained
integrated spectra and multifilter photometry for a representative
sample of 200 nearby galaxies. These galaxies span the entire Hubble
sequence in morphological type, as well as a wide range of luminosities
(MB = -14 to -22) and colors (B-R = 0.4
to 1.8). Here we describe the sample selection criteria and the
U, B, R surface photometry for these galaxies. The
spectrophotometric results will be presented in a companion paper. Our
goals for the project include measuring the current star formation rates
and metallicity of these galaxies, and elucidating their star formation
histories, as a function of luminosity and morphology. We thereby
extend the work of Kennicutt (1992a) to lower luminosity systems. We
anticipate that our study will be useful as a benchmark for studies of
galaxies at high redshift. We discuss the observing, data reduction,
and calibration techniques and show that our photometry agrees well with
previous work in those cases in which earlier data are available. We
present an atlas of images, radial surface brightness profiles, and
color profiles as well as tables of derived parameters. The atlas and
tables of measurements will be made available electronically. We study
the correlations of galaxy properties determined from the galaxy images.
Our findings include the following: (1) colors determined within the
effective radius correlate better with morphological type than with and
(2) 50% of the low-luminosity galaxies are bluest in their centers.
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ITH the advent of the Hubble Space Telescope,
8 m-class ground-based telescopes, and effective new instruments,
it is now possible to study the colors, morphologies, and spectra of
large samples of distant, faint galaxies. Frequently, our
interpretation of such data is limited by the scarcity of good
comparison samples in the local universe. Because distant galaxies
subtend angles comparable to spectrograph slit widths, we usually obtain
integrated spectra, while the same slits sample only the nuclear regions
of nearby galaxies. This observational issue complicates the comparison
of distant and nearby galaxy spectra.
In a pioneering effort, Kennicutt (1992a,
1992b) obtained integrated spectrophotometry for 90 galaxies spanning
the entire Hubble sequence. This study has had broad application for
the study of galaxy spectral properties at both high and low redshift.
Kennicutt's study is, however, limited to the brightest galaxies of each
morphological type, and no uniform, multiple-filter, surface photometry
is available for these galaxies. Also, only half of Kennicutt's sample
of 90 galaxies was observed at 5-7Å spectral resolution by trailing
the image of a galaxy across a long slit. The remaining half was
observed at 15-20Å resolution through a 45.5" circular aperture.
With our Nearby Field Galaxy Survey, our goal
is to significantly extend Kennicutt's work. We have obtained
integrated and nuclear spectroscopy and U, B, R
surface photometry for a sample of 196 galaxies in the nearby field.
This sample includes galaxies of all morphological types and spans 8 mag
in luminosity. We include galaxies from a broad range of local galaxy
densities, attempting to avoid a bias toward a particular environment.
Our use of the term ``field'' corresponds to that of Koo & Kron
(1992) and Ellis (1997).
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