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Astron. Astrophys. 357, L1-L4 (2000)

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2. Observations and reduction

Sample selection, observations, and data reduction are described in detail in Papers I and II, and will be repeated only briefly here. We have compiled a homogeneous set of 31 galaxies with well defined models of their three-dimensional disk luminosity distribution, out of our sample of about 60 highly inclined disk galaxies, selected from the UGC (Nilson 1973) and ESO-Lauberts & Valentijn (1989) catalog. The data were obtained at the ESO/La Silla 2.2m and the Lowell Observatory 42-inch telescope. Images are taken either in Gunn g, r, i, or Johnson R filters, with resulting pixel scales of 0.36" and 0.7", respectively. After standard reduction, images were rotated to the major axes of the disk. Although most of the images were taken during non-photometric nights we have tried to perform photometric calibration for each image by comparing simulated aperture measurements with published integrated aperture data, resulting in the best possible homogeneous calibration for the whole sample. The resulting typical values for the limiting surface brightness measured by a three sigma deviation on the background are: [FORMULA]mag[FORMULA], [FORMULA]mag[FORMULA], and [FORMULA]mag[FORMULA]. In order to obtain absolute values of the determined structural parameters, we estimated the distance of our galaxies according to the Hubble relation ([FORMULA] km s-1Mpc-1) using published heliocentric radial velocities corrected for the Virgo centric infall.

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© European Southern Observatory (ESO) 2000

Online publication: May 3, 2000